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IEEE Power Engineering Review, August 1998

T.J. Hammons, F. Taher, N.I. Voropai, L.S. Belyaev, S.V. Podkovalnikov, G.V. Shutov, D. Povh, D. Woodford, A. Vallee, G.J. Doucet, P. Meisen, L. Weimers

International High-Voltage Grids and Environmental Implications

A panel session on environmental implications and potential of international high voltage (HV) alternating current (ac) and direct current (dc) connections was held during the 1998 IEEE Power Engineering Society Winter Meeting in Tampa, Florida.

Interconnections for transmission are subject to environmental assessment to meet requirements of governments and international investors

Panelists focused on the proposed North African Supergrid, international connections in East Asia, system interconnections and use of power plants with low C02 output in Europe, justification of international projects in North America, quality-of-life and renewable-energy opportunities with long-distance transmission, and the new HVDC Light technology.

  • Fouad Taher, president of the Egyptian National Committee of CIGRE, prepared a presentation on the proposed North African Supergrid, focusing on its potentials and environmental implications. He summarized the existing power Systems in five North African countries (Egypt, Libya, Tunisia, Algeria, and Morocco), prospective development of these systems, advantages of interconnecting them through a supergrid, and environmental implications of the proposed grid. The presentation was given by Dennis Woodford on Taher's behalf.
  • L.S. Belyaev, Nikolai I. Voropai, S.V. Podkovalnikov, and G.M. Shutov of the Energy Systems Institute of Irkutsk, Russia, prepared a presentation on the creation of international interconnections in East Asia (East Siberia, Far-East Russia, Japan, China, Korea, and Mongolia) and their environmental implications. The presentation was given by Nikolai Voropai.
  • Dusan Povh, president of System Planning at the Siemens Transmission and Distribution Group in Erlangen, Germany, and chair of CIGRE Committee SC 14, discussed advantages of European interconnections with respect to environmental implications, system economics, and system operations. He focused on power plants with lower C02 emissions and utilization of energy from hydro plants.
  • Dennis Woodford, executive director of the Manitoba HVDC Research Center in Winnipeg, Canada, discussed the important role of feasibility studies in justifying investment in North American international interconnection projects.
  • Andre Vallee and G. Jean Doucet, of TransEnergy, Hydro-Quebec, Canada, prepared a presentation on environmental implications of cross-border powerline interconnections in relation to the new conditions created by free trade and deregulation. The presentation focused on environmental issues that are specific and strategic at the interconnection scale. The presentation addressed Canadian (national and provincial) environmental laws and regulation and examined how research and development in engineering and the environment is pivoted to keep up with competition and current issues. The presentation was given by Jean Doucet.
  • Peter Meisen, president of Global Energy Network Institute (GENI), discussed the relationship between long-distance transmission, tapping renewable energy for environmental protection, increasing universal living standards, and sustaining engineering development.
  • Lars Weimers, of ABB Power Systems in Sweden, discussed HVDC Light, a new and environmentally friendly electric transmission technology. HVDC Light consists of a converter station and a pair of ground cables. It can be used to connect small, remote generation plants to the existing ac grid. It represents a technical breakthrough in transmission technology in which high-speed power transistors are used instead of thyristors, and the station adapts itself to the voltage and frequency of the connecting ac grid.

 This article summarizes the panel session presentations.

This article summarizes a 1998 IEEE PES Winter Meeting panel session titled "Environmental Implications and Potentials of International HVAC and HVDC Connections" which was held in Tampa, Florida on 2 February 1998. The session was sponsored by the PES Energy Development and Power Generation Committee and was chaired by T.J. Hammons, University of Glasgow, Scotland.


North African Super-Grid: Potentials and Environmental Implications

Fouad Taher, Egyptian National Committee of CIGRE

The continent of Africa has a total area of about 30 million square kilometers and includes 53 countries. It could be divided into five distinctive geographic regions: northern, eastern, southern, western, and central. The northern region extends south of the Mediterranean Sea between the Red Sea and the Atlantic Ocean; the distance between them is about 5,000 kilometers. This region includes five countries (Egypt, Libya, Tunisia, Algeria, and Morocco), with a total surface area of about 5.3 million square kilometers.

The continent of Africa is endowed with large potentials of primary sources of energy; however, they are not evenly distributed. Oil and gas are available in the northern region, while hydro-electric energy is available mainly in the central region. Oil and gas reserves are estimated at 60 billion barrels and 9,760 million m3, respectively. Ninety percent of these fossil fuel reserves are in Libya, Nigeria, Algeria, and Egypt. Hydro power potentials additional to those already harnessed are estimated at 1,300 TWh per year, and about 58 percent of this potential is available In the central region.

According to United Nations statistics, the total installed capacity in generating stations in Africa in 1994 was about 80 GW, of which about 29 GW were in the northern region. The corresponding total electric energy production was about 352 TWh, of which about 103 TWh were in the northern region. The maximum demand in 1995 was 8,490 MW in Egypt, 1,967 MW in Libya, 1,120 MW in Tunisia, 3,483 MW in Algeria, and 1,974 MW in Morocco. The total sum of peak demands was 17,034 MW for the five countries. This gives a reserve margin for the five systems, if connected, of about 70 percent.

As for the transmission systems, a variety of voltage levels are used in the North African countries. The highest system voltage, is 500 kV ac and is used only in Egypt, with a total length of about 1,736 km. Other voltage levels are 220 kV, 150 kV, 132 kV, 90 kV, and 66/60 kV. In 1995, the total length of the 220 kV 150 kV, and 132 kV transmission lines was 5,392 km in Morocco, 6,028 km in Algeria, 2,773 km in Tunisia, 11,276 km in Libya, and 10,536 km in Egypt.

Development of Electricity Demand

During the period from 1982 to 1994, electric energy production in North African countries increased from about 47 TWh to about 103 TWh, with an average annual increase of about 7 percent. The countries of the northern region are in stages of economic development and will continue to be so through the beginning of the next century. Assuming that electric energy production will continue to develop at the same rate with small gradual decrease, electric energy production may reach the level of 400 TWh in the year 2015. If the reserve margin in the generating stations is assumed to continue at the same level, generation capacity requirements would increase to the order of 120 GW. Transmission systems will develop at a corresponding rate.

North African Supergrid

The advantages of power system interconnections have been realized by the countries of the northern region. Simple interconnections were implemented in the early 1970s between the power systems of Algeria and Tunisia and between Algeria and Morocco. The purpose was the exchange of reserve during emergency. The lines were, however, normally open. Permanent interconnection between the systems at the voltage level of 220 kV was effected between Algeria and Tunisia in 1980, and between Algeria and Morocco in 1988, and reinforced in 1992. Interconnection between Tunisia and Libya at the voltage level of 220 kV is expected to be commissioned in the year 2000, while the interconnection between Egypt and Libya at 220 kV voltage level is due to be commissioned in 1998.

The interconnection between the power systems of the five countries at the voltage level of 220 kV and with a distance of about 4,000 km between Cairo and Rabat does not seem to be quite rigid. Studies are being carried out for evaluating this interconnection as part of the Mediterranean Power Pool Interconnection. However, the potential of creating a North African Supergrid (NASG) is rather high, not awaiting the implementation of the Mediterranean Power Pool.

The interconnection would be used mainly for reserve sharing, which may result in savings in the reserve capacity of more than 1.2 GW in 2015. The time of the daily maximum demand differs from one country to another because of the time difference between them. Also, cold winters prevail in Morocco, Algeria, and Tunisia, while hot summers prevail in Libya and Egypt. This diversity of the time of the maximum demands will result in a reduced combined maximum demand when the five systems are rigidly interconnected.

There are also future prospects for the use of this supergrid for bulk power transmission of the expected low-cost hydroelectric energy imported from the central and eastern regions of Africa.

Figure 1. Technical assurances, risks, anticipated returns on investment, environmental impact, and sociocultural issues must all be considered when studying the feasibility of long-distance, high-voltage interconnections.

© PhotoDisc

Hydroelectric Energy Utilization

The Democratic Republic of Congo (ex Zaire) is planning to harness the hydroelectric potential of the Congo River. The first phase of development would be the Grand Inga hydroelectric project, with an installed capacity of about 40GW and a guaranteed daily average power of 26 GW. An 800 kV HVDC line is planned to be constructed to Cairo, Egypt, passing through Sudan, Chad, and the Central African Republic. The low-cost hydroelectric energy that is in excess of local needs would be 4 GW in the year 2010 and would reach 16 GW in the year 2030.

The power that would be in excess of the needs of the four countries through which the transmission line passes is estimated to be about 600 MW in the year 2010 and would increase to about 7,300 MW in the year 2030. This would be transmitted on the North African Supergrid to supply some of the needs of the

North African countries and the excess exported to Southern Europe. This bulk power should he taken into consideration in the design of the North African Supergrid. Both HVAC and HYDC should be evaluated with voltage levels of 400/500kV or higher.

Environmental Implications of Transmission Lines

Transmission lines are built mainly to transport the electric energy from generating stations to load centers. The source of fuel and the source of cooling water play an important role in the economic siting of generating stations, and the sites are in general not close to the load centers. Hydroelectric energy potential is in most cases far from the load centers, and transmission systems are essential. Development of the power system and extension of transmission lines must be assimilated with the environment. In the past, a compromise has generally been considered between the improvement of quality and safety and the corresponding increase of cost. This is now replaced by the compromise between the cost on one hand and the environmental impact, in addition to the quality and safety on the other hand. Any economic or social development project will result in an insertion into the environment and the reduction of the impact of this insertion has a cost: Zero impact on the environment is not a realistic possibility, and a balance is the key solution.

The environmental impact of the transmission lines may be summarized in terms of ecology, aesthetics, and electric system phenomena:

Ecology. Ecological impact reflects the influence on the vegetation and fauna when the transmission line is constructed or is being operated or maintained. The passage of lines in forest regions demands right-of-way clearance. Continuous trimming of trees in forests and cultivated areas would be necessary.

Aesthetics. Aesthetic impact reflects the effect of lines and electrical installation on the charm of the scenery of the landscape whether mountainous or greenery. Current research seeks to define the possible index to take into account when positioning the installations.

Electric System Phenomena. Electrical, magnetic, electromagnetic, and acoustic impacts result from the inherent phenomena of the electric system. Acoustic impact results from corona discharges on high-voltage transmission line conductors and from transformer noise. Electric and magnetic fields of the lines induce potentials and currents in nearby conducting material. There has been a long debate on the influence of electric and magnetic fields on humans. Power lines and installations are generally outside cities, and human exposure is rather remote. Corona discharge and other discharges produce high-frequency electromagnetic radiation, influencing radio and television reception. All of these, however, decay quickly with the distance from the transmission lines.

Experience in Egypt

In the early stages of power system development, the main concern was the safety against direct contact with or flashover from live parts to people, neighboring structures, or moving traffic under the transmission lines.

With the extension of the transmission lines, the concern was the safeguard against the influence of the power lines on open-wire communications lines running in parallel. Conductors insulated from ground close to HV power lines receive a voltage to ground due to the capacitive coupling. This voltage may be relatively high to cause harmful effects to operating personnel. Magnetic fields produced by the power lines will induce electromotive forces (EMF) in telephone lines in the vicinity, being proportional to the coupling impedance which depends on the distance between the two systems and the length of the parallelism. This indirect EMF may represent a danger to equipment and operation personnel of the communications systems. These problems were gradually eliminated through technological developments and the use of coaxial cables and microwave systems for the transmission of communications signals.

The transmission of large amounts of power for longer distances necessitated the use of higher voltages. In Egypt, the voltage level of 220 kV is used for the interconnection of large generating stations, and the voltage level of 500 kV is used for bulk power transmission from the Aswan hydroelectric stations to Cairo and other load centers. With the increase of voltage levels, the phenomenon of corona on the line conductors produced high-frequency electromagnetic waves that caused interference with radio and television reception. This was controlled by the proper dimensioning of the conductors of the transmission lines. In Egypt, bundle conductors are used to bring the voltage gradient to below the theoretical corona disruptive voltage gradient level. A bundle of two conductors is used for the 220 kV lines, and a bundle of three conductors is used for the 500 kV lines.

At present, there is an increased public concern over the possible hazards to health of the electric and magnetic fields produced by the power transmission lines and the electric utilization equipment. Magnetic fields from transmission lines are inevitable as long as heavy currents are flowing in its conductors. Several investigations including calculations and measurements are being carried out in Egypt to assess the magnitude and profile of the magnetic fields in the vicinity of the 500 kV and 220 kV transmission lines and substations. Actual measurements coincided very closely with the calculations. The results of the investigations will be used to modify the width of the transmission line corridors and the choice of the optimum design of the tower, which gives minimum spread of the magnetic fields. In substations where high magnetic fields may be encountered, continuous monitoring or portable monitors should warn the maintenance personnel to limit the time of their exposure.

It is worthy to mention that there are no forests in Egypt, and the routes of the transmission lines going through the cultivated land are chosen to avoid the fruit gardens. Difficulties have arisen, however, when routing the 220 kV lines near airports and scientific research laboratories, with sensitive measuring instruments. In laboratories with sensitive measuring instruments, shielding would be used.

Standard Limits of Electric and Magnetic Fields

At present, there are no international standards for the limits of electric and magnetic fields produced by transmission tines at the edge of the right-of-way. Some countries have set their own regulation for thc electric and the magnetic field limits. Some European countries are using the CENELEC prestandards. Some other countries have no set limits, as they have not found that there is scientific evidence that justifies setting standards for exposure to the magnetic fields of high-voltage overhead lines. In the United States, several states have established limits on the electric field strength at the edge of the power line right of way, and some states have limits on magnetic field strength.

The International Conference on Large Electric Systems (CIGRE) prepared a study in 1991 and issued a report on Electric Power Transmission and the Environment. The report indicates that guidelines for restricting the exposure of people to electric and magnetic fields are based on the safe limits of induction currents in the body. The World Health Organization stated that up to a current density of 10 ma/m2 induced by magnetic fields only minor biological effects have been reported. This factor formed the basis for the International Radiation Protection Association (IRPA) guidelines.

In Egypt, the Academy of Scientific Research is financing investigations, including actual field measurements and calculations for the electric and magnetic fields in the vicinity of overhead transmission lines in the range of 11 kV to 500 kV, as well as inside HV transformer substations and their neighborhood, hence, introducing any necessary modifications on the width of the right of way.

Environmental Implications of the Supergrid

The environmental implications of the North African Supergrid with a voltage level of 400 kV or higher have not yet been investigated. However, the experience gained in the design and operation of the 500 kV system in Egypt and the 220 kV systems in Egypt and the other North African countries could be used in assessing the environmental implications of the future supergrid.

The northern region is characterized by the prevailing deserts, which cover more than 90 percent of the total area. The fringes of the deserts close to the cultivated areas are very thinly populated. Even in cultivated areas, inhabitants cluster in cities, towns and villages. With these characteristics, transmission line corridors for the supergrid could be easily chosen to minimize their environmental implications. The lines can have free corridors in the desert, with no forest trees to cut or trim; the lines would be far enough from populated areas so that the EMFs would be below the harmful levels. The environmental implications would arise only when locating the sites of switching stations and transformer (or inverter) substations and, of course, when choosing the corridors of line approaches to reach these substations. Care should he taken to keep distances from the populated areas, which would be enough for the magnetic fields to decay to the level that is not harmful to health. In critical cases, underground cables with magnetic sheaths should be used. Care should also be taken so as to reduce the electromagnetic radio and television influence to low levels, compatible with the broadcast signals.

In case of the alternative of using RVDC for the future North African Supergrid, magnetic field hazards will not be present, as no currents will be induced from the unchanging magnetic field of the transmission line. However, radio and television influence due to corona discharges will be present. Care should be taken in designing the grounding electrode so as to limit the step voltage in case of single-pole operation causing the flow of high currents in the ground.

Finally, we must not forget the better side of the environmental implications. The interconnection of power systems will at low the use of larger generating units of higher efficiency thus reducing C02 emission. Also, as soon as the region receives the hydroelectric energy transmitted from the central region of Africa, about 20 percent of the C02 emission will be completely eliminated, which is for the betterment of the environment.

About the Panelist

Found Tuber was born in Egypt and received his BSEE from Cairo University, Egypt, MS from the University of Pennsylvania, and Ph.D. from Stanford University. He is a Life Fellow of the IEEE. He was appointed vice president for the Rural Electrification Authority responsible for planning, engineering and construction for the rural electrification program in 1971. During 1978-1,982, he worked with the Electricity Corporation of Saudi Arabia as a planning expert. During 1982-88, he was president of Electric Power Systems Engineering Company. Currently he is practicing as engineering counselor. He is president of the Egyptian National Committee of CIGRE.


Ways of creating International Connections in East Asia and Environmental Implications

L.S. Belyaev, N.I. Voropai, S.V. Podkovalnikov, G.V. Shutov, Energy Systems Institute of Irkutsk

Interconnection of electric power systems of states and individual territories acquires growing scales in world practice. At present, there arc interstate interconnections in Western Europe and in North America and the technical aspects of interconnecting western and Eastern Europe are being elaborated. Possibilities for creating interstate interconnections in Africa, South America, and the Near East are being studied. Potential variants in formation of the global electric power system are considered for a long-term future.

The East Asia region, comprising East Siberia and Far-East Russia, China, Japan, Mongolia, South Korea, and North Korea, has great potential in terms of possibilities for creation of an interstate interconnection.

Specific Features of the Region

The countries and territories of East Asia are characterized by the fact that though their economic systems arc geographically close, have different levels and rates of economic development, and possess different reserves of energy resources they complement each other and, hence, call interact to their benefit.

In principle, East Siberia and Far-East Russia are developing territories with respect to both energy and economy The existing crisis situation in the economy of Russia does not allow one to forecast rates and scales of their development with sufficient certainty. These territories are poorly provided with manpower and capital, but they possess enormous reserves of natural resources, including fuel and energy, that can be involved in the fuel balances of the countries in East Asia.

China develops impetuously its economy, and long-term development plans do not foresee a decrease in rates of economic growth. The most economically developed provinces are, mainly situated in southeastern China. However, the basic reserves of primary energy are located in northern (coal) arid western (hydro resources, oil) China, i.e., at a great distance from places of their main consumption. Manpower of China is considerable and obviously can be used for implementation of energy projects in the manpower- deficient countries of the region.

The economy of South Korea is developing intensively. Its long term development program envisages considerable growth of electricity demand. At the same time, South Korea is comparatively poor in fuel resources and depends to a great extent on import of gas, oil, and oil products.

Japan has a highly developed, stable economy but possesses comparatively small reserves of local energy resources and orients practically entirely to the import of liquefied gas, oil, and oil products.

Great technological and technical potentials, as well as considerable capital that can be efficiently invested (for example, in the developing energy sector of East Siberia and Far-East Russia), are concentrated in South Korea and Japan.

North Korea has considerable natural resources (mainly coal and hydro resources), and oil prospecting is being carried out. North Korea also possesses manpower, however, there is insufficient capital and up-to-date equipment.

From an economic standpoint, Mongolia seems to be the least developed compared to other countries of the region. However, it has sufficient reserves of coal and hydro energy resources, and there are also deposits of uranium ores. Geological prospecting of oil is being carried out. At present, Mongolia experiences a shortage of qualified manpower, capital, and modern equipment.

State of the East Asian Electric Utility Industry

Table I presents the data on the installed generating capacity and power generation for some territories of East Asia.

East Siberia (first of all Krasnoyarsk and Irkutsk systems) has surplus in terms of capacity and electric power, since development of its electric utility industry was aimed at both meeting the local needs and, to a considerable extent, supplying electric power to Ural and the European part of the country. However, the crisis in the economic development of Russia has lead to a decrease in electricity consumption. Electricity demand in the regions considered deficient before is mainly met at the expense of local energy sources, and power transmission from East Siberia to the west has sharply decreased. Thus, power system surpluses of power and energy in East Siberia were not called for. Taking into account favorable conditions for additional attraction of fuel and energy resources to the electric utility industry (hydro resources from the Angara- Yenisei basin, Boguchansk hydro power plant, coal from the Kansk-Achinsk deposit, Berezovsk condensing power plants; and gas), this territory can be considered as a reliable exporter for a rather long period. The authors estimate the export potential of East Siberia at up to 40 TWh at the level of the year 2010.

In Far East Russia, development of local fuel resources is envisaged there are possibilities for further construction of hydro power plants and construction of nuclear power plants is being discussed. Besides, there are unique possibilities for using tidal energy and the projects of tidal power plants are being worked through, first of all the Tugursk plant (about 7 GW) and later the more exotic Penzhinsk plant (up to 80 GW in a maximum variant). As to hydro resources, the reserves of hydro energy in the south of Yakutia (South-Yakutian hydropower plants) should be taken into account. Thus, a surplus of electric energy that can be efficiently used in other regions of East Asia can be created [in] Far-East Russia in the future.

China's electric utility industry has developed in accordance with the requirements caused by the economic development, of the country. The annual increase of the installed generating capacity and power generation was 9-10 percent for the past 10 years. The installed capacity of power plants increased 2.5 times, from 80 GW in 1984 to 200 GW in 1994. In the year 2010, the installed capacity is planned to be more than 500 GW and power generation is about 2,500 TWh. Generation of electric power and its distribution among the consumers is ensured now by fifteen provincial and regional (embracing several provinces) power systems based on 110 and 220 kV transmission lines.

As electricity consumption grows and power flows increased within the provincial systems and between them, the installation of 500 kV transmission lines started. Using these lines, it is planned to interconnect individual power systems and to create a unified electric power system by the year 2000. However, the distance from deposits of energy resources and lack of generating capacities at a high level of electricity consumption are causing a electricity deficit in southeastern China. In the future, a deficit is expected in a number of other provinces, in particular in northeastern China.

In South Korea, electricity consumption has increased on an average of 1.2 percent annually for the past 5 years. A long-term development program for the decade (1995-2006) envisages the annual increase of electricity demand by 8 percent, which makes development of nuclear energy likely due to of a shortage of local energy sources. Unlike China and Russia, the power system of South Korea operates at a frequency of 60 Hz.

Japan takes third place in the world in terms of installed capacity of power plants and electric power production. With comparatively small relative gains of capacity (2 to 3 percent per year) in absolute terms, the electric utility industry of Japan considerably increases installed capacity of its power plants. Due to a deficit of local energy resources, nuclear energy is considered to be the most promising source of electric energy. Electric power systems of twelve large and a set of small power utilities are interconnected (mainly by 500 kV transmission lines) into a unified system of the country with two operating frequencies (50 Hz in the northeastern part of the country and 60 Hz in the southwestern part). The border between them passes in the middle of Honshu island, and they are interconnected for joint operation by two back-to-back dc links with the total transfer capability of 900 MW.

During the period from 1975 to 1985, electricity consumption of North Korea was growing at a high rate, increasing annually by more than 6 percent. However, during the ensuing decades, these rates slowed down to almost 2 percent. Electricity demand of North Korea is met by local sources. At present, a little more than half the electricity is generated by hydro power plants; the other half is generated by thermal power plants. An offer is being considered to construct one or two nuclear reactors produced in South Korea. North 'Korea's power system operates on a frequency of 60 Hz.

Mongolia's power system covers only the central and parts of the western areas of the country. At present, electricity consumption in the country is at the 1985 level. The electric utility industry of Mongolia is based on thermal power plants. There are no hydro power plants so far, however, there is a suggestion concerning their construction to solve the problem of meeting a variable part of the load curve, Mongolia imports small volumes of electricity (0.4 TWh in 1995) from Russia.

Main Interstate Ties in the Region

At present, there are two local weak 220kV interstate ties between the interconnected electric power systems of Far-East Russia and northeastern China and the interconnected Systems of Siberia and Mongolia. Implementation of even some part of the indicated power flows requires construction of powerful interstate ties between power systems within the region. Specific parameters of electric ties (voltage, transfer capability, number of circuits) should be determined in the feasibility study performed for each of them, considering the functions performed (realization of the system effects, power transmission).

Interstate ties differ in two specific features:

  • They are rather long, as a rule above several thousand kilometers,
  • They connect power systems in which the requirements to power quality, methods, and means of dispatching control, differ substantially.

There are also distinctions in the ac frequency; hence, the indicated ties should be basically dc ties. This will decrease transmission losses, on the one hand, and guarantee asynchronous work of power systems to be interconnected, on the other hand

Examples of the Interstate Ties

The authors have performed studies on the interstate ties between Russia and Japan, with power transmission from the Uchursk hydro power plants, and between Russia, China, and South Korea from the Primorsk nuclear power plant.

Russia-Japan Tie. The Russia-Japan tie was considered as a 650 kV HVDC transmission line, about 3,000 km long, with three converter stations: a station near the Uchursk hydropower plants (for power output); a station in the area of Komsomolsk-on-Amur in the conventional center of electric loads in Far-East Russia (for realization of the effect as a result of interconnection of the power systems of Japan and Far-East Russia) and a station in the northern part of Honshu island. The tie crosses the straits by cable links: Mainland to Sakhalin Island, Sakhalin Island to Hokkaido Island, and Hokkaido Island to Honshu Island. The interstate tie's total transfer capability amounts to 10 GW.

Construction of the Uchursk hydro power plants is discussed in the south of Yakatia. Their total capacity can be increased to 5 GW, and the mean yearly production accounts for 17.2 TWh per year.

In summer, all power produced by the Uchursk hydro power plants is transmitted to Japan, where electric load at this time interval is maximal. This flow substitutes half-peak thermal power plants on fossil fuel in the Japanese power system. In winter, when electric load is maximal in the interconnected system of Far East Russia and it decreases in Japan, the flow from hydro power plants equal to their guaranteed capacity is directed to the interconnected systems of Far-East Russia, substituting thermal power plants on fossil fuel there. In this case, power from hydro power plants to Japan is not transmitted. At this period, additional loading of the Japanese power plants with transmission of their capacity to Far-East Russia is not envisaged; as far as for the considered time horizon (2010-2020) it is not planned to construct condensing power plants in the interconnected systems of Far-East Russia, which could be substituted by power flow from Japan. Therefore, the effect of noncoincidence of seasonal peak loads is realized in this case incompletely. Nonetheless the results of the study have shown that implementation of the considered IST project will decrease the volume of generating capacities commissioned at thermal power plants in both power systems by 10-11.5 GW (with regard to decrease in the total required operating reserve). The economic effect achieved due to project implementation remains positive, even at a discount rate of 12 percent.

Table 1. Basic characteristics of electric utility industry in East Asia region in 1995

Country, Territory

Electricity Production

Installed Capacity of Power Plants (GW)







Eastern Russia






Krasnoyarsk krai






Irkutsk oblast












Chita oblast






Arnur oblast






Southern Yakutia






Khabarovsk Ira






Promorye krai


















North East China






North China






East China






Central China






North West China






South West China






South China






Remaining Areas












North Korea






South Korea












HPP = hydro power plants

TPP = thermal power plants

NYP = nuclear flower giants


Russia-China-South Korea Tie. The tie between Russia, China, and South Korea is suggested as a 500 kV HVDC transmission line, 1,800 km long, with a transfer capability of 3 GW. The converter stations with a capacity or 3 GW each are sited near the Primork nuclear power plant and at the points of power takeoff in Shenyang and Seoul.

The Primorsk nuclear power plant, with a capacity of 1.3 GW and an annual production of 9 TWh, is discussed to be sited in the south of Primorye krai. In winter, it will meet electric loads of the power systems of Far-East Russia and northeastern China using all its capacity and hence substituting thermal power plants in the power balances of these systems. At this period, when the load level in the South Korean system is minimal, thermal power plants of South Korea are additionally loaded with transmission of their power to the systems of northeastern China, where it replaces fossil-fired power plants. In summer, when South Korea's loads are maximal and Far-East Russia's and China's loads are minimal, the nuclear power plant supplies all its power to the South Korean power system, replacing fossil-fired power plants in the power balances there. During this period, the thermal power plants of northeastern China are additionally loaded by the value of a spare part of interstate tie's transfer capability and their power is transmitted to South Korea, substituting fossil fired power plants there. Thus, the effect achieved as a result of coincidence of the annual load curves is realized between the power systems of northeastern China and South Korea. The Far-East Russia system does not participate in realization of this effect as the capacity of its thermal power plants is limited for the considered time span.

The studies have shown that the commissioning of the Primorsk nuclear power plant and interstate tie in combination with a decrease in the total required operating reserve allows savings of 7.2 GW of installed capacities in all the power systems to be interconnected, of which 2.4 GW are saved at the expense of nuclear power plant and 4.8 GW at the expense of the effect achieved due to interconnection. The project is absolutely economically efficient, as it guarantees lower capital and yearly costs against the competing measures.

East Siberia-China Tie. Recently, great attention has been paid to the question of electricity export from East Siberia to China. For this purpose, it is foreseen to construct of a 600 kV HVDC transmission line, 2,200 km long, with a transfer capability of 3 GW from the Bratsk hydro power plant through Irkutsk, Gusinoozersk, Ulan-Bator (Mongolia), to the power system of China in the area of Beijing.

Experts from the Irkutskenergo company have carried out studies on the steady-state and transient conditions of the Irkutsk power system for the considered interstate tie. They have confirmed the possibility of reliable collection and transmission of up to 3 GW of power to China at the stability margins accepted in Russia and showed a satisfactory character of transients after diverse contingencies. The economic efficiency of this line is rather high.

Environmental Implications

The environmental implications of these HVDC connections are being studied. It is necessary to consider the ecological benefits of dc in comparison with HVAC, not very high voltage level (500-650 kV), and relatively low population density in most of the corridors. The main environmental advantages are the use of hydro power resources in the eastern part of Russia instead of thermal power plants with their pollution in China, Korea, and Japan.

All discussed projects also result in essential environmental effect due to reduction in the fossil fuel demand and, hence, in emissions into the environment.

About the Panelist

Nikolai Voropal is director of the Siberian Energy Institute, Russian Academy of Sciences, Irkutsk, Russia. He is also head of the Electric Power Systems Department at the institute and a professor at the Technical University, Irkutsk. Re was born in Belarus in 1943. He graduated from the Leningrad (St. Petersburg) Polytechnical Institute in 1966, and has been with the Siberian Energy Institute since 1966. His research interests include modeling electric power systems, operation and dynamic performance of large interconnected power systems, reliability, security and restoration of power systems, and development of international interconnections. He is a member of CIGRE and is currently chair of the Russian IEEE PES Chapter.

L.S. Belyac, S.V. Podkovalnlkov, and G.V. Shutov are also with the Energy Systems Institute, Irkutsk, Russia.


Environmental Implication and Potential of International High-Voltage Connections

Dusan Povh, Siemens AG

We live in a time of fast changes. Changes in electrical energy systems are affected by a wide range of factors: resources, politics, demand, environment, public, markets, and technology. The limitations of existing energy resources, as opposed to a world population that continues to grow, especially in developing and emerging countries, will play an increasingly important part. Environmental matters, along with public acceptance of certain technologies which also have a political aspect (for instance nuclear power) will likewise become increasingly significant factors.

On top of these general trends, we have major changes in the market, resulting from globalization, liberalization, and deregulation of economies, involving various power supply models in different countries.

The most important factor in the environmental task is the reduction of C02 emission as concluded at conferences in Rio and Kyoto. In this aspect, power plants play an essential role. Development in the last decade made it possible to reduce the CO2 emission for fossil power generation. In addition, a considerable portion of new generation has shifted from coal-fired generation to oil and natural gas, which produce a lower amount of CO2 emission.

Figure 1 shows the C02 emission for different types of power plants. Plotted are operational emissions and emissions resulting from the fuel supply and the construction of the plant of course, the hydro power plant has the best performance regarding the environment. A similar value is valid also for nuclear energy; however, in the majority of European countries, it is politically not possible to build new nuclear power plants.

The development of European power systems is based on a slow increase in power demand and the difficulty to build new overhead lines. Therefore, economic advantages of interconnections are used with the increase of power exchange among the, systems. Economic and environmental advantages are given by HVDC transmission between the UCPTE and NORDEL systems, where water power energy is transmitted from Norway and Sweden to Central Europe.

There is, however, also a strong trend towards decentralized power supplies with the infeed into the distribution networks and consequently relieving of the HV network. This tendency results from both the decentralization of political structures and also from technological progress in the form of new and more economical power plants.

To illustrate the development of the systems, let us look at the UCPTE network in Europe. This network was rearranged some years ago to interconnect the CENTREL countries (Poland, Czech Republic, Slovakia, and Hungary).

Years ago, when the decision was made to enlarge the UCPTE system to the CENTREL countries, first common working groups were built. The important operational conditions of primary and secondary frequency control have been studied. The CENTREL system was disconnected in 1993 from the systems in eastern Europe, which were responsible for power frequency regulation. Major investments were therefore needed for frequency control equipment. The second condition of sufficient reserve at power plant outages has been fulfilled as the load has been reduced because of economic changes due to political transition after 1990. CENTREL countries then operated further their own systems disconnected from the UCPTE systems, however monitoring the operating conditions. Through more than a year of monitored operation, it was possible to confirm the satisfactory operation of the CENTREL system, and then the interconnection was started as a trial operation.

Romania and Bulgaria are also interested in joining the grid. Studies on this interconnections are in progress. The network is sizeable and highly complex; so far still relatively small power has been exchanged between the individual countries. Deregulation will doubtless cause this to change in the future.

New additional links are planned, including the schemes between UCPTE and NORDEL network in Scandinavia and to the Baltic States, Ukraine, Belarus, and Russia. It can be expected that the synchronous operation of enlarged UCPTE systems and the systems of Ukraine, Belarus, Russia, and Baltic states will not be realized for a long time. The reason for this is that the fulfillment of stringent operational conditions required in UCPTE system needs time and high investments. On the other hand, studies show that the advantages of an interconnection are reduced with the increased size of the systems.

The needed investments for synchronous operation increase with the complexity of the systems. The control of the total system must be decentralized, and the interconnection must be strengthened to keep the synchronous operation at outages. Further, the losses of the scheduled transmitted power between the systems increase with distance, and lines in the systems in between can be overloaded. Further, geographically large systems become sensitive on interarea. oscillation. This experience has been experienced already at the connection of CENTREL countries to the UCPTE system.

To gain the advantages of interconnection using the lower cost energy and the reserve power at outages, HVDC transmission can offer economic advantages. A five-terminal HVDC project connecting the systems of Russia, Belarus, Poland, and Germany has been studied for years and has proven to be feasible. The main task would be to transmit cheaper power from Russia to the West. All countries through which the overhead line would be constructed asked, however, for a terminal to participate in the exchange of power. However, the realization of the project still waits for the agreement on long-term contracts for delivery of energy.

A further step includes studies for an altered HVDC interconnection to the eastern pan of Europe, building a part of the future Baltic Ring interconnecting all the countries round the Baltic Sea partly by dc and ac. Provisional studies for the scheme showed that a nine-terminal HVDC scheme is technically feasible.

The aim of this interconnection is higher supply security for countries involved and better utilization of national resources by combining, e.g., the Scandinavian hydropower with the thermal power systems. In addition to economical advantages of the interconnection, the promotion of international cooperation is contributing to a broader international understanding.

Figure 1. CO2 emissions from electricity generation in different power plants

Cooperation on this project proceeded so well that the work will continue. A new forum has been established, called Baltic Ring Electricity Cooperation (BALTREL) to develop the idea of a common Baltic power market. A single Baltic region market could reduce variable costs of electricity production in this area by $132 million per year. The construction of reserve capacity can be reduced or postponed. The report recommend three projects at this stage: Construction of HVOC linking Poland and Lithuania and reconstruction and uprating of some power stations in Latvia.

About the Panelist

Dusan Povh is president of System Planning at the Siemens Transmission and Distribution Group in Erlangen, Germany. He has been with Siemens since 1962. He is involved in the field of system planning, insulation coordination, and the development of HVDC and FACTS devices. For several years, he was the head of the marketing department for HVDC and SVC. He is a

Fellow of the IEEE and a member of a number of IEEE and CIGRE committees. Re is chair of CIGRE Study Committee 14 on HVDC and FACTS. Re received his Dipl.-Ing. from the University of Ljubljana, Slovenia, and his Dr.-Inq. from the Technical University of Darmstadt, Germany. He is also a professor at the University of Ljubljana.


Environmental and Sociocultural Considerations for International HVDC Interconnections

D.A. Woodford, Manitoba HVDC Research Centre

International interconnections for electric power transmission are subject to environmental assessment to meet requirements of the respective national governments and international investors. Even at the feasibility stage, an initial environmental assessment is required to outline the issues to be addressed as required by regulatory agencies and investors. Technical assurances, risks, and anticipated returns on investment are traditionally dealt with in a feasibility study. Environmental and sociocultural impacts must also be included.

In North America, most international electric power transmission interconnections have spanned the Canada-U.S. border. Although large hydroelectric resources remain undeveloped in northern Canada, local generation in the United States from gas turbines and combined-cycle units are competitive with the long-distance transmission project. From an environmental aspect, each alternative has its advantages and disadvantages over the other.

The decision for selecting between a HV transmission interconnection and a local gas-turbine generation option is governed by availability of energy, return on investment and the risk of that investment The gas-turbine option may also be perceived as environmentally more acceptable. Investment in electric power transmission by nonutility investors is best applied to

interconnections rather than to grid transmission lines. Attracting nonutility investor participation will impact the way a feasibility study is prepared, particularly in achieving a short-term return on investment. International investors, the World Bank and most national governments will demand stringent environmental and sociocultural considerations.

Feasibility Study Considerations

The feasibility study for an international interconnection at any location must include an examination of possible substation locations, transmission alternatives, and corridor options, assess environmental impacts to determine preferences in routing and location and identify possible mitigation measures, all to evaluate the overall feasibility of the project. To neglect such environmental considerations at the feasibility-study phase may be a false economy and a fatal flaw. However, aspects of the project that are not environmentally significant can be identified and recommendations made to prudently drop such from consideration in the ensuing environmental-assessment reports. For example an HVDC transmission line has a lower environmental impact than an equivalent HVAC line in some aspects, and such can be identified and dealt with to a lessor extent than it would if the line was ac.

Environment, social development, and gender considerations are broadly defined as the "natural and social conditions surrounding all mankind, and including future generations." For a project, environmental considerations in the feasibility report could be considered as the first of the environmental-assessment reports, with the main objective being to help establish the viability of the interconnection project. Ensuing environmental-assessment reports may be required to satisfy governments, investors, and lenders that impacts on health, cultural and tribal properties, indigenous peoples, and the natural environment are properly considered and acceptably dealt with. Sociocultural effects of the project such as new land settlement, involuntary resettlement and induced development would also be included in the additional environmental-assessment reports.

The feasibility study can only proceed providing the governments involved have agreed to participate. Their respective inputs are essential to solicit cooperation and properly reflect cultural and political issues.

Identification of Essential Organizations

On both a national and provincial level, the ministries, agencies, and institutes that are the authorized license and permit issuing bodies for constructing the proposed transmission line must be identified. Also at the national, provincial and County/municipal level, both government and nongovernment organizations that might have influence on any aspect of the project should also be identified.

Interagency coordination is crucial to an effective environmental assessment, and the identification of these agencies will be important to launch it. From the limited perspective of the feasibility study, an estimation should be made of the effort involved in an environmental assessment of a project spanning two or more nations. The feasibility study should identify the authority and responsibility to collect information, prepare plans, approve designs, issue permits, allocate resources, develop budgets, monitor progress, and regulate activities. These will be spread over a number of agencies at all levels of government.

Initial Discussions

The chosen project team must meet together to develop the framework essential to the undertaking of the environmental portion of the feasibility study. Identification of other government agencies not represented on the team should be undertaken. Nongovernment organizations need identifying, and the means to practically involve them in the Feasibility Study should be determined. The project team can play an important role in maintaining progress for the project, particularly as it serves as an essential communication link between governments, nongoverment organizations, and the interconnection project promoters.

Special effort may be needed to ensure that the persons and communities impacted by the project are considered, particularly with emphasis to persons most vulnerable. The possibilities and options for social development should be explored, in particular, those communities that are impacted by the line and its substations but that will have no direct access to the energy being transmitted.

As discussions are initiated, basic considerations such as the following should be taken into account:

  • What are the country's national and regional laws regarding the environment and public participation? From both a legal and public administration viewpoint how will current government organization and legislative authority affect the project and its public participation aspects?
  • How decentralized is the country's public administration and how will this effect the environmental assessment process?
  • What are the structures of regional and local governments?
  • How do government ministries communicate with villagers in rural areas and the urban poor?
  • How are the interests of traditional social structures (e.g. tribal) communicated and taken into account in the administration of programs?
  • What role do political parties play?
  • How effective are the print and electronic media likely to be in informing the public about the project?
  • What is the capacity of the government or party structures to participate in the environmental-assessment process?
  • What is the relevant experience and technical capacity of the government agency that will be involved in the consultation process?
  • What national and international nongovernment organizations in the country are involved with environmental issues and/or environmental advocacy? Have they had any direct experience with the people in the effected area? What are the technical capacities of the nongovernment organizations that are likely to be involved in the Environmental Assessment? What is the current state of government/nongovernment organization relations in the countries?

Identifying Guidelines, Policies, Standards, and Responsibilities

It is only necessary in thc feasibility study to identify the basic policies, guidelines, and standards which governments may impose on the project for government, social development and gender issues. Investors and lenders may also demand a stand on these issues, and, in particular, the World Bank, if it is to be involved. The deficiencies for World Bank acceptability need to be identified and documented for addressing in the environmental assessment to be undertaken during the development phase of the project.

These policies, guidelines, and standards will be proposed and reviewed by the project team and an evaluation made on their impact on project feasibility.

Defining Preferred Corridor

Knowing the route of the transmission corridor and the location of the terminal stations are essential for the issues of environment, social development, and gender to be properly incorporated into the feasibility study for the project. Then the counties, townships, and municipalities across which the transmission line passes can be identified.

The alternative corridors for the transmission line must be defined. A corridor is specified herein as being 20 km in width, but this width could be increased or decreased. The corridors would be recommended by the government organizations identified earlier and the project team. It is anticipated that considerable effort will be required by all parties to determine alternative corridors and preferences.

Evaluating Costs

The feasibility study should consider how much the policies, guidelines, and standards will cost to implement and how the return on investment might be impacted. A preliminary evaluation of these costs and benefits imposed by the governments and lenders will be undertaken in the environmental assessment. To ignore these issues may result in greater costs down the road when the consequences of such neglect have to be dealt with.


The deliverables of all tasks will be incorporated into the interconnection project feasibility study and will reflect the consensus and compromise of all concerned. The chapters of the report thus compiled will be the introduction and first volume of the environmental assessment as it may be required by governments, lenders, and impacted communities.

Documentation should include essential points and guidelines to be addressed in future agreements required for the project. To attract investors to an international interconnection will require substantial effort to assure them that the project is as low risk as possible. The return on investment will be of little value if the interconnection project is not supported by the communities it effects. The feasibility study can provide assurance at an early stage of the project that these important aspects will be addressed in a responsible manner.

About the Panelist

Dennis Woodford graduated from the University of Melbourne in 1967 and from the University of Manitoba in 1973 with a M.Sc. degree. From 1967 to 1970, he worked with the English Electric Company in Australia and the UK. In 1972, he joined Manitoba Hydro and worked as a special studies engineer in Transmission Planning. In 1986, he joined the Manitoba HVDC Research Centre as executive direction. He is a member of IEEE, CIGRE, and the Canadian Electricity Association. He is an adjunct professor with the University of Manitoba and a registered professional engineer in Manitoba.


Environmental Implications or international Connections: The New Arena

André Vallée, G. Jean Doucet, TransEnergie, Hydro-Quebec

Hydro-Quebec is the public utility responsible to provide electricity to Quebec, Canada. Most of the energy is produced by 54 hydroelectric generating stations feeding an extensive HV grid exceeding 30,000 km of power lines. These rights of way cross a great variety of environments and habitats such as the boreal and the mixed forests, the St-Lawrence agricultural plains, large rivers, arid suburban zones. The TransEnergie interconnection network is truly a north-to-south network, with power produced mainly in northern Quebec and carried to southern markets, The interconnection network is made up of 735 kV, one 450 kV, and some 120 kV lines.

In 1997, to comply with the new rules of the continental energy markets and the functional separation of its operations, Hydro-Quebec changed the status of its transmission business unit to a division called TransEnergie and gave it for mandate to develop and manage the HV transmission network. TransEnergie must also ensure nondiscriminatory access by all accredited power producers, while maintaining the same quality of service. The TransEnergie division, with assets totaling $16.4 billion and 3,700 employees, comes under the jurisdiction of the Quebec Energy Board. One of the major objectives of this new division is to develop a client base through a system of power transmission interconnections. In May 1997, the United States Federal Energy Regulatory Commission (FERC) approved the main points of Hydro-Quebec's application to be permitted to deal on the United-States wholesale market. TransEnergie is already serving out-of-province customers through its existing interconnection system, delivering power to 15 utilities in the northeastern United States, Ontario, and New Brunswick. In addition, TransEnergie operates an interconnection with Newfoundland and Labrador Hydro, which entries energy produced by the Churchill Falls complex in Labrador. An underlying objective of TransEnergie is to be cost effective and competitive within the framework of a deregulated market.

Hydro-Quebec adheres to an environmental policy that applies to all the utility's activities, including the development and operation of the interconnection network. This corporate environmental policy is based on principles related to the six following themes:

  • Sustainable development
  • Environmental management
  • Environmental research
  • Environmental enhancement
  • Public participation
  • Environmental responsibility.

As a division of Hydro-Quebec, TransEnergie follows that policy. TransEnergie is in the process of implementing an environmental management system (ISO 14001) that dovetails with a series of environmental commitments related to Hydro-Quebec's membership in the Canadian Electricity Association.

The objective of this presentation is to discuss environmental implications of cross-border powerline interconnections in relation to the new conditions created by free trade and deregulation. The presentation focuses on environmental issues that are specific and strategic at the interconnection scale. These issues include environmental management systems, electric and magnetic fields, rare and endangered species, greenhouse gas emissions, environmental tradeoffs, research and development, and public participation programs.

Environmental Management Systems

In order to strengthen its corporate environmental practices, Hydro-Quebec has introduced an environmental management system that complies with the ISO 14001 standard, The associated commitments and changes will be those developed under the Environmental Commitment and Responsibility Program of the Canadian Electricity Association, of which Hydro-Quebec is a participating member. As a separate division, TransEnergie is presently in the process of introducing its own environmental quality plan based on the ISO 14001 standard and according to specific objectives. In 1998, TransEnergie will focus on the establishment of baseline or reference environmental conditions for all its installations and entire operation. Another objective is to develop standard procedures to identify environmental aspects and legal requirements of the division's activities. In time, TransEnergie will develop and integrate in its management system the standards associated with the ISO 14001, which has for its objective to balance environmental protection and pollution reduction with socioeconomic needs.

External environmental consultants working for Hydro-Quebec must comply to Hydro-Quebec's environmental management system to this effect, several environmental consultants are being certified ISO 9001, which is an internal management system that enables dovetailing with the environmental management system adopted by Hydro-Quebec. It specifically targets impact studies for power plants power lines, and substations, in this framework, each firm develops its own quality plan and, after implementation, is subject to external, verification for compliance.

Environmental Issues and Interconnections

In general the same environmental management criteria apply to the entire Hydro-Quebec HV power grid; including all interconnections. Interconnection issues can be problematic for the original transporter, because the latter faces the questions of meeting the standards, rules, and regulations of the secondary transporter and the final customer or users. Cross-border issues can result in having to deal with different environmental regulations and standards, along with different public and specific interest groups.

This presentation focuses on environmental issues that are specific and strategic at the interconnection scale; part of the discussion will address environmental questions related to alternative energy production sources. These issues include: electromagnetic fields, greenhouse gas emissions and environmental tradeoffs, rare and endangered species, research and development, and public participation programs. TransEnergie must respect Canadian and Quebec environmental laws and regulations. In addition, a tacit goal of TransEnergie is to meet the environmental standards of its interconnected customers. This goal focuses on respecting regulations already in place, but it raises an interesting question in relation to future regulatory requirements regarding energy corridors.

Electromagnetic Fields. The electromagnetic field issue remains a major issue for both the transporters and the customers. Hydro Quebec jointly with other utilities (Bonneville Power Administration, Ontario Hydro, Electricite de France, etc.) have conducted an extensive research program focusing on biological and physical aspects of this problem. Epidemiological studies have addressed human health, while other studies have targeted livestock and plants. This encompassing scientific research program failed to provide clear answers regarding this issue. Despite the gap between predictable risks determined by scientific knowledge and expressed preoccupations in the media or directly from the public, effects of electromagnetic fields remain an issue of international scope.

In a management framework, Hydro-Quebec has developed in 1986 a corporate action plan to address the electromagnetic field issue. The objectives of this action plan are to:

  • Organize corporate coordination
  • Intensify Hydro-Quebec scientific contribution
  • Communicate activities and results.

In 1998, research, communication, and openness remain prime concerns of this plan. Research is presently done on two aspects:

  • Neuroenclocrinological effects (melatonin) on human populations living near high voltage lines
  • In the impact on dairy cows (production).

The communication aspect includes the production of several documents on the topic and also the building and operation of the Electrium, a permanent indoor exhibit where the public can be informed on all aspects of the electric and magnetic field issue.

Part of Hydro-Quebec's action plan focuses on the adoption of a prudent attitude strategy. Adoption, in 1996, of the position of prudent management means vigilance, research, communication, standardization, and regulation. Many general activities remain acceptable near HV power lines, and Hydro-Quebec continues to encourage the secondary use of powerline rights-of-way, while giving preference to initiatives that do not significantly increase human exposure.

As we keep abreast of new information and development and monitor changes related to this issue, we cannot escape the following scenario; as to what would happen if cross-border customers (for example, in the United State's) would adopt standards (distances, field strengths, etc.) more stringent than those presently applied by TransEnergie. This issue certainly has the potential to raise questions in terms of interconnection installations and operation.

Greenhouse Gas Emissions. The World Commission on Environment and Development report (Bruntland 1987) discussed environmental issues associated with the various sources of power production. On a global scale, it is generally accepted that hydropower production is less pollutant than fossil fuel energy production. The WCED report (Bruntland 1987) recommends the development of energy production based on renewable resources, in the framework of reducing the pollution load into the twenty-first century. The vast majority of Hydro-Quebec energy production comes from powerful hydroelectric generating complexes, several of which are located in northern Quebec. The large reservoirs feeding the turbines carry their own gamut of environmental issues, mercury being one of the most prominent. However, the water required for Hydro-Quebec's hydroelectric generating facilities is renewed continuously and generates no significant greenhouse gas emissions.

On a large scale and from an environmental point of view, hydroelectric energy development can be an ideal complement to energy needs and parallel commitments to reduce greenhouse gas emissions. The analysis, however must account for the greenhouse gases produced by biomass degradation in reservoirs, and Hydro-Quebec is presently studying this phenomenon. In this global perspective (and consequently cross-border), maintaining or adding to Hydro-Quebec hydroelectric capacity is relevant in Canada's efforts to control its future greenhouse gas emissions (CEA 1997). In this framework, cross-border high voltage interconnections could provide strategic energy and development choices or alternatives. A North American network of energy transportation where hydroelectric production is pivotal could offer an alternative to reduce greenhouse gas emissions locally or regionally for given periods of time.

Thus, reducing the overall emissions of a country or continent could be enhanced significantly by hydroelectric development.

The Canadian government is likely to adopt, in the near future, measures to reduce greenhouse gas emissions in Canada. In this context, and to avoid the implementation of unfair sectorial measures, Hydro-Quebec supports the implementation, in Canada of a national tradable permit system for energy-related greenhouse gas emissions. This position submitted to the Canadian Electricity Association includes two conditions of implementation. A Canadian permit system is acceptable only if:

  • All fuel distribution in Canada is included, not just fuel used by the electric industry
  • The United States adopt a permit system or other measures that will ensure U.S. stabilization of emissions.

Rare And Endangered Species. TransEnergie must respect Canadian and Quebec laws on rare and endangered species. This means respecting regulations already in-place to protect rare and endangered plant and wildlife species. Quebec played a significant role in the development of the Canadian position in the development and signing of the Rio International convention on biodiversity. Since 1992, the government of Quebec has articulated a strategic plan to activate this convention through a detailed action plan, in which Hydro-Quebec is a player in specific areas related to the corporation's installations and activities.

The biodiversity issue is very complex, but the rare and endangered species aspects have become such a worldwide concern, that it becomes mandatory that we strive to meet the standards of our various interconnected customers. To achieve this, we keep abreast of new information in this field and we work closely with outside agencies and conduct in-house vanguard research on biodiversity and habitat fragmentation to address this issue in order to eliminate impacts and to develop effective mitigation measures at the planning and operation phases of powerline corridors. International conferences on environmental concerns in rights-of-way management held in Montreal in 1993 (Doucet et al 1995) and New Orleans in 1997 (Williams and Mahoney 1997) addressed these issues.

From a practical point of view, the presence of rare or endangered species in powerline rights-of-way presents a multifaceted problem: habitat loss, habitat fragmentation, habitat enhancement, collision, electrocution, vegetation control, and maintenance activities. Studies indicate that rare species can be found in rights-of-way (Smallidge et al 1995, Deshaye et al 1996, Wester and Kolb 1997). The presence of a rare species in a right-of-way can become complicated further when the right-of-way provides the habitat for the presence of this species in the area. An interesting example is the case of the Karner blue butterfly (listed as endangered by the U.S. Fish and Wildlife Service) which is attracted to rights-of-way in the Northeast by an increased abundance of lupines, which in turn are the results of herbicide treatment in rights-of-way (Smallidge et al 1995). This creates a catch-22 situation where both treatment and nontreatinent represent a threat to the butterfly habitat.

Within the process of issuing governmental authorization for the Levis-Des Cantons 735 kV line, the government of Quebec requested that Hydro-Quebec address the issue of rare plants along the selected route. Systematic inventory and monitoring were conducted during all phases of the project (1994-1998) to find plant species susceptible of being designated threatened or vulnerable by law. Five species susceptible of being listed were discovered in the right-of-way. Wild leek designated as vulnerable in 1995, was inventoried in several sites on the route Mitigation measures have been implemented for 14 populations of wild leek in the right-of-way. These include special clearing methods and translocations in forested areas near the right-of-way. As part of the monitoring program for the 735 kV Levis-Des Cantons powerline project (Belzile and Cohen 1997), a field monitoring and transplantation project or wild leek represents a first approach to deal with rare plants found in the areas of a project.

Research and Development. In order to respect the corporate commitments on reaching and maintaining high standards in the production and transmission of electricity, it is relevant and strategic to maintain a dynamic and aggressive research and development program in engineering and environment. The R&D program is important to maintain pace with various new regulations and public concerns. Environmental research makes us more competitive and better informed about new issues and innovative solutions targeting new problems in a management framework. We work closely with outside agencies and conduct in-house research to address these issue's in order to minimize impacts and to develop effective mitigation measures at the planning and operation phases to the satisfaction of customers. TransEnergie has adopted the position that research and development in engineering and environment is pivotal to keep up with competition and new issues that will arise over time. To this end, a TransEnergie biologist attended an EPRI workshop in Denver, Colorado, in October 1997 to participate in the elaboration of an environmental research program related to energy corridor rights of way.

Public Participation Program

In practice, any Hydro-Quebec activity could have an effect on the environment. The Public Participation Program developed by Hydro-Quebec has many facets, but suffice it to say for this presentation that it is structured to obtain all possible data in a sequence to enable managers to integrate these data in the study process. General data, concerns, and briefs are analyzed to determine real issues and propose orientations to facilitate management and integrate them in the final decision process (Hydro-Quebec 1994).

Quebec environmental law contains provision for public hearings in the case of major projects. HV transmission power lines are thus subjected to public hearings south of the 49th parallel. North of the 49th parallel, major projects are subject to the provisions of the James Bay and Northern Quebec Agreement.

In essence, the Public Participation Program is based on four modes of public participation: information, consultation, concertation and negotiation.

  • Information: formal and informal meetings, public meetings, initiate reactions
  • Consultation: meetings, polls, written briefs, evaluate reactions
  • Concertation: debate and working groups, look for consensus and solutions
  • Negotiation: mixed committees, joint decision (decision sharing process).

In general, public hearings and debates related to high voltage powerline projects are well attended by a broad spectrum of participants from affected communities and special interest groups. The Hydro-Quebec team at such hearings is made up of spokepersons and a solid support of engineering, environmental and socioeconomic specialists.

Hydro Quebec has participated in public hearings in the United States on an ad hoc basis. One can only speculate as to what direction the formal public participation process will evolve in relation to the deregulation issue and, to the cross-border interconnection environmental issues for high voltage power lines.

Advantages and Disadvantages

From an environmental point of view, cross-border interconnections offer advantages and constraints. One of the main advantages of cross-border interconnections is in the supplying of hydroelectric power rather than fossil fuel generated power in areas where demand is very high or for peak periods. This can contribute to reduce greenhouse gas emissions, which can be significant since many countries are signing agreements to reduce their greenhouse gas emissions in the next 10 years. Another advantage is the opportunity to transport energy in areas in need due to large-scale and/or long-term outages. This would reduce the scope of permanent back-up installations in given areas, thus reducing overall environmental effects.

The main disadvantage is in the commitment to meet environmental constraints of cross-border customers. This is especially relevant as rules and regulations, along with public concerns are changing at a different pace in each country. On the other hand, an effective cross-border interconnection network is likely to result in a tendency to respect the most stringent criteria by all participants.

Environmental issues will not disappear, and cross-border energy transmission is likely to make some environmental issues more complex. On the other hand, interconnections can present valuable environmental alternatives. For example a supply of cross-border hydro energy could be an alternate source of power in time and space to help reach governments' goals of reducing greenhouse gas emissions continent-wide.

Environmentally, in the field, we maintain the same standards for interconnections that we maintain on all of Hydro-Quebec's rights-of-way grid. At the same time,

TransEnergie strives to respect the environmental standards and issues of its cross-border customers. To meet this goal, TransEnergie is maintaining a transparent and aggressive environmental R&D program, keeping abreast of environmental issues including those of our cross-border customers. Finally, the environmental management system under development should place TransEnergie in a better position to have its environmental activities and standards accepted by cross-border customers and the general public.

About the Panelists

André Vallée received his degree in civil engineering from the University of Montreal in 1966. Rejoined Hydro-Quebec in 1981 Since then, he has been involved in HV power line construction and routing studies. He has managed numerous HV protection projects, including the 450 kV Des Cantons-New England interconnection between Southern Quebec and the United States. Further, he has directed impact participation programs. He joined TransEnergy in February 1997, which is Hydro Quebec's division responsible for energy transmission assets to ensure nondiscriminatory access to the transmission system by power producers. Currently, he is manager of Power Lines, Cables, and the Environmental Unit, which is responsible for preliminary routing studies. This unit also conducts technical and environmental research and development.

Jean Doucet is an environmental research scientist at Hydro Quebec. Previously, he worked with Lavalin and was at MacGill University, Montreal. He has been working on environmental aspects of powerline rights of way since 1973. Currently, he is engaged in research on habitat fragmentation and biodiversity in relation to HV power line corridors.


Linking Renewable Energy Resources:

A Compelling Global Strategy for Sustainable Development

Peter Meisen, Global Energy Network Institute

The expansion of HV ac and dc interconnected systems continues to develop around the world. The power pools of North America, UCPTE, CENTREL, CIS, and NORDEL networks are proven energy infrastructures, providing enormous cost savings in power trading, reduced capacity requirements and emergency backup. Economic growth in Latin America, India, China, and Southeast Asia is driving the demand for more capacity and the transmission systems to deliver this power.

As in the past several decades, the overwhelming majority of the power development is from fossil and nuclear sources. The most blatant contemporary example is China. Adding a large thermal station every month is planned over the next 20 years. While starting from a very low consumption per capita, this energy development rate is projected to make China the world's largest polluter within the next decade.

There is a solution to the dilemma of energy needs versus pollution. Long-distance transmission is now capable of reaching far beyond political boundaries. By tapping some of the planet's abundant renewable energy resources in remote locations, we can now provide the electricity necessary for development in an environmentally sustainable manner.

Global challenge

The 1996 report from the World Resources institute, World Bank, UNEP and UNDP projects major global challenges [1]. By 2025, our current population of 5.9 billion is projected to become 8.3 billion, with most of this growth in the developing countries. Megacities will emerge, as 90 percent of population growth will be in urban areas. Critical water shortages are expected. Today, humanity has not fully provided for itself. Over two billion people in developing countries live without electricity or clean drinking water. They lead lives of misery, especially women and children who walk several kilometers daily for water and firewood merely to survive.

The World Energy Council projects a doubling of primary energy demand over this same time period, driven by the population and economic growth of the developing nations [2]. The 1997 Kyoto Climate Agreement to reduce greenhouse emissions by 5 percent from 1990 levels was limited to OECD nations. Even with this commitment, greenhouse gas emissions will certainly increase as the developing world grows economically. When these trends are studied in total, the prognosis is not healthy for billions of people or the planet.

Yet a solution does exist that can provide a solid foundation for sustainable development. With the expansion of HVAC arid HVDC systems, the tapping of large renewable energy resources has the potential to:

  • Increase the standard of living for everyone
  • Reduce fossil fuel use and the resultant pollution
  • Reduce deforestation, topsoil erosion, and desertification
  • Reduce poverty and world hunger
  • Open markets and enhance world trade
  • Promote international cooperation and peace.

Global Design Science

The strategy proposed in this presentation is born from a unique method of inquiry, comprehensive anticipatory design science. This approach was championed by Dr. R. Buckminster Fuller, visionary engineer, cartographer, and mathematician. We argue that most problems cannot be solved in isolation, since most issues are interrelated in our global society. The problems of the world must be viewed comprehensively, planning must anticipate the trends to stay ahead of them, and then we must engineer solutions to meet both man's needs and environmental sustainability.

After thorough cataloging of the earth's resources and assessment of human survival needs, Fuller designed the global simulation called the World Game. Giving world planners the potential for global thinking and solutions, this simulation set aside politics, prejudice, war, and human ignorance. The purpose of the simulation is: "make the world work for 100 percent of humanity in the shortest possible time through spontaneous cooperation without ecological damage or the disadvantage of anyone."

From this broad approach to finding global solutions, it was found that the common denominator of all societal infrasystems (food, shelter, health care, sewage, transportation, communication, education, finance) is electricity. Upon further research into the electrical delivery system, it was proposed 25 years ago that the most globally economic, efficient, and sustainable strategy would be to interconnect regional power systems into a continuous world electric energy grid linking renewable energy resources. This was the premier solution of the World Game and a most compelling strategy for peace and sustainable development [3].

While this global vision is still decades away, the interconnection of regional power grids is well advanced in OECD countries. In 1971, the United Nations Natural Resources Council corroborated these findings, placing special emphasis on the untapped potential of large renewable sites in the southern hemisphere [4].

Leading to the Earth Summit in 1992, the United Nations Environmental Program called the energy grid solution to be one of the most important opportunities to further the cause of environmental protection and sustainable development" [5].

Technological Development Moves Power Further and Cheaper

Technological advances over the past 2 decades have extended the interconnection of international and interregional networks. Just 5 decades ago, electric power could only be efficiently transmitted 600 kilometers, In the 1960s, breakthroughs in materials science, improved alloys for conductors and better insulators, extended this transmission distance to 2,500 kilometers. Today, research from the International Conference on Large High-Voltage Electric Systems (CIGRE) shows that the feasible and economic distance of ultra-high voltage (UHV) transmission to be 7,000 kilometers for direct current and 4,000 kilometers for alternating current [6]. Transmission over this distance would allow for power interchange between North and South hemispheres, allowing utilities to compensate for variations in seasonal demand, as well as east and west linkages across continents and time zones. Buying and selling power is now common in all developed nations, as utilities desire to level the peaks and valleys of energy demand to save costs and increase reliability.

Win-Win Solution to Global Problems

Economic Benefits: Expanding and interconnecting power grids has proven to be economically desirable. In developed countries, billions of dollars are presently being saved through buying, selling and wheeling power between neighboring utilities and countries. This practice can expand even more to meet future demand. Also, the deregulation of utilities brings many new generation options, whether locally based or in a neighboring country. Savings are reflected in reduced customer costs, while expanding markets for each power producer, which is a massive win-win situation.

The economic potential of URV technology for developing regions is immense. Some of the world's most abundant renewable potential exists in the developing continents of Latin America, Africa, and Asia. Exports of this excess untapped potential could be purchased by the industrialized world, providing cheaper and cleaner power, and simultaneously sending needed cash to the developing world. History shows that equitable trade engenders cooperation. Thus, long-distance transmission via grid interconnections can contribute not only to expanding international trade but also world peace and security.

Environmental Opportunity: Presently, 82 percent of all power generation is nonrenewable, causing many of the world's most noxious environmental ills (greenhouse gases, acid rain, toxic wastes, etc.). Yet, enormous potential for hydro, tidal, solar wind, and geothermal sites exist around the world. These renewable resources are oftentimes in remote locations. With HVAC and HVDC, these renewables are now within economical transmission distance. These renewables are critical, given the projections of the World Energy Council of a doubling, of primary energy demand in the next 25 years as developing countries grow economically and in population. The Intergovernmental Panel on Climate Change (IPCC) has concluded man's impact on climate change, which will worsen if the WEC business-as-usual scenarios prevail. Global insurance companies are deeply concerned as weather-related property claims have tripled in the past decade [7].

In 1993, Johansson, Kelly, Reddy and Williams published "Renewable Energy, Sources for Fuels and Electricity." This landmark work offered a major shift in how we could meet our energy requirements in the coming decades. Using the same demand projections as the WEC, the authors projected that the renewable share could increase from 20 percent to 60 percent by 2025, with roughly comparable contributions from hydropower, intermittent renewables (wind and direct solar) and biomass. They cited benefits of this scenario that are not captured in standard economic models:

  • Increased economic and social development in rural areas can help reduce poverty and slow urban migration
  • Land restoration through biomass growth will help prevent erosion and provide wildlife habitat
  • Reduced air pollution caused from the burning of fossil fuels on both transportation and power generation
  • Abatement of global warming as renewable sources produce no carbon dioxide or other greenhouse gases
  • Diversity of the fuel supply would create more inter-regional energy trade, and users would become less vulnerable to monopolies or supply disruptions
  • Reducing the risks of nuclear proliferation as competitive renewables would reduce the incentive to build further nuclear supply.

Two conclusions of "Renewable Energy" are central to our argument. First, "the levels of renewable energy development indicated by this scenario represent a tiny fraction of the potential for renewable energy. Higher levels might be pursued if society, for example, should seek greater reductions of C02 emissions." Secondly, since most of the abundant renewable energy sites are in remote areas, oftentimes in neighboring countries, "most electricity produced from renewable sources would be fed into large electrical grids and marketed by electric utilities." A key environmental question in the developed economies is that of replacing present polluting generation over the next few decades as their economic life expires. Access to remote renewables and interconnection of power grids across political boundaries opens up new economical and environmentally sustainable alternatives.

The challenge for developing nations is to bypass the old development formulas and transition to sustainable prosperity. Of critical consequence for the planet is choosing the appropriate energy path for India, China, and Southeast Asia. Over half the world's 5.9 billion population lives there now, and linking renewable resources is essential if we are to reduce atmospheric emissions in the future.

It is important to remember that handling personal survival precedes environmental concern. So, while end-use efficiency is a priority in first world economies, energy efficiency and demand side management in the developing countries is difficult in times of accelerating energy demand. Providing the alternative of remote renewable energy can circumvent traditional polluting approaches to meeting energy needs, but will be limited by the availability of technology and financing. Efficiency improvements are vital but not sufficient for future trends, especially in the developing regions of the world.

It must also be noted that as a development strategy for the 2 billion who are unserved by electricity, what is needed today are small decentralized generators that can meet basic food, water and health care needs. Then as development demand increases and segments of the grid reach rural areas, the population could connect to the expanding grid network.

Sustainable Options for the Future

Several years ago, the IEEE PES International Practices Committee hosted a panel session on "Tapping Remote Renewables." A summary of the expert comments present strong evidence for the intentional development of large renewable resources linked by high-voltage transmission.

Len Bateman, retired chairman of Manitoba Hydro stated, "Over 100 interconnected lines, ranging from low voltage to 765 kV cross the border between Canada and the United States, transporting over 8,000 MW of electric power. The export of electricity is equivalent to the export of finished industrial products. With the export of hydroelectric power, there is no depletion on Canada's power resources. Undeveloped hydro potential in the world energy equation represents waste. If these sites are environmentally sound they represent a source of energy that can qualify as a sustainable development" [9].

A similar case is made in Africa by professor Luigi Pads of the University of Pisa, "Transmission is the best renewable energy available today. In Europe, the Inga (Central African hydro) can be delivered at a price competitive with the energy produced with oil. The implementation of the Grand Inga project will assure to the African developing countries may social benefits. It is important to know that the exported hydroelectric energy does not reduce the potential richness of the developing country, such as the case of oil or coal exportation" [10].

Another massive renewable potential exists in many tidal sites around the world. The Siberian Energy Institute reviewed the Shelikhov Gulf in the Okhotsk Sea in eastern Russia and found an 80 GW tidal resource potential. The Kimberly region of Australia has a tidal potential of 240 MW, which is eight times the current demand of the nation. Both of these locations are remote from any population centers or industry, so UHV transmission is the only way to deliver this electricity.

The Union of Concerned Scientists report on Powering the Midwest offers a representative example of the wind potential of many regions of the world. "Wind energy promises to be one of the least expensive and most abundant new sources of electricity for the Midwest U.S. The region's wind resources are second to none in the world... there is more than enough wind to supply all the region's electricity demand (although this would most likely be impractical" [11]. Here, the grid system is already in place.

Sanyo Electric is one of many companies working to make solar PV cost competitive. While many small scale applications for PV are in use in rural villages, Sanyo's plans call for large solar arrays in the deserts of the world connected to UHV transmission. Their studies show that an 800 km by 800 km area (just 4 percent of the world's deserts) would be sufficient to provide the entire electrical needs of the planet [l2].

System planner Michael Hesse Wolfe summarized Mid-East solar potential by saying, "There is enough for all. One statistic is enough. On the Arabian peninsula there is enough solar energy every year which is equivalent to their entire petroleum reserve that ever was. Every year... We have an abundance of renewable energy resources on hand. It is up to us as we near the turn of the century to think seriously about developing these resources for the benefit of humanity and the planet" [13].

How do we meet the energy demands of a growing world in an environmentally sustainable manner? The electrical interconnection of large renewable energy resources around the world offers a very compelling strategy.

About the Panelist

Peter Meisen, president Global Energy Network Institute (GENI), is a graduate (1976) of the University of California. San Diego with an applied mechanics and engineering sciences degree. In 1986, he founded GENI, a nonprofit organization conducting research and education on the interconnection of electric power networks between countries and continents with an emphasis on tapping remote renewable energy resources. He is a speaker and author on the global issues of renewable energy, transmission and distribution of electricity, quality of life and its relationship to electricity, the environment, and sustainable development.


HVDC Light: A New Technology for a Better Environment

Lars Weimers, ABB Power Systems

A new transmission and distribution technology, HVDC Light, makes it economically feasible to connect small-scale, renewable power generation plants to the main ac grid. Vice versa, using the very same technology, remote locations such as islands, mining districts, and drilling platforms can be supplied with power from the main grid, thereby eliminating the need for inefficient, polluting, local generation such as diesel units. The voltage frequency, active and reactive power can be controlled precisely and independently of each other. This technology also relies on a new type of underground cable that can replace overhead lines at no cost penalty.

Equally important, HVDC Light has control capabilities that are not present or possible even in the most sophisticated ac systems.

A hundred years ago, the transformer and the three-phase system made it possible to transmit ac power efficiently and economically over vast distances and to distribute the power to a multitude of users.

Since then, all aspects of transmission and distribution have developed by means of technical improvement and evolution. This ac transmission and distribution technology has made it possible to locate generating plants in optimum locations and to utilize them efficiently. This has also resulted in great environmental gains. Thermal plants have been located where they can be supplied with fuel through an efficient transportation system, thereby reducing waste and pollution. Hydro plants have been located where the hydro resources can be used at the greatest advantage.

Large generating plants have meant fewer overhead lines than a multitude of smaller generating plants would have required.

However, today's ac transmission and distribution systems are, at least in principle, based on ideas that haven't changed much since 100 years ago: to generate power, step up the voltage with transformers, transmit power, step down the voltage, and distribute power. Despite their proven advantages, it is difficult and expensive to adapt ac transmission and distribution systems to the numerous small-scale generating plants that are being built, or to the increasingly complex and variable production and load demands.

Environmental concerns and regulations also put heavy restrictions on building new rights of way and on small-scale, fossil fuelled generating plants, such as diesel generating plants.

These new trends require networks that are flexible. The networks must be able to cope with large variations in load and frequent changes in productions patterns, as well as with tougher environmental regulations. In such flexible networks, the power flow and the voltages require precise control in order to make the grids stable and economical.


As its name implies, 'HVDC Light is a dc transmission technology. However, it is different from the classic HVDC technology used in a large number of transmission schemes.

  • Classic MVDC technology is mostly used for large point-to-point transmissions, often over vast distances across land or under water. It requires fast communications channels between the two stations, and there must be large rotating units (generators or synchronous condensers) present in the ac networks at both ends of the transmission.
  • HVDC Light consists of only two elements: a converter station and a pair of ground cables. The converters are voltage source converters (VSCs). The output from the VSCs are determined by the control system, which does not require any communications links between the different converter stations. Also, they don't need to rely on the ac network's ability to keep the voltage and frequency stable. These features make it possible to connect the converters to the points bests suited for the ac system as a whole.

The converter station is designed for a power range of 1-100 MW and for a dc voltage in the 10-100 kV range. One such station occupies an area of less than 250 square meters (2 700 square feet) and consists of just a few elements: two containers for the converters and the control system, three small ac air core reactors, a simple harmonics filter, and some cooling fans.

The converters use a set of six valves, two for each phase, equipped with high-power transistors, Insulated Gate Bipolar Transistor (IGBT). The valves are controlled by a computerized control system by pulse-width modulation (PWM) Since IGBTs can be switched on or off at will, output voltages and currents on the ac side can be controlled precisely. The control system automatically adjusts voltage, frequency, and flow of active/reactive power according to the needs of the ac system.

The PWM technology has been tried and tested for two decades in switched power supplies for electronic equipment as computers. Due to the new, high power IGBTs, thc PWM technology can now be used for high power applications as electric power transmission.

HVDC Light can be used with regular overhead transmission lines, but it reaches its full potential when used with a new kind of dc cable. The new HVDC Light cable is an extruded, single-pole cable with the following characteristics:

  • Conductor: 95 mm2 aluminum
  • Insulaflon: 5.5 mm triple extruded dc
  • Screen: copper wires
  • Sheath: HDPE
  • Weight: 1.05 kg/m
  • Voltage: 100 kV dc
  • Current: > 300 A
  • Power: > 30 MW.

As an example a pair of cables with a conductor of 95 sq. mm aluminum can carry a load of 30 MW at a dc voltage of 100kV. The easiest way of laying this cable is by plowing. Handling the cable is easy. Despite its large power-carrying capacity it has a specific weight of just over 1 kg/m.

Contrary to the case with ac transmission, distance is not the factor that determines line voltage. The only limit is the cost of line losses, which may be lowered by choosing a cable with a conductor with a larger cross-section. Thus, the cost of a pair of dc cables is linear with distance. A dc cable connection could be more cost-efficient than even a medium distance ac overhead line, or local generating units such as diesel generators.

The converter stations can be used in different grid configurations. A single station can connect a dc load or generating unit, such as a photo-voltaic power plant, with an ac grid. Two converter stations and a pair of cables make a point-to-point dc transmission with ac connections at each end. Three or more converter stations make up a dc grid that can be connected to one or more points in the ac grid or to different ac grids.

The dc grids can be radial with multidrop converters, meshed, or a combination of both. In other words, they can be configured, changed, and expanded in much the same way ac grids are.

Overhead Lines

In general, it is getting increasingly difficult to build overhead lines. Overhead lines change the landscape, and the construction of new lines is often met by public resentment and political resistance. People are often concerned about the possible health hazards of living close to overhead lines. In addition, a right of way for a high voltage line occupies valuable land. The process of obtaining permissions for building new overhead lines is also becoming time-consuming and expensive.

Laying an underground cable is a much easier process than building an overhead line. A cable doesn't change the landscape and it doesn't need a wide right-of-way. Cables are rarely met with any public Opposition, and the electromagnetic field from a dc cable pair is very low, and also a static field. Usually the process of obtaining the rights for laying an underground cable is much easier, quicker, and cheaper than for an overhead line.

A pair of HVDC Light cables can be plowed into the ground. Despite their large power capacity, they can be put in place with the same equipment as ordinary, HVAC distribution cables. Thus, HVDC Light is ideally suited for feeding power into growing metropolitan areas from a suburban substation.

Replacing Local Generation

Remote substations often need local generation if they are situated far away from an ac grid. The distance to the grid makes it technically or economically unfeasible to connect the area to the main grid. Such remote locations may be islands, mining areas, gas and oil fields, or drilling platforms. Sometimes the local generators use gas turbines, but diesel generators are much more common.

An HVDC Light cable connection could be a better choice than building a local power plant based on fossil fuels. The environmental gains would be substantial, since the power supplied via the dc cables will be transmitted from efficient power plants in the main ac grid. Also, the pollution and noise produced when the diesel fuel is transported will be completely eliminated by an HVDC line, as the need for frequent maintenance of the diesels. Since the cost of building an HVDC Light line is a linear function of the distance, a break-even might be reached for as short distances as 50-60 kilometers.

Connecting Remote Power Grids

Renewable, power sources are often built from scratch, beginning on a small scale and gradually expanded. Wind turbine power generation is the typical case, but this is also true for photovoltaic power generation. These power sources are usually located where the conditions are particularly favorable, often far away from the main ac network. At the beginning, such a slowly expanding energy resource cannot supply a remote community with enough power. An HVDC Light link could be an ideal solution in such cases.

First, the link could supply the community with power from the main ac grid, eliminating the need for local generation. The HVDC Light link could also supply the wind turbine farm with reactive power for the generators, and keeping the power frequency stable. When the power output from the wind generators grows as more units are added, they may supply the community with a substantial share of its power needs. When the output exceeds the needs of the community, the power flow on the HVDC Light link is reversed automatically, and the surplus power is transmitted to the main ac grid.

Waste gas is usually burned at offshore drilling platforms, since it is too expensive, or technically difficult, to use the gas for power generation and transmit it by an ac cable to the main grid on the shore. Thus, the energy content of the gas is wasted, and the primitive burning process is a source of pollution. With HVDC Light underwater cable transmission, the gas can be used as gas turbine fuel, supplying both the platform and the main ac grid with power. The process of burning the gas in gas turbines would also produce much a cleaner exhaust than simple burning would do.

The dc underwater cable network could easily be extended to other offshore platforms.

Asynchronous Links

Two ac grids, adjacent to each other but running asynchronously with respect to each other, cannot exchange any power between each other. If there is a surplus of generating capacity in one of the grids, it cannot be utilized in the other grid. Each of the networks must have its own capacity of peak power generation, usually in the form of older, inefficient fuel fossil plants, or diesel or gas turbine units. Thus, peak power generation is often a source of substantial pollution, and their fuel economy is frequently bad.

A dc link, connecting two such networks, can be used for combining the generation capacities of both networks. Cheap surplus power from one network can replace peak power generation in the other This will result in both reduced pollution levels and increased fuel economy. The power exchange between the networks is also very easy to measure accurately.


HVDC Light technology saves the environment by replacing remote fossil-fueled diesel generators with cost-efficient transmission of power from efficient and clean, large-scale generation production units. The efficiency of a modern, large scale, thermal generating plant is usually 25 percent higher than that for a modern, small or moderate scale diesel generation plant.

HVDC Light provides a convenient and cost-effective way for connecting renewable and nonpolluting energy sources as wind power farms and photovoltaic power plants to a main grid.

The HVDC Light technology in itself has strong environmental benefits. Since power is transmitted via a pair of underground cables, the electromagnetic fields from the cables cancel each other. Any residual field is a static field, as opposed to the power-frequency fields radiated from ac cables.

Since HVDC Light transmissions are bipolar, they do not inject any currents into the ground. Ground currents can disturb communications systems or cause corrosion on gas or oil pipelines.

A pair of light-weight dc cables can be easily plodded into the ground at a cost that is comparable to or less than for a corresponding ac overhead line. As opposed to an overhead line, an underground cable pair has no visual impact at all on the landscape. Usually it is also much easier to obtain permissions and public approval for a cable transmission than for an overhead line, especially in residential areas.

About the Panelist

Lars Weimers was born in Sweden. He graduated with a Masters Degree in Electrical Engineering from Chalmers University of Technology in 1975. In 1979, he joined ABB and has subsequently held several positions in HVDC design, construction, and marketing. For the last 3 years, was been project manager for the development of HVDC Light. He is now general manager of HVDC Light, ABB Power Systems, Sweden.

Technical Articles

Updated: 2016/06/30

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