Boosting Transmission Capacity, Redux
Oct. 14, 2010 - Phil Carson - intelligentutility.com
The transmission system sees the lion's share of power per node and, thus, revenue, so it follows that it's been the recipient of "smarts" all along. That's a tradition based on return-on-investment, among other things, according to Merwin Brown, director of electric grid research at the California Institute for Energy and Environment (CIEE), University of California, Sacramento.
Fast forward to today: As the grid has grown larger and more complex, it needs new lines, existing lines must acquire flexibility to integrate new power generation and lines need to operate closer to capacity. Thus the focus of current research in this area, Brown told me earlier this week.
While integrating renewable energy is one modern driver of research efforts, various historical factors—including regional electricity markets—also drive the quest for improving the transmission system, according to Brown.
"We've been making a 'bargain with the devil,'" Brown said. "As utilities imported lower cost energy from greater distances, we've settled for a highly complex, highly integrated system that is becoming more difficult to manage. Every decade or so, for instance, there's a big blackout somewhere. In the West we had one in 1996, caused by a low-frequency oscillation. It's become clear that huge systems are fundamentally unstable, unless you pay a lot of attention to them."
That has driven transmission smarts long before "smart grid" became a fashionable phrase, Brown added.
Going forward, large system instability calls for new technologies that can read a variety of power quality variables, predict likely outcomes and enable very rapid decisions. Ultimately, automated decisions will be required to head off faults that could propagate at the speed of electron into dreaded blackouts.
One of the grid's nemeses—low-frequency oscillations—Brown likens to "great white sharks."
"Well, now we've got goggles"—phasor measurement units and synchrophasor data—"and we can see the sharks," he added. "Now what do we do about them? That's our current work. Technology can ward off the great white sharks."
The smart grid research agenda, of course, goes far beyond such wide-area visualization "goggles." Brown cited three primary areas that CIEE and its R&D peers across the country are pursuing: hurdles to new transmission lines and rights-of-way (RoW); integrating renewable energy sources with unique characteristics; and optimizing existing lines.
Among the hurdles to siting new lines, Brown named a few: proving need and value, distributing benefits, allocating costs, assessing and mitigating environmental impacts and gaining approvals from multiple jurisdictions. The cost and timeframe for new lines is impeding California's renewable energy policy goals, he added.
Among research objectives funded by the California Energy Commission is the development of a "stakeholder siting tool" for new transmission lines and rights-of-way to raise awareness of choices and trade-offs in the process, so that engineers and the public alike can grasp outcomes and unintended consequences. Another tool under development is aimed at analyzing the cost allocation and strategic benefits of new lines.
Yet there are limitations to technology in this application, he acknowledged.
"The siting of new transmission corridors is difficult to tackle from a technology point of view," Brown said. "Those decisions are more of a societal challenge."
But analysis tools such as these could bring rationality to the process, allowing stakeholders to plug in alternatives at each juncture and explore the ramifications. That might help bring order to the scrum that often characterizes such processes, he said. The California Energy Commission (CEC) has funded development of such a tool, for obvious reasons.
After all, in what I've dubbed "Brown's Law" he said that "every transmission line that gets sited makes it that much harder for the next one."
Tomorrow we'll look at four qualities of renewable energy (RE) that make RE integration into the grid a major focus of research, as well as work on optimizing the capacity of existing lines.