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Here comes the sun

Anthony Doman - Popular Mechanics
Tue, 25 Oct 2005

Despite a soaring oil price and a panic-stricken planet scrambling to counteract its profligate use of energy resources, there is a glimmer of sunshine. And sunshine is all it takes, says an enterprising South African academic who is sitting on potentially one of the biggest solar energy breakthroughs to date.

Against a background of dwindling, non-renewable fossil fuels and growing concerns about environmental impact, it’s not just the Greens who are seeking energy alternatives. Even the oil companies are feverishly joining the hunt for sources of renewable energy. Options range from exploiting biomass to harnessing the power of the oceans, wind, and sunlight.

But they all usually come up against one serious drawback: cost.

It’s taken 12 grinding years to come up with a workable solution. And now there is worldwide interest and support for the technology.

Just one-quarter the cost and significantly more efficient than conventional solar panels, the thin film technology is jointly owned by the University of Johannesburg and the head of its physics department, professor Vivian Alberts.


This article has been reproduced from the SA edition of Popular Mechanics.

Professor Alberts has spent most of his academic career focusing on silicon, the material that forms the rock — excuse the pun — on which the microelectronic industry has been built. The past decade of that career has been dedicated almost exclusively to finding a more efficient substitute that could be used in solar panels.

Glaze lightly, bake well

Solar cell technology has remained essentially unchanged since the phenomenon was first noted in the 1800s. The standard for today’s devices is still the silicon-based panels that have been steadily refined over the past half-century. Present conversion efficiencies are between 10 and 15 percent. In direct sunshine you can bank on between 100 and 150 watts per square metre of panel.

How to improve on that? Consider this telling comparison: a typical conventional panel uses silicon slabs over 350 microns thick because of the material’s poor absorption properties; the Alberts method produces a five-micron film. That’s a quarter of the thickness of a human hair.

So it’s thinner. That doesn’t necessarily make it better. But it is. “Let me put it this way,” says Alberts. “From the solar energy point of view, what we have developed is the best-absorbing material known to us.” Not only that, but it’s cheaper to produce.

He is talking about a patented semiconductor material, copper indium gallium selenium sulphide or Cu(In,Ga)(Se,S)2 for short. Five elements that, taken separately, are pretty pointless as collectors of sunlight. But then they’re subjected to a bit of high-tech alchemy… or should that be domestic science?

“You know, it’s a recipe… the whole thing is much like baking bread,” he says. “You start off with ingredients that have certain characteristics, and after mixing, preparing and baking you have a product whose characteristics are completely different to what you started with.”

Professor Alberts says the thin film technology he and his team developed can generate up to 150 watts of electrical power at a cost below R10 per watt peak. He adds that it has demonstrated not only high efficiency, but also long-term performance stability. “The pilot plant demonstrated that these thin film solar modules could be produced by highly scalable and proven industrial technologies such as physical vapour phase deposition and diffusion processes.” Commercial-scale thin film modules are being produced with output powers between 10 and 40W in direct sunlight.

Quoted costs of R10/Wp look highly favourable against the cost of “traditional” electricity. And better still against the R35 per watt production cost of conventional modules. The import price locally of a silicon-based 50W solar panel is about R2000 (R40/Wp).

[GENI editor's note: see universal currency converter here]
[As of 2006-04-17, that works out to about $6.58 for a 50W module, or $0.13USD/watt production cost.]

Small beginnings

Because development didn’t start in the research labs of a huge multinational, but in the often cash-strapped confines of a university, the early stages looked a bit Heath Robinson-ish. “In our labs, nothing is standard,” Professor Alberts says. “The thing is, we have a need for equipment that exists, but is being used for another purpose altogether. You cannot simply go to a company and say, 'Build me a diffusion furnace'.

“So everything is more or less custom built.”

In the early days, custom built meant scavenging, begging, and occasionally getting very, very lucky: “When the CSIR closed down certain strategic facilities in the early 1990s we were lucky enough to get some redundant equipment. Of course, it was not designed for our purposes, but we were able to remodel it to create something very useful.”

Eventually, the Department of Science and Technology’s Innovation Trust Fund granted them R13,5-million to put together a pilot plant that would demonstrate the technology’s potential for scalability. The Minister of Science and Technology officially opened the plant on the old RAU campus in November 2004.

The early fittings are a far cry from the comparatively massive modern equipment in the current pilot production plant. Gleaming stainless steel, comprehensive computer control and forced ventilation are signatures of the new pilot plant — sterile is the word.

The metals are deposited on a glass substrate by sputtering, a standard industrial process. (Sputtering is used commercially for reflective coatings, for instance.) The coated glass is then reacted in a diffusion furnace with specialised gases that transform the metallic layers into high-quality semiconductor films.

Although Professor Alberts spearheaded the process, he wasn’t entirely alone. “Naturally, I worked with a lot of students during the past 12 years. And there is one critical person, Erick Scholtz, who has been supporting me since 1993. He is my technical guy. He’s the one who keeps all the equipment functioning smoothly.”

Into production

The University of Johannesburg and Professor Alberts recently established a company, PTIP Proprietary Limited, that houses all the intellectual properties related to the photovoltaic technology. PTIP recently signed a licence and technology transfer agreement with a prominent German company, IFE Thin Film Technology.

The German company has been involved in renewable energy for more than 25 years and is ranked as the biggest silicon-based module manufacturer in Europe.

The licence agreement grants IFE a non-transferable, non-exclusive, right to construct and operate a manufacturing plant producing 25 MW of solar panels per annum — half a million 50 watt modules with a typical size of 120 x 50 cm.

Investment for the first 25 MW phase is €25 to 30-million. Production is scheduled to start in the fourth quarter of 2007, and the intention is to increase capacity rapidly once the initial phase achieves certain performance levels.

At the time of writing, discussions were being held with a second German company, which is ranked among the top three producers of silicon-based cell in the world.

“So in a way those perceived to be our biggest international competitors became our strategic partners!” says Professor Alberts.

International licences will hold for five years from now, during which period a South African consortium will also put together a local manufacturing facility. The intention is that, during the initial five-year period, technology transfer will take place between Germany and South Africa to enable the setting up of a South African production facility.

“It wouldn’t be practical to set up here in South Africa right now for several reasons. We do have the raw materials and will also have to import all the critical production equipment from Europe, which poses considerable technical risks at this stage. We also don’t have access to world markets to the same extent as the companies we have become involved with. Once the technology is established and distribution networks have been established, it’s a different story, of course.”

Future possibilities

The government has committed itself to finding clean alternative sources of energy, having targeted four percent of total energy production from renewable sources by 2012. Solar energy has a significant role to play here, and even for those millions of South Africans with no access to the national electricity grid. The prospect of cheaper solar technology will touch their lives, too.

Long-term, there are possibilities of a grid connection arrangement, typified by the German market. There, people are compensated for connecting their solar systems to the power grid and feeding in clean power, say Alberts. “It is possible to buy a solar farm. The owners make more money from harvesting solar energy than from using the land for traditional farming.”

Although currently the technology is being developed on glass, other possibilities beckon. “The Central Energy Fund is keen to develop this for use on rollable stainless steel, for instance. And we have already deposited the thin film semiconductor materials on polymer, which can take on any shape. When it comes to the substrate, it is really all just about adhesion.”

The product’s flexibility offers the potential for many niche applications. It’s hardly surprising that the arms industry has taken a keen interest. “In concept, the external surfaces of the soldier’s battledress can become an energy system. You can see the implications for mobility — no need to carry batteries.”

Professor Alberts is acutely aware that, although he has developed a product with tremendous commercial potential, there is stiff competition out there. “The likes of Sharp, Shell Solar Industries and BP are already active role players in the market and will certainly invest billions of dollars into the technology in the near future. ”

But for the moment the sun is certainly shining brightly for Photovoltaic Technology Intellectual Property (Pty) Limited. And, understandably, they’re making hay.


Updated: 2003/07/28