DLD08 A series of solar energy power stations in the Negev could supply all of Israel's power needs - or, if you wanted to be really ambitious, you could supply all of the world's electricity needs with the aid of slightly under 10 per cent of the Sahara. So says Professor David Faiman of Israel's Ben-Gurion University, man with a plan and current proprietor of the largest solar energy dish in the world.
The Negev Desert dish is operated by Ben-Gurion's National Solar Energy Center in the Negev, and speaking at the DLD (Digital Life, Design) conference in Munich earlier this week, Center director Faiman tallied off the economics of solar power generation. Conventional solar panels are expensive, because photovoltaic cells, which combine the capability to collect energy and to convert it to electricity, are themselves expensive.
One route to cutting the cost is being pursued by Nanosolar (Nanosolar director of products Roby Stancel was speaking at the same session as Faiman), which is printing the cells onto thin sheets. Taking a different approach, the Negev plant uses large curved glass mirrors to focus sunlight onto a 10cm x 10cm area of cells. Both routes have their advantages - if Nanosolar's price promises are fulfilled, then solar sheets could be cheap enough and thin enough to put anywhere and everywhere, while the dish approach could be applied cost-effectively to large scale power plants, up to and including 10 per cent of the Sahara. "We're effectively reducing the cost of photovoltaic by a factor of 1,000," says Faiman.
Cost has been a major brake on the take-up of solar power, and Faiman points out that solar has only caught on in countries like Germany, where it is subsidised. There, electricity suppliers are obliged to buy in surplus power from domestic solar systems at more than the market rate, which makes solar an attractive option for German consumers, despite Germany being relatively unattractive from the point of view of available sunlight. According a Faiman a German rooftop would produce the equivalent of one barrel of oil over two years, whereas the same roof in the Negev would do it in one.
This favourable economic climate also means that one of Nanosolar's first contracts is for a 1MW solar power station in Eastern Germany.
Faiman explains how solar could fix Israel's power requirements in 1 Gigawatt units. A single 1GW solar plant would be comparable in output to a large conventional power station, and would cost €1 billion to build. One plant would produce 2 Terawatt Hours of electricity every year, which would be enough to cover annual growth in Israel's power demand. With each plant producing the equivalent of €200 million, the first five plants pay for the sixth. Assuming a 30 year lifespan for each plant, in year 29 you have to start building two per year (unless, presumably, you think you've got enough electricity by then, or you've run out of customers and/or desert).
"This works after a fashion anywhere except Antarctica," says Faiman.
The amount of space the plants take up will depend on the efficiency of the cells - Faiman sees cells of 60 per cent efficiency being feasible, and it ultimately being possible to build 1GW plants on 5 km. sq. apiece.
Gotchas? Solar doesn't work at night, and Faiman concedes that storage of energy is therefore an issue. But if, say, you had a country that was switching over to electric cars, then much of the power for transportation would effectively be stored in batteries. Faiman also suggests that solar power could be used to split seawater into oxygen and hydrogen, giving you a supply of clean and portable fuel. This possibly presents a snag for anybody planning Sahara plant, but hey, Libya has a coastline and seawater, and Gaddafi's on our side now, right? ®