Solar without silicon Prof. Michael Graetzel has invented an entirely new method of solar energy production which mimics plants and uses no silicon. He tells "Globes" how he developed it, and how Israel stands to gain. by Gali Weinreb http://globes-online.com/ April 16, 2008 One of the constraints holding back the development of the solar energy market is the scant availability of the primary raw material used in producing cells that convert solar energy to electricity - silicon. Several other industries also compete for this material, and each producer can choose which one he gives priority to. As a result, every photovoltaic cell produced anywhere is snapped up, and with demand now outstripping supply, solar energy is now waiting for an alternative. Prof. Michael Graetzel of Switzerland has come up with just such an alternative - photovoltaic cells (the panels on rooftops that convert solar energy into electricity), that do not use silicon at all. They work differently - by mimicking the photosynthetic mechanism through which plants convert sun rays into energy. These cells, called "dye cells", could, some experts feel, provide a cheaper and perhaps even more efficient alternative to solar power production - they may perhaps provide genuine commercial competition to oil. Last month, Graetzel won the Technion Israel Institute of Technology Harvey Prize for science and technology, an award which has been given annually since 1972 to outstanding scientists. 11 of the winners later went on to win the Nobel prize. Oil as a reminder "I began my serious research in the 1970s during the oil embargo," says Graetzel in an exclusive interview with "Globes." "One could say that it was a window that opened briefly and showed us how the world would look on the day oil ran out. Alternative energy received considerable research funding at that time, but once the crisis passed, the interest in the field plummeted and the funding stopped. Despite this, I continued my research out of curiosity - I wanted to know whether the amazing process of energy production by plants could be imitated. And the technology has now reached maturity just when it's most useful, both because oil is indeed on the verge of running out and because of the fears of pollution. This goes to show that basic research shouldn't be held back." Globes: What, essentially, was your breakthrough? Graetzel: "When I began the research, it was known that when energy like that of the sun hits titania, which is a white pigment, it can be broken down into hydrogen and oxygen. Not all that efficiently, but it can be done. Later, we realized that for the sake of efficiency, the particles had to be made smaller, but reducing them to nanometer size made them transparent, so we coated them with a metallic paint (from which the dye cell industry got its name), just like the chlorophyll in plants; when you stimulate the color with light energy it loses an electron which is transferred to the titania, creating a charge there. "One of the big questions was what made the electrons gather in the cell and stay there. Gradually I, together with several other scientists in the field, among them Professor Arie Zaban, a specialist in nanotechnology from Bar Ilan University, figured out how it worked and used this knowledge to improve the cell." Graetzel says that today, "we make a distinction between two functions - electron release and current accumulation. The electron is created in the color and transferred by the titania's nano-crystals to the other side of the cell. Separating out the variables enabled us to use substances far less pure than those in a silicon cell. It also gives us the flexibility to implement the idea in all kinds of ways. There are a number of companies developing cells like these, and each one does it slightly differently. This is an important competition in which the best will win." How does the Israeli company 3G Solar differ from the other companies developing products on the basis of your technology? "They showed me a product that looks really good; it produces a very powerful current efficiently, using new materials that reduce the risk of corrosion." How does the dye cell compare with oil and, on the other hand, silicon in cost of use? "There's an enormous demand today for solar cells, largely as a result of the introduction of a law in countries in Western Europe and in parts of the US which provides that electricity companies have to purchase from consumers any surplus energy produced using solar panels. I believe that even without subsidies, we are now as competitive as oil in countries that have a lot of sun." And what about Israel? "Israel will need around 15 kilometers of coverage, not necessarily all in one place. I saw that you have kilometers of desert in the Negev region, and that will certainly suffice," he says. What is the view of Israel today in the solar energy world? "Solar water boilers are a reminder that Israel was once the standard bearer for solar energy. Today, the Weizmann Institute has several highly unique devices in the field, but you are progressing slower in the implementation of photovoltaic cells for the home. There is no government support - apparently politicians have other things on their minds. If there were at least some encouragement, the solar market here would explode, since this is a country with plenty of sun." Does your house operate on solar energy? "I'm about to install my first dye cell. I will also use it to charge the electric car that I'll be getting in the near future." Going where no electricity authority has gone before 3G Solar Ltd. (formerly Orion Solar) graduated from the Incentive Technological Incubator in 2005 and is currently funded by US VC technology fund 21 Ventures LLC. Sheldon Freedman, an Israeli-Canadian partner in the fund, promises that it will make at least six more investments in Israeli companies in the near future. "Companies operating in the field in Silicon Valley now have market caps running into hundreds of millions of dollars, despite their disadvantages - plants that are very expensive to build, expensive raw materials, and products which are only selling thanks to the subsidies they're getting. With us everything is the other way round - the product is cheap, the raw material is cheap, and the plant is relatively small and simple," he says. Although 3G Solar has not yet produced a commercial product and doesn't even have an operational prototype, it expects to have these in place within the next few months and begin commercial production in 2009. Most of the players focusing on solar energy have earmarked it for developed countries, which subsidize the use of green electricity. Graetzel also considers this the primary market for his technology. 3G Solar, on the other hand, has set its sights on another market. "In places like Eastern China or Africa, where there is no electricity grid and people either sit in darkness or use generators, a product like this can supply these people with electricity at the same price as they would have got it from an electricity company, but without having to connect them to the grid. Governments might even subsidize the products because it contributes to productivity in those regions," says Freedman.