Over the past decade the push to develop energy sources and materials that do not use oil and fossil fuels has ramped up, partly due to an increased interest in national energy security and partly due to advances in technology.
In terms of solar technologies, the single common ingredient has been silicon, which, while stable, is costly to manufacture. Worse, the process of manufacturing silicon consumes a lot of energy. It takes a lot of heat to rid silicon of it numerous microscopic imperfections, and that is part of the reason it costs so much more to line your roof with solar panels than to fill your furnace with fuel oil.
Enter SuryaTech, an idea-phase solar technology company formed by Princeton university professor James Sturm and two of his Ph.D. students, Yifei Huang and Soshobhan Avasthi. SuryaTech is working on a way to make solar cells just as strong and stable as silicon, but for far less money and a lot less heat.
SuryaTech took the $10,000 second prize at the 2011 Keller Innovation Forum at Princeton University on April 7 (see story on page 34). Its idea: to couple silicon with organic materials to create “grid parity,” the point at which the cost of solar and the cost of fossil fuel will even out, in three years as opposed to ten.
In layman’s terms, it means that SuryaTech has developed a way to combine traditional silicon solar cell technology, which offers stability and efficiency, with the types of materials used as the building blocks of plastics, resins, and polymers. These materials, organics, are not as stable or reliable on their own as silicon, says Huang, but they are far cheaper to manufacture.
For one thing, they require a lot less energy to make. Silicon, Huang says, is one of the most abundant materials available for high-tech manufacturing today. Made from sand, silicon is heat-formed into a substance that is strong like glass and durable like plastic. But because it is made from sand, Huang says, it is prone to tiny imperfections that can only be removed with extreme heat — 900 degrees Celsius is the typical temperature when it comes to manufacturing silicon solar cells. That’s 1,652 degrees Fahrenheit, and as you can imagine, Huang says, it takes a lot of energy to maintain such temperatures.
For another thing, silicon solar cell manufacturing requires a “clean room,” which looks like — and requires the same procedures as — a sterilized biotech lab. Clean rooms require special construction, special clothing, and a steady supply on ultra-pure gases to keep dirt, dust, and everyday air out.
Added up, Huang says, the costs to develop fully silicon solar cells can be heavy. Those costs are passed onto the consumer who, in turn, is forced to make decisions based on economics, rather than on what he believes is the right thing to do. This is the essence of grid parity — the cost of buying and using solar versus buying and using fossil fuels. Solar technology will achieve grid parity when the cost of using solar equals the cost of using oil.
Huang estimates, based on the timelines of previous tech trends, that traditional solar production will reach grid parity in another 10 years. SuryaTech, on the other hand, has found a way to eliminate the permanently high temperatures from the production process and the need for a clean room. Coating the silicon with organic materials can be done at 25 degrees Celsius (a mild 77 degrees Fahrenheit), Huang says.
Though it is in its earliest stages now, SuryaTech has managed to make a prototype — and working — model. It was produced by standard silicon manufacturing procedures because the company does not yet have the $680,000 it seeks to complete the first stage of its technology. Huang says that he and his partners are not looking to make an end product, but rather to develop the technology and then look for a manufacturing partner.
Huang, who was born in China and moved to New York at age 11, knew at an early age that he wanted to be in the hard sciences. His father, a math professor, wanted him to get the best education he could. Huang was enrolled in the Bronx High School of Science and then went on to study electrical engineering at Cooper Union. He came to Princeton for his Ph.D. specifically because he liked the research Sturm was doing in renewable energy. Huang had become interested in renewables while interning at IBM Research Lab.
Huang’s Ph.D. colleague Avasthi, who expects to receive his Ph.D. in electrical engineering from Princeton this year, holds a bachelor’s in electrical engineering from the Indian Institute of Technology in Kanpur. He also is an avid runner. His major area of research is semiconductors with a focus on solar cells.
From this vantage point, Avasthi thinks a lot about renewable energy. According to his blog, Insights, Diatribes, and Monologues (insightsdiatribesandmonologues.blogspot.com), the sun is “the ultimate source of all energy on the planet. On an average day the sun beats down around 174 pentawatts of power; that is more energy in one hour than what the total energy consumed by the world in 2002.”
Like Huang Avasthi laments the ease and power of petroleum and fossil fuels. “In some sense we have been spoiled by oil,” he says. “Our requirements of energy density are just way too high and unfair.”
Sturm has been teaching at Princeton for more than a decade and has more than 20 years experience in semiconductor devices and physics and integrated circuit fabrication. Born in Berkeley Heights, he earned his bachelor’s in electrical engineering from Princeton in 1979. He earned his master’s (1981) and Ph.D. (1985) in the same subject at Stanford, where he later spent a year doing research. He has worked at Intel, Siemens, and Western Electric. He will remain part of SuryaTech
About a year ago, Huang says, he, Strum, and Avasthi were looking into ways to bring down the cost and the need for extreme heat in the silicon manufacturing process. One of the things they tried was coating it with an organic material. At first, he says, they did not know the possibilities, but they took a good look at it and realized they had something.
The university is not the only entity that agreed. Since showcasing SuryaTech at the Keller Innovation Forum Huang says the company has been talking with investors eager to see if the company can make good on its promise. If it can, the lament that renewable energy isn’t worth it could fade away in three years.