MIT Spinoff Aims to Make Solar Power Cheaper Than Coal
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of 25 percent. Solar cells tend to reflect a lot of blue light (that’s why they look blue), as well as infrared light; Sachs came up with a way to etch light traps into the multicrystalline silicon that reduce that loss of energy. That’s almost half of the 25 percent increase; the rest comes from a better way to get the electricity out of the silicon. Here, Sachs came up with a method to make the conductive silver lines on the cell’s surface, which carry electricity out of the cell, thinner and taller. At about a sixth of the width, they cast less shadow so the cell absorbs more light. And the lines can be placed closer together, which means there’s less current lost as it travels across the surface. These improvements also allow the cell’s outer layer to be thinner, letting even more light into the solar cell in the first place, which translates into more electricity coming out.
The company has a third set of improvements planned, which van Mierlo says will increase the cells’ efficiency by yet another 25 percent. But because the company is in the very earliest stages of applying for patents on those improvements, he won’t say what they are.
In fact, Roberts says, the company has a whole suite of intellectual property beyond what it will publicly discuss, all of which gives him confidence in 1366’s prospects. And while there’s one school of thought that says silicon can’t be much improved—and so bets ought to be placed on other technologies—Roberts is of the belief that, “silicon’s not done, and it’s probably going to be around for a long time.”
With the increased focus on renewable energy and reducing greenhouse gases, a lot of researchers are working on other methods to make silicon-based solar cells cheaper, and van Mierlo says his company will likely be able to take advantage of those advancements. If someone designs a better type of rooftop module, for instance, combining it with the 1366 cells could prove a win for both companies. Van Mierlo also intends to spread around the cost-cutting advantages of 1366’s technologies through licensing agreements with other manufacturers, so that the whole market can benefit from economies of scale—and in doing so will create new customers for his company. “We believe that it’s very important that we do this in collaboration with other people,” he says.
1366 is using the $12.4 million investment in part to build a pilot plant to demonstrate the its manufacturing processes. Part of the funds will also go to expanding the company beyond its current dozen employees. The next step will be to raise more money to build an automated plant sometime next year, with commercially available solar cells planned to be on the market by 2010. 1366 aims to build the cells itself, and to provide them to other manufacturers who incorporate them into solar modules for rooftops or other uses.
While rooftop installations make the most sense, van Mierlo says, because they generate the electricity very close to where it will be used, highly efficient solar cells may also be appealing to big utilities, who might find big power installations attractive if they can combine cheap land with cheap infrastructure. “We’ll probably see both of those,” he speculates. Roberts agrees.
Oh, and if you were wondering about the name, 1366 refers to the solar constant, the average number of watts per square meter that reaches Earth just above the atmosphere. That 1366 watts per square meter means that enough solar energy hits the planet in one hour to satisfy the energy demands of the entire human race for one year.