Solar Sunny Days

Technology Review, USA
September 2005

By Spencer Reiss

Solar energy is finally getting its day in the sun, buoyed by renewable-energy incentives and snowballing economies of scale. Former Stanford University professor Dick Swanson, the founder and CTO of Sunnyvale, CA-based SunPower, says there's still an important place for the industry's incumbent technology: crystalline silicon.

Sharp, GE, Sanyo--you've got some very big competitors. Is that intimidating?
Of course it is. This industry is maturing fast, and it's going to be harder and harder to keep up if you don't have the resources to grow with the market. There's also a new wave of more aggressive entrepreneurial companies like Q-Cells in Germany. Thanks to a very aggressive incentives program, it's now the world's biggest solar market.

Is traditional silicon technology losing ground to thin-film and other new nanosolar technologies?
There's been a common belief in the solar industry that growing silicon crystals and then cutting them up with a saw is just hopelessly expensive. Most people are surprised silicon lasted as long as it has. But for the next ten years at least, it looks like silicon is going to continue to dominate, if only because of all the new capacity coming online.

How much further can you push silicon's efficiency?
Today's standard commercial module converts about 12 percent of the sun's energy into electricity. The record in a laboratory is 24.9 percent, so there's plenty of room for improvement. Our highest-performing commercial module today is 18 percent efficient, meaning roughly 50 percent more power for a given area than the industry standard. We've been able to put all the electrical contacts on the back of the cell, which eliminates what's known as shading.

Why do buyers settle for less efficient cells?
For now, anybody that has anything that even looks like a solar module can sell it. We're all running our lines flat out, and buyers take what they can get. But higher efficiency means we can charge a premium per watt. For a remote telecom site where you have to helicopter everything in, obviously the less material you need to achieve your rated power the better. On a suburban rooftop, that matters less.

But it does matter?
Absolutely. Roof space is finite. Installation costs are pretty well fixed. So ultimately the only way to be more cost effective will be to squeeze more electricity out of your panels.

Government incentives are clearly still a key element.
We still need them, but not necessarily for very long, and especially not in places with high retail electricity prices and a lot of sun. The industry's current momentum should drive things to about half the cost of where we are right now. That will open up new markets, which will drive costs even lower. But it's a step-by-step process.

CATEGORY_KEYWORDS:Energy Environment & Agriculture

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