Solar power in Seattle
The Earth gets so much energy from the sun in an hour that the entire world population could live off of it for a whole year. That includes the population of the U.S. — and every one of us consumes 11,000 Watts (about twice as much as a person in Japan or Denmark or Spain). Photovoltaics (solar cells that produce electricity) could harness this incredibly renewable solar power but are combating inefficiency and production cost. Expensive crystalline silicon based PV cells have now broken the 40% efficiency barrier — the ratio of electrical energy out over light energy in. Unfortunately, they require the mining of rare metals like indium and gallium. But all of the US energy needs would be met by an array of those PV panels the size of Delaware. The leader of solar cell manufacturing is Asia, but most deployment is happening in Europe, especially Germany. If you have a grid-tied PV panel on your property in WA, Utilities will pay you for the excess energy you produce.
All these things I learned at the Solar Day yesterday afternoon, the first event of its kind — a free public outreach day — that the IEEE Photovoltaics Specialist Conference sponsored. I hope they do it again, and I hope more research conferences make those kinds of events happen. But unfortunately for the organizers, a lot was going on in Seattle today, what with the Slut Walk / Pride Picnic on Capitol Hill, and the Fremont Solstice Parade. And Fathers’ Day, and probably a thousand other things. So the WA Convention Center felt a bit empty.
Hugh W. Hillside of UW’s Department of Chemistry talked about the high cost of solar energy production (currently at $4 per Watt) and the need for our support for fundamental and engineering research, and government incentives to jump-start an economy of scale for solar cells. His group is working on nanocrystal inks (12% efficient) that you could paint over surfaces to create a PV cell. And he has great hopes for printable solar cell technology.
Kristina Knesting, who is studying for a PhD and doing research at the Ginger Lab at UW showed me a new kind of PV cell that UW chemists and material scientists are working on — a flexible bio-cell made of a polymer blend. It’s only 3% efficient right now, but it doesn’t use any rare metals and therefore would be both much cheaper and less relying on a non-renewable resource.
Her own research, however, is about the traffic jams inside the semiconductors (like silicon) that make up the bulk of a solar cell. Backing up, how a solar cell works is by placing a semiconductor material mixed in with impurities in the path of sunlight. The sunlight energy is partially absorbed by the material, and that wrangles some of its electrons free of the atoms where they normally reside, leaving behind “holes”. What needs to happen next is for the electrons to flow in an organized way to actually produce current. This part — called charge carrier separation — is the traffic jam avoidance that Knesting is working to improve.
I missed the high school solar power competition itself, but the projects participants and their inventions were still hanging around in the afternoon. Ballard High School presented a solar-powered car that can go up to 60mph.
There was also a robotic solar clock, built on top of a Lego Mindstorms brick, that turned towards the sun to power itself. And Sealth International High School presented a solar-powered umbrella to charge cell phones and iPods, among other projects.
I asked Brent Nelson of NREL what the biggest news will be at the coming PV conference. His answer was: there’s always more technology. “The economists will tell you that the cost of solar energy is going down,” said Nelson, sketching a graph on a copy of the day’s schedule. “But what they don’t tell you is that it’s because of all the new technology.”
What it takes to succeed in the solar power business, said Nelson, is “both good tech people and good money people”. So many companies fail, he said, because one side underestimates the importance of the other and pushes the good people out.
And then, as the day’s events came to a close, an interesting thing happened. I got a press pass for the actual IEEE-PVSC research conference that starts tomorrow. This is pretty cool and I now feel totally legit as a — what? — science journalist? We’ll see what tomorrow brings.