As usual I'm late to the party, but I wanted to post a few thoughts about Nanosolar. On December 18, NanoSolar CEO posted the following on his company's blog (tangent: now that's message control):
After five years of product development – including aggressively pipelined science, research and development, manufacturing process development, product testing, manufacturing engineering and tool development, and factory construction – we now have shipped first product and received our first check of product revenue.There was a great deal of press, both mainstream and non-traditional, around this announcement.
The thin-film technology and industry isn't particularly new (given the lightning fast evolutions in the solar segment), and a great overview of the industry is available from Earth2Tech. What is unique about Nanosolar is that it has figured out how to manufacture and mass produce this thin-film technology. Two strong overviews of the Nanosolar technology are available from Popular Science magazine (where it was Innovation of the Year) and Celsias:
Ultimately, the reason for this excitement is understandable:
[Nanosolar has] successfully created a solar coating that is the most cost-efficient solar energy source ever. Their PowerSheet cells contrast the current solar technology systems by reducing the cost of production from $3 a watt to a mere 30 cents per watt. This makes, for the first time in history, solar power cheaper than burning coal.The one topic lacking from most of these articles, however, has been a discussion of the sunlight-to-energy efficiency concern. Traditional crystalline-silicon PV panels have an efficiency ratio of anywhere from 15%-17% (with some claiming up to 19%). Thin-film solar achieves half of that energy conversion. Thus while installation costs drop, the necessary installation size and area necessary (and thus overall system costs) rise significantly. Information from Nanosolar is difficult to find, but Celsias does some great research in this post:
Wikipedia has an updated snippet that adds to the mystery: "The company uses Copper Indium Gallium Diselenide—which can achieve up to 19.5% efficiency—to build their thin film solar cells."However, a commenter on the same post, Tom Rust, had an interesting follow-on, which I wanted to pass on:
Just because the material can achieve 19.5% efficiency, doesn’t necessarily mean that they are in practice. A little digging and I found a PDF in German... the document indicates they have an efficiency rating of 13.95%. This is pretty standard.
Although I applaud Nanosolars efforts to bring low cost PV to market, users should be clear about modules cost vs installed cost vs long term power output cost. I read the same article mentioned, and the 13.95% is for a 0.5 square cm test cell - NOT production. They hint at 10% modules in production. Miasole has had trouble achieving production volumes in CIGS and has only a few 9% modules - most are 6% or less.Ultimately, this is a great year-end development for Nanosolar and the solar industry in general, justifying some of the tremendous excitement and run-up in solar company valuations, and demonstrating why solar experts and some renewable energy thought-leaders have been so bullish on the space in the past few years.
CIGS also has relatively poor lifetime - NREL reports of past efforts have shown 1-2% degradation per year, vs 0.1-0.4% per year for silicon. So modules will likely have only a ten year warranteed lifetime.
My guess is when production finally stabilizes they will be around 6-8% efficiency.