And a London doctor consults Solar Advice for Free...
After an active debate for two years, Great Britain will begin offering a feed-in tariff (FiT) for residents and businesses producing energy with solar photovoltaics (PV).As of today, the tariff is set to peak at 36.5p (about 60 US cents) per kilowatt-hour produced. However, PV trade organizations in the UK--both profit and non-profit--are suggesting the tariff be bumped up another 10p to sufficiently jump start solar power in England. They point to the success of Germany which had both an attractive tariff and low-interest loans that stimulated tremendous growth for solar earlier in the decade and continuing today.
About ten days ago, Solar Advice for Free was contacted by a doctor in London who is considering taking the solar plunge. With the Dr. Stein's ascent, our exchange follows.
Saturday, Oct. 24, 2009Dear David
Your blogs are excellent!
I am a doctor but am becoming very interested in solar energy after watching a great docudrama called "Age of Stupid" that has caused a seismic shift in my awareness of global warming.
London (where I live) has little sunshine; nevertheless I heard that it is possible to generate solar electricity even on fairly overcast days. Is this correct or should I give up on the idea of promoting solar energy in England?
I would be most grateful if you could you point me to a minimum sunshine requirement before installing solar panels on my roof.
All best wishes
Mike
Dr. Mike Stein
Sunday, Oct. 25, 2009Dr. Mike: Thank you for your kind words and for your interest in solar photovoltaics (PV).
Funny you should say London gets little sunshine. I was in Richmond in '94 for my goddaughter's confirmation and the very day I got there we stood in line to get into Wimbledon "after tea" time. It was sunny and stifling hot and it dawned on me that evening that I had traveled all the way from San Diego to England to get a sunburn!
Anyway, although I am a strong advocate for solar power I cannot mince words: You simply will not get nearly as much power from a PV installation in the UK than you would here in the American Southwest. However, you will get some appreciable production and always remember that the source is always free, as reliable as tomorrow's sunrise, and clean. During summer when your days are quite long and you to get some real solar irradiation, PV panels will kick ass, as we Americans say. But even during cloudy weather, some production is made with standard silicon panels. Some other PV technologies will work better in indirect, diffuse light.
While standard panels, made from high-grade crystal silicon respond mostly to red/infrared light which is prevalent during high, mid-day sun. Amorphous silicon (implying non-structured chemical combos) is a thin-film technology that often has a dual- or even triple-junction structure: That is, instead of just responding to red/infrared, it also responds to the blue band of the spectrum (morning daylight) and green/yellow (later afternoon). Thus the triple-junction cell begins producing a little earlier in the day and produces a little longer in the afternoon as opposed to a standard crystalline cell. There are several thin-film makers using various chemical layers but UniSolar (out of Michigan) makes the oldest triple-junction PV cell in use. UniSolar used to sell their technology as framed modules, laminates and even shingles (mimicking asphalt shingles) but only produce the laminates now which can be bonded to steel-seam roof pans (metal tongue-and groove) or bonded to single-membrane roof material (common on newer large, flat industrial buildings). Ascent Solar (Colorado) is about to come out with a line of thin-film PV that could be an alternative for you. Either UniSolar and Ascent can be found online.
The downside of most thin-film is that it is less efficient than silicon panels, thus requiring more roof or ground space to get the same output. (Generally speaking, in temperate latitudes in summer at high noon on a clear day the sun will produce 1000 watts of electricity per square meter. Today's most advanced crystalline panel-available for sale-is about 22% efficient (SunPower). Most silicon panels run 13-16% efficiency and are the most affordable. Thin-film PV runs between 5-10%. First Solar (Arizona), the most popular thin-film PV is about 5% (and cheapest per-watt cost in the world) and UniSolar is about 7%; I haven't yet heard what Ascent's will be. (Ed note: Visiting Ascent's exhibit at Solar Power International last week, the company is claiming 10-12% efficiency now and adding 1% annually for the near future.)
I read last summer the UK is considering a very attractive feed-in tariff as high as about 69 cents per kilowatt hour produced by solar power[See updated information at beginning of this article]. This would be a whopping incentive. The reason Germany's PV movement was so strong earlier this decade is because the government gave a 57-cent incentive and low-interest loans that customer's could be paid with their utility bill. Last year Germany surpassed Japan as the leader of the world in PV installations (California is a distant last but way ahead of the rest of the US). China recently made a major commitment to solar so they could be #1 before long.
Should you be an advocate for solar? Absolutely. Even with limited sunshine this source of power never needs to be mined nor drilled for nor nuclear reacted to produce electricity. And, as I said earlier, it's as reliable as tomorrow's sunrise. Cheers!
David Brands
Sunday, October 25, 2009Dear David
Thanks for your words of encouragement and excellent information!
I always thought that it made sense to tap into the earth's largest off-shore nuclear power station so it's good to have that confirmed! I had been looking at wind and tidal power but am persuaded that solar makes much better sense for our little planet in the long term.
My intention now is to buy a solar system for my apartment (luckily I own the roof) and start reading about the science behind solar energy; and to do a correspondence course. (Have you thought about doing a series of webinars for beginners like me?)
Very good to be in touch with someone so passionate about solar!
All best wishes
Mike
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