Is Solar feasible - absolutely!
Earlier today TJ wrote a post about the possibility of solar power as an alternative fuel. Now I have to admit to having a vested interest in this field as recently I began work as a Solar Analyst for a renewable energy developer. I’ve spent the last six weeks conducting studies into every aspect of the solar market and its feasibility. Although some more outlandish technologies have been overstated, the future of solar is incredibly bright.
There are four main types of solar power on the horizon. Most people know about silicon photovoltaics, which are now reaching record efficiencies of 23%. A shortage of silicon in the last few years has stunted the market’s growth, with most installations coming in Germany, Spain and California where the government subsidies are attractive to companies. Silicon companies have invested billions in increasing production however and an increase in supply could lead to much more photovoltaics being available at a cheaper price. Market predictions for 2010 PV production vary between 5.6GW a year at the low end and more than 25GW at the most optimistic, with 12GW+ looking likely. A nuclear power plant typically provides 1GW of power, by comparison.
The shortage of silicon has been good for the other three types of solar power however. Thin-film photovoltaics have been a big hit in the news, with companies like Nanosolar and First Solar promising large scale production at a fraction of the cost of silicon PV, even if it is at lower efficiency. First Solar’s Cadmium Telluride thin-film converts 10.6% of light to electricity and they are aiming for 12% by 2010. NanoMarkets projects a $12Billion thin-film market by 2013, in addition to a $4Billion building-integrated market, most of which use thin-film.
Two types of solar power that aren’t receiving as much attention concentrate the light they receive to stronger concentrations using lenses or mirrors. The first type, concentrated solar thermal (or solar baseload as some are trying to rename it) has actually been producing power in the californian desert since the eighties, by heating water using concentrated sunlight and turning a turbine using the steam produced. Recent developments have replaced the water with molten salt, which can store the heat for up to 16 hours, allowing for production of electricity even when the sun isn’t shining. An incredible 6.4GW of installed solar thermal is predicted by 2012, 14 times what is currently installed. Half of this is in the Southwestern deserts of the US and most of the rest is in Spain. Solar thermal is already cost competitive in some places.
The final piece of the solar puzzle and perhaps the one with the most potential, is concentrating photovoltaics (CPV). By concentrating the sun’s power to between 2 and 1000 times stronger than normal, the amount of photovoltaic needed to generate the same amount of electricity goes down considerably. In addition, this allows you to use the more expensive, higher efficiency III-V photovoltaics currently used by satellites in space, which have efficiencies as high as 40.7%. CPV is the least commercialised of the four technologies, with a 3MW facility in Spain testing the effectiveness of 7 different companies’ products.
Having less reliance on photovoltaic material gives CPV long term cost advantage over both types of flat photovoltaics and the lack of water needs gives a similar advantage over solar thermal.
The future of solar is very bright and with government assistance in the coming few years to help companies build manufacturing capabilities, all four of these technologies could be as cheap if not cheaper than traditional power generation by the middle of the next decade. Solar Power is ready if we are.
[image of Solfocus test CPV array courtesy of SolFocus Inc]
I’m late to the party as far as announcing the arrival of the 
