Sunday, October 22, 2006

Pounding the Table for Solar Thermal

About 90% of the interest in solar energy seems to focus on solar PV, which remains anywhere from 1.5-4 times as expensive as metered electricity from fossil fuels (depending on local rates and solar resource). But some day soon America will wake up to the fact that solar thermal energy (i.e. solar hot water) is fully competitive with fossil fuels. Federal and state subsidies (to the extent they exist) are just icing on the cake.

Yes, solar thermal still requires a relatively large capital outlay on day one, but that is balanced by the low (some might say non-existent) O & M costs for the following 20-30-40 years of system life.

Any US business in the south (and every business in CA) which uses hot water (or steam) in significant quantities should look into adding a solar thermal system to SAVE MONEY and offset fossil fuel energy use during the day.

Solar thermal generates heat (on-site) for the equivalent of 4-6 cents kWh, almost half the national average utility rate for delivered kWh. The wide range is partly because solar resource varies by location. Since solar thermal delivers heat (BTUs) not electricity (kWh), please treat this figure as a guide. While solar PV is 15-20% efficient, solar thermal systems are between 60-80% efficient.

The economics of solar thermal are so good that 3/4 of the world's installed solar thermal capacity is in China, and 25 years ago Israel passed a law requiring solar thermal on all new construction. Today 90% of Israeli households own solar water heaters. I can't think of a simpler economic argument in favor of solar thermal energy than this.


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