This is an excerpt from EERE Network News, a weekly electronic newsletter.

November 24, 2004

Study: Worldwide Use of Solar Thermal Energy Underestimated

Photo of a solar collector, consisting of 20 parallel glass tubes, mounted on a roof

One type of solar energy collector is the evacuated-tube collector.
Credit: Alan Ford

Estimates of the world's use of solar energy for heating water and buildings have long been hampered by a technical issue: the difficulty of converting the size of the installed solar energy collectors into an energy capacity that could be easily compared to other capacity figures. Last week, however, the International Energy Agency's Solar Heating and Cooling Programme (IEA-SHC) and the world's major solar energy trade associations announced that they had agreed on a simple conversion factor for all types of solar thermal collectors: each square meter of solar collector, regardless of type, has the capacity to generate about 0.7 kilowatts of thermal heat. Applying that to worldwide estimates of installed solar collectors, the organizations found the world capacity to be nearly 70 gigawatts of thermal heat in 2001. That compares favorably with wind power, which at that time had a global installed capacity of 24 gigawatts of electric power. See the joint press release on the European Solar Thermal Industry Federation Web site, and for more information, see the IEA-SHC Web site.