The International Energy Agency’s Solar Heating and Cooling Programme and major solar thermal trade associations have published new statistics on the use of solar thermal energy. The new data – expressed for the first time in GWth, rather than in square meters of installed collector area – shows the global installed capacity to be 70 GWth (70.000 MWth). [see link at bottom for more information on units – ed]

“The worldwide contribution of solar thermal installations to meeting the thermal energy demand for applications such as hot water or space heating has been greatly underestimated in the past”, says Michael Rantil, Chairman of the International Energy Agency’s Solar Heating and Cooling Programme (IEA SHC), “With an installed capacity of 70 GWth solar thermal is one of the leading sources of renewable energy world wide. And its potential is much, much higher.”

The underestimation of the capacity of solar thermal was due largely to the fact that solar thermal installations have traditionally been counted in square meters of collector area, a unit not comparable with other energy sources. Making the installed capacity of solar thermal collectors comparable with that of other energy sources was a top priority at a joint meeting of the IEA-SHC Programme and major solar thermal trade associations, which was held in September 2004 in Austria.

At this meeting, solar thermal experts from 7 countries agreed on a methodology to convert installed collector area into solar thermal capacity. The represented associations from Austria, Canada, Germany, the Netherlands, Sweden and the USA as well as the European Solar Thermal Industry Federation (ESTIF) and the IEA SHC Programme agreed to use a factor of 0.7 kWth/m2 to derive the nominal capacity from the area of installed collectors. The groups called on all organisations publishing data on solar thermal markets and installations to use this conversion factor as well.

“Now the solar thermal capacity should show up in all statistics alongside the capacities of other renewable energies”, says ESTIF President Ole Pilgaard. “And seeing that the world wide capacity of solar thermal installations exceeds even that of wind power, people will realise that our technology can contribute tremendously to reducing greenhouse gas emissions and to making the global energy supply more sustainable.”