Worldwide Solar Thermal Capacity Underestimated

"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."

- Michael Rantil, Chairman of the International Energy Agency's Solar Heating and Cooling Program (IEA-SHC)

Paris, France [RenewableEnergyAccess.com] The International Energy Agency's Solar Heating and Cooling Program and major solar thermal trade associations published new statistics on the use of solar thermal energy. Using a new system of measurements that allow a more direct comparison with other energy sources, the organizations show solar thermal energy provides a considerably larger source of energy than previously estimated.

The new data - expressed for the first time in GigaWatt thermies (GWth), rather than in square meters of installed collector area - shows the global installed capacity to be 70 GWth (70.000 MWth).

"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 Program (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 Program and major solar thermal trade associations, which was held in September 2004 in Austria.

At this meeting, solar thermal experts from seven 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 Program 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 organizations 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 realize that our technology can contribute tremendously to reducing greenhouse gas emissions and to making the global energy supply more sustainable."

Its about time! and now the next baby step...

This standardization of solar thermal power capacity in 0.7 KWth/ sq m shall be very benefical barometer for the users as well as engineers-builders. It is a very good start and we hope standardization continues for solar thermal products and accessories. Is the 0.7 KWth per sq m output of the collector? There are many types of solar collectors like - evacuated pipe, flat plate etc. 0.7 KWth is applicable for what? What is data for other types? What is the efficiency? I understand the installed capacity of solarthermal is more than installed wind power capacity. What is the current installed wind capacity?

"The recommended conversion factor For the purpose of solar thermal statistics, the installed capacity ([kWth] – Kilowatt thermal) shall be calculated by multiplying the aperture area of the solar collector area [m2] by the conversion factor 0.7 [kWth/m2]. This factor shall be used uniformly for unglazed collectors, flat plate collectors and evacuated tubular collectors." Current wind is ~ 40 GWe

The installed capacity calculated with the conversion factor should not be misstaken by users or engineers-builders to give the actual output of a specific collector or even system. The installed capacity expressed in MW-thermal is similar to the notion of peak capacity of PV, wich is typically expressed in MW-peak and which gives the panel output under optimum conditions. An explanation of how the conversion factor was determined can be found at the IEA-SHC website at http://www.iea-shc.org/welcome/Technical_note_solar_thermal_capacity.doc

i prefer sq. ft.( or m^2) on buildings, so why not include both numbers. also both of the ratings, pv and thermal, are for peak conditions and don't allow for capacity factor. e.g. a 1000MW nuke or coal or gas plant produces that pretty much continuously, a 1000MW wind or pv plant produces that about 1/6 of the time depending on location. same is true for 1000MWth of solar water heater. www.solartoday.com for more info on them.

The idea is to compare solar thermal with other renewable energy sources (not nuke or coal). It is interesting to see that although solar thermal energy is rarely mentionned in these news articles, the installed capacity is considerably greater than PV or wind.