The argument in regard to solar and wind power not being suitable for baseload electricity supply purposes is steadily weakening. Molten salt batteries are now in use; gravel batteries are in development and various other technologies have been proposed alongside more traditional ones such as solar pumping in conjunction with hydro-storage.
While natural gas is often converted into electricity, process developed by the Center for Solar Energy and Hydrogen Research Baden-Württemberg (ZSW) and in cooperation with the Fraunhofer Institute for Wind Energy and Energy System Technology means renewable electricity can now be transformed into a substitute for natural gas – another source of power for electricity generation.
According to Dr. Michael Specht of ZSW, "Our demonstration system in Stuttgart separates water from surplus renewable energy using electrolysis. The result is hydrogen and oxygen. A chemical reaction of hydrogen with carbon dioxide generates methane – and that is nothing other than natural gas, produced synthetically."
During times of high wind speeds, wind turbines can generate more power than can be utilised. This new technology could soon keep green electricity in stock as
natural gas or renewable methane. The climate-neutral methane could be stored in existing gas storage facilities and the natural gas network, for use during unfavourable conditions – such as night time or calm weather.
The storage reservoir of the natural gas network extending through Germany comes to more than 200 terawatt hours; enough to satisfy consumption for several months.
A demonstration system built on behalf of Solar Fuel in Stuttgart is already operating successfully. By 2012, a substantially larger system in the double-digit megawatt range is planned to be launched.
While the efficiency of converting power to gas comes to around 60 percent, Dr. Specht points out it is better than a total loss in scenarios where wind power has to be curtailed.
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