Electricity generated using renewables can be transformed into a substitute for natural gas, according to new European research.
Until now, electricity has largely been generated from gas in the UK and across much of Europe, although coal and oil-fired plant are still used.
Now, a German-Austrian co-operation wants to go in the opposite direction. They would like to store surplus electricity by harnessing it to produce climate-neutral methane and to store it in existing gas-storage facilities and the natural-gas network.
Throughout the world, electricity generation is based more and more on wind and solar energy. So far, the missing link for integrating renewable energy into the electricity supply is a smart power-storage concept – because when the wind is blowing powerfully, wind turbines generate more electricity than the power grid can absorb.
Now, German researchers have succeeded in storing renewable electricity as natural gas.
They convert the electricity into synthetic natural gas with the aid of a new process developed by the Centre for Solar Energy and Hydrogen Research Baden-Wurttemberg (ZSW), in co-operation with the Fraunhofer Institute for Wind Energy and Energy System Technology IWES.
Currently, Solar Fuel Technology, the Austria-based partner company, is setting up the industrial implementation of the process.
One advantage of this approach is that it can use the existing natural gas infrastructure.
A demonstration system built on behalf of Solar Fuel in Stuttgart is already operating successfully.
A much larger system of double-digit-megawatt generating capacity should be ready by 2012.
In order to push the new energy-conversion technology forward, the two German research institutes have joined together with the company, Solar Fuel Technology of Salzburg. Starting in 2012, they intend to launch a system with a capacity of about 10 megawatts.
It should become operational in 2012.
“Our demonstration system in Stuttgart separates water from surplus renewable energy using electrolysis. The result is hydrogen and oxygen,” said Dr Michael Specht, of ZSW.
“A chemical reaction of hydrogen with carbon-dioxide generates methane – and that is nothing other than natural gas, produced synthetically.”
With the rapid expansion of renewable energies, the need for new storage technologies grows massively. This is of special interest to energy utilities and power companies.
“So far, we converted gas into electricity. Now, we also think in the opposite direction and convert electricity into ‘real natural’ gas,” said Dr Michael Sterner, of Fraunhofer IWES, who is investigating engineering aspects and energy-system analysis of the process.
“Surplus wind and solar energy can be stored in this manner. During times of high wind speeds, wind turbines generate more power than is currently needed.
“This surplus energy is being more frequently reflected at the power exchange market through negative electricity prices.”
In such cases, the new technology could soon keep green electricity in stock as natural gas or renewable methane.
One goal is to structure the delivery of power from wind parks on a scheduled and regular basis.
“The new concept is a game-changer and a new significant element for the integration of renewable energies into a sustainable energy system,” said Sterner, adding that the efficiency of converting power to gas is more than 60%.
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