Some German researchers have come up with an additional and novel way to store excess power from wind turbines when more power is being produced than can be absorbed by the grid: they convert it into natural gas. At a 60% efficient conversion rate with electric power already being 4X as efficient as fossil fuel we are looking at something very very interesting.
The full story is found at Science Daily.
Following are some selected quotes
ScienceDaily (May 5, 2010) — Renewable electricity can be transformed into a substitute for natural gas. Until now, electricity was generated from gas. Now, a German-Austrian cooperation wants to go in the opposite direction. In the future, these researchers and entrepreneurs would like to store surplus electricity -- such as from wind power or solar energy -- as climate-neutral methane, and store it in existing gas storage facilities and the natural gas network.
One advantage of the technology:it can use the existing natural gas infrastructure. A demonstrationsystem 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.
For the first time, the process of natural gas production combines the technology for hydrogen-electrolysis with methanisation. "Our demonstration system in Stuttgart separates water from surplus renewable energy using electrolysis. The result is hydrogen and oxygen," explains 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."
The storage reservoir of the natural gas network extending through Germany is vast: It equals more than 200 terawatt hours -- enough to satisfy consumption for several months.
"The new concept is a game changer and a new significant element for the integration of renewable energies into a sustainable energy system," adds Sterner. The efficiency of converting power to gas equals more than 60 percent. The predominant storage facility to date -- pumped hydro power plants -- can only be expanded to a limited extent in Germany.
Starting in 2012, they intend to launch a system with a capacity of approximately 10 megawatt.