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.
3 comments:
This is a welcome development, addressing the major problem with wind power. If we can capture the off-peak energy as chemical energy, this is both cheaper and more practical than batteries or pumped-hydro storage.
Electricity can also be used to generate ammonia, which can be used as fuel or feedstock.
Hi bc,
Thanks for your comment.
While I agree that this is a very welcome development, I'm not sure that it's more practical than batteries or pumped-hydro storage for ALL applications.
Here's why:
In smaller transportation applications such as light duty trucks/buses or automobiles, the technology already exists to develop either plug-in hybrids or else all electric vehicles (albeit at cost). This is more efficient by far than using electricity to generate methane and then burning methane in an internal combustion engine.
Why is this an issue?
Well for methane generated by electricity by this process we get 60% x 17% efficiency = 10% of the original generated electricity used to move the wheels of the vehicle.
In the case of electric vehicles we get 70-80% of the electricity used goes directly to powering the vehicles. That's a factor of 7 better.
In the case of peak oil, we need to start building nuclear reactors and windmills as fast as possible in order to address the shortfall of 1-5% decline in availability of conventional oil. That's on the order of a million barrels to five million barrels needed to be replaced (at a factor of 15% well to wheel efficiency with current petroleum infrastructure).
Using electricity directly in this case just makes far better sense because trying to go for a wholesale conversion means we would have to build many, many more windmills and nuclear power plants to get the same transportation utility at the end. It just doesn't make sense.
Where it's a better deal, however, is in large scale transportation formats:
Right now there just doesn't exist a battery technology that will allow sufficient energy density to enable the long distance trucking paradigm to continue in an all-electric format.
So for now we are stuck with some kind of fossil fuel equivalent as an absolute requirement for our heavy trucking fleets.
If, however, we can convert some (large) percentage of this fleet to natural gas powered we have the fallback option of shale gas combined with this new process. The impact on the logistics infrastructure would be very limited in this case.
Any case, thanks for the comment. I'm stoked about this new technology and as JD say:
"Peak Oil? Hit the snooze button".
DB
I agree with your comments wrt to transport, I was thinking of utility scale storage when I wrote that.
I was reading statements recently from wind farm operators which say that at time of high output they have literally no one to buy the electricity, and is effectively wasted.
So generating methane with off peak electricity and regenerating with a standard gas turbine is a scalable storage system, and has a dual use of providing transport fuel. Of course, this need not be co-located with the wind farm.
Either way, systems that dovetail with existing infrastructure are attractive options.
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