While wind power is one of the greenest renewable energies around, the wind doesn’t blow continuously at an optimum speed for offshore or onshore wind turbines. That means sometimes no energy is being generated and added to the grid. But an equal issue is that when you have a period of optimum wind, it is difficult to store any surplus electricity generated. Devotees of fracking often use these arguments to say that Governments should be concentrating on extracting shale gas (despite the environmental hazards) rather than investing in wind power. However, the rocks beneath our feet may have a use in wind power: Wind storage.
Recent research from scientists at BPA and the U.S. Department of Energy’s Pacific Northwest National Laboratory suggests porous rocks underground could store the wind’s intermittent power and make it possible to deploy renewable energy on demand and command.
Focusing on subterranean basalt reservoirs in eastern Washington State, the authors of this new study have examined the feasibility of deploying a system known as “compressed air energy storage”, or CAES. The researchers analyzed geological data from petroleum exploration to identify a pair of sites where volcanic rocks could store enough energy to power a total of about 85,000 homes per month.
We’re talking deep here: Far below the water table, in the kinds of places where you would find things like fossil fuels.
Haresh Kamath, energy storage program manager with the US Electric Power Research Institute (EPRI). said-
“Natural gas and other fuels can and have been held in “similar rock formations for millions of years under pressure, and nobody notices anything at ground level.”
In a CAES plant, the underground reservoirs could provide the vessels where compressed air could be pumped and stored using surplus wind energy. During times of higher demand, such as hot summer afternoons when people want their air conditioning on at full blast, the air would be uncorked, heated, and used to turn a turbine to generate electricity.
The air would be stored in naturally porous and permeable volcanic rock. The idea echoes an ancient one. For devotees of Greek mythology, this may sound familiar. The Greek gods kept blustery winds trapped in a hollowed-out mountain under the watchful eye of a jailer named Aeolus, who would unleash gales by stabbing his sword into the Earth.
Here Juno asks Aeolus to release the winds…
Researchers say these plants in the Northwest region of the US could switch between energy-storage and power-generation modes within minutes and make better use of the region’s abundant but intermittent wind power.
But this approach needn’t be limited to the Pacific Northwest. Northern Ireland, for example, has salt deposits where developer Gaelectric hopes to be able to build a 268-megawatt CAES Project in support of its growing wind capacity. Germany’s RWE Power is working to perfect a more efficient type of CAES plant using heat recovery and salt caverns in Stassfurt.
This is not going to happen overnight, but as wind power generation capacity increases across the world, the demand for storage of such energy will become increasingly urgent.