In Northern Germany, researchers are looking for underground sites of salt. Where wind energy as compressed air or hydrogen could be save. For Lower Saxony alone, the experts suggest a potential of 350 billion kWh.
Still power storage for excess electricity are the bottle-neck of renewable energies. With them, stands or falls the energy revolution. No wonder, then, that researchers on the project InSpee are looking for new storage facilities. In the North of Germany, where wind turbines generate much electricity, water storage power plant in question? No, because in the North German basin there are a few hills. For 697 salt structures are located in the Northern Mainland and the North and Baltic Sea. And these deposits of rock salt, rock formed millions of years ago from concentrated sea water could be the answer.
Huge salt caverns save compressed air or hydrogen
You can create so-called salt caverns from the salt domes. For pumping water into the ground, which washes out salt and gives rise to a cavity. He is perfect as a compressed air tank, which is impervious to the outside and does not react with gas. Energy storage power plant can generate compressed air with excess wind energy that later drives turbines for energy recovery.
The storage is highly secure due to the large distance to the Earth’s surface and the protection against external factors. This proves also the oldest air power plant of the world, that started in 1978 in Huntorf in Wilhelmshaven. The two salt caverns are located at a depth between 650 and 800 m and are 60 m wide and 150 m high.
One drill for deposit activation.
And there are other advantages of this storage solution. “Compared salt caverns characterized with other storage options in the geological substrate specific construction cost, being the construction and operation of the Chambers with a single hole”, said Gregor Sönke Schneider from KBB underground technologies, a specialist in salt storage and partner in the research project, the business week.
Alternatively hydrogen can be power surplus via electrolysis produce, which can be also stored in salt caverns. In addition to the back-fired power generation and the feeding into the natural gas network, also use as environmentally friendly fuel is conceivable.
The United States already use this storage option.
There is, however, no basis for the assessment of storage sites in Germany. The project InSpee is to change that. Scientists want to identify the salt structures, which are suitable for a cavern, and assess what amounts of energy stored in the geological underground can be. Partner of the project is also the Institute of geotechnical engineering of the University of Hanover.
Researchers suspect potential of 350 billion kWh in Lower Saxony, Germany
The researchers estimate the potential for energy storage in salt caverns for Lower Saxony alone to about 370 million kWh when filled with compressed air and on all 350 billion kWh in hydrogen.
Comparison: a household has an average power consumption of 3500 kWh per year. A single salt cavern can it absorb between 300,000 and 700,000 cubic meters. “Estimates for a medium-sized cavern a switch on or off memory rate of around 500 MW with a usable storage capacity of approximately 140 GWh”, said Schneider.