The need for power storage in Germany is expected to
be 16 TWh if 50 % of the total electricity consumption is generated by wind and
sun. If one assumes 150 storage cycles per year of 1 GWh each about 100 storage
units or cavern pairs are needed, which means that the storage requirements of
Germany could almost be covered by the erneo technology.
Onshore in North Germany, Denmark and the
Netherlands and offshore as well as worldwide many salt formations are suitable
for the construction of caverns. The process described here requires no special
restrictions on the depth of the cavern. The only challenge in the cavern
construction is the disposal of the brine. Because it is pure un-contaminated
salt water, an introduction to the North Sea is not a problem. In the northern
European coastal countries, several sites for the storage already exist of
natural gas . There are also sites where brine is produced for the chemical
industry. The disposal into permeable underground formations is also a common
practice. These leached caverns could be used for the storage of electricity.
The technical requirements for the storage procedure here described are largely identical to the existing for over 50 years, mature technology of natural gas storage.
The only "new" component would be the expansion turbine. There are also technical solutions of different manufacturers available, where the compression and expansion in a machine  can be combined in a single machine. The cold startup time of appropriate machinery for the expansion, i.e. power generation, is under 3 minutes, so that the plant can be used for the balancing energy market.
Storage of electrical power using the erneo concept can be combined with storage of natural gas. In an existing gas storage only an expansion turbine would be needed and integrated in the existing storage infrastructure. The requirements of gas storage and electricity storage can be harmonized by an intelligent software supported management.