The main problem of most renewable energies is well known: they supply energy intermittently, only during sunshine hours or on windy days. One solution is the installation of pumped-storage hydroelectricity plants, which in times of high supply and low demand use the surplus to pump water into a reservoir on a higher level in order to let it flow to turbines when needed. The disadvantage is the strong impact on the environment due to changing the relief of vast areas.
American engineer James Fiske, originally trained as an expert in magnetic levitation systems, has revolutionized this subject. He does not pump water upwards, but downwards to deep shafts, and installs heavy discs on top of them which are released when needed in order to force the water to flow through turbines. The advantage is that this system uses very little surface areas. Besides, it can use the shafts of abandoned mines. An idea inspired by the Blue Economy, to make use of available resources.