Yes, the car could indeed, one day take first place as far as energy storage is concerned. However, for this to happen, the number of plug-in hybrids, electric vehicles and also the intelligence of our electricity grids, would have to be drastically increased (see picture 4).

Thereby, we should not only be thinking of the temporary storage of electric power and of providing it again. It may rather, be all about the exploitation of left-over current, which, although it is renewably generated, at the moment is not needed.

For this to be realised, there would have to be large facilities for the production of methane-gas (see picture 4), which the natural gas networks and thus, also the affiliated filling stations could use. The production is not necessarly economic, but otherwise, the wind turbines would be shut down during strong winds. Indeed, the waste-heat can be used for other processess.

So, it doesn't have to be gigantic pumped storage dams (see picture 1). Compressed air, water or potential energy for turbines could be stored in, now defunct, giant cavities left behind by the coal mining industry or by the salt mines. The good old lead-acid battery or even those with lithium-ions (see picture 2), put together by the thousands, can hold a charge for a long time and show an efficiency unequalled by other methods.

Apparently, the so-called gravity energy storage is particularly reasonable. Electric energy can be generated and stored by raising heavy objects up and allowing them to fall again. The low investment costs seem to make this method particularly attractive. Not only can warmth be taken from inside the earth. It can also be pumped in and recalled when needed.

In reality, the problems with renewable energy sources, actually lie in the extension of the electricity grids. At the moment, our neighbours are suffering through having to take electricity from us to cover their peak-periods, even though, by doing this, they know that their grids are being overloaded. The countries in Europe are already so interlocked, that one central-lying country, which is moving more and more towards renewable energy, can become a problem.

It's quite possible, that the situation of having a particularly large amount of electricity, could bring our grids to their knees. It's a matter of prevention, so that the public's acceptance of the renewable energies remains, even then when possibly, larger power cuts occur. The experiences that we've had in this field are rare, and they date back to quite a long time ago. Other countries have been hit much harder.

Since up to now, we've enjoyed the comfort of having a stable and secure power supply, we would sincerely like it to stay that way. Nobody, other that the legally obliged hospitals, is prepared for a longer power cut. Thus, the problem of no longer having unlimited, ready for use, electric cars anymore, is the least of our worries. 10/13