The world is moving in the direction of using electricity derived from renewable sources. With the mass production of devices to enable the production of energy from such sources (wind, solar and tides), peak power capacity is competitive with that of deriving the electricity from fossil fuel. The problem is that the profile of power production does not match that of the requirements. This problem is not new, but it has become more acute: due to the extremely peaky nature of the power from the new sources, unless there is efficient energy storage, it is necessary to maintain the capacity to generate power to cover the full load in certain climatic conditions. While nuclear power is clean and would be ideal for satisfying the requirements of base load, the capital cost of nuclear plants (which should include that of decommissioning) makes the real cost of such power more expensive than that which can now obtained from renewables (and from burning gas or coal, of course). Ever since there have been electrical grids, companies have looked for ways to efficiently store energy so that power can be delivered on demand with minimum capital investment. A wide range of technologies is employed, and is being developed, so that everyday needs can be met. Energy storage is resource neutral: it allows us to use electricity from any power source more efficiently. However, it involves considerable capital investment, and can occupy a lot of space. The idea of moving towards reliance on renewable sources of energy has been taken up by a large segment of the population but there is technically still a lot to do, especially with regard to the essential corollary of energy storage. In addition to the challenge of producing the means to store energy, many other issues must be addressed. These include maintainability and longevity of the equipment (both for producing the energy and storing it). In this report we explore and compare the different methods available for storing energy and investigate trends.