We are heading for a world powered by renewable energy but there is a problem with the main renewable energy systems of solar power and wind energy. How do you keep a supply of power going when the sun goes down causing solar power systems to stop generating and what can you do when the wind stops blowing and wind energy production stops?

We need to find new ways of storing the energy they produce when working at full generating capacity and use that energy when low or even no power is being produced. There are adaptions of current energy production systems we can use but there are also some new ideas that might prove to be a solution to the problem of energy storage.

The first option is perhaps the simplest and is something that is already carried on in some parts of the world. We currently use a lot of hydro electric power and we can use wind and solar energy to keep the water storage reservoirs topped up when the energy would otherwise go to waste.

Dinorwig in Wales is the site of one of the more imaginative pumped energy storage systems that uses spare electrical capacity in times of low demand to pump water into a storage lake which can then be used to supply water to the turbines to produce power on demand when required. Currently this system uses normal electrical supplies but this would be a great way of using surplus wind and solar power to store energy as a hydraulic battery.

Flywheels can be spun up using surplus energy and the kinetic energy thus stored can be used to produce power when required. New materials have enabled flywheels to achieve astonishing speeds of up to 100,000 rpm. Using magnetic bearings and housing the flywheel in a vacuum gives almost frictionless rotation allowing the kinetic energy to be stored for later use with little loss. The concern is that if a large flywheel were to break up at these speeds of rotation the parts might be difficult to contain within the housing and cause serious damage and injury but there is great potential for future power storage stations housing many giant flywheels to provide power on demand.

I love the idea of a giant clockwork motor being used to power dynamos to generate electricity when needed. It would be wound up using surplus renewable energy and stored indefinitely ready to be used as and when required. The energy available would probably only be available for a relatively short duration but it would great to imagine all our high tech gadgets and computers being powered by electricity produced by a clockwork motor. A giant clockwork power station would most likely be too expensive to produce reasonably priced electricity but clockwork mechanisms have been reliably used for centuries so we know they work well and with modern design and materials this might yet be a realistic possibility.

Compressed air could be produced when surplus solar power and wind energy was available by using an electrically powered compressor to generate the high pressure air which is then stored in tanks or even hollowed out mountains and used to generate electricity through a turbine at a moments notice.

Broadly similar in concept to the pumped water storage systems a compressed air would be more easily installed as a small household sized unit powered by a domestic sized windmill or solar panels as part of a diy renewable energy project but could be scaled up to almost any size of energy storage system.

There are ways of storing energy and these could be key factors in making the best use of renewable energy supplies in the future. Cost is always a factor and any of these storage sysems would require huge investment to enable them to be set up but once that initial installation cost is covered energy storage systems like these could be very profitable for companies who have the vision and enthusiasm to make these energy storage systems work.