How is Renewable Energy Stored?

With climate change and renewable energy on practically everyone’s agenda, the focus has turned to finding the most effective way of storing this energy. Although green energy has the potential to provide millions of us with power for generations, unless we can store it successfully, it won’t be a viable source. This is incredibly important, especially when the EU has unveiled new targets to cut the emissions of greenhouse gases by 40 per cent by 2030.

With this in mind, scientists have been looking at several different ways of storing the natural renewable energy, and some might surprise you.

Batteries

Researchers in Germany are using fish as a type of battery to store energy. The fish are frozen to below the optimum temperatures during the time when renewable energy is working. Then, when the energy is not available, the power is turned off, the fish defrosted and warmed up to the optimum storage temperature. They then act as a type of battery.

Water Turbines

At the Sir Adam Beck station near Niagara Falls in Ontario, water is pumped uphill into a reservoir using renewable power when it is available. Then, when there is no sun or wind, the water flows downhill and passes through a water turbine creating energy during peak demand.  

Hydrogen and Methane

Scientists have been researching a new technology called Power-to-Gas, which involves converting green energy into hydrogen and methane from water via electrolysis. The addition of carbon dioxide creates synthetic methane. This can  then be pumped into the gas distribution grid and used for heating or to produce electricity.

Some experts believe that converting energy into chemicals is the best way to store it:

“If you want to store energy over a long time, then I think a chemical energy carrier is the only option,” Dr Michael Specht told BBC News.

“The other ideas such as pumped water or large batteries, typically have storage times of one or two days - but with this system we have storage times of weeks or months,” he added.

Private companies

Getting involved in storing energy appears to be big business for green energy companies, as several are testing ways of storing green energy, and using the public as guinea pigs. Dimplex North America Ltd are installing thermal bricks as a way of storing and releasing energy, whilst Convergent Energy and Power LLC are currently testing a flywheel that converts electricity to kinetic energy which is then stored in a rotor system.

Of course, it is not just the storing of renewable energy that is important, but how this energy is accessed once it is added to the main power grid.

Leonard Kula, director of operations at IESO, said: “We want to understand how best to incorporate them to improve the efficiency of our electricity market.”