Ecotricity Explains – What is battery storage?

The National Grid needs to match energy production to consumption – every second – so that the electricity is balanced and to prevent voltage anomalies, overloading and drops in availability. With fuel-dependent power stations, more generation can be brought online quickly to match peaks in demand such as people cooking dinner in the early evening. This is harder with renewables, where the energy they create is more intermittent; for example, depending on the time of day and what the wind is doing. It’s not just that generation drops sometimes, there are also issues when green energy sources produce more electricity than the transmission lines can handle in a local area, meaning clean energy production has to be capped. To make the most of renewables, we need to smooth out the energy output so that we’re not wasting power – and we need to be able to supply extra electricity at the drop of a hat, to match any sudden increase in demand from homes and businesses. This is where battery storage comes in, capturing and storing green energy that isn’t needed at the time of generation and saving it until it’s called upon. It’s an important part of a modern National Grid and a network of grid-scale batteries is essential for Britain to end its reliance on fossil fuels.

Battery energy storage systems are far bigger and far more advanced than the rechargeable batteries we use in our smartphones and laptops. Nonetheless, when it comes to the fundamentals, they’re very similar indeed. Power goes in, it’s stored in the battery, then flows out again when needed. Grid-scale batteries use energy management systems to coordinate energy storage with energy production, deciding when to increase the reserve or release energy to the National Grid. In this way, green energy generated at times of low consumption is stored for use when demand peaks. Up until now, these peaks have been filled in by firing up extra generation capacity in a fossil fuel. As more battery storage is installed to match continued increases in green generation, there will be less and less need for fossil power. Batteries can also react at a speed that no rotating mechanical machine can match – making them a really efficient answer to power and voltage needs.

Our first battery project is currently underway at Alveston in Gloucestershire, a 10 megawatt 24 MWh project. When it comes to size, grid-scale batteries are chunky beasts. A standard shipping container can hold a 1-3 megawatt battery (Alveston is in 6), and a 50 megawatt battery would need a site around the size of a quarter of a football pitch. However, compared to other grid-scale infrastructure, they don’t make too many demands in terms of space and they’re not intrusive – batteries are silent in operation. Innovations in energy storage are crucial in the fight against the climate crisis. But we don’t actually need to wait – today, we have proven technology that can generate and store enough green electricity to supply the entire country from renewables. All we have to do is get on and build the wind and sun parks, along with the batteries to help manage the flow of electricity.