This article first appeared in our ‘Love is all we need’ issue of My Green Pod Magazine, published on 14 February 2022. Click here to subscribe to our digital edition and get each issue delivered straight to your inbox
Whirring away beneath Arsenal’s Emirates Stadium are several rows of large white boxes.
At a glance they’re unassuming, but in actual fact they’re gamechangers: massive batteries with enough energy to power the entire stadium for a full 90 minutes.
Installed in 2018 by Octopus Energy and Downing LLC, the groundbreaking Arsenal batteries can stop as much carbon going into the atmosphere as would be emitted by 2,700 homes over the course of a football match.
This is the future of energy, and the only way society could one day be powered by 100% renewables, 100% of the time.
Energy storage is a hot topic. From big batteries like the ones at the Emirates Stadium to the smaller smart batteries popping up in homes across the UK, the ability to store energy is a vital part of a plan to make renewables work on a massive scale.
It’s all because they bring flexibility to the grid, creating a smarter, more complex, dynamic system that’s not unlike the internet.
At this very moment, teams of ‘flexperts’ are hard at work putting batteries at the service of the green energy revolution, bringing the benefits to ordinary people up and down the country.
What is energy flexibility?
To give a bit of background, our electricity grid must always be well balanced. If there isn’t enough energy being pumped in to meet demand there can be power cuts, and if more energy is pumped in than is being used up it can damage grid infrastructure.
When it was first built over 100 years ago, our energy grid revolved around huge coal power plants where tonnes of dirty fossil fuels were burned to meet the nation’s energy demand.
Any flexibility in the system came from being able to adjust the supply; if the country began to use more energy, we could just turn on more coal plants to keep up.
In recent years, we’ve come to understand the threat that burning fossil fuels poses to people and ecosystems around world, and have begun to pivot to cleaner, greener energy like wind and solar.
Wind turbines and solar farms are quite simply wonderful; not only are they green, but the fuel itself is 100% free and abundant.
The electrons they generate are remarkably cheap – already the cheapest way to produce energy globally.
Yet renewable energy is intermittent; we can’t say for sure when the wind will blow or the sun will shine, and we can’t just turn renewables on whenever we want.
On some especially windy days we already have far more wind power than we need, and we actually have to pay to turn wind generators off in order to protect the electrical grid.
It’s an utter waste of low-carbon power, especially given that when energy demand peaks – usually 16.00-19.00 when the sun is low – the grid often has to ask generators to burn more fossil fuels.
This is the central challenge of the energy transition: if we can no longer rely on turning large, dirty generators on and off to match our ever-changing energy demand, then flexibility will have to come from somewhere else. Only then can we smooth the sun and wind’s spiky, erratic power into a stable and controllable 24/7 supply.
Is energy storage the answer?
Batteries like those at the Emirates Stadium can charge up when renewables are abundant and energy is therefore at its very cheapest and greenest.
Arsenal can then choose to run a full 90-minute game off its batteries and avoid using the grid whenever energy is dirtier and more expensive.
But that’s not all. Given that games at Arsenal happen relatively infrequently, the Arsenal batteries can fill up on green energy and then send it back to the grid to give neighbouring homes cleaner energy whenever the UK is in danger of being short of power.
This represents another way to unlock flexibility. By storing renewably generated electrons for use later on, we’re now able to call on green energy whenever we need it.
In other words, energy storage devices like the one Octopus helped install at Arsenal allow owners to get paid to help make renewables work on a huge scale.
In the near future, we might well see other ways of storing energy come to the fore – Octopus and RES have recently pledged to invest £3bn in developing green hydrogen over the next decade, some of which will be used to explore green hydrogen storage.