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Grid · 18 June 2026

Britain built the power stations.
It forgot the batteries.

We have spent twenty years and a lot of money building things that make electricity. We have spent considerably less on things that hold onto it. That mismatch is now showing up as negative prices, curtailment payments and margin warnings, sometimes in the same week.

The shape of the problem GENERATION lots STORAGE not lots FLEXIBILITY barely started

Not to scale, but the shape is right. The gap is where your bill lives.

🏗️ We solved the wrong half

The renewables build-out has been a genuine success. Britain went from a coal country to a wind country inside a generation and barely stopped to congratulate itself.

But generation was always the easy half. You can put a wind farm where the wind is and walk away. The hard half is matching what gets made to what gets used, minute by minute, forever.

We have a system that makes enormous amounts of electricity at moments of its own choosing, and a population that uses electricity at moments of its choosing, and almost nothing in between to reconcile the two.

🧱 Big batteries are being built, and it is not enough

Grid-scale batteries are going in fast, and they are doing well out of exactly the volatility described in these posts. Good for them.

But a grid battery needs land, a planning application, a grid connection and several years. There is a queue, and the queue is long.

Meanwhile there are already millions of batteries plugged into British homes, sitting on driveways. They are called cars. They cost the grid nothing, they needed no planning permission, and on any given evening about 95% of them are doing absolutely nothing.

🚙 The cheapest grid asset is the one you already bought

A car battery holds enough energy to run a typical home for two or three days. It spends most of its life parked.

Nobody is asking to drain it. Shifting when it charges, by a couple of hours, on days when the grid is drowning, is enough. You wake up to a full car either way.

The difference is that on one version you paid peak price, and on the other the grid paid you.

We built a country that can produce more clean electricity than it can swallow, and then acted surprised when it started giving it away. The batteries are already here. They are just parked outside, doing nothing, with the keys in the bowl by the door.

The cheapest battery you already own

The post above is about storage nobody built. Your hot water tank is storage you already have. It just needs to be switchable.

Secure E7+ smart immersion controller
£67.29 · 5.0★
Puts your hot water tank on a schedule you do not have to think about. A tank is a thermal battery that most people have never once thought of as one.
£71/yr
on the grid
View →
Tapo P110 smart plug (2-pack)
£13.32 · 4.6★ · 53,155 reviews
Measures the energy going through it, and can be switched remotely. The cheapest way to turn a dumb appliance into something the grid will pay for.
£19/yr
on the grid
View →

Some links here are Amazon affiliate links. If you buy through one we may earn a small commission, at no cost to you. We only list kit that actually works with FlexMyPower. The commission is trivial. The reason we care is that these devices are what let the grid pay you in the first place.

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Written by Hoesna Mahmood, founder of FlexMyPower. Published 18 June 2026.

FlexMyPower pays UK households to shift when they use energy. Any tariff, any supplier, no switching. More articles.

© 2026 FlexMyPower Ltd · Companies House 17138164 · Not an energy supplier.