It is 1:12 am in March 2030. In a suburban cul-de-sac there’s no movement except a hungry fox scavenging for bin snacks. At number 16, electrons begin to flow silently through a cable into the battery of an electric car. Upstairs, the occupants remain undisturbed. 

While the household sleeps, its energy supplier sends a signal that demand is low and cheaper energy is available, automatically prompting the electric car to begin charging. But the setup doesn’t just benefit the family at number 16. By doing their bit to smooth electricity demand, they are helping the grid balance supply and demand, making it more resilient to power cuts, reducing carbon emissions and helping to keep their neighbours’ bills down too.

Most of us take for granted that the lights will come on when we flick the switch, but ensuring the grid always has the right amount of generation capacity to meet fluctuating demand is a constant conundrum. That will become more challenging for grid operators as demand for electricity increases and sources of power become more varied. Building more capacity to generate electricity might seem the obvious answer, but new research suggests another option—that changing the collective behaviour of ordinary consumers can make a huge difference.

The problem stems from matching demand and supply. Typically, there is far higher demand in the evenings, as people come home from work, turn on lights, boil kettles and power up computers, monitors, kitchen appliances and so on (see graphic).

The UK has a variety of sources for meeting this demand. Renewable electricity generation is an increasing part of the mix and cheaper than power from gas power stations, which currently accounts for around a quarter of the energy generated in the UK. It also has a lower carbon footprint and contributes to energy security. But the power output is intermittent, which can put pressure on the grid when demand is at its highest.

To balance these demand and supply fluctuations, the grid needs capacity that can be called on at short notice. This isn’t new. Existing flexible assets include gas-fired generators called peaker plants, grid-scale batteries and pumped hydro. But the gap is set to grow. 

Researchers at energy consultancy Cornwall Insight have calculated a looming gap of around 10 per cent of the existing or planned flexible capacity. To fill that would require the construction of around 100 grid-scale battery storage assets or 400 gas-fired peaker plants along with their significant carbon emissions. That would be expensive and require other grid upgrades.

Cornwall Insight’s work establishes that there is significant untapped potential in households increasing, decreasing or shifting their electricity use. That means encouraging consumers to change their behaviour or automating ways of modulating home energy use.

It is already starting to happen (see box), with energy providers rewarding customers for reducing power use at peak times by shifting some of their energy use to periods when there is lower demand or to times when there is an excess of renewable energy on the grid, such as sunny or windy days. 

A less hands-on approach is for consumers to choose automated systems for charging their EVs and home batteries. Smart switches, connected to smart meters can be set to charge when demand is low or renewable supply is plentiful. This can help to shave the peaks and avoid the need for extra generation.

“[Consumers] can absolutely be blissfully ignorant and entirely agnostic of whatever is happening on the energy system side,” says Jacob Briggs, co-author of the study by Cornwall Insight on consumer-led flexibility. 

With enough consumers on board, this can make a big difference. Briggs and his colleagues calculated that consumer-led demand flexibility could avoid up to £4.6 billion in extra grid costs by 2030 and £14.1 billion by 2040. The 2030 figure averages out to £153 per household. That goes to everyone, whether they modify their electricity demand or not. But those who do modify their demand could save even more. 

“That’s three gigawatts of network capacity that we don’t have to build, or of gas peakers that don’t need to be connected, or of renewable generation that can now find a home at a different time of the day,” says Briggs. 

What this needs is an army of households who are flattening out the peaks in demand by changing when they use some of their energy. This group can have a material impact on demand and hence the required grid capacity.

But any army needs the right kit, and key enablers of flexibility are smart meters which send secure accurate usage readings to suppliers in near real time. Crucially, the meter records and shares when you are using electricity, not just how much. As of December, 72 per cent of household meters in Great Britain were smart or advanced, according to government figures. 

Ideal flexibility

Adoption of flexible energy tariffs and schemes amongst people with smart meters is increasing, particularly driven by EV owners. 2.8 per cent of consumers, or 835,000 households, were signed up to the “time of use” tariffs required to drive flexibility as of January 2026. Whilst a growing number of suppliers are introducing flexible energy schemes, such as free or cheaper energy at weekends or rewards for using less at peak times. How much does uptake of these tariffs and schemes need to grow and what do those consumers need to do to fill the gap? 

Cornwall Insight has calculated that one million fully smart homes would be sufficient to fill the gap, meaning they have an EV smart charger, heat pump, solar PV with battery storage, all automatically responding to flexibility signals.

Having so many homes with ideal flexibility is unlikely to happen by the end of the decade, but households with less advanced kit can still make a difference. We just need more of them. 

One combination would be three million homes with electric vehicle smart chargers, one million with heat pumps—currently around 250,000—and 15 million engaging in smaller-scale actions like shifting some of their electricity use to early mornings or late in the evening. Together, that would involve 19 million of the UK’s projected 28 million households in 2030. Businesses could provide additional flexibility, further reducing the contribution required from households.

This scale of consumer engagement would be new for the UK’s energy system. But advocates hope that the benefits are compelling enough to bring people on board. After all, like the residents of number 16, who wouldn’t want to save money from the silent movement of electrons while they sleep?

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