When the Wind Doesn’t Blow

The Problem Nobody Can Legislate Away

T J THORNE

There’s something about wind power that’s been bothering me for quite a while. Actually, that’s not quite right. It isn’t wind power itself that bothers me. Wind turbines work. They generate electricity without burning anything, and here in Britain, surrounded as we are by sea and blessed, if that’s the right word, with rather a lot of wind, it seems perfectly sensible to make use of it. No, my problem is rather simpler than that.

What happens when the wind doesn’t blow?

I know that sounds almost too obvious a question. Perhaps it is. But the more I look at our plans for Net Zero, the more I find myself coming back to it. We are steadily building an electricity system that depends increasingly on the weather. And the weather, in my experience at least, has never taken much notice of government policy.

We have certainly built a lot of wind power

Let’s give credit where it’s due. Britain has changed its electricity system enormously. Our last coal-fired power station, Ratcliffe-on-Soar, closed on 30 September 2024, while renewable electricity has grown remarkably.

According to the Government’s own Energy Trends figures, renewable sources produced a record 152.5 terawatt-hours of electricity in 2025, 52.5% of all UK electricity generation.

Wind alone produced a record 87.1 TWh, or 30%. That’s a lot of electricity. There’s no point pretending otherwise simply because it doesn’t suit an argument. But here’s another figure from exactly the same Government report. Gas produced 91.6 TWh.

So, in the same year that renewable electricity broke all records, gas was still Britain’s largest individual source, providing 31.5% of our generation. Why? There were several reasons. Nuclear output fell substantially and Britain imported less electricity during 2025. But there’s another rather obvious one. Sometimes the wind doesn’t blow.

The Germans have a word for it

They call it Dunkelflaute. I rather like that word. It sounds suitably gloomy. It describes a period when there isn’t much wind and there isn’t much sunshine either. A dark lull, more or less.

If your electricity system relies heavily on wind and solar, that’s rather more than an interesting bit of weather. It’s a problem. And this isn’t something dreamed up by people like me who are sceptical about Net Zero. The National Energy System Operator — NESO, the people who actually have the job of keeping Britain’s electricity system working, has conducted a specific research project into Dunkelflaute.

It describes these events as periods of simultaneous low wind and solar production and says that understanding them becomes increasingly important as we depend more heavily upon those sources.

So clearly I’m not the only one wondering about it. And we don’t have to imagine what one might look like, we’ve already experienced it.

Nine rather inconvenient days in November

Between 1 and 9 November 2024, Britain experienced what NESO itself described as a particularly low wind and solar period. On 5 November, offshore wind, onshore wind and solar combined provided just 2.85% of the generation mix. Two point eight five per cent. NESO also noted that during this period there was greater dependence on gas-fired generation than during the rest of the month.

That, to me, rather brings the problem to life. We can install more wind turbines and over the course of a year they will generate more electricity. But when a large area experiences very little wind, more turbines don’t necessarily solve the problem.

A gas-fired power station can generate electricity when we ask it to, provided of course that it has gas. Nuclear can provide dependable generation too, subject to maintenance and outages. With wind, the weather has a vote. That’s quite a difference.

Annual averages don’t boil kettles

Electricity isn’t like most things we buy. If Tesco runs short of baked beans this afternoon, nobody is going to panic. Well, I hope not. They’ll put some more on the shelf tomorrow and life will carry on.

Electricity doesn’t work like that. If millions of us arrive home at six o’clock on a cold winter evening, put the lights on, start cooking dinner and turn the heating up, the electricity has to be available then. Not tomorrow morning. Not when the wind gets up. Then.

This is why generating “capacity” can be a slightly misleading term. We are often told that a new offshore wind development has enough capacity to power so many million homes. Fine. But can it power those homes at seven o’clock on a cold, still February evening? Because that’s when I’d quite like my electricity, thank you very much.

Producing enough electricity over a year and having enough available at the precise moment we need it are not necessarily the same thing. Annual averages don’t boil kettles. So what do we do?

There are answers. Batteries. Imports. Demand management. More transmission lines. Backup generation. All perfectly reasonable. But every answer seems to produce another question.

Take batteries. Battery storage is extremely useful. It responds quickly and helps the grid balance supply and demand. But providing flexibility for a few hours is one thing. Supplying Britain through a prolonged period of low wind and solar is something rather different.

Interestingly, the Government itself acknowledges this. Its energy policy says many storage facilities currently being deployed provide storage for hours, but cannot cost-effectively cover prolonged periods of low wind and solar output.

Technologies capable of storing energy for much longer exist or are being developed, but many are not yet available at the scale required, or have geographical limitations. So this isn’t me saying batteries don’t work. They plainly do. The question is how much storage we need, for how long, and what it will cost. And before you can take electricity out of a storage system, somebody has to put it in.

What about importing it?

Britain has interconnectors linking our electricity system with other countries. We can export electricity when we have too much and import it when we need more. Again, sensible. Except that weather has the irritating habit of ignoring national borders.

A Dunkelflaute can affect much of northern Europe at the same time. NESO specifically considers this possibility when assessing Britain’s electricity security. That doesn’t make interconnectors useless. Far from it.

But neither should we simply assume that whenever Britain is short of wind-generated electricity, somewhere across the Channel will automatically have plenty to spare. Perhaps they will. But “perhaps” is not a word I particularly want attached to the electricity supply.

Or we can change when we use it

Another answer is “demand flexibility”. In plain English, that means persuading us to use electricity when there is plenty available and less when there isn’t. There’s some common sense in that.

If my electric car is sitting on the drive all night, I don’t particularly care whether it charges at eleven o’clock or three in the morning. If three in the morning makes life easier for the grid and costs me less, that’s fine by me.

But you can only move demand around so much. Eventually the car needs charging. Factories need to operate. People need to cook. And if we’ve replaced millions of gas boilers with heat pumps, people are going to want their homes warm when it’s cold outside. Cold weather is not something most of us are prepared to reschedule for next Thursday.

And then, quietly, gas comes back into the room

According to the Government’s figures, fossil-fuel electricity generation actually increased by 2% in 2025. Gas generation increased by 4.7%. Think about that for a moment. Renewable electricity reached a record high and gas generation went up as well.

As I’ve already mentioned, falling nuclear generation and lower electricity imports were important reasons for that. Nevertheless, gas remains an important part of the system because it can respond when required. NESO itself said in March 2026 that gas-fired generation remains essential in providing dispatchable flexibility, while nuclear supplies reliable low-carbon generation during periods of low wind and solar output.

And that creates a rather interesting situation. As we build more wind farms, gas power stations may operate less frequently, but we may still need substantial dispatchable capacity available for those occasions when renewable output is low. Somebody still has to maintain it. Somebody has to make sure the necessary fuel and infrastructure are available.

It’s a little like buying a very expensive spare tyre that you hope you’ll hardly ever use. Except that when you do need it, you really, really need it.

But someone has to pay for it whether it’s being used or not. I have a sneaking suspicion I know who that someone will be.

To be fair, there is another side to this, and it deserves mentioning. NESO says a wind drought does not automatically mean gas-fired power stations have to run continuously at high output. Britain operates a Capacity Market designed to make sure sufficient resources are available during periods of system stress.

That includes gas and nuclear, but increasingly batteries, demand-side response and other technologies too. NESO says its modelling includes cold, still weather and that the system remains within its required reliability standard under those conditions. Good. I find that reassuring. But it also rather makes my point.

Keeping the lights on in an electricity system increasingly dependent upon wind and solar requires considerably more than wind turbines and solar panels. It requires storage, backup, interconnectors, demand management, transmission infrastructure and enough dependable capacity sitting somewhere in the system ready to respond when required. All of that is part of the electricity system. And all of it has to be paid for.

Perhaps technology will solve it

I don’t know what technology will look like in twenty years’ time. Nobody does. Long-duration storage may become cheap enough to solve a substantial part of the problem. Hydrogen may provide backup. Carbon capture may allow gas to continue playing a role.

Perhaps we’ll finally get serious about nuclear power. I hope some or all of those things work. In fact, the Government’s plans envisage a combination of long-duration storage and low-carbon dispatchable generation to deal with daily, weekly and even seasonal periods of low renewable output.

So there is a plan. My concern is rather simpler. Important parts of that plan still have to be built, developed and paid for. That’s not quite the same thing as having them.

We appear to be setting firm dates for getting rid of parts of the existing system while some fairly important parts of the replacement are still preceded by words such as “could”, “may” and “expected to”. I suppose I’m old-fashioned. I’d rather build the bridge before burning the boat.

I’m not against wind power. If we can generate large quantities of electricity from something that blows past our coastline for nothing, we’d be rather silly not to use it. Wind generated 87.1 TWh of British electricity in 2025. That’s real electricity. Good. But acknowledging that doesn’t require me to pretend wind power has no limitations.

The real question isn’t whether wind turbines work. Of course they work. The question is what else we need in order to make an electricity system heavily dependent upon them, work all the time.

Storage. Backup generation. Interconnectors. New transmission lines. Demand management. Possibly hydrogen. Possibly carbon capture. More nuclear, perhaps.

And once we’ve added all of those things together, I’d quite like somebody to tell us what the complete system is going to cost. Not just the wind turbines. All of it. Because that’s the number that matters.

And there we are

Britain has decided that it will reach Net Zero by 2050. That’s not merely an aspiration. The Climate Change Act was amended in 2019 so that the UK’s net carbon account in 2050 must be at least 100% below the 1990 baseline.

Governments can pass laws requiring us to change our cars, our boilers, our factories and the way we generate electricity. They can set targets. They can subsidise one technology and tax another. They can close power stations.They can build wind farms. What they can’t do is order the wind to blow at six o’clock on a freezing February evening.

Perhaps we’ll have enough storage. Perhaps we’ll import the electricity. Perhaps we’ll have hydrogen plants standing by. Perhaps gas with carbon capture will do the job. Perhaps nuclear will finally come back into fashion. I hope somebody knows. Because when I switch the kettle on, I don’t particularly want a policy. I want electricity.

There we go.