For the first time, wind is the single largest source of electricity in Great Britain. In 2025 wind turbines generated more than 85 terawatt-hours (TWh) — close to 30% of everything the grid produced — overtaking gas. The country splits its wind fleet almost evenly between turbines on land and turbines at sea, and it is racing to roughly triple the offshore total by 2030. But the same success has exposed a hard problem: Britain is building turbines faster than it is building the wires to carry their power south, and the bill for that mismatch is now measured in billions. This article walks through the whole picture — onshore, offshore, the build pipeline, floating wind, and the grid bottleneck that keeps forcing perfectly good turbines to stop.
Current status of the UK grid
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1. Wind on the land: onshore
Onshore wind is the cheapest large-scale power source Britain can build, and it quietly does an enormous amount of work. The UK has roughly 15–16 GW of onshore capacity spread across hundreds of wind farms, the bulk of it in Scotland, Wales and the windier uplands of England. Because turbines on land are cheaper and faster to erect than anything offshore, onshore wind has long been the backbone of the renewable fleet — even though a decade of restrictive planning rules in England slowed new building to a crawl.
That is now changing. The effective ban on new English onshore wind was lifted, and the government wants to nearly double the fleet: its target is 27–29 GW of onshore wind by 2030. Industry forecasters think something closer to 23 GW is realistic on current planning and grid timelines — still a very large jump from where we are today.
2. Wind at sea: offshore
Offshore is where Britain leads the world. The UK has around 16.6 GW of offshore wind operational as of early 2026, with a further 11.7 GW already under construction in the North Sea. Offshore turbines are far bigger than their onshore cousins — the newest are over 260 metres tall with single blades longer than a football pitch — and they sit in some of the windiest, shallowest seas on Earth. In 2025, offshore wind alone produced about 52 TWh, roughly 19% of UK electricity.
The crown jewels sit off the Yorkshire coast. The Hornsea zone is the largest offshore wind complex on the planet, with more than 5 GW of combined capacity, and the neighbouring Dogger Bank project is on track to overtake it. Both are effectively small power stations built out of seawater and steel.
Figure 1 — UK wind capacity, onshore vs offshore (approximate, GW). Onshore built out first and has grown slowly through a decade of tight English planning rules; offshore has climbed steeply and is now roughly level with onshore. The dashed markers show the government's 2030 ambitions — around 27–29 GW onshore and 43–50 GW offshore. Figures are rounded to show the trend.
3. What's actually being built right now
Nearly 12 GW of offshore wind is under construction at this moment — a build-out bigger than the entire existing offshore fleet of most countries. The two headline projects dominate the North Sea skyline:
| Project | Capacity | What's happening | Status |
|---|---|---|---|
| Dogger Bank A/B/C | 3.6 GW | All 95 turbines installed on phase A (Feb 2026); full commissioning targeted 2027 | Building |
| Hornsea 3 | ~2.9 GW | Up to 231 × 14 MW turbines; first export cable laid March 2026; complete end-2027 | Building |
| Moray West, EA3, others | ~5 GW+ | A cluster of Scottish and East Anglian projects in construction and commissioning | Building |
Dogger Bank, when fully commissioned, will be the world's largest offshore wind farm. Hornsea 3 connects to the grid via two HVDC cables landing in Norfolk. Together these projects add roughly 2.6 GW of new capacity coming online during 2026 alone — about a 20% jump in the offshore fleet in a single year.
4. What's planned — and the new bids
Behind the diggers sits a much larger pipeline of projects that are consented, contracted or being competed for. Three things define the 2026 outlook.
The record-breaking AR7 auction (January 2026)
The government's main lever for building offshore wind is the Contracts for Difference (CfD) auction, which guarantees developers a fixed "strike price" for their power. The seventh round, AR7, closed in January 2026 and was the biggest ever: it secured a record 8.4 GW of offshore wind — more than double the previous round — after ministers used new powers to roughly double the budget mid-auction, from £900 million to about £1.8 billion. Projects cleared at a strike price of about £91/MWh (up around 11% on the year, reflecting higher financing and supply-chain costs), and the round is expected to unlock some £22 billion of private investment and power up to 12 million homes. RWE alone took contracts for 6.9 GW.
The leasing rounds: ScotWind and the Celtic Sea
Further out sits the seabed itself, leased by the Crown Estate. Two rounds matter:
- ScotWind — one of the world's largest leasing rounds, with around 28–30 GW of Scottish seabed awarded, most of it earmarked for floating turbines in deeper water.
- Celtic Sea Round 5 — up to 4.5 GW of floating wind off South Wales and South West England, with preferred bidders (Equinor, an EDF/ESB venture, and Ocean Winds) selected through 2025. The government wants space for a further 12 GW in the Celtic Sea beyond this.
These are not yet under construction — they are the 2030s pipeline — but between AR7, ScotWind and the Celtic Sea, the UK has visibility on far more wind than it can currently connect to the grid. Which brings us to the two topics that will decide whether all this steel actually delivers cheap power: floating turbines, and the grid.
5. Floating wind: the new frontier
Almost every offshore turbine spinning today is fixed-bottom — its foundation is driven into the seabed, which only works in water up to about 60 metres deep. That rules out most of the deep Atlantic and much of the North Sea off Scotland, exactly where the wind is strongest and most constant. Floating offshore wind solves this: the turbine sits on a buoyant platform, tethered to the seabed by mooring lines and cables, so it can be placed in water hundreds of metres deep.
Britain is one of the leaders. It already runs early pilot arrays (Hywind Scotland and Kincardine), and the near-term commercial pipeline is now taking shape:
| Project | Capacity | Notes | Status |
|---|---|---|---|
| Green Volt (Scotland) | 560 MW | INTOG lease; poised to be one of Europe's first large commercial floating farms. FID due 2026, power ~2030 | Consented |
| INTOG round (Scotland) | up to 5.5 GW | 13 projects tied to decarbonising North Sea oil & gas platforms plus innovation sites | Leased |
| Celtic Sea Round 5 | up to 4.5 GW | Preferred bidders selected 2025; commercial-scale floating off Wales & SW England | Planned |
| White Cross (Celtic Sea) | ~100 MW | Test & demonstration array 52 km off North Devon | Planned |
Floating wind is still more expensive than fixed-bottom — the platforms, moorings and dynamic cabling add cost — but it unlocks vastly more sea area and steadier wind. If Green Volt and the Celtic Sea projects deliver on time, the UK could have the first meaningful gigawatts of commercial floating wind spinning by the end of the decade.
6. The elephant in the room: paying wind farms to switch off
Here is the uncomfortable truth behind the good-news headlines. Most of Britain's best wind — onshore and offshore — is in Scotland and the North Sea. Most of the electricity demand is in England, especially the South East. The wires connecting the two are not big enough. So on windy days there is more power in the north than the cables can carry south, and the grid operator has to pay Scottish wind farms to stop generating — and then pay gas plants in England to switch on to make up the shortfall. This is called constraint (or curtailment), and it is expensive twice over.
What we spent in 2025
Britain spent roughly £1.5 billion in 2025 managing this bottleneck — about £380 million paying wind farms to turn down, plus around £1.08 billion paying gas plants to turn up to replace the wasted wind. Direct curtailment payments to wind were about £363m. On the worst single days, more than £1 million was paid just to switch turbines off. For a typical household, constraint costs added somewhere around £15–35 to the annual electricity bill — and every bit of it is money spent on power that was never delivered.
And it is getting worse before it gets better, because turbines are being connected faster than the grid can be reinforced. Constraint costs have risen more than five-fold since 2020, when they were around £280 million. The national system operator (NESO) warns that on current trends the annual bill could reach £8 billion a year by 2030 if the wires aren't built in time — and even in the better scenarios it stays in the £2.8–4 billion range.
Figure 2 — The cost of the bottleneck (£ billion/year, approximate). Total constraint spending — wind turned down plus gas turned up — has climbed steeply since 2020. The amber bars show NESO's 2030 range: as low as ~£3 billion if the grid upgrades land on time, as high as ~£8 billion if they slip. Actuals rounded; 2030 figures are forecasts, not certainties.
The fix: the Great Grid Upgrade and the "bootstraps"
The answer is not more turbines — it's more copper. Britain is embarking on the biggest expansion of its high-voltage network in generations, the so-called Great Grid Upgrade, lifting transmission investment from an average of about £11 billion a year over the last four years to well over £40 billion a year through 2030. The single most important pieces are the north-south links that will finally let Scottish wind reach English demand.
Chief among them are the Eastern Green Links — giant subsea HVDC "bootstrap" cables running down the seabed from Scotland to England, each carrying about 2 GW. (They're often loosely called "interconnectors", though strictly an interconnector links two countries; these link two ends of Britain.)
| Link | Capacity | Route | Target online |
|---|---|---|---|
| Eastern Green Link 1 | 2 GW | Torness → Hawthorn Pit (Co. Durham) | ~2029 |
| Eastern Green Link 2 | 2 GW | Peterhead → Drax (Yorkshire) | ~2029 |
| Eastern Green Link 3 | 2 GW | Peterhead → Lincolnshire | ~2033–34 |
| Eastern Green Link 4 | 2 GW | Westfield (Fife) → Lincolnshire | ~2033 |
EGL1 and EGL2 are already in construction; EGL3 and EGL4 are financed and consented but arrive later in the decade. A fifth link (EGL5) is advancing through planning. Onshore, the equally critical Norwich to Tilbury and Sea Link projects in the east of England are the ones NESO singles out as make-or-break: delivering them on time could cut constraint costs by around £4 billion.
The prize is large. NESO estimates that delivering the bulk of the planned transmission projects on schedule would cut constraint costs by roughly threefold — turning a potential £8 billion-a-year problem into something closer to £2–3 billion, and eventually far less as the network catches up with generation. In effect, the money spent on cables now is spent to stop spending money on switching turbines off later.
So how much will we spend just turning turbines off?
Put the numbers end to end and the scale becomes clear. Britain has already spent on the order of £6–7 billion on constraint management cumulatively across 2020–2025. Looking forward, even on an optimistic path where the grid upgrades broadly land on time, annual costs stay around £2.5–4 billion through the second half of the decade; on a pessimistic path they climb toward £8 billion. That points to a plausible cumulative bill of £15–25 billion between 2026 and 2030 — money spent not on generating electricity, but on managing the fact that we built the turbines before we built the wires. It is, bluntly, the single largest avoidable cost in Britain's wind story — and the one number that will decide whether the public sees wind as a bargain or a boondoggle.
The bottom line
UK wind in mid-2026 is a genuine success with a genuine flaw. Wind is now the country's biggest power source; the offshore fleet is the envy of the world; the pipeline — a record AR7 auction, ScotWind, the Celtic Sea, and the first commercial floating turbines — is enormous. But the grid that carries all this power was built for a different era, and until the Eastern Green Links and the eastern England reinforcements are finished around 2029–2030, Britain will keep paying billions to switch its cleanest, cheapest electricity off. The turbines aren't the hard part any more. The wires are.