Wind Energy in Great Britain: How Offshore Wind Powers Your Home
Great Britain is one of the world's leading nations for wind energy. Surrounded by the North Sea, the Irish Sea, and the Atlantic, the UK sits in a zone of persistent westerly winds that makes it one of the best locations on earth for generating electricity from wind.
Understanding how wind energy works — where it comes from, when it generates, and how it affects your electricity prices and carbon footprint — helps make sense of why some days are so much greener and cheaper than others.
GB Wind Capacity in 2026
Great Britain currently has around 30–32 GW of installed wind capacity:
| Type | Installed capacity | Key locations |
|---|---|---|
| Offshore wind | ~20 GW | North Sea, Irish Sea, Scottish coasts |
| Onshore wind | ~14 GW | Scotland, Wales, northern England |
Total: roughly 34 GW of wind capacity, with more coming online throughout 2026 and 2027 as projects from the CfD auctions complete construction.
On a very windy day, wind can generate 15–18 GW — covering 40–50% of total GB electricity demand. On a calm day, it may generate just 1–3 GW, requiring gas, nuclear, and imports to fill the gap.
You can see the current wind output in real time on the Generation Mix dashboard.
Offshore vs. Onshore: Why Offshore Dominates
Most of the recent expansion — and most of the capacity additions to come — is offshore. Here's why:
Stronger, more consistent wind: Offshore wind speeds are typically 15–25% higher than onshore in the same region, and more consistent. Higher wind speed = much more power (power scales with the cube of wind speed, so 20% more wind = 73% more power).
Larger turbines: Without the planning constraints and visual impact concerns of onshore wind, offshore turbines can be much larger. The latest turbines (Vestas V236, Siemens Gamesa SG 14-222) have rotor diameters of over 220 metres and generate 14–15 MW each — enough to power thousands of homes from a single turbine.
Hornsea 1 and 2: Located in the North Sea off the Yorkshire coast, Hornsea 1 (1.2 GW) and Hornsea 2 (1.4 GW) are among the largest offshore wind farms in the world. Hornsea 3 and 4 will add further capacity.
Social acceptance: Onshore wind faces persistent local opposition in England, making planning approval difficult. Scotland and Wales have more onshore development. Offshore avoids many of these issues.
When Does Wind Generate?
Wind output is driven by weather systems passing across Great Britain. The key patterns:
Winter: The strongest and most consistent winds. Atlantic weather systems bring repeated windy periods from October through March. Wind is frequently the largest single electricity source in winter.
Summer: Generally lighter winds, more variable. Solar PV partly compensates during daylight hours.
Anticyclonic conditions: High pressure systems bring calm, settled weather — often the coldest and hottest spells. During anticyclone conditions in winter ("cold snaps"), wind can drop to very low levels for days at a time. This is when the GB grid is most stressed.
Day vs. night: Unlike solar, wind generates around the clock. Overnight wind is particularly valuable because demand is low — this is what creates the cheap overnight Agile price windows and low overnight carbon intensity.
How Wind Affects Carbon Intensity
Wind energy has a lifecycle carbon intensity of roughly 7–15 gCO2/kWh — around 20–30 times lower than natural gas (490 gCO2/kWh). When wind output is high, it displaces gas on the margin, dramatically reducing the carbon intensity of electricity.
The relationship is direct:
| Wind output (GB) | Typical carbon intensity |
|---|---|
| 15+ GW | 50–100 gCO2/kWh |
| 10–15 GW | 100–150 gCO2/kWh |
| 5–10 GW | 150–250 gCO2/kWh |
| Under 5 GW | 200–350 gCO2/kWh |
These figures vary with other factors (nuclear, solar, imports, demand levels), but wind output is the single strongest predictor of GB carbon intensity at any moment.
How Wind Affects Electricity Prices
Wind energy has near-zero marginal cost — once the turbine is built, generating another MWh costs almost nothing. When large quantities of wind are on the system, it pushes down the wholesale electricity price because:
- Wind generation offers into the market at low prices (near zero)
- This displaces more expensive gas generation, which sets the marginal price
- With less gas on the margin, the clearing price falls
This is why very windy nights can produce negative Agile prices — there's genuinely more electricity than the grid needs, and generators (including wind farms) effectively pay consumers to take it.
It's also why the Market Prices view shows such a strong correlation between wind generation and low prices.
Wind Curtailment: When There's Too Much
Sometimes the grid produces more wind than it can use:
- Demand is low (overnight, mild weather)
- The transmission network can't carry all the wind from Scotland to where demand is in England
- Interconnectors are already fully loaded with imports
In these cases, National Grid ESO pays wind farms to curtail — to switch off or reduce output despite having the wind to generate. Curtailment costs have run to hundreds of millions of pounds per year in recent years.
Home batteries, EVs, and smart appliances responding to cheap overnight prices help reduce curtailment by absorbing surplus wind electricity. This is one of the clearest arguments for consumer flexibility: it makes better use of renewable generation that would otherwise be wasted.
The Future: Floating Offshore Wind
Fixed-bottom offshore wind is limited to water depths of around 60 metres. Much of the best wind resource in the UK — particularly off the west coast of Scotland and the Atlantic — is in deeper water.
Floating offshore wind uses turbines on floating platforms anchored to the seabed. This unlocks enormous additional resource:
- Hywind Scotland (30 MW) is the world's first commercial floating wind farm, operating off Peterhead
- The Scottish government has awarded seabed leases for over 10 GW of floating wind
- Government targets include 5 GW of floating offshore by 2030
When operational, floating wind will further increase GB wind capacity and reduce the periods of low-wind dependency on gas.
What This Means for You
As a consumer, understanding wind's role in the grid helps you make better decisions:
- Check the forecast: Is it a windy day or a calm day? A windy day means cheaper electricity, lower carbon, and less gas consumption
- Time your flexible loads: Wind-heavy periods are the best times to charge EVs, run major appliances, or charge home batteries
- Understand price spikes: Calm winter periods drive high Agile prices — this is the market accurately reflecting grid stress
The Generation Mix dashboard shows wind's real-time contribution to GB electricity. It's the fastest way to see whether right now is a good time to charge your EV or wait.
Summary
- GB has 30–34 GW of installed wind capacity, predominantly offshore
- On windy days, wind covers 40–50% of GB demand — driving low carbon intensity and low prices
- Offshore wind is stronger, more consistent, and supports larger turbines than onshore
- Wind generates 24/7 — overnight wind is what makes cheap overnight Agile prices possible
- Calm anticyclonic periods are the grid's most stressed moments — when gas runs hardest and carbon is highest
- Floating offshore wind will open up far greater deep-water resources from 2026 onwards