Cluster 1 · What it is
Hornsea Two — the key facts
Complete specification
Location: North Sea, approximately 89 km off Humberside coast, East Yorkshire, UK
GPS: approximately 53.9°N 1.6°E (centre of wind farm zone)
Operator: Ørsted (Danish company — formerly DONG Energy, renamed Ørsted after selling oil assets)
Installed capacity: 1,386 MW (165 turbines × 8.4 MW average; turbines rated at 8.0 MW nominal)
Turbine model: Siemens Gamesa SG 8.0-167 DD (direct drive, 167 m rotor diameter, 87 m hub height)
Commissioned:
Capital cost: approximately £3 billion (~$3.8 billion)
Export cable: Two AC submarine cables to Horsea Island substation, Hull; connected to National Grid
UK Contract for Difference (CfD) strike price: £57.50/MWh (2015 auction, 2012 prices)
Homes equivalent: approximately 1.3 million UK homes/year
Source: Ørsted Hornsea 2 project page · GEM Wind Tracker CC BY 4.0
GPS: approximately 53.9°N 1.6°E (centre of wind farm zone)
Operator: Ørsted (Danish company — formerly DONG Energy, renamed Ørsted after selling oil assets)
Installed capacity: 1,386 MW (165 turbines × 8.4 MW average; turbines rated at 8.0 MW nominal)
Turbine model: Siemens Gamesa SG 8.0-167 DD (direct drive, 167 m rotor diameter, 87 m hub height)
Commissioned:
Capital cost: approximately £3 billion (~$3.8 billion)
Export cable: Two AC submarine cables to Horsea Island substation, Hull; connected to National Grid
UK Contract for Difference (CfD) strike price: £57.50/MWh (2015 auction, 2012 prices)
Homes equivalent: approximately 1.3 million UK homes/year
Source: Ørsted Hornsea 2 project page · GEM Wind Tracker CC BY 4.0
Context: Hornsea One and the wider complex
The Hornsea offshore wind zone
Hornsea One (adjacent, 1,218 MW)
Hornsea One (GPS: 53.87°N 1.17°E) was commissioned in 2020 and was itself briefly the world's largest offshore wind farm. 174 turbines × Siemens Gamesa SG 7.0-154 (7 MW each). Strike price: £119.89/MWh (2014 auction). Together Hornsea One and Two form a combined complex exceeding 2,600 MW — a single integrated offshore wind zone the size of Greater London.
Source: Ørsted Annual Report 2023 · BEIS CfD Register
Source: Ørsted Annual Report 2023 · BEIS CfD Register
Hornsea Three and Four (planned)
Ørsted received planning consent for Hornsea Three (2,400 MW) but cancelled it in 2023 when CfD auction maximum strike price was insufficient to cover rising construction costs. Hornsea Four (2,600 MW) is in planning. The cancellations reflect the offshore wind cost crisis of 2022–2023 when rising steel, cable, and financing costs made previously agreed prices uneconomic.
Source: Ørsted press release · UK DESNZ
Source: Ørsted press release · UK DESNZ
Questions
Questions people ask
Why is offshore wind so expensive?
Offshore wind costs £3 billion for 1,386 MW (~£2,166/kW) — roughly 2–3× the cost of onshore wind. The extra cost comes from: (1) Foundation installation in deep water (monopiles driven to 30–40 metres into the seabed by hydraulic hammers from jack-up vessels); (2) Submarine cable installation (expensive specialised cable-laying ships); (3) Higher maintenance costs (technicians travel by vessel or helicopter in rough North Sea conditions); (4) Anti-corrosion engineering for saltwater environment. The higher capacity factor (offshore 45–55% vs onshore 25–45%) partially offsets the extra capital cost. Source: Lazard LCOE 2024 · Ørsted Annual Report 2023.
Source: Lazard LCOE Analysis 2024 · Ørsted Annual Report 2023
What is the Siemens Gamesa SG 8.0-167 turbine?
The SG 8.0-167 DD is a direct-drive offshore wind turbine — "direct drive" means the turbine shaft connects directly to the generator without a gearbox, reducing maintenance complexity. The "8.0" refers to its 8 MW rated power. The "167" refers to its 167-metre rotor diameter — the swept area is approximately 21,900 m². Hub height: 87 metres above sea level. The tip of the blade reaches approximately 170 metres above sea level. At Hornsea Two's typical 8+ m/s average wind speed, the turbines spend most of their operational hours at or near rated output. Siemens Gamesa (now fully owned by Siemens Energy) is one of the world's three dominant offshore wind turbine manufacturers alongside GE Vernova and Vestas. Source: Siemens Gamesa product documentation.
Source: Siemens Gamesa SG 8.0-167 product documentation
How much electricity does Hornsea Two produce annually?
Hornsea Two generates approximately 5,900 GWh per year — enough to power approximately 1.3 million UK homes (Ørsted estimate at ~55% capacity factor). For context: the average UK home uses approximately 4.5 MWh/year. At 48% average capacity factor (conservative), 1,386 MW × 0.48 × 8,760 hours = 5,828 GWh/year. The UK's total electricity consumption is approximately 340 TWh/year — Hornsea Two alone supplies approximately 1.7% of total UK electricity. Source: Ørsted Hornsea 2 project documentation · BEIS UK electricity statistics.
Source: Ørsted Hornsea 2 · BEIS/DESNZ UK Energy Statistics
What is a Contract for Difference (CfD) and how did it fund Hornsea Two?
A Contract for Difference (CfD) is the UK government's main mechanism for supporting new renewable electricity. Developers bid a "strike price" — the minimum price per MWh they need to finance the project. If the market electricity price falls below the strike price, the government pays the difference to the developer. If the market price rises above, the developer pays back the difference — protecting bill-payers. Hornsea Two's CfD strike price was £57.50/MWh (2015 Round 2 auction, in 2012 prices — approximately £70–75/MWh in 2022 prices accounting for inflation). This was a landmark low price that demonstrated offshore wind could compete with gas. The CfD gave Ørsted 15-year revenue certainty, enabling project financing at low cost. Source: UK DESNZ CfD register · BEIS.
Source: UK Department for Energy Security and Net Zero · CfD Allocation Round 2 results
What is the offshore wind outlook for India and Asia?
India has approximately 70 GW of offshore wind potential identified by NIWE (National Institute of Wind Energy), primarily in the Gulf of Khambhat (Gujarat) and off Tamil Nadu. India's first offshore wind auction was planned for 2023–2024. The government targets 30 GW of offshore wind by 2030 under the National Offshore Wind Energy Policy. Key challenges: deep waters along much of India's coast require floating foundations (more expensive than fixed monopiles used at Hornsea Two), and the supply chain for offshore installation vessels does not yet exist in India. Asia-Pacific offshore wind is dominated by China (globally the largest offshore market, ~37 GW in 2023), Taiwan, Japan, and South Korea. Source: GWEC Global Offshore Wind Report 2024 · NIWE India · MNRE India.
Source: GWEC Global Offshore Wind Report 2024 · NIWE India · MNRE National Offshore Wind Energy Policy
How long do offshore wind turbines last?
Offshore wind turbines are designed for a 25-year operational lifetime — the period over which financing is typically structured. In practice, components degrade and are replaced: blades (GRP composite) last approximately 15–20 years before refurbishment or replacement; gearboxes (where present) approximately 10–15 years; tower and foundations (steel) can last 40+ years with corrosion management. "Life extension" — continuing operation beyond 25 years after structural assessment — is increasingly common as early offshore wind farms (built 2002–2010) approach end-of-design-life. Alternatively, "repowering" replaces old turbines with larger, more efficient models on existing foundations. Hornsea Two, commissioned in 2022, would reach end of designed life around 2047. Source: ORE Catapult · WindEurope.
Source: ORE Catapult Offshore Wind Cost Reduction Pathways · WindEurope Life Extension Studies
ØrstedHornsea Two project data · Annual Report 2023orsted.com/investors
GEM Wind TrackerGlobal Wind Power Tracker · GPS, capacity · CC BY 4.0globalenergymonitor.org/wind-tracker
UK DESNZCfD register · Hornsea Two strike price and contractgov.uk/contracts-for-difference
Siemens GamesaSG 8.0-167 DD turbine specificationssiemensgamesa.com