Floating Solar: The UK's 3.2 GW Reservoir Opportunity

FPV arrays sit on engineered floats anchored to the reservoir bed. The water below keeps modules 5-12°C cooler than identical land-based panels, delivering 8-11% higher annual yield. Algal growth is suppressed in shaded zones (a benefit for drinking water reservoirs). And the planning friction is dramatically lower — you're not converting agricultural land.

The QEII reservoir near Walton-on-Thames hosts the UK's flagship FPV: 6.3 MW across 23,000 modules, supplying ~25% of Thames Water's local pumping demand. Performance ratio 84.2% (vs 78-80% typical for UK ground-mount).

The UK has 2,800 reservoirs over 1 hectare. The Environment Agency, Scottish Water, Welsh Water, Thames Water, Severn Trent, Yorkshire Water, and Northern Ireland Water collectively own ~62,000 hectares of water surface. Covering just 5% in FPV (with conservative spacing for maintenance access and bird flight corridors) delivers 3.2 GW of peak capacity — enough to power ~1.1 million homes.

The South West Water region alone has 110 reservoirs that pass all engineering filters (depth >2 m, surface area >2 ha, grid access <2 km). Cumulative potential: 420 MW.

Floats must survive 25 years of UV, ice, biofouling, and wave loading. Modern HDPE floats are warrantied to 20 years; the industry is rapidly converging on standards. Mooring is bespoke per site — anchored to reservoir bed where possible, tensioned shoreline where not. Cable management uses submarine cables (£12-£28/m) routed to a shoreline inverter shed.

Bird strike is the most-asked-about concern. Pre/post studies at QEII and elsewhere find net-positive effects: black-headed gulls, coots, and waterfowl rapidly adopt the arrays as roosting and nesting platforms. Maintenance teams report more bird droppings than expected and very few collisions.

Capex for utility-scale FPV: £820/kW (vs £680/kW for ground-mount). LCOE: £52/MWh (vs £58/MWh for residential rooftop). The capex premium is more than offset by higher yield, lower land-rental costs, and faster planning.

The CFD AR6 auction (2024) cleared FPV at £45/MWh — competitive with onshore wind. AR7 in late 2026 is expected to allocate a dedicated FPV bucket, which would accelerate development by 18-24 months.

Three projects to watch in 2026-27: Wraysbury (28 MW, Thames Water, COD Q4 2026), Kielder Water (40 MW, Northumbrian, COD 2027), and Llyn Brianne (proposed 22 MW, Welsh Water, planning Q3 2026). Combined, these will quadruple UK FPV capacity.

We're also seeing the first hybrid wind+FPV+battery proposals — the resource synergy is compelling. Watch the Trent valley and Severn estuary for combined projects in 2027-28.