Floatovoltaics Viability Map

Floating PV (FPV) systems use specially designed buoyant pontoon platforms that support solar panels over the water surface. In the UK, these are typically anchored to the reservoir bed using cables, with electrical output transmitted via marine-grade underwater cables to a junction box on the bank. Larger installations use inverters on floating platforms or on the bank. UK reservoirs, being typically man-made, already have grid connections serving water treatment works — which can often accept solar export without significant infrastructure upgrades.

Yes. The UK has operational FPV installations — most notably the 6.3 MWp system at Queen Elizabeth II Reservoir in Walton-on-Thames (Thames Water, 2016 — one of Europe's first), and several gravel pit and quarry installations in the South East. As of 2025, the UK FPV pipeline has grown significantly, with projects at multiple operational reservoirs and numerous planning applications across England. The technology is proven; the constraint is planning, ecological consent, and operator appetite.

FPV systems on reservoirs typically require planning permission from the local planning authority (LPA), as the water surface is generally not covered by the same permitted development rights as building-integrated or ground-mounted solar. For any site within or adjacent to an SSSI, SPA, SAC, or Ramsar site, consent from Natural England (or NatureScot/SNHRE in Scotland) is also required. Environmental Impact Assessment (EIA) is mandatory for FPV systems above 0.5 MWp. Ecological surveys (breeding bird, wintering bird, aquatic ecology) are typically required.

Research shows mixed effects. Reduced light penetration can decrease algae growth (beneficial in eutrophic reservoirs) but may reduce food availability for some fish species. The floating structures provide shelter and foraging opportunities for some bird species. The main ecological concerns are for migratory birds using reservoirs as resting/feeding sites — panels covering more than 10–15% of a water body risk displacing these populations. Responsible FPV development includes seasonal access management and ongoing monitoring as a planning condition.

As of 2025, the Sungrow-supplied 8.5 MWp project at Whittle Colliery (a former industrial lagoon, not a drinking water reservoir) is one of the UK's largest operational FPV sites. The 6.3 MWp Queen Elizabeth II Reservoir (Thames Water) remains the largest FPV system on a drinking water reservoir. Multiple projects in the 20–50 MWp range are in planning or early development across the UK (2025–2027), including sites in Cambridgeshire and Kent.