Turning reservoirs into power stations – without losing an acre of farmland
Floating solar farms, sometimes called floatovoltaics, are solar panel arrays mounted on buoyant platforms that float on bodies of water. Rather than using valuable agricultural land, these installations sit on reservoirs, lakes, quarry ponds, and industrial water bodies. The panels work exactly like land-based systems but benefit from water cooling that boosts efficiency by 10-15%, while also reducing water evaporation and algal growth beneath them.
The UK has significant untapped potential for floating solar. Research from Bangor and Lancaster universities found that covering just 10% of eligible UK water bodies could generate 2.7 TWh of electricity annually, enough to power around one million homes. Parliamentary estimates suggest covering 15% of UK reservoirs could add 16GW of capacity and effectively double the nation’s current solar generation without touching an acre of farmland.
This guide explains how floating solar works, the current UK installations, the potential for expansion, costs and benefits, environmental considerations, and whether floatovoltaics could solve the tension between solar development and agricultural land preservation.
Floating Solar at a Glance
What it isPanels on buoyant platforms
Largest UK installationQEII Reservoir (6.3MW)
Largest approvedPort Barrow, Cumbria (40MW)
UK potential (10% coverage)2.7 TWh/year (1m homes)
Efficiency benefit10-15% higher than land-based
Global capacity (2022)13GW; 62GW projected by 2030
Standard PV modules (often with anti-corrosion coating)
Mooring system
Anchors and cables fixing array position
Electrical cables
Underwater cables connecting to shore
Inverters
Usually shore-based; convert DC to AC
Grid connection
Links to local network or private wire
Why Water Improves Performance
Factor
Benefit
Cooling effect
Water keeps panels cooler; efficiency drops ~0.5% per °C above 25°C
Chimney effect
Cool air from water surface rises past panels
Less dust
No ground-level dust accumulation
Reflection
Some additional light reflected from water surface
Net efficiency gain
10-15% more output than equivalent land installation
Current UK Floating Solar Installations
Queen Elizabeth II Reservoir
Location
Walton-on-Thames, Surrey
Capacity
6.3MW
Panels
23,046
Floats
61,000
Coverage
57,000 m² (approximately 10% of reservoir)
Annual output
5.8 million kWh (~1,800 homes)
Completed
March 2016
Purpose
Powers ~20% of adjacent water treatment works
Other UK Installations
Project
Location
Capacity
Status
Godley Reservoir
Greater Manchester
~3MW
Operational (2015)
Port of Leith
Edinburgh
Small scale
Operational (2023)
Port Barrow
Cumbria
40MWp
Approved (construction pending)
Whisby Solar Lakes
Lincolnshire
Up to 18MW
Proposed
UK’s largest approved: The Port Barrow project at 35-40MWp will feature approximately 47,000 panels on 60 hectares of floating pontoons. Approved in late 2025, it will become the UK’s largest floating solar farm when completed.
UK Floating Solar Potential
Research Estimates
Study
Finding
Bangor/Lancaster Universities
2.7 TWh/year possible (10% coverage of eligible lakes)
UK Parliament estimate
16GW potential covering 15% of reservoirs
Current UK solar capacity
~17GW installed
Doubling potential
Floating solar could match current ground-mounted capacity
Suitable Water Bodies
Type
Suitability
Notes
Drinking water reservoirs
Excellent
Water authority approval; evaporation benefits
Quarry lakes
Very good
Brownfield; often private ownership
Industrial ponds
Very good
Water treatment; mining; cooling
Agricultural reservoirs
Good
Farmer income opportunity
Recreational lakes
Limited
Public access conflicts
Natural lakes
Challenging
Environmental designations; landscape concerns
Costs and Economics
Cost Comparison
Factor
Floating Solar
Ground-Mount Solar
Upfront cost
10-15% higher
Baseline
Land cost
Lower (water leases)
Higher (land purchase/lease)
Energy output
10-15% higher efficiency
Baseline
Maintenance
Slightly higher (boat access)
Easier access
Lifetime cost/kWh
Comparable or lower
Baseline
Economic Benefits
No land use competition
Preserves agricultural land and avoids planning conflicts
Limited with appropriate coverage; can provide shade
Plastic degradation
HDPE floats rated for 25+ years; recyclable
Visual impact
Site-specific; reservoirs often screened
Coverage Limits
Environmental guidelines typically recommend covering no more than 10-30% of a water body surface to maintain healthy aquatic ecosystems. Most UK projects target 10-15% coverage, balancing energy generation with environmental protection.
Global Context
Worldwide Growth
Year
Global Installed Capacity
2018
1 GW
2020
3 GW
2022
13 GW
2030 (projected)
62 GW
Leading Countries
Country
Status
China
World leader; largest installations (100s MW)
India
Major growth; reservoir focus
Japan
Early pioneer; limited land drove adoption
Netherlands
European leader
UK
Early mover (2016) but limited growth since
Summary
Floating Solar – Key Facts
What it isSolar panels on floating platforms anchored to water
UK potentialCould double solar capacity without using farmland
Efficiency benefit10-15% higher output than land-based
Current UK capacity~10MW operational; 40MW approved
Environmental benefitsReduces evaporation, algal blooms; preserves land
Main barrierHigher upfront costs; limited policy support
Floating solar represents a significant opportunity for the UK to expand renewable energy capacity without the controversial use of agricultural land. Research suggests covering just 10-15% of suitable UK water bodies could generate enough electricity for over a million homes and potentially double the nation’s installed solar capacity. The technology is proven, with the Queen Elizabeth II reservoir installation operating successfully for over a decade.
Water cooling improves panel efficiency by 10-15% compared to ground-mounted systems, while the shade provided reduces water evaporation by up to 70% and helps control algal blooms. These co-benefits make floating solar particularly attractive for water utilities, who can generate clean power while protecting their water resources.
However, the UK sector remains small despite early leadership. Higher upfront costs, limited specialist expertise, and a lack of specific policy support have slowed deployment. The approval of the 40MW Port Barrow project signals growing interest, and parliamentary debate has highlighted the technology’s potential to resolve the tension between solar development and food security.
For landowners with suitable water bodies, floating solar offers potential income without losing productive land. For the UK’s renewable energy targets, reservoirs and industrial water bodies represent an untapped resource that could deliver gigawatts of clean capacity with minimal controversy.
