Floating solar panels on reservoirs: the innovation that doubles efficiency

Floating solar panels ('floatovoltaics') are one of PV's most promising innovations. China deployed them first in 2014. Today 6 GW installed globally. Spain starts in 2025.

Why on water

1) Water keeps panels 9-18 °F cooler than land: production +5-10%. 2) Covers usable surface without occupying farmland. 3) Reduces reservoir evaporation 30-70%. 4) Shading water slows algae growth. Triple benefit.

How they're built

HDPE polyethylene modular floating platform. Each module supports 1-2 panels. Anchored to bottom or shore with stainless steel cables. Special submarine cabling. Inverter on shore, not floating.

World's largest installs

Dezhou, China: 320 MW (under construction 2025). Shengfa, China: 200 MW operational. Sirindhorn, Thailand: 45 MW. Alqueva, Portugal: 5 MW (Europe's largest). USA: limited deployments under 5 MW (Healdsburg CA, Sayreville NJ).

Cost and ROI

20-30% pricier than ground-mount due to flotation. But +5-10% production and no land cost = similar or better IRR. Platform lifespan: 25 years. Maintenance more complex (boat access).

Residential application: limited

Not for your pool (panels would block use). Yes for irrigation ponds on large property, private lakes or slow rivers. Cost-benefit only positive above 50 kWp. For homes, traditional install always wins.

Risks to consider

Earthquakes can break anchors. Storms with big waves damage panels. Ice in cold climates: breaks structure. Hence only viable in calm waters and mild climates.

Compare with agrivoltaics.