A typical solar photovoltaic (PV) panel cooling system that uses water consumes on the order of about 15.6 liters of water per panel per day during operation when the panel temperature exceeds 45°C, as demonstrated in experimental research using a sprinkler system to cool panels and improve their efficiency. This amount was observed with small 36–37 W panels cooled intermittently during the hottest parts of the day.
For large-scale systems, water use for cooling can be much larger when cooling is done by evaporation. For example, in a calculated scenario of a 100 MW·hour solar panel system with approximately 200,000 panels, daily water consumption for cooling by evaporation was estimated at about 742 cubic meters (742,000 liters) per day. This calculation assumes each panel requires about 3.7 kg (liters) of evaporated water daily to reduce panel temperature from 45°C to 35°C.
However, it is important to distinguish between solar photovoltaic (PV) panels and solar thermal power plants:
- Typical PV panels do not require water for electricity generation or cooling; water is mainly used for occasional cleaning (washing) to maintain efficiency, which uses very minimal amounts compared to traditional power plants—on the order of 2 gallons (~7.5 liters) per megawatt-hour or less.
- Solar thermal power plants that generate electricity from concentrated sunlight often do use water for cooling turbines or heat transfer. Some use wet cooling, which can involve significant water consumption, but many are adopting air or dry cooling to reduce this.
In summary:
| Cooling System Type | Water Use Per Day (Approx.) | Notes |
|---|---|---|
| Small-scale PV panel spray cooling | ~15.6 liters per panel (36–37 W module) | Intermittent spraying above 45°C improves power output |
| Large-scale evaporative cooling for PV | ~3.7 liters per panel daily × number of panels; e.g., 742,000 liters for 200,000 panels (100 MW·hour system) | Evaporative cooling requiring substantial water, mostly practical in dry climates |
| PV panel cleaning (maintenance) | Very low; around 2 gallons per MWh (~7.5 L/MWh) | Usually done once or twice per year to eliminate dust/dirt |
| Solar thermal power plants with wet cooling | Hundreds to thousands of gallons per MWh | Water used for turbines/heat exchangers; can be reduced with dry cooling |
Therefore, a typical solar panel water cooling system for small panels consumes roughly 15.6 liters of water per day per panel when actively cooled by spraying water, while large-scale evaporative cooling systems may consume thousands of liters per day depending on system size and climate. Actual water consumption depends heavily on technology used and climate conditions.
Photovoltaic panels themselves do not need water cooling during electricity generation, making solar PV one of the most water-efficient energy technologies. Water is mainly consumed during cleaning or specialized cooling systems designed to improve efficiency in hot climates.
Original article by NenPower, If reposted, please credit the source: https://nenpower.com/blog/how-much-water-does-a-typical-solar-panel-cooling-system-consume-daily/
