Efficiency (solar)

Efficiency (solar)

Solar efficiency describes the share of solar energy that a photovoltaic cell or solar module can convert into electrical energy. It is a key indicator of the efficiency of PV systems and directly affects energy yield per area and economic performance.

How it works

Incoming solar radiation strikes a solar cell. Part of this energy is converted into electricity, while the rest is lost as heat or reflection.

Efficiency indicates what percentage of the incoming solar energy is actually converted into electrical energy — for example 20% in modern monocrystalline modules.

Efficiency always depends on the cell type, module design, temperature, and irradiation conditions.

Typical applications

• Selection of PV modules where roof or ground area is limited
• Comparison of different module technologies (e.g. monocrystalline vs. polycrystalline)
• Business case calculations for solar power plants
• Planning of Agri-PV or façade systems with specific requirements
• Optimization of yield per square meter in combination with Battery Energy Storage Systems (BESS)

Key figures

• Cell efficiency (%): laboratory value of individual solar cells (up to approx. 26%)
• Module efficiency (%): actual efficiency of complete solar modules (typically 18–22%)
• System efficiency: overall efficiency of the system including inverter and cable losses
• Temperature coefficient: power loss when module temperature rises (e.g. –0.35% / °C)
• Area yield (kWh/kWp/m²): amount of electricity generated per installed capacity and area

Summary

Solar efficiency is a key parameter for evaluating the performance and land use of a PV system. Higher efficiency means that more electricity can be generated from the same area — which is particularly important where installation space is limited or high energy yields are required.

Companies benefit from higher efficiencies through lower electricity generation costs and better use of available space.