Sizing Photovoltaic Systems for Business

The right size gives the best possible return

An oversized installation produces surplus energy that you may not receive full compensation for, while an undersized installation fails to realise its potential. The key is to match production with consumption patterns.

Step-by-step calculation

1. Analyse your energy consumption (preferably with 15-minute data). 2. Map available roof area and orientation. 3. Calculate potential production using local solar data. 4. Assess the share of self-consumption vs surplus sales. 5. Add a BESS if the self-consumption share can be significantly increased.

Rules of thumb

A typical Norwegian industrial roof with good orientation can accommodate approximately 150–200 Wp per square metre. This means a 1,000 square metre roof can host a 150–200 kWp system producing 120,000–200,000 kWh per year. At current electricity prices, the payback period can be 5–8 years.