How to calculate the energy production for a 5 kW PV system is based on several factors, including the rated power of the system, location-specific solar conditions, and the efficiency of the equipment used. Here's how you can calculate approximately how much energy such a system will produce in a year:
Calculation formula for annual energy production:
Annual production (kWh/year) = System power (kW) × Number of sunshine hours per day (h/day) × Number of days per year (day/year) × System efficiency (%)
System power (kW): In this case, it is a 5 kW system. This represents the maximum power that the system can produce under ideal conditions.
The number of hours of sunshine per day: It varies according to geographical location and climatic conditions. For example:
- The southern area of Romania (eg: Bucharest, Constanța): on average, 4-5 hours of sun per day during a year.
- Central area (eg: Brașov, Sibiu): approximately 3.5-4 hours per day.
- The northern area of Romania (eg: Suceava, Bistrita): approximately 3 hours per day.
Number of days per year: There are 365 days in a year, but depending on the summer and winter season, PV systems will produce more energy in summer than in winter.
System efficiency: Although a PV system is rated at 5 kW, it will not always operate at full capacity due to variable sunlight conditions. Typically, system efficiency is around 80-90% of the theoretical value. So, we will use an efficiency factor of 0.8 (80%).
Calculation example for annual energy production:
Let's assume that the system is installed in an area with 4 hours of sun per day (in the south of Romania) and with an efficiency of 80%:
Annual production = 5 kW × 4 hours/day × 365 days/year × 0.8
Annual production = 5 × 4 × 365 × 0.8 = 5,840 kWh/year
So the 5 kW system will produce approx 5,840 kWh per year.
Other considerations:
- In the summer, when there are more hours of sunshine and the days are longer, the system can produce much more than in the winter, when the sunlight is weaker and the days are shorter.
- If your home or business consumes less energy than the PV system produces, the excess can be stored in batteries (if the system is off-grid or hybrid) or sold back into the grid (in the case of an on-grid system).
Conclusion:
This calculation is an estimate and may vary depending on specific installation conditions, panel orientation, shading and other factors. A 5 kW photovoltaic system in southern Romania could produce approx 5,000 – 6,000 kWh per year, while in the more northern areas of the country production would be lower. These estimates can be refined with the help of a specialist who can specifically assess the local conditions of each location.
