Commercial Solar Power Systems

The number of average daily sun hours is referred to as “solar insolation.”   Peak sun hours refers to the solar insolation which a particular location would receive if the sun were shining at its maximum value for a certain number of hours. Since the peak solar radiation is 1 kW/m², the number of peak sun hours is numerically identical to the average daily solar insolation. For example, Baltimore receives 4.7 kWh/m² per day, which then means that Baltimore  receives 4.7 hours of sun per day at 1 kW/m².

The daily amount of solar radiation striking any location  varies from sunrise to sunset due to clouds, the sun’s position in the sky, and the atmosphere. Maximum solar radiation occurs at solar noon—the time when the sun is highest in the sky, compared to the rest of the day. Sunlight in the morning and evening does not deliver as much energy as it does during midday because at low angles, there are more atmospheric filters to sunlight. Besides day-to-day differences, there are also seasonal effects.

In midsummer, due to the sun’s higher position in the sky, an hour of sunshine packs more energy than the same hour of sunshine in the winter.  Power production for commercial solar power system installations will be greater during the summer because of the sun’s more direct position over an installed PV array.