Percentage Solar Energy

Building a solar energy system that covers 100% peak electrical power needs is expensive and impractical as utility companies will not reimburse consumers (at year end) for excess electricity produced. 

When solar is installed, consumers are usually required to convert to a time-of-use tariff schedule where different utility rates are paid for electricity depending on the time of day.  A solar system generates the most energy during midday, when electricity demand is at a peak and utility tariffs are at their highest.  As most of this energy is fed back into the grid (because the homeowner is at work), significant credit is built up under net-metering rules.  Homeowners use up a portion of these credits in the evening, when overall electricity demand has dropped, and utility rates are at their lowest.      

The net result of selling at a high utility rate and buying or using power at a low utility rate (under net metering rules) creates significant value for consumers.  Accordingly, solar electric systems are usually sized between 50% and 60% of the maximum/peak electric power required which equates to 70%-85% of total electric utility expense.