Taking the Mystery Out of Grid-Tied Solar Power Systems

A main concern for many individuals who thinking about investing in a solar photovoltaic (PV) system is whether or not the electricity it provides will be constant enough to meet their electricity demands. This is a valid concern considering that the sun doesn’t shine all day long, nor does it generate the same quantities of radiant heat at all hours of the day. Put simply, solar is a variable resource.

A grid-tied solar power system resolves this issue. A grid-tied solar power system is one that is connected to the electrical grid. In this way, home and business owners never have to go without electricity. During the evening when the sun is down or during day when it’s cloudy or the sun’s radiant light isn’t very intense, a grid-tied solar power system can switch gears from the solar PV system to draw direct current from the grid itself. In essence, the solar power system is the central source of electricity and the grid is a back-up power system.

The way it works is fairly simple and key to the equation is the system’s inverter. Inverters are on all grid-tied solar power systems. Essentially, inverters monitor the alternating current and determines when electricity should be drawn from the solar array and when it should switch to the grid supply. The transition is fully automated and inherently seamless from the residents’ standpoint. Having this “plan B” has made solar a truly reliable energy source for all.

Another advantage of grid-tied solar systems is that the benefit works in both directions – from grid to homeowner and homeowner to grid. In other words, during certain times of day – most likely around the noon hour when radiant light from the sun is at its strongest – a solar power system may generate more electricity than what is currently needed to meet energy demand. During these windows, a grid-tied solar power system can actually put excess electricity generated back onto the grid, thereby offsetting the need for power generation from dirtier sources of energy like coal or natural gas.

The cherry on top of this arrangement is that in some cases, homeowners can actually get paid for selling this excess electricity back onto the grid. To support the solar industry and adequately compensate home and business owners for this grid contribution, many states have enacted “net metering” policies in which owners of grid tied solar systems are compensated for each kilowatt hour they produce for the grid. Net metering payments are typically to the tune of just a few cents per kilowatt hour (whatever the price of electricity is in that particular jurisdiction) and they often show up as credits on customers’ utility bills.

This is a win-win for grid-tied solar power system owners – not only do they save on their monthly energy bill for independently generating power from their solar PV system, but through net metering, they can actually get paid by their utility company while feeling good about producing green power.