How to Tie in a Solar Grid

Use a grid-tie inverter -- also called a "synchronous inverter" -- to connect a home- or small business-based solar energy generation system to the electric utility grid.

Grid-tied solar electric generation systems feed excess power back to the electric utility grid.Grid-tied solar electric generation systems feed excess power back to the electric utility grid.
As with all inverters, direct current (DC) from a solar array is converted to alternating current (AC) used by appliances and lighting systems. A synchronous inverter takes electricity collected by a solar panel array and applies it to a power distribution panel. The electricity may then be used to supply power loads, or sent out to the utility grid. When no solar energy is available, such as on cloudy days or at night, the inverter then allows the utility to supply the power for loads in the home or business.

Check first with the local energy supplier to find out whether a grid-tie configuration -- also called "net-metering" -- is permitted, allowing the homeowner to sell electricity back to the utility.

Purchase a grid-tie inverter, also called a synchronous inverter, matched to the solar electric generation system being used. The inverter must be matched to the wattage output of the solar panels. Where a metering system from the utility is already in use, simply tie into that meter. If no meter is in use, the utility company will require a kilowatt hour meter to measure the amount of electricity being sold to the utility.

Mount the inverter in the chosen location, preferably close to the electric meter and safe from bad weather. Use a mounting bracket as specified by inverter manufacturer. Attach the mounting bracket using hardware supplied by the manufacturer. Connect as specified to both meter and solar array connections using electrical wiring. If the system uses a battery bank, connect as specified to the battery bank.

Things You Will Need

  • Synchronous (grid-tie) inverter
  • Inverter mounting bracket
  • Electrical cable
  • Electrical connectors

Tips

  • A national law requires investor-owned utilities to allow net-metering, but rural electric cooperatives are exempt.
  • Grid-tie inverters may be used with or without a battery bank to store solar-generated electricity. Federal and some state guidelines recommend systems with no battery banks.
  • Check with state solar renewable energy programs before installing a net-metering system. New Jersey, for example, has a Solar Renewable Energy Credits program that offers higher value for solar-generated electricity than mere "net-metering."

Warning

  • Only a licensed, professional electrician can make connections to the power grid via an electric meter.

About the Author

Bert Wylen began writing professionally in 1979. His articles have appeared in “The Burlington County Times,” “The Philadelphia Inquirer,” “The Philadelphia Gay News,” Brandywine.Net Business Report, “Daily Local News,” "The Courier-Post," “Small Business News,” “Software Developer & Publisher,” “The Advocate” and for radio networks Pacifica and Public Radio International. Wylen holds a Bachelor of Arts in English literature from Temple University.