Net Meter

Solar power is fed into my electrical box, and during the daytime, solar cells supply power to the house. Any solar power that isn't used by the house is fed into the electrical grid. If the output of the solar system is insufficient to cover the operation of the house, such as when the air conditioner is in use, power is drawn from the grid. The power company charges me for the difference between power taken from the grid and power fed into the grid.

The meter that measures the two amounts of power is called a Net Meter. The meter used by my local utility company displays two amounts of power, and each source of power is identified by a code that is displayed on the meter. Code 14 is the power taken from the grid, and code 24 is the solar power put into the grid. I will be charged for the difference between the two amounts, as follows.

Power charged = Code 14 power - Code 24 power

If that difference, or net, is zero or negative, I don't pay anything to the power company for the power because my solar system is producing enough energy to compensate for any power provided by the power company. If that difference is positive, I pay the power company for the difference. I am, though, charged a fixed amount per month for being connected to the grid, and I'm charged other fees, too.

The net meter is digital, and the net meter has an arrow that points to the left if power is being put into the grid and to the right if the grid is supplying power to my house. If a solar system is turned on without a net meter being installed, the meter thinks power from the solar system is power from the grid, and the person is charged for that power.

Utah allows the power company to zero out in March any power-credit that might have been accumulated. The result is that during March one wants the difference to be close to zero.

Rocky Mountain Power Paper