SPG Solar, Inc. (SPG) engineers each residential solar system to take advantage of California’s Net Metering law, which requires public utilities to credit renewable energy producers at the “retail rate” for the electricity they send out to the grid.

In the California region where most of the company's systems are installed, SPG is one of PG&E's Net Energy Metering (NEM) Services top clients. In fact, for Standard NEM small business and residential installations of 10 kW and below, SPG had the second highest number of interconnections in 2004. For the Expanded NEM projects ranging from 10 kW to 1 megawatt (mW), SPG had more interconnections than any other company in the PG&E territory in 2004.

The NEM program is for customers (residential, commercial, or government entities) who install the means to generate up to 1 mW of solar, wind, or hybrid (solar and wind) power. These customers continue to purchase power from the utility and also deliver surplus generated power back to the distribution grid.

Net metering reduces the demand on the public utility grid during long hot summer days when energy demand is at its highest, and simultaneously allows solar producers to reduce or eliminate their energy bill based on annual energy credit. Under net metering the utility company must credit solar energy producers for any surplus electricity they send back to the grid. On sunny days the electric meter spins backwards and the solar system earns credit for the energy at the utility’s retail energy rate.

Utilities are required to credit solar energy producers at the retail rate at the time of day that the energy is sent to the grid. PG&E has a retail rate schedule that is unique in the U.S., charging more for energy at three tiered rates.

• On sunny days the solar producer sends surplus energy out to the grid.

• The electric meter spins backwards and the solar system earns credit for the energy at the utility’s retail energy rates.

• At night or on rainy days, the grid provides the power and the building taps into the credit the solar system earned while the sun was shining.

• The credits earned from excess energy production under the Net Metering law zeros out your net annual electric bill.

Utilities are required to credit home solar energy producers at the retail rate for the time of day that the energy is sent to the grid. SPG designs each home solar system to collect the most sunlight during peak demand periods, when you also receive the highest credit for excess energy produced by solar. The surplus energy value nearly quadruples during the peak demand period.

Noon to 6 PM during the months May through October is the “solar sweet spot.” This is when the sun is highest in the sky during the summer. It's also when the utility charges the highest retail rate for energy, to lower demand on the grid by encouraging conservation and the development of renewable energy sources like solar.

During the high demand months the utility charges the Off-Peak rate from 6 at night until Noon the next day. Between Noon and 6 PM (the Peak Rate period) the utility charges 3.7 times as much for energy as the Off-Peak rate. The rate goes back down to Off-Peak after 6:00.

Valuable Peak Rate utility credits help pay down the cost of a home solar system, while the surplus energy flowing out to the grid supplies much-needed power to the community during peak demand periods.