Net Metering

When you install a solar electric system to your utility company's wiring, any surplus energy produced by your photovoltaic (pv) system will be used by your electric company and you will receive a credit to be used during periods when the PV system is not producing enough to meet your needs. This means that the electric meter actually spins "backward" when power is flowing from the PV panels to the utility and spins "forward" when electricity is flowing from the utility into the building. At the end of the month, only the net consumption is billed. It is the amount of electricity consumed, less the amount of electricity produced. The electric company acts much the same as a battery, crediting the energy account for later use if you produce more than you use. This process is called "Net Metering".

As it stands right now, the utility companies won't pay you for excess electricity. Your solar electric system should be sized to provide you with about 90 to 95% of your electric usage if your budget for the system permits. When sizing a PV system, don't exceed your electric usage because you won't get any money back.

For more information about states with net metering legislation and incentives for renewable energy systems, refer to the Database of State Incentives for Renewable Energy (DSIRE) located at www.dsireusa.org.

Solar Energy Basics

People see those panels on the roof of homes and ask me "How does the hot water turn into electricity?" Well it doesn't. You see, the solar panels you see today that are generating electricity use silicon cells to do the job. There is no water involved. Years ago, the big application for solar was heating hot water which is still around today. I'd rather use my precious roof space for photovoltaic (PV) panels to replace my expensive electric bill. The PV panels change the sunlight directly to electricity using solar cells.

Solar cells or PV cells for short can be found on many small appliances, like calculators, and even on spacecraft. They were first developed in the 1950s for use on U.S. space satellites. They are made of silicon, a special type of melted sand.

When sunlight strikes the solar cell, electrons (red circles) are knocked loose. They move toward the treated front surface (dark blue color). An electron imbalance is created between the front and back. When the two surfaces are joined by a connector, like a wire, a current of electricity occurs between the negative and positive sides.

These individual solar cells are arranged together in a PV module and the modules are grouped together in an array. Some of the arrays are set on special tracking devices to follow sunlight all day long but these are usually mounted on the ground.

The electrical energy from solar cells can then be used directly. It can be used in a home for lights and appliances. It can be used in a business. Solar energy can be stored in batteries to light a roadside billboard at night. Or the energy can be stored in a battery for an emergency roadside cellular telephone when no telephone wires are around. Your home or business doesn't know the difference between the electricity that comes from the utility company or from your solar panels. Effectively, its the same (except the solar electricity is free and clean).

Some experimental cars also use PV cells. They convert sunlight directly into energy to power electric motors on the car.

For more information on the benefits, both financial and environmental, of converting the sun's energy into electricity check the solar energy guru's website.