solar and wind net-metering

Solar photovoltaic, wind and hydro systems for power generation can be grid-tied or off-grid... A grid-tied solution requires Net Metering, that is, it requires a system to keep track of the difference between the electricity you store in the grid and the one you take from it. With solar and wind Net Metering, if your system generates more electricity than your consumption, the electric meter will spin backward...

Note:
There is no difference between Net Metering for solar, wind and small hydro systems. The information in this page is valid for any of these systems, or for hybrid systems.

Stand alone solar PV systems aren't connected to a public or private grid and are more expensive due to their backup system (a set of batteries). That's why most PV solar systems for power generation are grid-tied.

Net metering & system size

The size of your solar, hydro or wind power system doesn’t interfere with Net Metering.

If you have a small system and your production is lower than your consumption, you just have to pay the difference. If you have a large grid-tied system and your production exceeds your consumption you can store or even sell the excess generation to the utility.

Conditions & Net Metering

All residential producers of solar electricity, hydro electricity or wind electricity are eligible for Net Metering.

Most residential grid-tied PV solar and wind systems range between 2 and 4 kilowatts, but in most cases there isn’t a required minimum size to be eligible for Net Metering. Law often demands the system to be located on your property and may set a production ceiling (typically very high), but just that.

Current electric meters

Most current residential meters are bi-directional, that is, they can measure both electricity outputs and inputs.

If this is your case, your current meter is suitable for Net Metering, but some utilities demand a special two metering system: one to measure the power input flow and other to measure the output. Most companies do not demand this last type of metering, but you should contact your utility to know...

Net metering agreements

Net metering requires an agreement between you and your utility or electric provider. Typically the meter will be read once a month to estimate the difference between the electricity you take from the grid and the one you store into it. And that’s that difference that you will have to pay (if positive).

In most American states there are power companies (Electric Service Providers) and power distribution companies (Local Distribution Companies) or companies doing both functions. Usually Electric Service Providers handle the Net Metering billing and accounting, while local distribution companies handle the technical stuff: connection to the grid, safety, inspections...

Selling energy to the grid

If some states, if your electricity production is higher than your consumption, the utility or electric provider doesn't have to pay the excess, unless otherwise agreed.

Typically, law doesn't force to utility to pay for possible excess generation, but the agreements may consider the payment – and you may look for utilities or electric providers buying excess generation. Current practices of the electric providers and utilities vary.

Net Metering Billing

There are details concerning solar and wind net metering that varies between states, or between the parts. In what concerns billing, utilities use to read meters monthly, sending to power producers monthly statements with the amounts of the electricity consumption and production.

Annual billing is also possible.

Advantages of Solar and Wind Net Metering

Net metering is part of tied-grid renewable systems. With tied-grid hydro, solar or wind tied-grid systems you don't have to store excess generation in batteries (which would be costly), you don't incur the risk of electricity disruption, you may use excess generation in peaks of demand, ir you may even sell that excess.