Net metering is a billing system that lets a home with solar panels send extra electricity to the utility grid and receive credit for it. It matters because solar panels often make the most power during sunny midday hours, while a home may use more power in the evening. By tracking electricity flowing both ways, the electric meter helps solar energy become more useful and affordable.
Net metering connects a home renewable energy machine to a larger energy network.
Key Facts
- Solar panel power is measured in watts: P = VI.
- Electrical energy use is measured in kilowatt-hours: energy = power x time.
- 1 kWh = 1000 W used for 1 hour.
- Net grid energy = energy taken from grid - energy sent to grid.
- If solar production is greater than home use, extra electricity flows to the grid.
- A net meter records both imported energy and exported energy for billing credits.
Vocabulary
- Net metering
- Net metering is a billing method that credits a solar customer for extra electricity sent to the utility grid.
- Solar panel
- A solar panel is a device that converts sunlight into electrical energy using photovoltaic cells.
- Smart meter
- A smart meter is an electric meter that measures and reports electricity flow, often in both directions.
- Grid
- The grid is the network of power lines, transformers, and generators that delivers electricity to homes and businesses.
- Kilowatt-hour
- A kilowatt-hour is a unit of electrical energy equal to using 1000 watts of power for 1 hour.
Common Mistakes to Avoid
- Confusing power with energy is wrong because solar panels are rated in watts, while electric bills usually charge for kilowatt-hours.
- Assuming solar panels always power the whole house is wrong because production changes with sunlight, weather, panel angle, and time of day.
- Thinking extra solar electricity is stored in the grid is wrong because the grid does not act like a battery for one home, it balances supply and demand across many users.
- Ignoring the difference between imported and exported electricity is wrong because net metering credits depend on how much energy flows in each direction through the meter.
Practice Questions
- 1 A home uses 28 kWh in one day and its solar panels produce 34 kWh. How many kWh are sent to the grid as extra energy if all solar power is used first by the home?
- 2 A solar array produces an average of 4.5 kW for 5 hours. How many kWh of electrical energy does it produce?
- 3 Explain why a house with solar panels may still need electricity from the grid at night, even if it produced extra solar energy during the day.