Net Metering explained
Net metering is a billing policy widely used in the United States, Canada, Australia, and other countries (but not the UK) that allows solar panel owners to "bank" surplus electricity on the grid and draw it back later at the same retail rate.
How it works: your electricity meter runs forwards when you import from the grid and backwards (or separately credits you) when you export solar power. At the end of the billing period, you only pay for the net difference between what you imported and exported.
Example: you generate 500 kWh of solar in a month and import 300 kWh from the grid. Net metering means your bill only charges you for the 300 kWh import, while the 500 kWh export is credited at the full retail rate (e.g. $0.15/kWh) — not a lower export rate.
This is significantly more valuable than the UK's SEG: full retail credit vs 3–15p/kWh. Net metering policies dramatically improve solar payback periods compared to export-rate systems.
Net metering policy is changing: many US states are moving to "net billing" or "net energy metering 3.0" (NEM 3.0 in California) which credits exports at a lower wholesale rate rather than retail. This reduces the financial benefit of grid export and increases the value of battery storage.