provides energy without needing batteries
During hours when electricity
is being generated, the meter runs backwards if you are producing
more power than you use. At night, the meter will run forward as
you use energy from the grid. If the meter shows negative numbers
by the end of the year, the power company will buy the energy it
used from your system.
Net-metering and batteries provide emergency power
In the event of a black out the inverter will automatically switch
consumption from the grid to energy stored in your batteries.
Batteries are not essential, but very convenient
If you only have solar cells without batteries, you can only get
power when the sun is out. If you have batteries they can store
the electricity surplus during the day and provide ample power at
Legalities and Liabilities
Most inverters come ready to do net-metering with or without batteries
as well as the ability to work with off-grid PV systems. The
photovoltaic system must match the voltage requirements of the
inverter. Batteries can then be matched according to size and voltage
with the PV and inverter voltage and usage.
The net-metering connection rules of the local service provider must
be followed in order to protect both you and your system and the providers
technicians. Be sure that the power switches and circuit breakers,
etc. are in accordance with local power authority regulations to prevent
accidents in blackout situations.