What is Net Metering?
Net Metering is a service to an electric consumer under which electric energy generated by that electric consumer from an eligible on-site generating facility and delivered to the local distribution facilities may be used to offset electric energy provided by the electric utility to the electric consumer.
In Indonesia Net Metering has been mandated by PLN in Regulation 0733.K/DIR/2013 (December 2013), which obliges PLN to ‘credit’ energy produced by solar to a customer’s account. To apply Net Metering, customer simply applies for installation of a 2-way meter.(source: Wikipedia)
Battery Storage vs. Net Metering
Solar systems produce power from sunlight. They only produce electricity when there is sunlight and the level of production is directly related to the level of sunlight available. Solar is not an on-demand electricity source. This presents a problem in that demand and supply are not automatically matched: sometimes there is more energy demanded than supplied, and sometimes it is the other way around.
The normal solution to this mismatch is ‘storage’ so that when supply exceeds demand, the surplus gets stored, and when demand exceeds supply, the shortfall is taken from the storage. The problem with this is that electricity can only be stored in chemical batteries, which are not very efficient, very expensive and do not last very long. Having to use a battery bank to overcome mismatches of load and supply is very painful.
Instead of locally storing the surplus energy locally, it gets send into the grid (basically for someone else to use), and you get credited. Your electricity meter measures a) the energy coming in from the grid, and b) the energy going out to the grid, and you only pay for the difference.
This means that you can ‘over-produce’ during the day and use that over production at night. It allows you to become ‘net-zero’ energy from the grid.
Feed in Tariffs vs. Net Metering
Feed-In Tariffs work in the same way, except that the energy you feed in to the grid is valued higher than the energy you take out of that grid, so you actually profit from the energy you feed in.
How Does Net Metering Work with PLN?
(1) PLN installs a kWh meter of the ‘import export’ type for PLN customers that use electrical energy from Photovoltaic next to from PLN.
(2) The electrical energy ‘received’ by PLN will be offset by the electrical energy that PLN sends to the customer.
(3) In the case where the amount of PV-generated electricity received by PLN as mentioned in 2) is bigger than the amount of electricity supplied by PLN, then the surplus will be made eligible as kWh-credits to be accounted for the following months, and so on.
(4) The customer will continue to pay Minimum Account connection charges while still connected to PLN.
To apply Net Metering to your PLN bill, we simply have to request the 2-way meter type from PLN. In some cases they may inspect the installation.