Solar Metering
Now a days generating solar electricity energy is easier. Drastic price decline in the last decade, combined with policy incentives for rooftop systems, have attracted more and more consumers to install solar system on their rooftop. However, considering expensive to store electricity, solar power generated systems are connected to the grid so that surplus can be exported to the grid and deficit can be imported from the grid. Two arrangements are often defined by governments when designing the regulations for solar rooftop system – Gross and Net metering.
Net Metering
Net metering is an arrangement in which solar plant owner can use generated electricity energy and extra electricity exports to grid. Where owner gets credit of units against extra electricity export to grid, which will be deducted from the total electrical energy units consumed by owner in monthly bill.
In this case, Bi-directional meter will be installed by DISCOM, which account for both import and export of electrical energy.
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If the exported electricity is lower than the imported electricity, a consumer have to pay only for difference units. Accordingly, owners are billed only for the ‘net’ energy use.
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If the exported electricity is higher than the imported electricity, a consumer may be compensated for the excess electricity being fed into the grid by DISCOM (depending up a state’s net metering policy).
How does Net Metering Work?
The solar power systems are connected to the utility grid via the customers’ main service panel and meter and, when generating more power than is needed at the site, return excess electricity to the grid through the power meter, reversing the meter from its usual direction. Thus, a bi-directional meter is needed to avail net metering. Since the meter works in both directions (i.e. bi-directional meter)– one way to measure power purchased (when on-site demand is greater than on-site power production), and the other way to measure power returned to the grid – the customer pays the “net” of both transactions.
Gross Metering
Gross metering is an arrangement in which a consumer is compensated at a fixed feed-in-tariff for the total number of units of solar energy generated and exported to the grid (accounted by a unidirectional ‘gross meter’) and has to pay the electricity distribution company (discom) at retail supply tariff for the electricity consumed from the grid. The feed-in-tariff and retail supply tariff are typically different rates.
