20 July 2016 08:05:57 IST

Better net metering rules crucial for rooftop solar

Unfriendly net metering norms are tripping rooftop solar adoption in the country

Think of colleges and universities, you think of expansive, flat-topped buildings and large, verdant campuses. India has 36,670 of them. All of these (as well as many of the 14 lakh schools) are excellent candidates for rooftop solar plants, and can contribute handsomely to the government’s plan of getting 40 GW of rooftop solar by 2022. Many of these institutions have acres of roofs, but assuming conservatively that only 200 kW of solar on an average on educational institutions, there is scope for at least 10,000 MW (including schools).

These educational institutes are also consumers of power, whose needs generally match what a rooftop solar plant could produce. Often, the power the solar plants produce cost roughly the same as the grid power, and while grid power tariffs could go up, solar prices will remain constant. By blind logic, every one of the colleges and universities should have solar plants. But very few do.

The problem, ask any college Principal, is simple. You put up a solar plant on the roof of a university for self-consumption of the power, but what will you do with the electricity produced on holidays, and during vacations? Zero gain from solar on weekends and 2-3 months of summer vacations, and solar economics go for a toss.

At the heart of the issue is regulation relating to net metering. In a robust regime, any ‘prosumer’ (producer-consumer) should be able to sell the surplus power to the utility. The mechanism of selling the surplus is ‘net metering’ where meters measure the power exported to the grid; the consumer is given credit for the exported power, lightening his bill. But in India, each state has its own net metering rules, which are often not prosumer-friendly. Experts divide rooftops into four broad categories — residences, commercial establishments such as malls and hotels, educational institutions and industries (factories).

Of these, solar is still not very attractive to the ‘residence’ segment even with subsidies. Commercial establishment have very little roof space to spare, as they need the space for other activities, such as air-conditioner outdoor units, or cafeteria. However, solar plants could easily come up on educational and industrial roofs, provided net metering rules are friendly.

A regulation flaw Today, they are not, says Kuldeep Jain, Managing Director, CleanMax Solar, one of the larger rooftop solar plant owners in the country. Tamil Nadu, for instance, does not allow net metering for industries. This means, if a factory with a large roof (such as a car plant) puts up a solar plant overhead, it has to consume all the power the solar generates, or waste it.

To compound matters, if the electricity is put back to the grid (if only for the ‘nice feeling’), the meter does not recognise the direction of flow of current and treats the electricity supplied as consumed. Maharashtra, Kerala and Rajasthan allow net metering only up to 1 MW – if you have a larger rooftop plant, sorry, consume the power yourself or let it go waste. Madhya Pradesh allows even less.

More critical now Net metering is even more critical today because the ‘rooftop’ movement is going ‘opex model’; the roof owner does not own the solar plant. The solar is owned by a third party who invests in the plant and sells power, typically, to the roof owner. Since the rooftop solar plant owner (such as CleanMax Solar) is a power company, selling every unit of electricity generated matters.

Unless net metering rules are rationalised, there is little scope for the rooftop movement living up to its expectation, says Vineeth Vijayaraghavan, a renewable energy analyst and editor, Panchabuta.