The solar revolution is taking off across the world, but the fastest growth seems to be happening on the rooftops of India.

Last year, India added more rooftop solar capacity than in the previous four years combined. That makes solar the fastest-growing area of the country’s clean energy market. According to a report from Bloomberg New Energy Finance, the country added 715 megawatts of solar power to the system, up from just 2227 the year before. Now, the country is running 1.3 gigawatts of solar energy and is estimated to reach 9.5 GW by 2022.

The major boost can be attributed to the lowering cost of rooftop solar units in India, which has dropped by 50 percent in the last five years, making it cheaper than commercial and industrial power in the country. Now, setting up a rooftop solar system is cheaper in India than the global average by 39 to 50 percent.

Image: Green Matters

In this climate, the government of India is also pushing for more solar with a target of reaching 40 gigawatts, a steep goal that is causing the government to create incentive programs and policies to encourage the change. This has included holding auctions to have companies set up over 1 gigawatt of rooftop projects in the first nine months of 2017.

Incentives and all, the initiative to reach 40 gigawatts is still running behind. So far, only 3 percent of the goal has been achieved, and over half the rooftop solar units are concentrated in just six states, according to the report. This could be because of confusion over the main incentivizing reason to install solar units in the first place: "net metering," or selling surplus power back to the electricity utility.

With that oversight, the majority rooftop solar growth is driven by commercial and industrial users, and the residential segment has been slow to take off.

“The high upfront capital expenditure compared to commercial and industrial (C&I) consumers, a lack of financing options, and cheaper grid electricity for residential consumers with low consumption currently make rooftop PV (photo voltaic) less attractive for residential consumers than their C&I counterparts,” the report reads.

Image: Green Matters

On top of that, India’s power distribution companies see solar as a drain on their income potential, and those are not exactly going out of their way to promote it.

However, net metering could provide the push needed to get residents on board. While businesses have a harder time generating surplus power and reaping the benefits of selling it back, residential homes forgo the need for power during much of the day, meaning a surplus is easy to obtain.