A two-kilovolt (KV) solar system for homes costs around Rs. 1.80 lakh without subsidy, half the rate three years ago and enough to power a two-room house with one air-conditioner.
"It means that cost of each unit of power for the next 25 years would be Rs. 6 per unit - slightly higher than the per-unit cost of thermal electricity," said Tarun Kapoor, joint secretary and head of Jawaharlal Nehru Solar Mission in the ministry.
Cost of a unit of power through Delhi discoms is about Rs. 4.5-5 per unit.
Rapid improvement in solar technology over the past few years has produced high-efficiency panels that generate more power in smaller space.
A two-KV system would require about 200 square feet on the roof, the size of a drawing room in a DDA two-BHK home.
Tapping the emerging potential of solar power, many top companies are now selling solar inverters, a smaller version of the home system.
Delhi has been slow in catching up with the solar revolution that has gripped many of the southern and western Indian states, which have almost same amount of good sunshine -about 10 months.