India has pledged to build the world's most powerful solar plant. With a nominal capacity of 4,000 megawatts, comparable to that of four full-size nuclear reactors, the "Ultra-Mega Green Solar Power Project" will be more than ten times larger than any other solar project built so far, and it will spread over 77 square kilometers of land - greater than the island of Manhattan. The first phase of the project, which will be for 1,000 megawatt capacity, is expected to be completed in three years.

Six state-owned companies have formed a joint venture to execute the project, which they say can be completed in 7 years at a projected cost of US$ 4.4 billion. The proposed location is near Sambhar Salt Lake in the northern state of Rajasthan.

The solar photovoltaic power plant will have an estimated life of 25 years and is expected to supply 6.4 billion kilowatt-hours per year, according to official figures. It could help to reduce India's carbon dioxide emissions by more than 4 million tons per year, estimates Parimita Mohanty, a fellow at the Energy and Resources Institute (TERI) in New Delhi.

India currently has a grid-connected solar-power capacity of 2,208 MW - up from a mere 17.8 MW in 2010, when the central government launched the Jawaharlal Nehru National Solar Mission (JNNSM). The JNNSM aims for India to reach an installed capacity of 20,000 MW (or 20 gig watts) of solar power by 2022.