before the prime minister formally inaugurates the mission here Monday, official sources said.

The sources said Friday that the Jawaharlal Nehru National Solar Mission may now have the goal of producing 4,000 MW for the grid from solar energy instead. The mission is one of the eight announced as India's National Action Plan on Climate Change.

Centre for Science and Environment Director Sunita Narain, who is also a member of the Prime Minister's Council on Climate Change, said the 20,000 MW plan had been found to be prohibitively expensive.

"The mission plan is to provide Rs.17.50 per MW feed-in tariff to solar power generators for 20 years," Narain said. "Out of this, Rs.5.50 will be paid by the utilities and the central government will pay the rest.

"For 20,000 MW, the cost of this was coming out to be Rs.270,000 crore (Rs.2,700 billion/$54 billion) over 20 years, and the finance ministry pointed out there was no way it could find this kind of money."

So the goal is being reduced to 4,000 MW, official sources said, which would cost the government Rs.90,000 crore over 20 years.

Countries around the world have paid generators of renewable energy feed-in tariffs to make them competitive with generators of power from fossil fuels or dams.

Since India has already announced a goal of producing 20,000 MW through solar power by 2022, the mission document may now stick to that figure, but most of it would be off-grid, an official of the Ministry of New and Renewable Energy added.