The cost per unit of power produced by TAPP-4 is likely to be around Rs 2.65. The Maharashtra State Electricity Board had three years ago refused to lift power from the Dabhol Power Company citing high cost--Rs 4.10 per unit--leading to the mothballing of the controversial $2.9 billion, 2,184 MW project.
Maharashtra has been purchasing power from Power Trading Corporation and other private sector players at over Rs 3 per unit.
Maharashtra Energy Minister Dilip Valse-Patil recently said the state was willing to purchase power at Rs 2.20 per unit from the Dabhol plant once it restarted.
"The capital cost of a nuclear power plant is higher but the variable cost is much lower. So, as time passes, the per unit power cost comes down as the fuel cost is stable and capital cost depreciates. For instance, Tarapore I and II today produce power at less than Re 1 per unit," said Anil Kakodar, chairman of the Atomic Energy Commission and secretary, department of atomic energy.
While the fuel cost in a thermal power plant accounts for 70 per cent of the total running cost of the plant, in the case of a nuclear power, it is only 10-15 per cent. "Since fuel cost is prone to escalation, thermal power plants are affected but in the long run per unit power cost in a nuclear plant comes down," explained a DAE source.
The impact is felt once a nuclear plant crosses 10 years. Technically, a nuclear plant can live 50-60 years.
The average cost of nuclear power, produced by 14 reactors, is Rs 2.50-3 per unit, comparable with thermal power but as the reactors age, the cost of nuclear power comes down.
Currently, the capital cost of building a nuclear power plant is Rs 5-6.5 crore per MW in contrast to Rs 4 to 5.5 crore per MW of a thermal power. However, the capital cost will come down as the capacity of the next round of nuclear power project is being scaled up to 700 MW.
"The capital cost will come down by about 20 per cent once the capacity goes up," pointed out Kakodkar.
Designed and built by Nuclear Power Corporation of India Ltd, a public sector undertaking under the DAE, the capital cost of TAPP-4, situated 100 km north of Mumbai, is around Rs 6,000 crore (Rs 60 billion), about Rs 625 crore (Rs 6.25 billion) less than what was envisaged. It took about five years to attain criticality, seven months ahead of schedule.
The DAE is also set to enter the commercial domain of the second stage of its nuclear power programme by migrating to the fast-breeder reactor technology for the next round of plants. The first 500 MW prototype fast breeder reactor is slated for completion in 2011.
"If we go for thermal reactors using natural uranium, we can only produce 10,000 MW more as the resource is modest. The fast breeder reactor design will use the spent fuel of pressurised nuclear reactors to produce power. By this process, the production can go up by 50 times to 500,000 MW," said Kakodkar.
Meanwhile, another 540 MW plant, TAPP -3, is expected to achieve criticality over the next few months.
Together, these two plants will generate 1,080 MW to be distributed in Maharashtra, Gujarat, Madhya Pradesh, Chhattisgarh, Goa and Daman and Diu.
Early this month, TAPP-4 achieved criticality, signifying that the pressurised heavy water reactor has reached the stage of self-sustaining chain reaction and is able to produce the heat required for electricity production.
It uses natural uranium as fuel and heavy water as moderator and coolant. At present, 14 operating nuclear power plants collectively produce 2770 MW -- about 3 per cent of India's power production--while thermal power accounts for 86.3 per cent, hydroelectric power 10.3 per cent and other non-conventional sources, including wind power, 0.4 per cent.
In India it can go up to 10 per cent by 2022 and 26 per cent by 2052. Even then, it will not be comparable with the global scenario--nuclear power accounts for 80 per cent of power in France, 35 per cent in Japan and 20 per cent in the US.
While some sections cry foul at the risk associated with nuclear power, Kakodkar insisted it was safe, besides having zero greenhouse gas emission.
"It is the most environment friendly, least carbon dioxide emitter comparable with the low end of hydel power," he said.
The per capita electricity consumption in India is 650 unit annually against the world average consumption of 2,500 unit. Some of the OECD countries' per capital power consumption is 10-15,000 unit and even more.
The total installed capacity in India is about 1,11,000 MW. While developing future energy technology mix, nuclear can play an important as it is most environment friendly and cost effective source of power, said a source in DOE.
Incidentally, the entire nuclear fuel cycle in India -- from mining of uranium to processing, fabrication of fuel, production of heavy water, design, construction and operation of nuclear reactor, generation of power, reprocessing of spent fuel and radio active waste management -- is indigenous.