Nuclear power is seeing a renaissance. Power-starved India, which has the largest number of reactors under construction, is at the forefront of this revival of interest in nuclear power.

India is building seven of the 30 reactors under construction around the world. This is likely to increase significantly once the India-US agreement on nuclear cooperation is accepted by the rest of the world (read the Nuclear Suppliers' Group), according to industry officials.

India will add about 3,400 Mw generation capacity through these seven reactors. While the largest of these reactors is of 1,000 Mw capacity, the country has generally been more comfortable with smaller reactors, given the "constrained capacity of the grid," according to a senior official of the Nuclear Power Corporation of India.

The NPCIL and the Bharatiya Nabhikiya Vidyut Nigam Ltd (Bhavini) are the only companies authorised to build nuclear reactors in the country.

Contrast this with what is happening in Finland, which is working on the first-of-its-kind European pressurised water reactor (EPR) with a capacity of 1,600 Mw. This is expected to be commissioned by 2010-11.

There is another reason behind India's reluctance for the large reactors. "In India, what we will be looking at is technologies which are already proven, and not the untested reactors," the official said.

India's current nuclear power generation capacity of 3,900 Mw is dominated by boiling water reactors (BWRs) and pressurised heavy water reactors (PHWRs). Of the plants under construction, four are PHWRs, two are light water reactors and one is a fast breeder reactors (FBRs).

The nuclear revival can be traced to two key factors - it is cheap and there are no messy carbon emissions that are responsible for the global warming. However, there is the problem of reprocessing or disposing off highly radioactive spent fuel.

"Even after factoring in all the costs, it is still the most cost competitive form of energy." says Anneli Nikula, senior vice president at TVO (Teollisuuden Voima Oy) which is constructing Finland's fifth nuclear plant based on the EPR reactor, even as debate has begun on the feasibility of a sixth one in the country.

According to a recent study quoted by the company, the power generation cost per megawatt of nuclear power is about 25 euros, which is about half the cost of power generated from other fuels. The fuel cost is a small slice (3 per cent) of the overall cost and is largely predictable.

Not surprisingly, therefore, India plans to increase nuclear generation capacity at least five-fold to 20,000 Mw by 2020. "However, if we get access to other reactors (through the India-US deal), the capacity could go up to 40,000 Mw by 2020," the NPCIL official said.

India has been commissioning nuclear reactors in record time of "under five years". The capital cost per megawatt in the case of nuclear plant is Rs 5 crore, which is higher than the average cost of the thermal plants (Rs 4 crore or less). However, with the fuel cost being much lower than the thermal plants, nuclear power becomes an appealing option.

"You also need to realise that supply of fossil fuels will diminish," the official said. India's proven coal reserves of 95 billion tonnes, for example, are expected to run out in 45 years, according to some estimates.

"India's energy security requires us to look at the nuclear option seriously," says Leena Srivastava, executive director at The Energy and Resources Institute.

According to TERI's projections, India could be importing as much as 95 per cent of its crude oil requirement over the next 25 years against 78 per cent currently. "We could be importing upwards of 60 per cent of our coal and natural gas needs as well (if we continue business as usual)," said Srivastava.