A range of energy options is available, and many others will become available as technical advances take place. Which sources should India focus on? Which source would provide the best cost-benefit differential? Which would be the least harmful environmentally? Should the government decide at all what source of energy India should focus on? Or should we let national and international market forces decide?

As of now, we have several options to generate power. The most significant ones are thermal, hydel and nuclear. Within thermal, the predominant sources are coal, oil and gas. Of course, there are variations within these broad classes. Then there are the curiously labeled ‘environmentally friendly’ methods — that include windmills, solar power, and so on.

Two broad issues need to be addressed. One, which is the most environmentally friendly, and two, which ones provide the best cost-benefit differential. In the latter case, benefits and costs should ideally also build in environmental costs and benefits.

Petroleum, coal, hydel, solar or wind -- each of these has a potential negative environmental impact. Fossil fuels’ impact on the environment works through the carbon-dioxide route. It is most likely a very important contributor to global warming. Hydel power has limited potential, but here too, is a possible environmental implication on sub-surface stresses and consequent impact on the likelihood of earthquakes. This becomes a critical issue as the significant part of our hydel potential is in the seismically sensitive Himalayan region.

Wind power is friendly, but only on a very small scale. Solar cells also have a negative environment impact. For one, more energy is required to produce a solar cell than it will produce in its entire lifespan. Two, energy produced per unit area covered is low, and a large area would need to be covered if this were to become a significant source.

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