SINCE the industrial revolution 200 years ago, mankind has depended on fossil fuel. The notion that this might change is hard to contemplate. Greens may hector. Consciences may nag. The central heating's thermostat may turn down a notch or two. A less thirsty car may sit in the drive. But actually stop using the stuff? Impossible to imagine: surely there isn't a serious alternative?

Such a failure of imagination has been at the heart of the debate about climate change. The green message—use less energy—is not going to solve the problem unless economic growth stops at the same time. If it does not (and it won't), any efficiency saving will soon be eaten up by higher consumption per head. Even the hair-shirt option, then, will bring only short-term relief. And when a dire prophecy from environmentalism's jeremiad looks as if it is coming true, as the price of petroleum rises through the roof and the idea that oil might run out is no longer whispered in corners but openly discussed, there is a temptation to believe that the end of the world is, indeed, nigh.

Not everyone, however, is so pessimistic. For, in the imaginations of a coterie of physicists, biologists and engineers, an alternative world is taking shape. As the special report in this issue describes, plans for the end of the fossil-fuel economy are now being laid and they do not involve much self-flagellation. Instead of bullying and scaring people, the prophets of energy technology are attempting to seduce them. They promise a world where, at one level, things will have changed beyond recognition, but at another will have stayed comfortably the same, and may even have got better.

This time it's serious

Alternative energy sounds like a cop-out. Windmills and solar cells hardly seem like ways of producing enough electricity to power a busy, self-interested world, as furnaces and steam-turbines now do. Battery-powered cars, meanwhile, are slightly comic: more like milk-floats than Maseratis. But the proponents of the new alternatives are serious. Though many are interested in environmental benefits, their main motive is money. They are investing their cash in ideas that they think will make them large amounts more. And for the alternatives to do that, they need to be both as cheap as (or cheaper than) and as easy to use as (or easier than) what they are replacing.

For oil replacements, cheap suddenly looks less of a problem. The biofuels or batteries that will power cars in the alternative future should beat petrol at today's prices. Of course, today's prices are not tomorrow's. The price of oil may fall; but so will the price of biofuels, as innovation improves crops, manufacturing processes and fuels.

Electrical energy, meanwhile, will remain cheaper than petrol energy in almost any foreseeable future, and tomorrow's electric cars will be as easy to fill with juice from a socket as today's are with petrol from a pump. Unlike cars powered by hydrogen fuel cells, of the sort launched by Honda this week, battery cars do not need new pipes to deliver their energy. The existing grid, tweaked and smartened to make better use of its power stations, should be infrastructure enough. What matters is the nature of those power stations.

The price is right

They, too, are more and more likely to be alternative. Wind power is taking on natural gas, which has risen in price in sympathy with oil. Wind is closing in on the price of coal, as well. Solar energy is a few years behind, but the most modern systems already promise wind-like prices. Indeed, both industries are so successful that manufacturers cannot keep up, and supply bottlenecks are forcing prices higher than they otherwise would be. It would help if coal—the cheapest fuel for making electricity—were taxed to pay for the climate-changing effects of the carbon dioxide produced when it burns, but even without such a tax, some ambitious entrepreneurs are already talking of alternatives that are cheaper than coal.

Older, more cynical hands may find this disturbingly familiar. The last time such alternatives were widely discussed was during the early 1970s. Then, too, a spike in the price of oil coincided with a fear that natural limits to supply were close. The newspapers were full of articles on solar power, fusion and converting the economy to run on fuel cells and hydrogen.

Of course, there was no geological shortage of oil, just a politically manipulated one. Nor is there a geological shortage this time round. But that does not matter, for there are two differences between then and now. The first is that this price rise is driven by demand. More energy is needed all round. That gives alternatives a real opening. The second is that 35 years have winnowed the technological wheat from the chaff. Few believe in fusion now, though uranium-powered fission reactors may be coming back into fashion. And, despite Honda's launch, the idea of a hydrogen economy is also fading fast. Thirty-five years of improvements have, however, made wind, solar power and high-tech batteries attractive.

As these alternatives start to roll out in earnest, their rise, optimists hope, will become inexorable. Economies of scale will develop and armies of engineers will tweak them to make them better and cheaper still. Some, indeed, think alternative energy will be the basis of a boom bigger than information technology.

Whether that boom will happen quickly enough to stop the concentration of carbon dioxide in the atmosphere reaching dangerous levels is moot. But without alternative energy sources such a rise is certain. The best thing that rich-world governments can do is to encourage the alternatives by taxing carbon (even knowing that places like China and India will not) and removing subsidies that favour fossil fuels. Competition should do the rest—for the fledgling firms of the alternative-energy industry are in competition with each other as much as they are with the incumbent fossil-fuel companies. Let a hundred flowers bloom. When they have, China, too, may find some it likes the look of. Therein lies the best hope for the energy business, and the planet.