Gas, oil, et al

Usage examples of fuels.

Harper-Erickson isotopic artificial fuels had been developed three years before it had seemed that, in addition to solving the dilemma of an impossibly dangerous power source which was also utterly necessary to the economic life of the continent, an easy means had been found to achieve interplanetary travel.

Curie piles did not provide the fierce star-interior conditions necessary to breeding the isotopic fuels needed for an atomic-powered rocket.

They would make the trip, they would prove it could be done, then, if safer fuels were needed, there would be the incentive to dig them out.

They forget, if they ever knew, how foul the air was growing, how close we were to exhausting the fossil fuels and ores that made the machines possible, when the gengineers offered us an alternative.

Sam said nothing more to them, nothing about shortages of fuels for the machines, shortages of steel and other minerals, nor of the problems of chemical, industrial pollution that human civilization had largely left behind when it chose a more organic path.

We do not have enough liquid fuels or metals for both tractors and jet engines, not to mention spacecraft.

And the fossil fuels that had powered the Machine Age, either directly as fuels for engines or indirectly as fuels for electric power plants, were gone.

The world population would have to be much smaller if it was to require no more resources--food, fuels, solar and hydroelectric energy, wood, ores, etc.

They were forecasting that when the population exceeded the resources necessary to support it--whether because the fuels and ores were used up and soil fertility lost, or because the population simply grew too big--billions of people would die.

They had given it the resources it needed to stay civilized when fossil fuels and ores had been near exhaustion.

As the fuel was burned up it imparted its energy to what was left of the payloada point that had been lost on some of the early critics of space travel, who insisted that not even the most powerful known fuels contained enough energy to boost themselves to escape velocity.