Peter Odell, professor of international energy studies at Erasmus University, Rotterdam, and author of the bestselling World and Oil Power, said the drive to limit greenhouse gases was likely to be held back by both technology and economics.
Painting a gloomy picture of the short-term outlook for renewables, Odell told Reuters that even with a growing global effort to limit carbon dioxide emissions, the world would still be relying on hydrocarbons by 2100.
Oil use won't peak until 2050, Odell said in an interview. It will decline thereafter but even by 2100 oil supplies will be 20 percent higher than they were in 2000.
He said alternative, renewable forms of energy would increase 15-fold over the 21st century to become the biggest single source of energy by the year 2100, but even then alternative energy would still only account for 35-40 percent of the total energy mix.
This would be well short of what environmentalists have said needs to be accomplished in order to avert the worst effects of global warming, which many say is due to the burning of fossil fuels.
Coal, oil and gas will continue to dominate the energy market throughout the 21st century, he said.
The British government said on Wednesday it planned to produce 40 percent of its electricity from low carbon energy by 2020 to help meet legally-binding targets to cut emissions and tackle climate change.
Unveiling what it hopes will be a map to a low carbon future, Britain aims to cut UK emissions of greenhouse gases by 34 percent by 2020 from 1990 levels and by at least 80 percent by 2050 to help curb global warming.
The low carbon energy would come from nuclear, wind, solar and marine power, as well as clean coal, Energy and Climate Change Secretary Ed Miliband said.
But Odell said those kinds of targets involve very high costs.
The targets the UK is setting are almost impossible to meet and they are being developed at a cost that is going to affect consumer prices significantly, he said.
Odell said global energy demand could increase four-fold this century under some scenarios to as much as 38 giga (billion) tons of oil equivalent (gtoe) by 2100 from 9 gtoe.
He forecast world use of hydrocarbons would rise to a peak of 16.5 gtoe by 2070, from 5.8 gtoe in 2000.