
The world could be dependent on "dirty, insecure and expensive" energy by 2030, an influential report has warned.
Current trends showed that demand for power was set to grow by 53% by 2030, the International Energy Agency said.
But if governments delivered on their promises to push cleaner and more efficient supplies, demand could be cut by about 10%, the agency suggested.
Greater use of nuclear power could be a "valuable option" to cut imports and curb CO2 emissions, the study added.
The International Energy Agency's (IEA) World Energy Outlook (WEO) 2006 also echoed the findings of a recent UK report that said the benefits of cutting emissions outweighed the costs of climate change.
"WEO 2006 reveals that the energy future we are facing today, based on projections of current trends, is dirty, insecure and expensive," said Claude Mandil, executive director of the IEA.
"But it also shows how new government policies can create an alternative energy future which is clean, clever and competitive," he added.
The document considered two scenarios:
Overall, the WEO says primary energy demand would grow by about 53%, with fossil fuels accounting for 83% of the increase between 2004 and 2030.
But it said that the alternative policy scenario projected that demand for energy could be cut by 10% by 2030 - the equivalent to China's current total energy consumption.
It also said this scenario would deliver 16% less carbon dioxide (CO2) emissions than the business as usual scenario, the same as the current total emissions from the US and Canada combined.
The WEO champions the role of nuclear power, saying it could make a "major contribution to reducing dependence on imported gas and curbing CO2 emissions".
It forecasts that the total global generation capacity of nuclear power plants could increase from 368 gigawatts in 2005 to 519 gigawatts in 2030.
The additional nuclear power plants would also have the advantage of being less vulnerable to fuel price changes than coal or gas-fired generation, helping to enhance the security of electricity supplies.
However, it said that governments would have to convince the private sector that the initial investment of about $2bn-3.5bn (£1-1.8bn) per reactor would be a wise move.
The report also projected that biofuels were set to play an increasing role in road transport, providing up to 7% of the total consumption in 2030.
To meet this demand, the IEA envisaged that the total amount of arable land required would be equivalent to at least the combined size of France and Spain.
But the WEO warned that the growing demand for food would limit the potential of the plant-derived fuel produced using current technologies.
Yet the emergence of new "second generation" technologies, which allow more of a plant's material to be turned into fuel, could allow biofuels to play a much bigger role in either of the projections outlined in the report's two scenarios, it said.
As for the financial viability of the alternative policy scenario, the IEA reached a similar conclusion to the findings outlined in a report by Sir Nicholas Stern, who was commissioned by the UK government to assess the economic impact of climate change.
"The good news is that these policies are very cost effective," said Mr Mandil. "There are additional upfront costs involved, but they are quickly outweighed by savings in fuel expenditure."
He added that every $1 invested in energy efficient appliances and equipment delivered a $2 saving on power generation.
The report concluded that a shift to the alternative scenario would "serve all three of the principal goals of energy policy: greater security, more environmental protection and improved economic efficiency".