GENEVA – The environmental group WWF argued on Thursday that a radical, near total elimination of oil and shift to clean energy within 40 years would generate four trillion euros ($5.4 trillion) in savings a year.

"The Energy Report" produced by WWF and consultancy Ecofys seeks to make the case for a concerted move away from high carbon fossil fuels such as oil, coal and gas to 95 percent clean energy by 2050 through "massive" investment to tackle climate change.

The report advocates a one to 3.5 trillion euro annual investment in renewable sources and energy efficiency as well as lifestyle changes over the next quarter of century.

As major oil companies started to unveil their large profits for 2010 and investment plans, WWF admitted that its proposals were "ambitious" and would mark "a radical departure from humanity's current course."

WWF Director General James Leape acknowledged that the initial need to gather huge capital finance was a major challenge, as well as the likely inevitable "substantial" use of biofuels for aircraft, ships and trucks, potentially clashing with food crops and land use.

However, Leape said it was now technically and economically feasible as well as unavoidable to cut carbon emissions and tackle global warming, based on "conservative estimates".

"What we found is that even with the technology available today it is fully possible to meet the needs of all the world's population for energy from clean renewable sources," he told journalists.

"And we can do it without major impacts on global growth."

Currently, fossil fuels account for 80 percent of the world's energy while investment in clean energy worldwide reached 110 billion euros by 2009, according to the report.

"By 2050 we save nearly four trillion euros per year through energy efficiency and reduced fuel costs compared to a 'business-as-usual' scenario," it added.

Despite the huge costs involved in a switch the report claimed the balance could break even by 2040.

The WWF highlighted savings from an end to fossil fuel subsidies around the world totalling 500 billion to 800 billion dollars a year, based on recent International Energy Agency (IEA) and OECD estimates.

It also estimated that the steps would produce a net 15 percent decrease in overall global energy demand by 2050, even with population growth, industrial expansion and increasingly wealthy populations.

Apart from more commonly advocated massive changes in fuels for transport and power supplies, the report pinpoints a huge range of steps to achieve less energy use that would affect different walks of everyday life, from housing to travel and eating habits.

Saudi petroleum and energy minister Ali Ibrahim Al-Naimi predicted in Geneva this week that the global energy mix would settle at about 50-50 split between oil and renewables or other sources.

The OPEC stalwart highlighted a near 40 percent growth in overall energy needs over the coming decades predicted by the IEA, typified by the recent surge in demand for oil from emerging nations like China and Brazil.

"The world does not have the luxury of discarding any particular energy source," argued Naimi. He has supported technological measures to reduce pollution and emissions from oil.