A long-term decline in the demand for oil could undermine the huge investments in Canadian tar sands, which have been heavily opposed by environmentalists, according to a report published today.

The report, by Greenpeace, will make uncomfortable reading for the companies that are investing tens of billions of pounds to exploit the hard-to-extract oil in the belief that demand and the price would climb inexorably as countries such as China and India industrialise.

Citing projections from the oil producers’ cartel Opec and the International Energy Agency, as well as various oil experts, the report casts doubt on the conventional assumption that consumption and prices will begin gathering pace once the world pulls itself out of recession.

It argues that alongside the cyclical fall in the oil price there are more fundamental structural changes taking place. These are driven by advances in energy efficiency and alternative energy, cleaner vehicles, government policies on climate change and concerns over energy security. Greenpeace has posted the report to 200 shareholders in Shell and BP, including pension funds, in an effort to put pressure on the companies to think again. BP reports quarterly results tomorrow and Shell on Thursday.

Lorne Stockman, the author of the report, said: “A peak in oil demand was barely discussed even a year ago, but now it is a viable idea. When it happens, I wouldn’t want to guess, but it will happen sooner than we thought. There has been lots of talk about a supply peak, but it is good to start talking about a demand peak, and that has huge implications for these companies.

“All of the international oil companies as you look beyond 2020 need a high oil price to be profitable, because they are increasingly being pushed to develop expensive resources in not just the tar sands, but in deep water and offshore Arctic sites.

“But there is something more structural going on,” he added. “Governments are beginning to act, and not just the Obama administration. In the EU, the policy driver is climate change, and in China and the US, it is about energy security and the vulnerability of the economy to volatility in the oil price.”

The rush to exploit the tar sands in Canada has been described as a modern day gold rush that has led to a huge boom in once sleepy towns in the province of Alberta. The oil was once considered too difficult and expensive to extract as it is a mixture of clay, water and bitumen.

Many of the projects have been mothballed until the oil price recovers. It has fallen from a peak of $147 a barrel and is currently at about $68. Merrill Lynch estimates that the price would need to settle at about $80 to make further investment viable. Critics argue that tar sands extraction is disastrous to the environment, causing deforestation, requiring huge amounts of water and greenhouse emissions three to five times greater than conventional crude.

The report notes that Opec and the IEA have been revising projections for oil demand downwards since 2006, with by far the sharpest revision this year. Opec has revised its 2025 oil forecast down by 12% within the past four years.

Peter Hughes, who spent much of his career at BP and BG, and is now director for global energy at consultancy firm Arthur D Little, recently wrote a report titled ‘The Beginning of the End for Oil?’ He supports the Greenpeace view and said the correlation between oil demand and GDP growth has been weakened. “It is widely accepted that demand in OECD countries has plateaued and is going into decline but it has also been thought that would be massively outweighed by growth in China. But the Chinese think long-term and identified some time ago that the biggest threat to their economic growth was an increasing dependency on imported energy, which is anathema to them. The conclusion is clear – to reduce the reliance on hydrocarbons through energy efficiency and fundamental technology change. I think we will reach peak oil demand in the middle of the next decade.”

About 50% of oil demand in the US fuels cars and the report takes hope from the Obama administration having tied recent bailouts for the industry to the development of cleaner vehicles. But it notes the US is far behind China, where government mandates mean new Chinese cars are 56% more fuel-efficient than those built in Detroit. Fuel-efficient cars in China attract 1% sales tax and sports utility vehicles, 40%.

Greenpeace also contends that a high oil price is simply unsustainable. It cites research from Cambridge Energy Research Associates, which suggests that economies become constrained when the price moves into a band between $100 and $120 a barrel, causing the price to fall back. Another report from energy business analysts Douglas Westwood puts the “recession threshold” even lower, at $80 a barrel.

Shell, which has delayed a number of tar sands projects, argues that energy supply will struggle to keep up with the demands of a growing global population and that in the long term there will be upward pressures on energy prices that justify investing in the Canadian tar sands. “Our first oil sands operation, the Athabasca Oil Sands Project (60% Shell share) was built between 1999 and 2003, when the oil price was considerably lower,” a spokeswoman said. Shell has the highest exposure of the majors to the tar sands and is most at risk from a decline in demand.

There are contrary views. The Saudi oil minister warned in May that the world could be facing another oil shock, with prices above $150 within two to three years through a lack of investment in new capacity. The International Monetary Fund has expressed similar concerns. Even Greenpeace does not suggest that there will not be temporary squeezes on demand and price spikes. But it believes that the world might fast be approaching a tipping pointthat could have profound implications.

A wind farm in the Ngong hills on the outskirts of Nairobi, Kenya Photograph: Stephen Morrison/EPA

One of the hottest places in the world is set to become the site of Africa’s most ambitious venture in the battle against global warming. 

Some 365 giant wind turbines are to be installed in desert around Lake Turkana in northern Kenya – used as a backdrop for the film The Constant Gardener – creating the biggest windfarm on the continent. When complete in 2012, the £533m project will have a capacity of 300MW, a quarter of Kenya’s current installed power and one of the highest proportions of wind energy to be fed in a national grid anywhere in the world. 

Until now, only north African countries such as Morocco and Egypt have harnessed wind power for commercial purposes on any real scale on the continent. But projects are now beginning to bloom south of the Sahara as governments realise that harnessing the vast wind potential can efficiently meet a surging demand for electricity and ending blackouts. 

Already Ethiopia has commissioned a £190m, 120MW farm in Tigray region, representing 15% of the current electricity capacity, and intends to build several more. Tanzania has announced plans to generate at least 100MW of power from two projects in the central Singida region, more than 10% of the country’s current supply. In March, South Africa, whose heavy reliance on coal makes its electricity the second most greenhouse-gas intensive in the world, became the first African country to announce a feed-in tariff for wind power, whereby customers generating electricity receive a cash payment for selling that power to the grid.

Kenya is trying to lead the way. Besides the Turkana project, which is being backed by the African Development Bank, private investors have proposed establishing a second windfarm near Naivasha, the well-known tourist town. And in the Ngong hills near Nairobi, the Maasai herders and elite long-distance athletes used to braving the frigid winds along the escarpment already have towering company: six 50m turbines from the Danish company Vestas that were erected last month and will add 5.1MW to the national grid from August. Another dozen turbines will be added at the site in the next few years. 

Christopher Maende, an engineer from the state power company KenGen, which is running the Ngong farm and testing 14 other wind sites across the country, said local residents and herders were initially worried that noise from the turbines would scare the animals. 

“Now they are coming to admire the beauty of these machines,” he said. 

Kenya’s electricity is already very green by global standards. Nearly three-quarters of KenGen’s installed capacity comes from hydropower, and a further 11% from geothermal plants, which tap into the hot rocks a mile beneath the Rift Valley to release steam to power turbines. 

Currently fewer than one-in-five Kenyans has access to electricity but demand is rising quickly, particularly in rural areas and from businesses. At the same time, increasingly erratic rainfall patterns and the destruction of key water catchment areas have affected hydroelectricity output. Low water levels caused the country’s largest hydropower dam to be shut down last month. 

As a short-term measure KenGen is relying on imported fossil fuels, such as coal and diesel. But within five years the government wants to drastically reduce the reliance on hydro by adding 500MW of geothermal power and 800MW of wind energy to the grid. 

Not only are they far greener options than coal or diesel, but the country’s favourable geology and meteorology make them cheaper alternatives over time. The possibility of selling carbon credits to companies in the industrialised world is an added financial advantage. 

“Kenya’s natural fuel should come from the wind, hot underground rock and the sun, whose potential has barely even been considered,” said Nick Nuttall, spokesman for the United Nations Environment Programme. “After the initial capital costs this energy is free.” 

The Dutch consortium behind the Lake Turkana Wind Power (LTWP) project has leased 66,000 hectares of land on the eastern edge of the world’s largest permanent desert lake. The volcanic soil is scoured by hot winds that blow consistently year round through the channel between the Kenyan and Ethiopian highlands.

According to LTWP, which has an agreement to sell its electricity to the Kenya Power & Lighting Company, the average wind speed is 11metres per second, akin to “proven reserves” in the oil sector, said Carlo Van Wageningen, chairman of the company. 

“We believe that this site is one of the best in the world for wind,” he said. If the project succeeds, the company estimates that there is the potential for the farm to generate a further 2,700MW of power, some of which could be exported.

First, however, there are huge logistical obstacles to overcome. The remote site of Loiyangalani is nearly 300 miles north of Nairobi. Transporting the turbines will require several thousand truck journeys, as well as the improvement of bridges and roads along the way. Security is also an issue as the region is known bandit country, and many locals are armed with AK-47 assault rifles. 

LTWP also has to construct a 266-mile transmission line and several substations to connect the windfarm to the national grid. It has promised to provide electricity to the closest local towns, currently powered by generators. 

The greening of Africa

At the end of 2008, Africa’s installed wind power capacity was only 593MW. But that is set to change fast. Egypt has declared plans to have 7,200MW of wind electricity by 2020, meeting 12% of the country’s energy needs. Morocco has a 15% target over the same period. South Africa and Kenya have not announced such long-term goals, but with power shortages and wind potential of up to 60,000MW and 30,000MW respectively, local projects are expected to boom. With the carbon credit market proving strong incentives for investment other types of renewable energy are also set to take off. Kenya is planning to quickly expanding its geothermal capacity, and neighbouring Rift Valley countries up to Djibouti are examining their own potential. As technology improves and costs fall, solar will also enter the mix. Germany has already publicised plans to develop a €400bn solar park in the Sahara.

“Ultimately for Africa solar is the answer, although [costs mean] we may still be decades away,” said Herman Oelsner, president of the African Wind Energy Association.