Across Britain, cities are plunged into darkness. In London, the Underground grinds to a halt, leaving panicked commuters stranded in oppressively hot carriages. In office blocks, lifts stop operating and the air-conditioning shuts down. Employees swelter in stifling conditions. This is not the postapocalyptic vision of some film-maker, but a realistic scenario as Britain grapples with a looming energy crisis. The statistics are frightening. In only eight years, demand for energy could outstrip supply by 23% at peak times, according to a study by the consultant Logica CMG. The loss to the economy could be £108 billion each year. "The idea of the lights going out is not a fantasy. People seem to accept that security of energy supply is a right. It is not. The industry will have to work hard to maintain supply and for that we need a clear framework," said Simon Skillings, director of strategy and energy policy at Eon UK, Britain's largest integrated energy company. This Wednesday, the government's delayed energy white paper will attempt to provide some answers. It is a crucial document that will determine whether Britain can deliver on its pledge to slash carbon emissions by 20% from 1990 levels by 2020. The white paper will seek to tackle a host of tough issues - from nuclear power to energy efficiency, renewable power sources and clean-fuel projects. A planning white paper, due tomorrow, is also seen as crucial after a number of energy projects have been delayed for years or slapped down by local authorities. The scale of the challenge is immense. By 2015, Britain's generating capacity could be cut by a third as ageing coal and nuclear power stations are closed. Britain is also moving from being self-sufficient in oil and gas as North Sea production declines. In 2005, the UK became a net importer of gas. By 2010, imports could account for 40% of British gas needs; by 2020, 80% to 90%. The most contentious area is likely to be nuclear power. Nuclear reactors account for about 20% of Britain's electricity, but this will shrink to 6% in 20 years as ageing plants are closed down. By 2023, only Size-well B could be in operation.

The water shortage across eastern Australia is now so acute it has begun to affect power supplies, and the country is at risk of electricity shortages next year. "I think we are in denial, and are going to have brownouts in NSW if we don't get snow this winter," a source within the electricity market said. Coal and hydro power generation require very large amounts of water, and the Snowy scheme depends on it for 86 per cent of its generation capacity. "Last year we had the lowest snowfall ever recorded. If this happens again we are in trouble," the source said. He declined to be named because electricity pricing and supply is a politically charged subject. Prices are already tipped to double in South Australia. The news comes amid calls for the Government to adopt a carbon emissions trading scheme. This would have the effect of making alternative forms of energy generation - such as solar, wind and geothermal - more competitive with coal-fired power stations. It would also offer greater certainty to those looking to develop power assets. Reports that the Government is close to adopting a scheme with nations in the Asia-Pacific region have come under fire, with Labor's environment spokesman Peter Garrett arguing it has come too close to an election to be credibile. It's understood carbon trading will be on the agenda at the APEC summit in September, when the leaders of 21 countries meet over three days.

BP's Russian unit, TNK-BP, may have to halt production at a large Siberian gas field by the end of this month, Russia's environment agency has warned. The agency told Reuters it seemed "obvious" that an inspection in the next few days would say TNK-BP was not complying with production obligations. Both TNK-BP and UK energy giant BP have declined to comment.

Analysts say the move is just the latest attempt by the Kremlin to gain control of Russia's energy supplies. ... The firm, which is equally owned by BP and Russian group Alfa Access Renova, earlier this month won the right to challenge in court the threat to its Kovykta licence.

Yet the deputy head of the Russian environment agency, Oleg Mitvol, said he was not concerned by the possible legal challenge. "They [TNK-BP] have yet to win the case and I hope the court takes a just decision," he said. Analysts say the Kremlin wants state-run gas firm Gazprom to gain a majority stake in the Kovykta field on cheap terms. Last year Gazprom secured a majority stake in a similarly large Russian oil and gas field formerly led by fellow UK energy firm Shell.

Shell and its partners granted Gazprom control of the Sakhalin 2 project off Russia's far east coast after Russian authorities repeatedly refused to grant them the necessary environmental certificates. The Kremlin rejects any claims that it is using underhand tactics to gain state-control of Russian energy supplies.