CONSUMERS will use twice as much energy to power electronic devices by 2010 as they do now.

A report released today suggests TV set-top boxes alone, which are expected to escalate in number following the digital switchover, will cost up to GBP780m to run annually in the UK.

The study by the Energy Saving Trust, called the Rise of the Machines, also found mobile phone chargers left plugged in waste enough energy to power the electricity needs of 66,000 homes annually.

According to the organisation, which addresses the damaging effects of climate change, this "insatiable" appetite for gas and electricity has outstripped progress in making goods more energy efficient.

Between 1972 and 2002, the amount of electricity used by traditional domestic "white goods" appliances doubled. That figure is set to rise by a further 12per cent in the next four years, the report warns.

But consumption is on track to increase even further, with the amount of energy used by the new wave of consumer electronics - such as iPods and DVD players - expected to double by 2010.

A typical 1970s home contained just 17 energy-using products, including TVs, washing machines, toasters and vacuum cleaners. Three decades later, that number has escalated through innovations like computers, juicers, extractor fans, games consoles and electric toothbrushes.

The report warns: "While the energy efficiency of some products has greatly increased over the past few decades, the sheer quantity and choice of products available has swamped any savings made through rises in energy efficiency."

Rising numbers of houses in the UK - many inhabited by fewer people than in the 1970s - also means that an increasing number of buildings consume gas and electricity. Central heating and gas- powered water heating systems accounted for 83per cent of the UK's total domestic energy use in 2000, the report says.

Paula Owen, head of information at the trust, said: "Energy used powering consumer electronics is anticipated to nearly double by 2010 from today.

"This is largely due to the sheer volume of products available and the phenomenal growth of the market, but also in part to the forthcoming digital switchover which will see an explosion in the number of set-top boxes used."

The trust is calling for a series of measures to help stem domestic gas and electricity use. These include minimum standards for standby power consumption, tighter standards for energy- efficient domestic appliances, a tax on inefficient products and even an outright ban on energy-guzzling household goods.

A study undertaken to coincide with the launch of the trust's report found Scots consumers claimed to be shifting loyalty to products that benefit the environment in light of concerns about climate change.

According to researchers, the "climate chic" phenomenon has arrived with more than half (54per cent) of consumers surveyed saying they would pay more for environmentallyfriendly products compared with 22per cent willing to pay more for designer labels.

Around 54per cent of consumers were also more inclined to buy a product for its energy-saving quality. This compared with 41per cent who would buy for fair trade, 39per cent for organic quality, and 23per cent if it was recycled.

Almost three-quarters of respondents backed "green" labels such as the "energy saving recommended" logo, which identifies the most energyefficient appliances.

Mike Thornton, head of the trust in Scotland, said: "Extending the success of the 'energy saving recommended' label to consumer electronics could reap huge savings and help towards the goal of saving 20per cent of the energy we use by 2010."