"In the long-run it's where society's going... there'll be a rush to exurbia," he says, referring to the rural zone beyond US city suburbs that are still close enough to reach the city centre, and known as the stockbroker belt in Britain.

The idea is you buy a field, wood or building plot -- but don't pay the premium for mains access to water, gas and electricity. You skip that by installing your own solar or wind power, with a diesel generator back-up, and dig your own well.

A quarter of a million US households and 100,000 Britons live off grid, estimates writer and broadcaster Rosen.

Rosen's idea isn't to return to a 1960's-style "green" idealism. He sees off-grid becoming mainstream, and appealing as much to well-off people who want a self-contained, second home.

"The only thing that's stopping an exodus now in Britain is planning permission. But the rules are bending," he says.

Britain says it has no plans to relax strict rules on building homes in the country, but has launched a drive to build 3 million new homes by 2020 and wants all new homes to be zero carbon from 2016.

On Rosen's website (http://www.off-grid.net/) his own personal request has no offers yet.

"Land wanted in the UK: To live on. Mixture of woodland and meadow. South facing with water. Nowhere near a big road."

CONCESSIONS

Investment in solar and wind power and batteries is paring the price of traditionally more expensive renewable energy compared to fossil fuels, and wireless technology makes it possible to access email, internet and work wherever there's a phone signal.

But going off grid is still expensive for incumbent house owners who don't benefit from that cheap plot of land to start.

A renewable energy system to cover an average British household's entire electricity needs would cost around 20,000 pounds (US$41,130) for solar power and 13,500 pounds for wind, including grants, estimates the Centre for Alternative Technology (CAT) -- compared to an annual electricity bill of about 400 pounds.

If you have a river at the bottom of your garden the cost of a hydropower system is around 7,500 pounds.

"For most people living in houses, they have a grid connection and the easiest way to save energy is through energy efficiency," said CAT's Lucy Stone.

In addition, renewable sources of heating such as wood-burning stoves are much cheaper than renewable electricity, said Stone, and given heating accounts for by far the biggest slice of the average household energy budget -- and carbon emissions -- that's a better place to start.

What about the convenience of living off-grid?

I look around my kitchen where I interview Rosen -- coffee machine, radio, electric juicer, dishwasher, spotlights, gas cooker, kettle, are all plugged into energy grids at the flick of a switch or turn of a dial.

"You just have to make concessions," Rosen replied: you can't have a television, washing machine and electric lights all on at the same time in an off grid house powered by wind or solar power, for example, he says.

"Society has already accepted that we have to make concessions," he said, referring to growing consensus that carbon emissions must be cut.

"It's going to need more than just turning down the thermostat a notch and recycling your rubbish."

"It might take continuing high oil prices, severe droughts, or a power, water or food shortage, to make off grid urgent."

In lieu of actual disasters, imaginary ones will do in the hunt for a reassuring protection.