Farming plankton, sending solar panels into orbit, remodelling hydrogen -- for the latest wave of entrepreneurs suggesting easier ways out of climate change, it's all in a day's pitching.

Beyond grabbing headlines, such notions are attracting serious scientific attention and venture funding from investors who at least until the collapse of Lehman Brothers lent credibility to high-risk investment propositions.

Some plans seek radical alternatives to fossil fuels. Other businesses are dreaming of geoengineering -- planning to tweak the earth's climate by removing heat-trapping carbon dioxide (CO2) or reflecting sunlight into space.

Among new energy fixes presented to Reuters in recent days is US-based BlackLight Power.

The company says it may have tapped the energy that cosmologists have struggled to explain, called dark matter, which fills the universe. The concept involves shifting electrons in hydrogen molecules -- obtained cheaply from water -- into a lower orbit, releasing energy in the process.

'It represents a boundless form of new primary energy,'  Randell Mills, founder and chief executive, told Reuters in a telephone interview.

'I think it's going to replace all forms of fuel in the world.'    

Britain's top science academy, the Royal Society, this week urged more funds be channelled into research on geoengineering, but for some climate commentators the unproven, technical solutions smack of society's craving for pain-free get-outs.

 They note politicians may prefer to feed that habit rather than face tough choices in redressing global warming.

Greenpeace chief scientist Doug Parr says geoengineering projects will be seized upon by polluters as a quick fix, and the former climate change adviser to oil firm BP said they are simplistic.

'People are being naive ... looking for a technological fix,' said Chris Mottershead, who is now head of research and innovation at King's College London.

'Anything of the necessary scale will have its own unintended consequences, even if they are not recognised at the moment.'     

He pointed out that the age of nuclear energy -- a radical carbon-free energy concept that humanity has tried and tested -- is still waiting to be reborn, mainly because of political and social concerns.

Sponsors of the radical route argue its offerings may serve as a Plan B if politicians fail, a 'lifeboat' just in case climate change reaches a point of no return for Earth.

'You do everything in your possible power to make sure you never ever have to use the lifeboat but the emergency equipment has to be there,' said Alan Knight, who heads a $25 million contest for a radical solution on behalf of UK-based Virgin.

'At the moment we don't have a lifeboat,' he told Reuters. The Virgin award focuses exclusively on carbon removal.

Since 1991, BlackLight's founder says his company has raised $60 million from private investors who have included -- on a personal basis -- the former chairman of Morgan Stanley, Dick Fisher, and the bank's now retired head of energy. Mills says his goal is to produce a 250 kilowatt prototype by end-2010.

The estimated capital cost of the energy at $500/KW would be less than coal power, one of the cheapest forms of energy now. Several utilities have bought licences, in case it works.

Last month New Jersey-based Rowan University engineers said the BlackLight process in the lab had produced heat some 1.6-6.5 times beyond levels that can be easily explained.

'It does portend some type of novel energy source,' said Peter Jansson, associate engineering professor at Rowan.

In another energy fix, California-based Solaren wants to launch solar panels into orbit to send back ra