With coal being too dirty and wind farms and nuclear power plants arriving late, it seems the world is left with a stark choice: keep on polluting or turn out the lights. Unless, that is, someone comes up with an alternative.

Energy executive Rune Bjornson thinks he has the answer. "Natural gas, more than any other fuel, is an option we have here and now,"  and, he adds, there is plenty of it around - unlike scarcer resources such as oil and coal.

Given that Mr Bjornson heads up the gas division at the Norwegian energy giant Statoil, it comes as no surprise that he should hail the virtues of gas. “ We look at shale gas as a potential game changer ” Rune Bjornson, head of gas division,

Statoil but he is not alone in his predictions. In June this year, the Potential Gas Committee, which is connected with the Colorado School of Mines, raised its estimate of gas reserves in the US by 35% to 2,074 trillion cubic feet (58.74 trillion cubic metres), the highest reserves since the group started tracking the information 44 years ago.

The upgrade came after new technology made it easier and cheaper to extract gas from shale rock, a prehistoric clay, which has hitherto been deemed too expensive and tricky to recover. The implications for global power balances could be enormous, in both the energy and the geopolitical sense.

What next? Upgraded shale gas reserves are particularly relevant  with respects to the Copenhagen summit, as it could help the world meet the Kyoto targets for carbon emission cuts, Mr Bjornson insists. "Gas has very low carbon emissions when compared with many other energy sources," he says. Indeed, he insists, gas - whether offshore gas reserves or from shale rock - is "not competing with" tomorrow's technologies.

The need to reduce emissions from energy production means nuclear power, carbon capture and storage, as well as wind and other renewable energy sources, will become leading power suppliers in the future as current energy production becomes unsustainable, Mr Bjornson predicts. "It is no longer a question of whether climate change is real or not," he says. "That was yesterday's discussion. Now, it is a question of what we do next."

But while the world waits for wind farms, nuclear power plants and carbon storage facilities to be built, gas could deliver vast reductions in emissions, Mr Bjornson says. "If Europe was to convert all coal-fired power stations to gas they would reduce emissions by 40%," he claims, pointing to how gas power stations emit about about a third less than modern coal-fired power stations and about two-thirds less than old ones.

Peter Dea, chief executive of Cirque Resources in Denver, Colorado, goes further. He believes gas could not only replace coal as the main source of electricity in the US, it could deliver fuel for America's cars as well. His optimism is based on  the Potential Gas Committee's estimate, which suggests the US has a 100-year supply of gas.

New techniques have been developed, where liquid, chemicals and sand is injected horizontally into shale rock to break open pathways for the gas to leak to the surface. The shale gas reserves are expected to boost economic growth, help reduce carbon emissions and reduce US dependence on energy imports, Mr Dea predicts. "It is truly a win-win-win situation," he says.

Eager to take part in this development, Statoil last autumn joined forces with Chesapeake Energy to extract shale gas from the North East, Marcellus foundation that stretches across Pennsylvania and New York State. “ As shale gas fields come on line in the next five years, it is likely that European prices will drop in half ”

Paul Sterne, managing partner of mergers and acquisitions advisers Sterne & Co "It has come as a surprise to the industry that the reserves were so good and that it was competitive in terms of cost," Mr Bjornson says. "We look at shale gas as a potential game changer." and not only in the US. "We believe there are huge resources in others areas, including Europe," Mr Bjornson says.

Shale reserves are believed to be vast in Poland, Germany, France and Sweden, and there could also be similarly enormous shale gas areas in India and China. "But it hasn't gotten much attention," says Mr Bjornson. "It is an industry that is still young." Sceptics such as Arthur Berman, who was speaking at a recent energy conference in Denver, is one of them.

The Texas-based geological consultant believes the latest estimates are vastly exaggerated and suggests the shale gas reserves are neither as large as nor as profitable as many in the industry predict. But "in the midst of a boom or a bubble, it's hard to sit on the sidelines", he says. "If you're not in on these plays, Wall Street says 'well, what's the matter with you guys?'"

Others point to how shale gas extraction can damage the environment as the chemicals used in the pressure-washer style drilling methods can leak into the ground water. Energy security Such sceptical voices do not ring loud in energy circles, however. advocates argue that the ability of shale gas to help curb carbon emissions makes it a worthy, and in macroeconomic terms worthwhile, risk to take.

But what is really exciting executives and policy makers alike is shale's potential to unseat leading natural gas suppliers such as Russia, Iran, Qatar and Algeria from their dominant positions, elevating the US, Europe, India and China into pole positions.

This could help improve energy security across the world, leaving few countries reliant on gas imports from countries often governed by unstable regimes. It could also hit current energy exporters where it hurts, namely in their wallets, as new gas sources send energy supplies soaring thus depressing prices across the world. Already, there are signs of such developments in the US, where natural gas is priced at up to $4 per million British thermal units - equivalent to crude priced at about $23 a barrel. (A barrel of crude contains on average 5.80 MBTU).

That is a seasonal rise from an average spot price of $2.50 during summer 2009, sharply down from 2008 when rising shale gas supplies pushed the average gas spot price down from almost $14 to about £10 per MBTU. "Longer-term, the cost of producing shale gas is estimated at about $6 per MBTU, equivalent to crude priced at $34.80 per barrel," observes Paul Sterne, managing partner of mergers and acquisitions advisers Sterne & Co, in an article published by Ground Report.

"Unconventional gas will exert downward pressure on energy prices for years to come," predicts Mr Sterne - in the US, as well as elsewhere. "As shale gas fields come on line in the next five years, it is likely that European prices will drop in half." Consumers might find that an appealing prospect, particularly in some of the world's poorest countries.

Such sharp price falls should go a long way to relieve fuel poverty and indeed hunger. But elsewhere, notably in Russia, many ordinary people could also see their lives transformed in less-than-desirable ways as it could lead to a painful reversal of the country's recent economic prosperity, which was based largely on highly-priced gas and oil exports.

The geopolitical implications are both obvious and enormous, so it is far from certain that a sharp and sudden rise in global gas supplies will be a blessing rather than a curse. But if the gas is there, do not expect such concerns to prevent it from being extracted.

A major hurdle to producing fusion energy using lasers has been swept aside, results in a new report show.

The controlled fusion of atoms - creating conditions like those in our Sun - has long been touted as a possible revolutionary energy source. However, there have been doubts about the use of powerful lasers for fusion energy because the "plasma" they create could interrupt the fusion.

An article in Science showed the plasma is far less of a problem than expected. The report is based on the first experiments from the National Ignition Facility (Nif) in the US that used all 192 of its laser beams. Along the way, the experiments smashed the record for the highest energy from a laser - by a factor of 20.

Construction of the National Ignition Facility began at Lawrence Livermore National Laboratory in 1997, and was formally completed in May 2009.

The goal, as its name implies, is to harness the power of the largest laser ever built to start "ignition" - effectively a carefully controlled thermonuclear explosion.

INERTIAL CONFINEMENT FUSION  

192 laser beams are focused through holes in a target container called a hohlraum  Inside the hohlraum is a tiny pellet containing an extremely cold, solid mixture of hydrogen isotopes  Lasers strike the hohlraum's walls, which in turn radiate X-rays  X-rays strip material from the outer shell of the fuel pellet, heating it up to millions of degrees  

If the compression of the fuel is high enough and uniform enough, nuclear fusion can result It is markedly different from current nuclear power, which operates through splitting atoms - fission - rather than squashing them together in fusion. Proving that such a lab-based fusion reaction can release more energy than is required to start it - rising above the so-called breakeven point - could herald a new era in large-scale energy production.

In the approach Nif takes, called inertial confinement fusion, the target is a centimetre-scale cylinder of gold called a hohlraum. It contains a tiny pellet of fuel made from an isotope of hydrogen called deuterium. During 30 years of the laser fusion debate, one significant potential hurdle to the process has been the "plasma" that the lasers will create in the hohlraum.

The fear has been that the plasma, a roiling soup of charged particles, would interrupt the target's ability to absorb the lasers' energy and funnel it uniformly into the fuel, compressing it and causing ignition. Siegfried Glenzer, the Nif plasma scientist, led a team to test that theory, smashing records along the way. "We hit it with 669 kiloJoules - 20 times more than any previous laser facility,"

Nif's Siegfried Glenzer said That isn't that much total energy; it's about enough to boil a one-litre kettle twice over. However, the beams delivered their energy in pulses lasting a little more than 10 billionths of a second. By way of comparison, if that power could be maintained, it would boil the contents of more than 50 Olympic-sized swimming pools in a second.

Crucially, the recent experiments provided proof that the plasma did not reduce the hohlraum's ability to absorb the incident laser light; it absorbed about 95%. But more than that, Dr Glenzer's team discovered that the plasma can actually be carefully manipulated to increase the uniformity of the compression.

"For the first time ever in the 50-year journey of laser fusion, these laser-plasma interactions have been shown to be less of a problem than predicted, not more," said Mike Dunne, director of the UK's Central Laser Facility and leader of the European laser fusion effort known as HiPER. "I can't overstate how dramatic a step that is," 

 "Many people a year ago were saying the project would be dead by now." Adding momentum to the ignition quest, Lawrence Livermore National Laboratory announced on Wednesday that, since the Science results were first obtained, the pulse energy record had been smashed again.

They now report an energy of one megaJoule on target - 50% higher than the amount reported in Science. The current calculations show that about 1.2 megaJoules of energy will be enough for ignition, and currently Nif can run as high as 1.8 megaJoules.

Dr Glenzer said that experiments using slightly larger hohlraums with fusion-ready fuel pellets - including a mix of the hydrogen isotopes deuterium as well as tritium - should begin before May, slowly ramping up to the 1.2 megaJoule mark. "The bottom line is that we can extrapolate those data to the experiments we are planning this year the results show that we will be able to drive the capsule towards ignition," said Dr Glenzer.

Before those experiments can even begin, however, the target chamber must be prepared with shields that can block the copious neutrons that a fusion reaction would produce. But Dr Glenzer is confident that with everything in place, ignition is on the horizon. He added, quite simply, "It's going to happen this year."