The United States has joined forces with Britain to investigate a hi-tech new way of producing ‘clean energy’ – not from wind or waves, but from firing huge arrays of high-powered lasers at pellets of hydrogen.
The process causes the hydrogen atoms to fuse together into helium – the same reaction found in hydrogen bombs and stars such as our Sun – but in a controlled reaction that could power homes and businesses.
Recent experiments at America’s National Ignition Facility (NIF), have produced huge bursts of energy from the technology – using a stadium-sized building housing an array of 192 lasers which fire a 500-terawatt flash at a drop of hydrogen atoms just 1mm across.
For the instant during which NIF’s laser is fired, it uses more power than the electricity consumption of the whole of America. But the returns are increasing.
In an experiment this week, a burst of power was released from the fusion reaction that was equivalent to the entire world’s consumption.
The UK company AWE and the Rutherford Appleton Laboratory have now formally joined forces with the American facility, in a meeting at London’s Royal Society.
‘This is an absolutely classic example of the connections between really high-grade theoretical scientific research and a fundamental human need: our energy supply,’ said David Willets, the UK’s science minister.
‘Controlled’ nuclear fusion – the reaction in a hydrogen bomb is uncontrolled – is a Holy Grail of clean energy that scientists have sought to crack since the Fifties.
Recent breakthroughs in America have drawn closer to the technology’s final aim – a reaction that produces more energy than is put in to achieve it.
Previous UK approaches to nuclear fusion have focused on a different technology – magnetic containment fusion, in which a doughnut-shaped ‘torus’ houses a stream of circling atoms heated by huge towers firing particle beams to many times the temperature at the centre of the sun.
The huge JET (Joint European Torus) facility outside Oxford has achieved reactions which release energy, but has never achieved ‘break even’ – the point at which the amount of energy released by the fusion reaction is equal to the energy put in.
But magnetic containment fusion is extremely expensive – a new reactor planned for Europe was budgeted to cost more than the Large Hadron Collider, and could be the most expensive science project since the International Space Station.
Laser fusion was expected to take longer to achieve than magnetic containment fusion, but recent results from NIF have hinted that the break-even point in laser fusion might happen earlier than was thought possible. A similar project in the UK, called HIPER, the High Power Laser Energy Research began work in 2005.
‘NIF director Ed Moses said, ‘Our goal is to have ignition within the next couple of years.’
Ignition would be a self-sustaining reaction that would release vast amounts of energy far surpassing the ‘break even’ point.
Last week, a single shot of NIF’s laser released, for a tiny fraction of a second, more power than was being consumed in the entire world.
To hit the point of ‘ignition’, that energy release needs to rise by a factor of around 1,000. The technology challenges are considerable.
John Parris, of Europe’s HiPER project, said ‘This is save-the-world science. Fusion is the only serious answer to future energy demands – this is the energy Holy Grail. The human race has a massive, ravenous demand for power. Fusion will be an ideal solution in the clean energy mix for the future.’
NIF, however, is working already. The facility uses pellets of the hydrogen isotopes deuterium – found in ‘heavy water’ – and tritium, and fires lasers to compress the pellets to a few hundredths of its starting size.
The reaction fuses the atoms into helium atoms, and releases fast-moving subatomic particles called neutrons which can be used to heat water and drive steam turbines.
NIF estimate that a fully functioning laser fusion plant would need to use 10 hydrogen fuel pellets per second, firing the laser array each time. So far, the plant has only fired 305 times in total, using energy stored in huge battery-like capacitors.
For a long period, NIF’s vast power means the facility could only be fired once a month.
Fusion is not, however, uncontroversial. The NIF is also associated with weapons programmes in the US – the process of fusion is also used in hydrogen bombs, and NIF works with America’s Stockpile Stewardship and Management programme, designed to ensure its nuclear arsenal stays active.
Environmental groups such as Greenpeace claim that research into fusion diverts funding from research into proven technologies such as wind and wave power.
Via Daily Mail