Visualisation of anti-matter powered rocket
One of the major advantages of fossil fuels is that they are energy dense. A challenge with renewable energy sources such as wind power and solar power is that the energy is very diffuse and to collect significant quantities is space intensive. For example to generate all the United State's current electricity demand would take several million wind turbines.
As part of my ongoing research into alternative energy technology I have come across several "out-there" potential sources. Barring a major breakthrough in alternative energy technology these aren't likely to be providing our power anytime soon.
The first source I am going to posting about is anti-matter.
Anti-matter is literally the opposite of matter. The first evidence of anti-matter was found by Carl Anderson in 1932, who discovered positrons - electrons with a positive instead of negative charge.
When matter comes into contact with antimatter it produces an explosion of pure radiation, traveling outwards at the speed of light. Both particles that created the explosion are completely destroyed, leaving behind only other subatomic particles. It's a perfect conversion of mass into energy. It releases about 10 billion time the energy of a chemical reaction and 1000 times more than nuclear fission in a nuclear power plant.
So why haven't we built a matter/antimatter power plant yet?
There seems to be very little antimatter in the universe (and certainly in our immediate vicinity).
So how do we get hold of some antimatter?
One way is create it using particle accelerators, like CERN. However particle accelerators only produce a few trillionths of a gram of antimatter each year. This is only enough to power a 100watt lightbulb for a few seconds.
Currently, antimatter is the most expensive substance on Earth, about $80 trillion a gram.
The world's largest maker of antimatter (according to CNN in 2002), the Fermi National Accelerator Laboratory in Batavia, Illinois, makes only one billionth of a gram a year at a cost of $80 million. At that rate, it would take one million years and $80 quadrillion (80,000 trillion) to produce one gram.
Harold Gerrish of NASA/Marshall and others estimate that improvements in equipment to slow and trap the antiprotons could bring the price down to about $5,000 per microgram. This is $5 million a gram, if the cost could be brought down to $1.5 million a gram this is the equivalent of 6 cents per a kilowatt hour.
Some people have theorised that comets contain significant quantities of anti-matter. A metric ton of antimatter could provide all the world's electricity for one year. 355 grams would produce the energy equivalent of burning a million tons of coal. (these figures are taken from the matter-antimatter.com website see note below)
Anti-matter as a material is the greatest source of energy (when combined with regular matter) that we know of. However the quantities we currently produce are trivial. Barring a breakthrough in production costs and volumes or the discovery of a source and the technology to collect antimatter in space and return it to Earth, meeting our energy needs with antimatter will remain a dream for the foreseeable future.
Latest news on particle accelerators (August 2004):
How Stuff Works - Explanation of Anti Matter & how it could be used for rocket propulsion
Matter/AntiMatter - mentions anti-matter in comets
(note this guy believes in Atlantis & thinks Nasa may cause armageddon in 2005)