Slide 1 of 21
New energy sourcesScientists are racing to perfect greener sources of energy to improve the environment and reduce dependence on oil and other fossil fuels. Some predict a hydrogen economy. Others say solar is the way to go. Wilder schemes involve sky-high wind turbines or antimatter engines. LiveScience explores the expectations, myths and realities of 10 top possibilities.
AntimatterSlide 2 of 21
AntimatterAntimatter is the Bizarro twin of matter, made up of antiparticles that have the same mass as ordinary matter but with opposite atomic properties known as spin and charge. When the opposed particles meet, they annihilate each other and release tremendous amounts of energy as dictated by Einstein’s famous equation, E=mc2.
Antimatter is already in use in a medical imaging technique known as positron emission tomography (PET), but its use as a potential fuel source remains in the realm of science fiction.
The problem with antimatter is that there is very little of it in the universe. It can be produced in laboratories, but currently only in very tiny amounts, and at prohibitively high costs. And even if the problem of production could be solved, there is still the knotty question of how to store something that has a tendency to annihilate itself on contact with ordinary matter, and also how to harness that energy once created.
NASA funds research into creating antimatter drives that could one day take humanity to the stars, but dreams of antimatter-powered starships as seen on Star Trek are still a long way off, all experts agree.Slide 3 of 21
Fuel CellsSlide 4 of 21
Fuel CellsAt first glance, hydrogen fuel cells might seem like the perfect alternative to fossil fuels. They can generate electricity using only hydrogen and oxygen and are pollution free. An automobile running on hydrogen fuel cells would not only be more efficient than one powered by an internal combustion engine, its only emission would be water.
Unfortunately, while hydrogen is the most abundant element in the universe, most of it is bound up in molecules such as water. That means pure unbound hydrogen must be produced with the help of other energy sources -- which in many cases involve fossil fuels. If that’s the case, then many of the environmental benefits of hydrogen as a fuel are negated. Another problem with hydrogen is that it cannot be compressed easily or safely, and requires large tanks to store. Also, for reasons that are not fully understood, hydrogen atoms have a tendency to bleed through the materials encasing them, thus weakening their containers.
Honda introduced last year a scooter that uses fuel cell technology.Slide 5 of 21
NuclearSlide 6 of 21
NuclearAlbert Einstein told us that the line between matter and energy is a fuzzy one. Energy can be produced by either splitting or combining atoms—processes known as fission and fusion respectively.
Nuclear fission releases harmful radiation and produces large amounts of radioactive material, which can remain active for thousands of years and can destroy entire ecosystems if leaked. There is also concern that nuclear material could be used in weapons.
Currently, most nuclear power plants use fission, as fusion requires tremendous amounts of energy to produce and maintain the necessary high temperatures. But a natural phenomenon known as sonoluminescence might one day provide a means of duplicating the power of the stars—which are themselves just giant nuclear fusion reactors -- in a beaker of liquid.
Sonoluminescence refers to the flash of light produced when special liquids are struck by high-energy sound waves. The sound waves rip through the liquid and produce tiny bubbles that rapidly expand and then violently collapse. Light is produced in the process, but more importantly, the insides of the imploding bubbles reach extremely high temperatures and pressures -- enough, some scientists speculate, for nuclear fusion to occur.
Scientists are also experimenting with methods to create controlled nuclear fusion by accelerating "heavy" hydrogen ions in a powerful electric field.Slide 7 of 21
Ocean Thermal Energy ConversionSlide 8 of 21