The Uses of Non-Conventional Sources of Energy

In the early part of the 21th century, the need for alternative energy sources became clear. As traditional fossil fuels were depleted and the development of mainstream renewable energy via wind, solar, hydro-electric and geothermal generators only fulfilled some of the world's energy demands, researchers and engineers began to seek other methods of energy production.

Methane Power Plants

• Large amounts of methane gas are produced by certain industries, such as coal mining, and it is problematic because methane is 20 times more potent that carbon dioxide, another greenhouse gas. In an effort to make use of what was otherwise a waste product, engineers in China looked to the Australian model of adapting methane as fuel, and developed a method to repurpose the troublesome gas. One model of methane repurposing involves bringing methane up from the mine via a pumping station, then using it to power a Caterpillar engine. This system produces 120 megawatts of continuous power, which is enough to power 82,000 American homes.

Hybrid Cars That Utilize Compressed Air

• Hybrid cars that merge gas and electric propulsion are one means of combining power systems, but others exist. Air hybrid engines have been developed that use compressed air to reduce fuel consumption and boost a conventional engine's power. These hybrid systems had achieved a 65 mpg efficiency rate and a 30 percent reduction in emissions as of 2011, but had not yet become widely available to consumers. Additional advances in this technology, such as those at Brunel University's School of Engineering and Design, adapted the regenerative braking concept from conventional hybrid cars and implemented a system by which the engine and brakes replenish some of the compressed air supply to extend the vehicle's range.

Solar-Powered Computers

• Both Apple and Motorola have filed patents concerning the integration of solar cells within their mobile devices. Hoping to use solar energy to power iPods and MacBooks, Apple planned to add photovoltaic panels to various parts of their computers, which include display and input devices, coated materials and materials from which the logo is etched. Motorola's patent specifically involved building solar cells into the display screen, which would make use of a large amount of available surface area to house solar cells.

Nanogenerators Powered by the Human Heartbeat

• Nanogenerators make use of zinc oxide nanowires, which generate an electric current when strained or flexed. Researchers at the Georgia Institute of Technology made use of this property to develop piezoelectric devices, which produce small amounts of electricity in response to motion. Although these devices were only in early development in 2011, researchers believed that they would be able to stack nanogenerators together in small arrays to boost output. By doing so, they hoped to produce battery chargers and small electronics that could be powered by walking, rolling tires, wind or even the wearer's own heartbeat.