A few lesser-known alternative energy sources

There are many ways to generate energy other than burning oil or coal — some methods are old, some fashionable, some expensive, and a few are still technological dreams. Here's a few alternatives:

Secondary alternative energy systems range from the large scale that produce useful amounts of energy only at an industrial level to applications modest enough to be used by an individual household.

• A bicycle can be adapted to directly turn the drive shafts of various small household appliances such as blenders, juice extractors and power drills.
• When a bicycle is connected to a generator, turning the pedals produces an electric charge. Unfortunately, although the bicycle is mechanically efficient, its output is limited by the comparatively small amount of power that human muscles can generate.
• A methane digester contains anaerobic bacteria that convert manure, vegetable matter and other waste into methane, which can be used for heating, lighting and cooking.
• The bacteria work in a tank that contains no oxygen, unlike the process that occurs in a septic tank, where aerobic bacteria use oxygen to convert organic wastes into carbon dioxide, fertilizer and water.
• To make enough methane to meet the cooking needs of an average family, the manure of one or two horses or cows, or of several hundred chickens, must be available in a steady supply.

Ethyl alcohol (ethanol) is a gasoline-substitute made by the ­fermentation of organic matter high in sugars and starches, such as sugar cane and wheat.

• Although the basic technology is thousands of years old, ethanol is more expensive than gasoline and is unlikely to come into wide use unless gas prices rise substantially.
• Methyl alcohol (methanol) is made by the distillation of vegetable matter high in cellulose.
• Methanol does not work as well in internal combustion engines as ethanol, so its practical applications are generally considered to be limited.

• Vegetable oil:  Crops such as sunflower, safflower and canola (rapeseed) yield vegetable oils that may be used as a substitute for diesel oil. Engine performance is about the same using either fuel.
• Geothermal energy:  Heat from within the earth can be made into electricity by using the steam associated with it to power turbines. Geothermal power is well established in New Zealand.
• Waste conversion:  Two high-temperature processes for fuel production, hydrogenation and pyrolysis, produce oil from manure, paper, wood, garbage or agricultural refuse.
• Magnetohydrodynamics:  Conventional generators pro­duce electricity by passing wires through magnetic fields. A magnetohydrodynamic generator re­places the wire with a current-conducting fluid pressured by heat to pass through the fields. Since no moving parts are used, the process wastes little heat. Unfor­tunately, costly temperature-resistant materials are needed to contain the hot fluid.
• Tidal power:  Energy from the twice-daily emptying and filling of coastal basins and inlets around the globe can be transformed into power. A barrier is built across a basin with sluices that allow it to fill at high tide. The escape of water through the barrier at low tide drives turbines that generate electricity.

Traditional sources of energy won't last forever. Even small changes to your energy use can have a large impact -- both on your personal carbon footprint and on your energy bill. Save the planet and possibly save yourself some money by adopting a few of these alternative energy sources!