The A to Z of Unusual Renewable Energy Sources

By Hannah Corbett

The use of renewable and sustainable energy sources is growing worldwide. Subsequently, new technologies for sustainable energy are ever-emerging, and some are rather unusual. Outside of the more commonplace solar, tidal and wind energy sources, researchers have uncovered some uncommon ways of producing and harnessing renewable energy, and decreasing worldwide dependency on fossil fuels.

Anaerobic Digestion – Anaerobic digestion is slowly becoming a more ordinary method of energy production for both businesses and households alike. It involves harnessing the gasses that are produced as a result of biodegradation. Anaerobic digestion can be used on both large and small scales -- even for everyday household food waste, creating a useful form of waste management for homeowners.

Algae – Algae, yes the slimy green stuff you find at the bottom of a pond, contains cells which produce oil. Half of its body weight, in fact, is lipid oil. Lipid oil can be harvested and converted into fuel. The resulting biodiesel is more clean and efficient than petroleum, as well as more sustainable.

Although there are a few obstacles stopping algae fuel from being utilized on a huge scale, much research is being done to overcome these problems. The space that’s required to grow enough algae to produce a significant amount of oil, for example, is one obstacle. As is that fact that conditions, such as temperature, must be exact to enable optimum growth, and some of these conditions may be difficult to control.

Chocolate – There are a few different ways in which chocolate has been used to produce clean energy. The waste left over from a chocolate factory in the U.K. was fed to E. coli bacteria, which resulted in the production of hydrogen. Hydrogen is one of the cleanest fuels, it’s only by-product being water. Fat from chocolate was also converted into biofuel and used to power a racing car, which reached 130 miles per hour on the racetrack.

The shells of cocoa beans can also be converted into biofuel: A chocolate factory and power plant in New Hampshire recently joined forces to include cocoa bean shells, many of which are produced as waste from the chocolate factory, as an additional fuel source. Read more about it here.

Dance floors – The sustainable dance floor converts kinetic energy into electricity. Kinetic energy is generated by movement, such as people walking or dancing. The electricity is used to power the LED lights in the floor itself. Excess electricity can also be fed back the grid and sold, much in the same way excess energy from a solar panel might be, or it could be used to power other systems within the same building.

The technology used in the sustainable dance floor could potentially be applied to other situations and locations, such as a bus train station for example, to make the most of kinetic energy generated by movement.

Space-based solar power – Solar power has become increasingly popular in recent years, so much so that even some road signs are powered by the sun. But, solar power as we know it may take a big step in the future.

Space-based solar power has yet to happen, but the idea has been around for years. What it is, basically, is the concept of launching solar panels into space to harvest the sun’s energy, rather than doing so down here on Earth. This method would require no water or space on the Earth’s surface and would have zero carbon emission and produce no waste. One of the key factors stalling the launch of space-based solar is how the energy would be wirelessly transmitted back to Earth, and also how much the whole thing would cost.

Sound waves – Sounds can be converted in electricity through something called piezoelectricity. Piezoelectric materials generate energy when put under some form of mechanical stress, such as a sound wave. It is thought that piezoelectric materials can be utilised in electronics, such as mobile phones, to produce self-charging devices.

Zinc – In 2012, a New Jersey startup developed a type of zinc-air battery that it claimed could revolutionize renewable energy storage. Claimed by Eos Energy Storage to be twice as dense as a lithium-ion battery, the zinc-air battery could potentially replace natural gas 'peakers' (or plants that only turn on during peak demand), allowing for fully renewable power. The startup recently raised $15 million in Series B round funding to develop the technology, which also has potential for the electric vehicle industry.

Some of these sustainable energy technologies are still in development stages and not ready to be properly utilised, yet. However, there are a number of methods, such as the aforementioned wind, solar and tidal technologies, which are widely available to commercial and domestic environments. Even when renewable energy is not easily accessible, you can still play your part by supporting green energy suppliers and reducing your energy consumption as much as possible.

Image credit: caveman_92223, Flickr

Hannah Corbett is a writer specialising in all things green and renewable energy. Follow her on Twitter, or connect on Google+ to keep up to date with all the latest news in green technology.