All over the world, governments and commercial organisations are looking at ways to harness alternative energy sources. Gas and electric suppliers are often at the forefront of these developments as they seek to overcome their reliance on fossil fuels that are becoming more difficult and more expensive to harvest all the time. From a business perspective as well as an environmental one, it makes sense for them to diversify.

We're all aware of one of the main directions this has taken: wind power. Huge turbines can be seen marching across countries all around the globe. There has also been considerable investment in many areas in solar power. Even in cooler climates, if there's enough daylight then there's power to be had.

But these are far from the only technologies being developed, so we thought it would be interesting to look at some of the others, from those that are perhaps less well-known, to the quite surprising!

Wood and Straw

One widely-used alternative power source that seems to receive remarkably little publicity or news coverage comes under the general heading of biomass - basically the conversion of biological material into electricity through combustion. Although frequently this is done using things like wood waste, sugar cane and straw, sewage sludge and animal manure can also be used.

There are numerous advantages to biomass energy, not least of which is that it can be produced on demand. Sometimes the sun doesn't shine and the wind doesn't blow, but it seems we always have sufficient waste material to burn.

Opponents claim that there are environmental problems with the process and that burning of plant material releases carbons into the atmosphere, adding to global warming. There's also the argument that if you grow plants for electricity production you're using land that ought to be used for feeding our ever-expanding populations.

While the latter continues to be widely debated, the former is not accurate. Biomass electricity simply recycles existing carbon. It was in the atmosphere before being absorbed by plants, and goes back again. The process does not release additional carbons, like the burning of fossil fuels does. Burning straw is also a better option than letting it decompose, when it releases high levels of methane - an even more serious contributor to global warming.

At the moment, global biomass electricity production is second only to wind power.

Water, Water, Everywhere

Although we're used to hearing the phrase "wave power", there are actually several different approaches to harvesting energy from the sea, and not all of them are reliant on motion.

Osmosis, for example, is energy created when fresh water and salt water meet each other. Remarkably high pressures are generated as a result and several trials are underway to see how this can best be turned to our advantage. Prototype plants in Norway and Holland already suggest there's a lot of potential. Statkraft, the Norwegian state-owned power company have estimated that, if successful, the technology could provide as much as half of Europe's entire electricity needs.

Another non-wave generation technique is OTEC: Ocean Thermal Energy Conversion, which relies on the difference in temperature between surface water and deep water. The warm surface water is used to heat liquid ammonia - which has a very low boiling point. The vapour created then powers a turbine, so generating electricity. The cold sea water is then used to condense the ammonia back into a liquid - and the whole process starts again. The only real challenge with this technology is that at the moment a seawater temperature difference of at least 35° fahrenheit is required - restricting it to tropical areas.

As for wave power, there are a number of different approaches being tested, including tethered bouys, mechanical wave followers, sausage-like oscillating converters and tidal barriers. Many of the world's major gas and electric suppliers have divisions investigating the enormous potential wave power represents, but as yet there is no commercial-scale power production that uses any of these methods.