Whilst much of the focus on micro-renewables is concentrated on wind turbines and solar panels, there is a diverse range of larger renewable energy technologies that don’t often get the coverage and discussion they deserve. Renewable technology is not limited to wind and solar generation in its traditional forms and there are many other forms of generation being developed. Some technologies are expanding rapidly whilst others are more conceptual ideas, including the suggestion that even energy sources such as lightning and tornadoes could be utilised in the future. Here, we have tried to summarise a few technologies that may soon be attracting a good deal more interest.
Algae are a group of small microscopic plants that grow in large numbers, in various locations and conditions. These plants can be grown quickly and efficiently in large numbers,
and produce oil similar to those found from more traditional biofuels such as soy beans and sugar cane. This oil can then be used to generate electricity or fuel in the transportation industry. Algae have the potential to produce 150 times the biolfuel (per acre per year) that soy beans produce.
Algae can be grown in large open pools, fermented tanks, or smaller more concise installations. These installations also have the benefit of using waste as a nutrient supply for the algae, and so has multiple applications. Algae energy technology is still in its infancy and relatively expensive, but costs are expected to fall rapidly as the industry develops, and make it more cost effective.
Put simply, wave energy generation harnesses the energy carried by ocean waves as they approach the shore. It has the potential to be one of the most environmentally friendly forms of generation, due to its benign nature. There is little disturbance during energy extraction, due to the already turbulent nature of the environment.
Wave technology is however plagued by the issue of variability, with a highly alternating output depending on the weather conditions. It also required a large number of smaller installations that cover a large area, which some have suggested is illogical.
Various Devices are currently in development. Some examples are
The Pelamis technology is one of the more established in this field. It utilises ocean surface movement using a snake like device, with energy being generated at various joints along its structure due to the vertical movement of the water it floats on.
The Oyster technology uses an anchored device that utilises the surface wave movements using a light buoyant component, and produces energy via a hydraulics system. Recently an 800KW device was developed by Aquamarine Power and installed in Orkney, with an 8 device array planned to supplying energy for up to 15,000 houses. These new installations plan to lower costs and maintenance with improved survivability and structural integrity.
Tidal energy also comes in various forms. Tidal energy can be harnessed in one of two ways.
Tidal stream technology is very similar to wind technology. The idea being that a horizontal axis turbine is sited in an area of high tidal velocity, and as the water moves through the area, the turbine generates electricity. Although the water moves slower than wind, it is denser, and so can still generate a significant amount of power. There are already devices being tested by SeaGen and Marine Current Turbines, but these are yet to be commercially developed on a large scale.(www.marineturbines.com/)
Tidal range technology harnesses the energy found in the difference between high tide and low tide. Installations seal off their channel at high tide, and release this dammed water after the ebb, allowing the difference in height to drive the water movement, and power a generator in doing so.
There are some established installations such as La Rance in France (http://energie.edf.com/), but most tidal schemes are still in development. They are seen as very costly and environmentally challenging due to the large amounts of water being manipulated.
With the huge variety of renewable energy resources beginning to present themselves, there appears to be more options for filling the impending energy gap. The question is, why are we struggling to reach our 2020 targets, when there is such a depth and variety of alternative energy sources. It may be that the current government, promising to be the greenest ever, has failed to take up the renewable energy mantle. The unfortunate timing of the current economic crisis has meant that it was seen as unjustified to pump money into a small growing industry, and instead attempt to keep the larger more established industries afloat, despite the fact that investment in renewables will lead to job creation, increased growth, and energy dependency.
The failure to invest in green energy during this pivotal time, may ultimately leave the UK lagging behind the rest of Europe in terms of our energy prices and reaching our energy targets, as well as preventing healthy renewable competition in the future.