Marine Renewable Energy
The UK market for electricity supply is currently valued at £10b per year and is presently supplied by 97.5% non-renewable sources. The White Paper produced by the government in 2006 states that 10% of our energy must come from renewable sources by 2010, increasing to 20% by 2020 (DTI, July 2006).
Wind power has been the most strongly supported renewable energy source since the technology is well advanced and proven. However, the UK does not have the land mass to be able to site many new large onshore developments and gaining permits to develop new sites faces strong opposition. There are also large issues associated with offshore wind with regards to maintenance and cost implications in not being able to access the turbines due to the hostile conditions so often experienced offshore. Finally, the wind source is intermittent which proves problematic when trying to match output with demand. Marine renewable energy refers to both the energy available in tidal flow and in waves.
Tidal stream power has many advantages associated with it not least that it is predictable, unlike wind and therefore waves. The predictability of the source means that engineering the technology to capture the energy is much more straight forward than for waves. The environmental issues regarding tidal barrages have led to much more innovative approaches to capture the energy available in the tidal current hence, in recent times there have been large developments in tidal stream technologies.
NRE are currently developing the first full scale Neptune Proteus demonstrator for a site at Humber St. Andrews on the north bank of the Humber Estuary. The device has a negligible environmental impact as it only intersects a capture area of about 100 m2 compared with the channel cross section of >30,000 m2 representing less than 0.5% of the total cross-section. The device is described as a meso-scale generator with 500MW installed power and will form part of an array of, for example, ten devices.
In addition, NRE are making progress with researching a nearshore point absorber wave power device Neptune Triton which will not only extract the energy in the waves but in addition when placed in array will act as a semi-permeable breakwater, thus providing a form of coastal protection.