Engineering Design for Sustainability
TIDAL WAVE ENERGY
Tidal power is a form of energy which derives directly from the relative motions of the Earth/Moon system, and to a lesser extent from the Earth/Sol system. Tidal energy is gained from the exchange of large bodies of water. Changes in water levels, and associated tidal currents, are due to the gravitational pull of the Sun and Moon. This makes Tidal Power completely predictable; furthermore, because it is created by relative motion of the special bodies, it is in-exhaustible. Therefore Tidal power is much more reliable than other renewable sources such as wind or solar power and will long outlast fossil fuels. Tidal Power in the UK
It is estimated that tidal power could generate around 20% of Britain's requirements by 2020. There are great practical challenges associated with this form of hydropower and only around twenty sites in the world have been identified as being ideal locations for tidal power stations. Eight sites are to be found in Britain, potentially making the UK a key player in the World Green Energy market. The Severn, Dee, Solway and Humber estuaries are all potential sites for tidal energy generation in the UK. Political view
In common with wind resources, the UK has some of the best wave and tidal resources in Europe, with the potential to provide a considerable proportion of the UK renewable power market in future decades. There is a range of estimates which show that between 15% and 20% of current UK electricity demand could eventually be met by wave and tidal energy. Tidal power is highly predictable compared with some other forms of renewable energy and this has important implications for managing an uninterrupted energy supply that makes use of several different power generation technologies.
One of the Government’s key long-term goals for energy policy is to cut carbon dioxide (CO2) emissions.
The Climate Change Act (2008) has introduced a legally binding target to reduce greenhouse gas (GHG) emissions by 80% by 2050, and by at least 26% by 2020. Government had set a target of achieving 10% of electricity supply from renewable energy by 2010. This has now been superseded by a binding target of 20% of EU energy consumption to come from renewable sources by To put these targets in perspective, in 2006, only 1.2% of total UK energy consumption came from renewable sources, with 4.6% of total electricity generation being produced through renewables, predominantly from wind energy, sewage and landfill gas, co-firing biomass in power stations and large scale hydro-electric generation. The proportion of electricity from renewable sources will require an increase from 4.6% to around 35% - 45%, entailing an increase in generating capacity from 5 to 55 GW (11 fold increase).
The government issued its Renewable Energy Strategy for consultation in June 2008. This recognised the potential long term contribution of wave and tidal energy generation, but that the technology is in its infancy and unlikely to make a significant contribution by 2020. It proposes that 2% (around 2GW) of the UK’s current electricity needs could come from wave and tidal stream power by 2020, rising to 30GW by 2050. Tidal range technologies (i.e. barrages and lagoons) could provide at least a further 5GW of UK electricity supply.
In August 2007, the Sustainable Development Commission produced a report on tidal energy in the UK, which included an evaluation of proposals for a Severn Barrage. The report concluded that a tidal barrage could be developed in the Severn Estuary, but must be compliant with the European Directives on habitats and birds. It also concluded that tidal stream, lagoons and wave powered devices needed to be further developed and tested, with further impetus from Government.
Following the publication of this report, the Government instigated a feasibility study into the Severn Tidal Power options.
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