Transcript Slide 1
SustainableEngineering@Edinburgh Tidal Technologies Some of the main considerations are; • Ecology – Even the most fish friendly of turbines have a 15% fish Tidal Range Tidal stream •Tidal energy is extracted mortality rate on passing. Fish migration, loss of habitat can occur due to changes from the movement of water in in physical environment. Fish, birds and mankind all effected. Barrages Lagoons the oceans caused by the interaction • Noise, visual environment, water/air quality and cultural heritage between the gravitational fields of the - Changes in salinity and turbidity can occur plus possibility of algae blooms which sun, moon and earth with the water feed on pollutants. Potential for commercial shipping, fishing, recreation Existing and Proposed Schemes bodies in the oceans. and tourist damages in construction and operation Country Project Capacity Type • Seabed, sediments and currents - Tidal power schemes will •Potential of meeting 8-10% of UK electricity (MW) reduce the tidal range it encloses, but also physical change demand – approximately 4.7% could be met by Existing due to erosion and deposition occurs around structure the Severn Estuary alone (~17 TWh/year). France La Rance 240 Range resulting in sandbanks disappearing •Positive overall carbon benefit – zero CO2 Canada Annapolis Royal 18 Range emissions during operation. •Tidal energy extraction is variable with time, but it is periodic and completely predictable. The power output can be forecasted accurately at any given time. But reduced carbon emissions compared with other generation techniques •Small operation and maintenance costs – greatest expenditure is capital cost. Generation Tidal Power China UK Russia Jiangxia Strangford Lough Kislaya Guba Proposed Russia Penzhinskaya Bay Russia Mezen UK Pentland Firth UK Severn Estuary 3.2 1.2 1.2 Range Stream Range 87,000 19,200 10,000 8,640 Range Range Stream Range Group 16: Ronan Kelly 0840408; Zafeirios Triantafyllidis 0789807; Jonathan Phair 0679681 IMS3 Sustainability Module Introduction Environmental Impacts Tidal Lagoon •A solid structure used to impound water by isolating part of a channel •As the tide goes out water is trapped within the structure •When the tide has fully gone out, the water is released through sluices •The released water works turbines to extract water Tidal Barrage •A solid wall spans an estuary or basin •Sluices in the barrage are opened to allow approaching tide to fill behind the wall •As the tide goes out the sluices are closed , trapping the water. •Sluices are then opened allowing the trapped water to flow back out to sea (by gravity) •The energy from the flowing water is harnessed from turbines placed at the sluices References •Kerr, D. (2005) “Marine energy: getting power from tides and waves”, Civil Engineering, 158(6), 32-39 •Sustainable Development Commission (May 2007), Research Report 2 - Tidal technologies overview http://www.sd-commission.org.uk/publications/downloads/TidalPowerUK2-Tidal_technologies_overview.pdf •http://en.wikipedia.org/wiki/Tidal_power Tidal Stream •Smaller than Barrages or Lagoons ( no need for a long solid barrier) •Extract energy from the tidal stream flowing past by using an actuator •Only aims to extract a fraction of the energy from the flow •Farms can be installed in stages and can be expanded