TIDAL POWER -­‐ALTERNATIVE ENERGY PITCH-­‐ Rachel Weissberg Christina Jenkins What is “Tidal Power”? “Tidal power exploits energy drawn from the movement of ocean tides to produce electricity.” *  Energy can be drawn from tides in two ways: *  1. Changing sea levels – The tides are manipulated with the help of turbines to generate electricity. *  2. Sunken turbines in the sea floor – Fast flowing currents turn the generator blades much like with a wind turbine.` Tidal Barrages “Tidal barrages utilize the potential energy from the difference in height between high and low tides.” Tidal Turbines “Tidal turbines are very much like underwater windmills except the rotors are driven by consistent, fast-­‐moving currents. The submerged rotors harness the power of the marine currents to drive generators, which in turn produce electricity.” Video of how it works: http://www.youtube.com/watch?v=qRUl1mJQHmc Politically Pros *  There are some signs of government support: *  Ex: ComFIT – tidal tariffs of 78 cents/kWh now in Nova Scotia. *  Ex: BC’s Race Rocks – funded by the Canadian government – $550 million fund for clean technologies. *  More countries around the globe taking on this clean energy: *  Canada, China, Russia, France, South Korea, United Kingdom, and South Korea have stations. *  Philippines and India are at the proposal stage. Cons *  Lack of government support prevents new projects from making progress. Economically Cons Pros *  Costs are expected to decline to around 5-­‐7 cents/kWh. *  Tidal Barrages: *  Long plant lives (structure – 100 yrs, equipment – 40 yrs). *  Low operation and maintenance costs. *  0.5% less than the initial capital costs. *  Tourism sites and centers have a potential to provide more employment. *  Costs are in the range of 11-­‐25 cents/kWh. *  Capital cost should be $700,000 USD/Mw – current technology – not realistic – industry produces no net benefits *  Tidal Turbines: *  Large capital costs *  $5.4 million/Mw *  High operation cost * 
$ .03/KwH *  Fish industry impacts. Environmentally Pros *  Barrages: *  Does not emit climate gases. *  Does not take up a lot of space. *  Fish passages can be used with some success to avoid death or damage by collision. Cons *  Barrages: *  Changes in fish migration. *  Water level changes on the basin behind the barrage. *  Lower salinity in the basin – low ocean water levels. *  Currents become less able to transport & suspend sediments. *  Reduces the tidal range by half. *  Sea animal death or damage by barrage or turbine collision. *  Destroys intact ecosystems (especially in estuaries). *  A study at the Annapolis estuary concluded: "that the introduction of tidal turbines into open ocean current systems will cause widespread impact on marine populations resulting in significant declines in abundance." Environmentally Pros *  Turbines: *  Low rotation speeds – unlikely to injure marine life. *  Screens in front of blades – deters possible marine animal collision. *  Small amount of tidal energy extracted from the current. Cons *  Turbines: *  New technology – little data to see the negative effects. Environmentally Pros *  Tidal Fences: *  Screens and slow rotating speeds help to prevent marine life collisions with the turbines. Cons *  Tidal Fences: *  Changes in the natural tidal range – also effects the shore. *  Extensive development effects: undersea cables and land-­‐based, or floating facilities, can have displaced marine life. Environmentally Pros *  Tidal Power & Climate Change: *  Operation is emissions-­‐free. *  Tidal power use increases, conventional energy is then replaced, therefore green house gases are reduced. *  Less vulnerable to climate change effects. *  Good carbon cost “pay back”. Cons *  Tidal Power & Climate Change: *  Installation process produces emissions (i.e. greenhouse gases). General Pros & Cons Pros *  Renewable *  Green *  Predictable *  Effective at Low Speeds *  Long Lifespans Cons *  Environmental Effects *  Close to Land *  Expensive Looking Forward: Tidal Power *  Little amounts of CO2 emissions. *  Less vulnerable to the effects of climate change. *  Predictable and quantifiable. *  Impact upon marine life is continuing to be reduced. *  Malfunctions do not cause any major damage (unlike nuclear). Bibliography *  http://www.energybc.ca/profiles/tidal.html *  http://www.marineturbines.com/Tidal-­‐Energy *  http://energyinformative.org/tidal-­‐energy-­‐pros-­‐and-­‐
cons/ *  http://www.buzzle.com/articles/tidal-­‐energy-­‐pros-­‐and-­‐
cons.html *  http://www.youtube.com/watch?v=qRUl1mJQHmc *  http://education.nationalgeographic.com/education/
encyclopedia/tidal-­‐energy/?ar_a=1 General Pros & Cons Cons *  Renewable/Sustainable/
Inexhaustible/Predictable – The tides move to the orbits of the Earth, Moon, and Sun. *  New tidal power technology leaves a smaller environmental footprint. *  Carbon free. *  No fuel needed. *  Clean energy source. *  Long life spans. *  Relatively low cost of operation. *  Minimal maintenance. Pros *  Older tidal barrage technology can cause severe damage to the health of shorelines and aquatic ecosystems. *  Current tidal barrages need dams along ecologically fragile coastlines. *  Difficult to transmit. *  Short period of time during which power is yielded. *  Effects of weather.