TIDAL POWER - ALTERNATIVE ENERGY PITCH- Rachel Weissberg Christina Jenkins

Transcription

1 TIDAL POWER - ALTERNATIVE ENERGY PITCH- Rachel Weissberg Christina Jenkins

2 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.`

3 Tidal Barrages Tidal barrages utilize the potential energy from the difference in height between high and low tides.

4

5 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.

6

7

8 Video of how it works:

9 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.

10 Economically 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. Cons * Costs are in the range of 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.

11

12 Environmentally * Barrages: Pros * 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."

13

14 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.

15 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.

16 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).

17 General Pros & Cons Pros * Renewable * Green * Predictable * Effective at Low Speeds * Long Lifespans Cons * Environmental Effects * Close to Land * Expensive

18 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).

19 Bibliography * * Energy * energy- pros- and- cons/ * energy- pros- and- cons.html * * encyclopedia/tidal- energy/?ar_a=1

20 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.