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Renewables definition

Renewables definition. Renewable Energy is energy obtained from the natural and persistent currents of energy in the environment e.g. sunshine, wind, rainfall ------------------------------------------------------- considered “Green Energy” intrinsically non-polluting

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Renewables definition

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  1. Renewables definition • Renewable Energy is energy obtained from the natural and persistent currents of energy in the environment • e.g. sunshine, wind, rainfall ------------------------------------------------------- • considered “Green Energy” • intrinsically non-polluting ------------------------------------------------------- • “Direct” RE from natural environment • “Indirect” RE from society’s wastes

  2. Totalrenewableenergy flows through the biosphere: unit 1015 W (109 megawatt) Solar radiation Geothermal heat Gravitational potential Reflected 50 Absorbed 120 80 0.3 absorbed as heat kinetic wind waves 3 heat 0.001 tides 40 0.03 water phase change hydro flow photon interaction photosynthesis radiation to outer space

  3. Per capita Renewable energy: kilowatt per person on Earth i.e. solar is equivalent of 20,000 one-bar electric heaters for each man, woman and child Solar radiation per person Geothermal heat Gravitational potential Reflected 8,000 kW Absorbed 20,000 kW 13,000 kW 50 kW absorbed as heat wind, waves 500 kW 0.2 kW heat tides 7,000 kW 5 kW water evaporation, rain & hydro flow photosynthesis (plants, crops) radiation to outer space

  4. Renewable energy technologies Solar radiation Geothermal heat Gravitational potential heat pumps wind turbines, wave power Solar water heaters, Solar buildings Tidal range power; e.g. Severn estuary & Tidal stream power Fuel wood, biomass biodiesel, ethanol, wastes Hydro-electricity; very large (GW) to very small (100 W) scale Photovoltaic solar cells

  5. solar buildings solar water heating solar thermal electricity solar cell photovoltaic electricity solar driers solar refrigeration hydroelectricity micro-hydro wind turbines wave power photosynthesis biomass crops pyrolysis biofuel oils biogas sewage gas urban waste geothermal heat tidal range tidal stream power fuel cells Renewable energy technologies forheat, electricity, transport fuels

  6. Scaling: energy fluxesconfigure the technologies • bright sunshine 1 kW/m2 • brisk wind (10 m/s) 1 kW/m2 • house heating boiler 10 kW/m2 • coal power station boiler 100 kW/m2 • nuclear power boiler 1,000 kW/ m2

  7. So, for renewables…………………... • potential very large and sufficient • free (no cost) in the environment • but dispersed and variable • need to capture, deliver, utilize and store • encourages local enterprise & cash flow • manufacturing growth from environmental push and commercial pull • but….RE plant is relatively large • so…..RE plant is capital intensive

  8. Conclusions: renewables … • proven technologies • most are in the market place • credit for environmental and sustainable benefits • favoured by world, European, national & local policies • but still much to do

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