11.3 Renewable Energy Sources Learning Goals: Learn about the variety of renewable technologies used to generate electrical energy Explore the effect energy production has on the environment and society

Renewable Sources Renewable Energy Source: energy source that can be replaced in a relatively short period of time There are various sources of renewable energy: 1.Hydro-Electric Generation 2.Wind Generation 3.Photovoltaic Generation 4.Thermal Generation using Biomass 5.Geothermal Generation

Hydro-electric Generation Hydro-electric energy: Using the energy of falling or flowing water to move turbines connected to generators AdvantagesDisadvantages Does not release pollution into the air or water Disrupts the natural water flow pattern Can restrict fish movement unless fish ladders are built Large land areas behind dam are flooded, resulting in habitat loss Expensive to build Suitable locations are rare

Wind Generation Wind Generation: using the energy from wind to turn blades of a turbine connected to a generator AdvantagesDisadvantages Wind is free and does not need to be transported Changes the landscape and scenic views Wind farms are less expensive than generating stations that use fossil fuel or uranium Need large areas for wind farms Can be built anywhere winds are reliable and strong Noise pollution to nearby communities Location issues because of migrating birds and bats

Photovoltaic Generation Photovoltaic Generation: changing solar energy directly to electrical energy without the use of turbines and generators Light from the Sun excites charged particles to move, creating an electric current AdvantagesDisadvantages Free and readily availableCurrently expensive and inefficient Can be installed anywhere that receives enough sunlight Can only work during the day, but small systems can use batteries to store electricity for nighttime use Does not create air or water pollution

Thermal Generation using Biomass Biomass (biofuel): burning forms of bacterial, plant or animal matter to produce thermal energy to produce steam connected to a turbine and generator AdvantagesDisadvantages Always renewable: -Trees and crops replanted -Plant and animal waste always produced Burning biomass produces greenhouse gases Using crops as fuel results in lower food production

Geothermal Generation Geothermal Generation: converting the heat from deep within the earth into thermal energy that powers turbines and generators Usually located near areas with volcanic activity AdvantagesDisadvantages Geothermal energy is always available deep in Earth’s crust Suitable geothermal areas are rare; few near populated areas Geothermal fluids can be continuously pumped back underground to be reheated and reused Generating stations are difficult and expensive to build Does not produce pollution or greenhouse gases

Ontario’s Electricity Generation by Type (Comparison 2003 and 2013)

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