Biomass
- Energy that is derived by directly burning plant material and animal waste, or by burning gasses and fuels produced from plant material and animal waste can be used to create electricity from methane harvested from decomposing municipal waste
- Charcoal- Produced by burning wood to remove moisture.
- Advantages- higher energy content, easy portability, available in developing countries
- Disadvantages- deforestation, negative effect on respiratory system of producers and consumers
- Energy can be produced by burning garbage to produce steam for electricity
- Methane produced by bacteria decomposing waste can be harvested to generate electricity
- Garbage is readily available
- Requires development of infrastructure to develop and transport methane from landfills
- Ethanol- alcohol produced by fermentation of plant materials
- produced from corn in the USA and sugarcane in Brazil
- Mixed with gasoline to make gasohol
- Advantages- domestic availability, cleaner burning that gas alone, infrastructure in place already
- Disadvantages- using food resources to produce fuel, lower energy content than gas alone
- Biodiesel- produced by removing oil from plants or algae. Mixed with diesel or burned directly in modified diesel engines
- Advantages- high net energy, lower CO and CO2 emissions
- Disadvantages- Land used for fuel instead of food, high land use, net energy dependent on type of crop
- Oil from algae- Algae is a promising source of oil
- It can be grown in tanks with little land disturbance, food prices not affected, CO2 from power plants and factories can be used to feed algae.
- Burning Solid Biomass- directly burning wood, plant materials, etc to produce heat, cook and use electricity
- Turbine is used in every electrical power plant
- Turbine converts force into rotational motion, causes generator spinning.
- Can spin with steam, wind, and moving water
- Steam made from coal, oil, solar, geothermal, nuclear, burning biomass, and natural gas
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Using heat underground to produce electricity and other uses
- Small percentage of use
- Cooling homes in summer by fluid circulation underground and building
- Heating homes by same method
- Generates electricity: cold water pumped down, hot water pumped up generating turbine and generator= electricity
- Cold water pumps hundreds of feet down under
- Pros: renewable, lower greenhouse emissions, wide application, done anywhere with geothermal
- Cons: subsidence, seismic activity, high start-up costs, deep wells drilled for electricity production
- Moving water, hydroelectric dam and tidal energy
- Efficient and predictable source, high net energy, downstream flood control, reservoirs for recreation and irrigation, municipal water us
- Habitat destruction from creation of reservoir, high initial construction cost, disruption of fish migration routes, high CO2 production from decomposition of organic material
- Controlling nuclear fission for electricity
- Uranium ore mined
- Nuclear fission reaction initiated in nuclear reactor
- Reserves large
- Australia 30% uranium reserves
- Pros: little CO2, low risk of nuclear incidents, low environmental impact other than accidents
- Cons: low or negative energy yield, nuclear accidents cause major impact on env., toxic, public resistance due to incidents
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- Photovoltaic cells- thin layers of silicon imbedded with metals. When sunlight strikes the PV cell, electrons are produced to make electricity
- Advantages- No direct emissions, systems are expandable and portable, little maintenance, production is inexpensive
- Disadvantages- high start up costs, solar systems must have battery storage or 'grid-connection', requires the sun
- Passive Solar heating
- Advantages- Little disruption of habitat, inexpensive, low or no emissions, high net energy
- Disadvantages- High initial cost, passive solar must be planned during building design process, only works when the sun is shining
- Turbines turned by power of wind
- Connected to electrical generator producing energy as long as turbine spinning
- Pros: many sites suitable, high net energy, easy to expand, no emissions, land used for purposes as well, little land disruption
- Cons: initial cost of wind turbines high, require maintenance, noise pollution, turbine kills