Non-Renewable Energy Resources: How do dead things power our lives? Life requires energy it is stored, transferred, and converted Ultimate source of energy for life the Sun For humans, our source of energy is food Fuel any substance that can be used for energy Fuel is never 100% efficient only 5-20% of what is received is actually used During conversions, some energy is lost - some is converted into heat, light, or sound energy Human need for energy has changed through time Hunter-Gatherers wood Industrial Revolution oil, coal Contemporary use many types of energy sources
Evaluating Energy Resources The types we use determine our quality of life and the amount of harmful environmental effects Questions to ask ourselves: How much of the energy source will be available in the future? What is this source s net energy yield? How much will it cost to develop, phase in, and use this resource? How much will extracting, transporting, and using the energy resource affect the environment? What will using this energy source do to help sustain Earth?
Net Energy The total useful energy available from the resource over its lifetime minus The amount of energy used, lost, and wasted in finding, processing, concentrating, and transporting it to uses
Non-Renewable vs. Renewable Non-renewable resources that cannot regenerate quickly (takes thousands or millions of years) Renewable resources that regenerate quickly (within decades)
Nuclear Energy What is It? Produced through the fission (dividing) of uranium atoms heats water to produce steam drives turbines to produce electricity
Nuclear Energy Pros Nuclear power plants don t emit air pollutants (when operated properly) Water pollution (thermal pollution) and disruption of land are low to moderate Safety measures reduce the likelihood of a catastrophic accident
Nuclear Energy - Cons Harmful radiation leaks into the environment Chernobyl (4-26-86): reactor explosions in the Ukraine killed 3,576 people (officially, but other estimates say 32,000) and over 500,000 were exposed radioactivity causing cancer, tumors, eye cataract, and genetic mutations Three-Mile Island (3-29-79): plant in Pennsylvania lost is coolant water (mechanical and human errors); no known injuries/deaths were reported, but some studies show increased cancer rates in the area from radioactive materials leaking into the atmosphere Radioactive Waste High-level waste must be stored for 10,000-240,000 years Low-level waste must be stored for 100s of years (dumped in the ocean during the 1970s) After 15-40 years, the nuclear reactor becomes too radioactive and must be dismantled or shielded with a barrier Used to be inexpensive, but maintaining the building and storing wastes is now expensive
Fossil Fuels What is It? Fuel formed hundreds of millions of years ago from the remains of dead plants and animals Made of hydrocarbons When combined with oxygen light and heat energy are released (combustion) Types: Coal, Natural Gas, Petroleum/Oil
Coal Plant remains converted by heat and pressure into a solid rock over millions of years Has stages of development that concentrates the coal and the energy it produces Peat low amount of carbon / least amount of energy (not true coal ) Lignite 40% carbon, must be mined from below ground Bituminous Coal 85% carbon, deep in Earth s crust, most abundant type in the United States Anthracite Coal 95% carbon; deepest in the ground; has the least amount of water and impurities and has the greatest amount of energy
Coal Pros and Cons Pros Most abundant fossil fuel (should last at least 220 years at the current rate of use) High net energy yield (25-28%) Cons Coal mining is dangerous (accidents, black lung disease) and harmful to the environment (land and water pollution) Dirtiest to burn and release many air pollutants (carbon monoxide, carbon dioxide, and radioactive elements) Threat to human health (respiratory diseases from air pollutants) and results in property damages
Natural Gas Mixture of mostly gaseous hydrocarbons (methane is the primary component) Forms from the remains of plankton, plants, and animals living in shallow water millions of years ago
Natural Gas Pros and Cons Pros Cheaper than oil Reserves are expected to last 125-200 years Can be transported easily Has a high energy yield (4.9%) Produces less air pollution than any other fossil fuel Extraction damages the environment less Can be used to power vehicles and highly efficient fuel cells Cons Toxic sulfur can be released into the air In order to ship it over the ocean, it has to be converted to liquid, which is expensive and dangerous (explosions) Leaks from pipelines, tanks, and distribution facilities increases the amount of methane (greenhouse gas) in the atmosphere
Petroleum/Oil Forms the same as oil Can gush out of the ground or need to be pumped to the surface with drilled wells Refined to make a variety of products Gasoline, jet fuels, diesel fuel, fuel oil, grease (Vaseline), asphalt, nylon, polyester, plastics, styrofoam
Petroleum/Oil Pros and Cons Pros Relatively cheap Easily transported within and between countries High net energy yield (4.7%) when easily accessible Cons Reserves may be depleted with 85 years Oil-drilling process cases damage to the environment which increases erosion Oil spills contaminate soil and/or water Burning fuel oil releases carbon dioxide which leads to global warming and other air pollutants that harm people, crops, trees, fish, and other plants/animals
Used to make fuels, plastics Remains of organisms Takes millions of years Source depleting Rich in hydrocarbon energy Requires combustion for energy Spills contaminate the ecosystem Should we reduce our dependence on fossil fuels?