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CHAPTER 17.1: ENERGY RESOURCES AND FOSSIL FUELS
Fossil fuels – energy derived from dead organisms. the remains of ancient organisms that changed into coal, oil, or natural gas. So solar energy is contained in fossil fuels. The modern world depends on them but there are 2 main problems:the supply is limited and obtaining/using them has environmental consequences 5 factors that influence the value of a fuel:1. cost2. availability3. safety4. energy content/efficiency5. byproducts of its use 4 main uses for fuel – transportation, manufacturing, heating/cooling, electricity (main use) Most is converted to electricity since electricity is more convenient to useit is done using electric generators – they convert mechanical energy to electric energy- in an electric generator – fossil fuels are burned to make heat à the heat is used to heat water à the water turns to steam à the steam turns a turbine à the turbine turns an electrically conductive material in a magnetic field inside the electric generator à electricity is produced we use a lot of energy (developed societies use more energy than developing societies)most energy in the US is used for industrial purposes- the price of nearly every product or service reflects the cost of energy There are 3 main fossil fuels: (Advantages of using them = versatility)1. Coala. how it forms – swamplands are covered with layers of sediment and put under high temperature and pressure for millions of yearsb. uses – electricity generation and heatingc. environmental effects – removal of mountaintops during excavation, pollution of streams from mine debris, air pollution, acid precipitation2. Oila. how it forms – marine organisms are buried by sediment. As the remains decay they are transformed to petroleum (crude oil straight from the ground is called petroleum, and is converted to gas in a refinery)b. uses – produce fuels, chemicals, and plastics (petroleum products).c. environmental effects – pollution from burning it contributes to smog, health problems, acid precipitation, global warming. Leaking cars and spills pollute waterways (ships now have to be double-hulled to prevent spills)3. Natural gas (solid natural gas = methane hydrates)a. how it forms – same as oilb. uses – fuel in electric power plants and vehicles, heating and cookingc. environmental effects – produces air pollution Fossil fuels of the futureOil production is slowing- To help predict the future of oil production we have to consider the number of oil deposits found, the cost of obtaining fuels, and changes in technology, dangers and damage associated with obtaining fuels- there are still reserves out there – some haven’t been discovered, many aren’t easily accessible- as the supply decreases we may begin to rely less on oil, and have to use it more selectively- things that can (like cars and power plants) will begin to rely on other energyCHAPTER 17.2: NUCLEAR ENERGY
Nuclear power plants get their power from nuclear energy.Nuclear energy – the energy in the nucleus of an atom – from nuclear fission How nuclear fission works:- the nuclei of uranium atoms are hit with neutrons à the collisions cause the nuclei to split (fission) àit releases energy, more neutrons, and new nuclei à the neutrons collide with more nuclei à it is a chain reaction that releases a ton of energy-uncontrolled – atomic bomb- controlled – energy we can harness in a nuclear reactor-the reaction is kept in check by control rods that are inserted into the reactor à the rods are made of boron or cadmium which absorb the neutrons and stop the reaction How a nuclear power plant works:- similar to fossil fuel-generated electricity-heat from the nuclear reaction is used to heat water à steam turns a turbine à the turbine generates electricity-Waste heat is released from the plant as steam (3 pipe circuits pump water through the reactor, the turbine, and the cooling tower) Advantages:- Concentrated energy source (one U pellet is like a trainload of coal)- No air-polluting gases are produced- When done right, it releases less radioactivity than coal-fired plants- It provides an alternate energy source for countries with limited fossil fuels Disadvantages:- Construction and maintenance is expensive- Hard to store nuclear waste (the waste is radioactive for thousands of years) - must be stored in geologically stable places- Safety concerns. Poor design can let reactions get out of control (like Chernobyl in the Ukraine and three mile island here) Possibility of the future – nuclear fusionWhen lightweight nuclei are combined to form a heavier nucleus – releases lots of energy- powers the stars- produces less dangerous waste- technically difficult (super high temps, confinement, high concentrations)Another possibility - switch to renewable energy where none of these are issues!
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