1. Energy Resources and Human Impact

2. Fossil fuels: our dominant source of energy Fossil fuels = combustible substances from the remains of organisms Electricity = a secondary form of energy that is easy to transfer and apply to a variety of uses Oil, coal, and natural gas have replaced biomass as our dominant sources of energy

3. Resources are renewable or nonrenewable Renewable energy = supplies will not be depleted by our use – Sunlight, geothermal energy, and tidal energy Nonrenewable energy = we will use up Earth’s accessible store in decades to centuries – Oil, coal, natural gas, nuclear energy – To replenish the fossil fuels we have depleted so far would take millions of years

4. Regions vary greatly in energy consumption The U.S. has 4.5% of the population but uses 20% of the world’s energy

5. Coal = organic matter (woody plant material) – Compressed under very high pressure in swamps to form dense, solid carbon structures – Very little decomposition occurred – The world’s most abundant fossil fuel

6. Coal is mined using two major methods Strip mining = for deposits near the surface – Heavy machinery removes huge amounts of earth to expose the coal Subsurface mining = underground deposits are reached by digging tunnels to follow seams (layers) of coal Mountaintop removal = entire mountaintops are cut off – Environmentally destructive – Common in the Appalachian Mountains

7. Natural gas The fastest growing fossil fuel in use today It is versatile and clean-burning – Emits ½ as much CO 2 as coal, ⅔ as much as oil Liquefied natural gas (LNG) = gas converted to liquid World supplies are projected to last about 60 more years

8. Petroleum Oil is the world’s most used fuel – Accounts for 35% of world’s energy use – Nearly 67% of the world’s proven reserves of crude oil lie in the Middle East Crude oil (petroleum) = a mixture of hundreds of different types of hydrocarbon molecules – Dead organic material was buried in marine sediments and transformed by time, heat, and pressure

9. We drill to extract oil Exploratory drilling = small, deep holes to determine whether extraction should be done Oil is under pressure and often rises to the surface – Drilling reduces pressure, and oil becomes harder to extract Primary extraction = the initial drilling and pumping of available oil Secondary extraction = solvents, water, or steam is used to remove additional oil, but it is expensive We lack the technology to remove every bit of oil – As prices rise, it becomes economical to reopen a well

10. Petroleum products have many uses Petroleum products are central to our lives

11. Fossil fuel emissions pollute Carbon dioxide is released into the air – Driving changes in global climate Emissions cause severe health problems – Cancer, irritation, poisoning Technology and legislation can reduce pollution Carbon dioxide is the greatest impact of fossil fuel use

12. How will we convert to renewable energy? Fossil fuel supplies are limited, and their use has consequences Nations have several options for future energy use: – Continue relying on fossil fuels until they are no longer economically practical – Immediately increase funding to develop alternative energy sources dramatically – Steer a middle course and gradually reduce our reliance on fossil fuels We need to prolong fossil fuels through conservation

13. Personal choice and efficiency Energy conservation can be accomplished in two ways Individuals can make conscious choices to reduce energy consumption and increase conservation – Drive less, turn off lights, buy efficient machines Energy-consuming devices can be made more efficient – Cars and power plants lose ⅔ of energy as waste heat

14. Efficiency in homes and consumer products Improvements can reduce energy to heat and cool homes Appliances have been reengineered to increase efficiency Federal standards reduce electricity used Consumers need to vote with their wallets by buying energy-efficient products If all Americans bought energy-efficient appliances, U.S. energy expenditures would be reduced by $200 billion

15. Alternatives to Traditional Energy

16. Fission releases nuclear energy Nuclear energy = the energy that holds together protons and neutrons within the nucleus of an atom Nuclear fission = the splitting apart of atomic nuclei – The reaction that drives the release of nuclear energy in power plants This chain reaction keeps a constant output of energy Nuclei of large atoms are bombarded with neutrons, releasing energy and neutrons

17. U.S. storage of high-level radioactive waste Waste is held at 125 sites in 39 states 161 million citizens live within 75 miles of nuclear waste

18. Bioenergy Bioenergy (biomass energy) = energy obtained from organic material that makes up organisms – Wood, charcoal, agricultural crops, manure Over 1 billion people use wood for heat, cooking, and light

19. Overharvesting and developing new sources Biomass is only renewable if it is not overharvested – Overharvesting causes deforestation, erosion, and desertification – Heavily populated arid regions are most vulnerable – Cooking produces indoor air pollution New biomass sources are being developed Biopower = biomass sources are burned in power plants – Generating heat and electricity Biofuels = liquid fuels used to power automobiles

20. Ethanol can power automobiles Ethanol = a biofuel made by fermenting carbohydrate- rich crops Congressional mandates will increase ethanol production

21. Hydroelectric power (hydropower) Hydropower = uses the kinetic energy of moving water to turn turbines to generate electricity Storage technique = water stored in reservoirs behind dams passes through the dam and turns turbines Run-of-river approach generates electricity without disrupting the river’s flow – Flow water over a small dam that does not impede fish passage – Useful in areas away from electric grids

22. Hydropower has negative impacts Damming rivers destroys wildlife habitats – Upstream areas are submerged – Downstream areas are starved of water Natural flooding cycles are disrupted – Downstream floodplains don’t get nutrients Downstream water is shallower and warmer Periodic flushes of cold reservoir water can kill fish Dams block passage of fish, fragmenting the river and reducing biodiversity Large dams can cause earthquakes or collapse

23. Solar energy The sun provides energy for Earth’s processes Each square meter of Earth receives about 1 kilowatt of solar energy (energy from the sun) -17 times the energy of a light bulb Passive solar energy = buildings are designed to maximize absorption of sunlight in winter Keep cool in summer Active solar energy collection = uses technology to focus, move, or store solar energy Solar energy has been used for hundreds of years

24. Wind has long been used for energy Wind energy = energy derived from movement of air – An indirect form of solar energy Wind turbines = devices that convert wind’s kinetic energy into electric energy Windmills have been used for 800 years to pump water

25. Geothermal energy Geothermal energy = thermal energy from beneath Earth’s surface Radioactive decay of elements under extremely high pressures deep inside the planet generates heat – Which rises through magma, fissures, and cracks – Or heats groundwater, which erupts as geysers or submarine hydrothermal vents Geothermal power plants use hot water and steam for heating homes, drying crops, and generating electricity Geothermal energy provides more electricity than solar – As much as wind

26. Wave energy Wave energy = the motion of waves is harnessed and converted from mechanical energy into electricity Many designs exist, but few have been adequately tested Some designs are for offshore facilities and involve floating devices that move up and down the waves Wave energy is greater at deep ocean sites – But transmitting electricity to shore is very expensive Another design uses the motion of ocean currents, such as the Gulf Stream – Underwater turbines have been erected off of Europe