1.What are the 1 st and 2 nd Laws of Thermodynamics? 2.How has energy use changed in the U.S. from the pre- Industrial Revolution era to the present? 3.Explain the difference between renewable and nonrenewable sources of energy 4.What is OPEC? What is it responsible for? 5.Explain why hydrofracking is controversial. Do Now

Energy Lesson 2 Nuclear & Hydroelectric Energy

Nuclear Fusion can occur when extremely high temperatures are used to force nuclei of isotopes of lightweight atoms fuse together, which can cause large amounts of energy to be released A coal-fed electrical plant producing 1,000 MW of electricity in one day produces 30,000 tons of CO2 gases, 600 tons of SO2 gas, and 80 tons of NO2 gas In contrast, a fusion plant producing the same amount of electricity would produce 4 pounds of harmless helium as a waste product Nuclear Fusion

Nuclear Fission -an atom splits into two or more smaller nuclei along with by-product particles (neurons, photons, gamma rays, and beta and alpha particles. Nuclear Fission is an exothermic (gives off heat) reaction If controlled, the heat that is produced is used to produce steam that turns generators that then produce electricity If the reaction is not controlled, a nuclear explosion can result Nuclear Energy

The potential energy contained in nuclear fuel is 10 million times more than that of more traditional fuel sources (coal, petroleum) However, nuclear wasted remain highly radioactive for thousands of years and are difficult to dispose of The most common nuclear fuels are U-235, U-238, and Pu- 239 Nuclear Energy

Isotope of uranium Uranium that has been processed to separate out U-235 is enriched uranium Enriched uranium is an issue with Iran and North Korea Nuclear weapons contain 85% or more U-235 Nuclear power plants contain about 3% U-235 The minimum amount required for a chain reaction is called the critical mass The half life of U-235 is 700 million years U-235

The most common (99.3%) isotope of uranium Has a half-life of 4.5 billion years Most depleted uranium is U-238 Decays into Pu-239 U-238

Has a half life of 24,000 years Produced in breeder reactors from U-238 Plutonium fission provides about one third of the total energy produced in a typical commercial nuclear power plant Control rods in nuclear power plants need to be changed frequently due to the buildup on Pu-239 that can be used for nuclear weapons and due to the buildup of Pu-240, a contaminant Pu-239

Nuclear power production began in the U.S. in the 1960s and increased rapidly until the 1980s As of 2005, nuclear power provided 6% of the world’s energy and 15% of the world’s electricity The U.S. produces the most nuclear energy, which accounts for 19% of the energy we consume Electricity Production

Water serves as the moderator and coolant Pressurized-water reactors allow water coolant to operate at a high pressure before pumping it to the core of the reactor Boiling-water reactors allow water to boil within the core of the reactor by operating at a lower pressure Light-Water Reactors

Deuterium oxide (D2O) is a form of water in which each hydrogen atom contains one proton, one electron, and one neuron Hydrogen normally has no neurons Used in reactors where it acts as a neutron moderator to slow down neutrons so they can react with uranium Heavy water use increases the effectiveness of the nuclear reaction Heavy-Water Reactors

Uses light-water for cooling, graphite for moderation, and uranium for fuel These reactors require no separated isotopes (enriched uranium or heavy water) Initially built by Russians; very unstable; no longer produced (Chernobyl) Graphite-Moderated Reactors

Fast-breeder reactors and other experimental installations are in this group Breeder reactors produce more fissionable material than they consume Exotic Reactors

ProsCons No air pollutantsNuclear waste takes millions of years to degrade (half-life) and is difficult to store Releases one-sixth of the CO2 of fossil fuel plants The process of commissioning and decommissioning nuclear power plants is regulated by the Nuclear Regulatory Commission and is costly and dangerous Water pollution is lowLow-net energy yield; energy is required for mining uranium, processing ore, building and operating the plant, dismantling the plant, and storing wastes Land disruption is low to moderateSafety and malfunction concerns Environmental Advantages & Disadvantages of Nuclear Power

Chernobyl Nuclear Reactor Meltdown-Ukraine, Mile Island Nuclear Disaster-United States, 1979 Fukushima Nuclear Reactor Meltdown-Japan, 2011 Radiation and Human Health

Current Concerns: Biscayne Bay, FL study-finds-link-in-bay-to-turkey-point- canals

Dams are built to trap water which in turn is then released and channeled through turbines that generate electricity. Hydroelectric power supplies about 10% of the electricity in the U.S. and about 3% worldwide Hydroelectric Power

ProsCons Dams control floodingDams create large flooded areas behind the dam; displaces people; slow water breeds pathogens Low operating and maintenance costsDams destroy wildlife habitats and prevent fish from migrating No polluting waste productsSedimentation doesn’t reach farmland Long life spansExpensive Moderate to high net-useful energyDestroys wild rivers; water loss because of increased evaporation Areas of water recreationLarge-scale projects are subject to earthquakes Environmental Advantages & Disadvantages of Hydroelectric Power

Channelization -straightens and deepens streams Dams -stores water in reservoirs Identify & Manage Flood-Prone Areas - precautionary building practices emerge as a result Levees or Floodwalls -raised embankments to prevent rivers from overflowing; can break, as they did in New Orleans during Hurricane Katrina in 2005 Preserve Wetlands -preservation maintains natural floodplains and biodiversity Flood Control

Salmon

Reservoirs in tropical areas have slow moving or still water, which is a breeding ground for infectious disease Displacement of people due to flooding and destruction of croplands Deprives downstream areas of nutrient-rich water Migration and spawning cycles are disrupted Silt particles build up behind dams and must be removed/dredged Silting and Other Impacts