Energy Concepts

• Mechanical Energy - Potential and Kinetic

• Thermal Energy Heat is the internal energy in substances.

• Chemical Stored in bonds between atoms in a molecule.

• Electrical Results from the motion of electrons

• Nuclear - Stored in the nuclei of atoms

• Electromagnetic - Travels by Waves

• Power and Units

  • Power is the amount of work done per time

• Units of Energy

  • BTU - Amount of heat required to raise the temperature of 1 pound of water by 1 fahrenheit.

  • Horsepower - 1 horsepower is 746 watts of power

  • Kilo - 1000 watts

  • Mega 1 million watts

  • Kilowatt hour - unit of energy equal to 1000 watt hours or 3.6 mega joules.

• First Law

  • Energy cannot be created or destroyed

• Second Law

  • When energy is converted from one form to another, a less useful form results. Energy cannot be recycled to a higher quality.

Energy Consumption (Past)

• Wood was the primary source of energy until the mid to late 1800s.

• Coal became dominant in the late 19th century.

• Oil took over in the mid 20th century, when natural gas usage rose quickly.

• Coal and oil were the primary sources of energy from the late 19th century to the early 21st century.

• The 3 major fossil fuels together provided 87% of the total US energy over the past decade.

Energy Use (Present)

• 40% of the world’s energy is consumed in the Asia Pacific region, 25% in Europe, and 20% in North America.

• Energy Crisis

  • The price of energy is driven by the principles of supply and demand.

  • Energy crisis can be brought on by a failure of world markets to adjust prices in response to shortages.

• Nonrenewable Energy Resources

  • A resource of economic value that cannot be replaced by natural means on a level equal to its consumption.

  • In the US, most of the current energy demand comes from nonrenewable energy sources.

• Coal

  • Produced by the decomposition of ancient organic matter under high temperature and pressure,

    • Lignite - Lowest Heat content

    • Bituminous - High sulfur content, 50% of the US coal reserve.

    • Anthracite - High Heat content, low sulfur content.

  • Coal supplies 25% of world energy.

• Oil

  • Produced by the decomposition of deeply buried organic material under high temperature and pressure for millions of years.

  • Up to 70% of the oil reserve has been depleted and it is estimated that there is only 50 years of oil left.

• Natural Gas

  • Formed when layers of buried plants and gases are exposed to intense heat and pressure over thousands of years.

  • Energy that the plants obtained from the sun originally is stored in the form of chemical bonds in the methane molecules.

• Fracking

  • With hydraulic fracturing, chemicals are mixed with large quantities of water and sand and injected into wells at an extremely high pressure to create fractures in a rock that allow oil and natural gas to escape and flow out of the well.

• Nuclear Fission

  • During nuclear fission, an atom splits into two or smaller nuclei along with by-product particles.

  • This reaction gives off heat.

  • This heat, if controlled, is used to produce steam that turns generators and can produce electricity.

  • If this is not controlled, this can cause a meltdown.

• Nuclear Fuel

  • U-235

    • Ability to produce a fission chain.

  • U-238

    • The most common isotope of uranium.

    • When hit by a neutron it decays into Pu-239 eventually.

  • Pu-239

    • Produced in breeder reactors from U-238

    • Plutonium fission provides ⅓ of total energy produced in a typical nuclear power plant.

• Nuclear Power

  • As of 2017, 30 countries were operating 449 nuclear reactors for electricity generation. These provided 11% of the world’s energy requirements.

  • The US is the world’s largest producer of nuclear power, accounting for more than 30% of the worldwide nuclear generation of electricity.

• Nuclear Reactor Components

  • Core - Contains up to 50000 fuel rods. Each fuel rod is stacked with many fuel pellets, each pellet has the energy equivalent of 1 ton of coal.

  • Fuel enriched U-235 is usually the fuel. The fission of an atom of uranium produces 10 million times the energy produced by combustion of an atom of carbon from coal.

  • Control Rods - Move in and out of the core to absorb neutrons.

  • Moderator - reduces the speed of fast neutrons, allowing a sustainable chain reaction.

  • Coolant - Removes heat and produces steam to generate electricity.

• Other Nonrenewable Energy Resources

  • Methane Hydrates

    • Recently discovered sources of methane that form at low temperature and high pressure.

    • Found on land in permafrost regions.

    • Found beneath the ocean floor at water depths greater than 1640 feet.

    • Found on continental shelves.

  • Oil Shale

    • Organic-rich, fine-grained, sedimentary rock that contains significant amounts of an organic compound known as kerogen.

    • If the oil shale is heated in the absence of air, the kerogen converts to oil.

  • Synfuels

    • A synthetic fuel is any fuel produced from coal, natural gas, or biomass through chemical conversion.

  • Tar Sands

    • Contain bitumen, which is a semi-solid form of oil that does not flow.

Renewable Energy Sources

• Energy that is collected from resources that are naturally replenished on a human time scale.

• Biogas

  • Anaerobic digestion is a collection of processes by which microorganisms break down biodegradable material, in the absence of oxygen, to produce methane gas which can be burned to produce energy.

• Biomass

  • Biological material derived from living, or recently living organisms that can be burned to create steam that is used to generate electricity.

• Biofuel

  • Fuel that is produced from living organisms.

• Geothermal

  • Heat contained in underground rock and fluids from molten rock, hot dry-rock zones, and warm-rock reservoirs.

  • This steam can be used to drive turbines which can then be used to generate electricity.

• Hydroelectric Power

  • Dams are built to trap water, which in turn is then released and channeled through turbines that generate electricity.

  • There are ~75000 dams in the US that block 600,000 miles of what had been once free-flowing rivers.

  • Dams now block every major river system in the West.

  • Many of these dams destroyed important spawning and rearing habits for salmon.

  • Fish passage facilities and fish ladders have been built to help juvenile and adult fish migrate over or around these dams.

• Solar

  • Consists of collecting and harnessing radiant energy from the sun to provide heat and/or electricity.

• Worldwide Growth in Solar Power

  • Photovoltaic systems are gaining momentum on a worldwide scale.

  • Asia is the fastest growing region in the world for installation of PV systems.

• Wind

  • Wind turns giant turbine blades that then power generators.

  • Turbines can be ground in clusters called wind farms.

• Other (Future) Renewable Energy Sources

• Hydrogen Fuel Cells

  • Nine million tons of hydrogen is produced in the US every day.

  • This is enough to power 20 to 30 million cars or 5 to 8 million homes.

  • The hydrogen fuel cells operate similar to a battery. It has two electrodes with a catalyst to form negatively charged electrons and positively charged hydrogen ions.

• Nuclear Fusion

  • Can occur when extremely high temperatures are used to force nuclei of isotopes of lightweight atoms to fuse together, which causes large amounts of energy to be released.

• Ocean Waves and Tidal Energy

  • The natural movement of tides and waves spins turbines that generate electricity.

  • Only a few plants are operating worldwide.

• Small-Scale Hydroelectric

  • Utilizes small turbines connected to generators submerged in streams to generate power.

Energy Conservation

• Energy Star is a joint program of the US Environmental Protection Agency and the US Department of Energy. It is designed to protect the environment through energy-efficient products and practices.

• There are hundreds of ways to conserve energy.

  • Minimize Phantom Loads - Refers to the energy that an appliance or an electric device consumes when it is not actually turned on.

  • Use more energy-efficient appliances.

  • Change to more efficient LED lighting

  • Change to a programmable HVAC thermostat.

  • Add extra insulation and seal air leaks.

• Smart Grids

  • A modernized electrical grid that uses digital information and communications technology to gather and act on information, such as information about the behaviors of supplies and consumers.

Transportation

• Transportation needs are a major factor for petroleum consumption in the US.

• The Corporate Average Fuel Economy standards are regulations in the US that are designed to improve the average fuel economy of cars and light trucks produced for sale in the US.

• CAFE stands include

  • Automobile designs that reduce air resistance and friction

  • Reduced tire-rolling resistance

  • Engine improvements

  • Optimized transmission improvements

  • Performance-based tax credits

• Types of Fuel

  • Many states and the federal government are working to increase the use of alternative fuels such as electricity, natural gas, hydrogen, and biofuels.

  • Methods that can be used to encourage the use of environmentally friendly vehicles include

    • Governments only buying vehicles that use alternative energy

    • Increasing taxes on traditional fossil fuels

    • Allowing cars that use alternative energy sources the right to travel in HOV lanes

    • Building more charging stations

    • Providing tax rebates for the purchase of alternative fuel vehicles

    • Providing subsidies to companies to develop vehicles that use alternative fuels

    • Increasing CAFE Standards

• Types of Vehicles

• CNG

  • Stands for Compressed Natural Gas.

  • There are about 23 million vehicles worldwide that use CNG as their fuel.

• Electric Cars (PEVS and HEVS)

  • Automobiles that are propelled by only an electric motor and by using electrical energy stored in batteries.

  • There are 2 types of electric cars available today.

  • Plug in Vehicles (PEV) - run on rechargeable batteries and have a finite distance they can travel.

  • Hybrid Electric Vehicles (HEV) - Able to run on rechargeable batteries or gasoline power.

Mass Transit

• Includes such transportation methods as rail, bus services, subways, airlines, and ferries.

• Often determines where people live, where they work, and how much air pollution they are subjected to.

• In the US, private cars are the primary mode of transportation.

• In the rest of the world, mass transit is.

• Bus Rapid Transit

  • Includes the bus dedicated grade-separated right-of-ways, bus lands, bus boarding islands, curb realignment, off-bus fare collection, and level boarding.

• Car Sharing

  • A model of car rental where people rent cars for short periods of time, often by the hour.

• Light Rail

  • Consists of trains that share space with road traffic and trains that have their own right-of-way and are separated from road traffic.

• Environmental Advantages of Mass Transit

  • Environmental advantages include:

    • Less air pollution

    • Reduction in wet and dry acid precipitation

    • Reduction in greenhouse gases

    • Reduction in particulate matter stemming from both vehicles and refineries.

    • Fewer oil wells and fracking sites