APES Unit 6: Energy Resources and Consumption

Nonrenewable

cannot be replaced (ex: oil, coal, natural gases, nuclear energy)

Renewable

can be replenished naturally (ex: wind, solar energy, Hydro Power, biomass, geothermal)

What determines which energy source people use?

availability, price/convenience, government regulations

Leader in petroleum resources

Middle East

Leader in Uranium

Australia

Highest per Capita in energy consumption

China

What does combustion produce?

heat

thermal power plant operation

water heats up turns into steam, spin in a turbine, activates a generator, then creates electricity.

3 types of coal

Ignite, bituminous, anthracite

coal pros

abundant compared to oil and gas, easy to extract through surface mining, and very few technological demands, easy to transport, very cheap

coal cons

very dirty, impurities are released causing air pollution and contributes to climate change, heavy water use

Petroleum pros

liquids are convenient for transport and use, compared to coal very energy dense and cleaner burning

Petroleum cons

toxins released into the atmosphere, oil refining, potential leaks and spills (Exxon Valdez and deep water horizon), habitat destruction, gas flares

Natural Gas

uses fracking

Natural Gas pros

the cleanest out of all three fossil fuels, emits 30% less CO2 than coal convenient through pipeline delivery.

Natural Gas cons

natural gas (methane) is a green house gas, fracking can lead to groundwater contamination.

Co generation

occurs when a fuel source is used to generate both heat and electricity.

Nuclear Power

• radioactivity releases energy from the nucleus

• more unstable a atom is then the more radiation it gets off

• Nuclear fission- Neutron strikes a large atomic nucleus

• this releases more neutrons and heat energy

• these neutrons in turn release more energy in a chain reaction

• energy is used to produce steam

Nuclear Power Pros

No emissions during operation, high density, very predictable of energy source

Nuclear Power Cons

Nuclear accidents (three mile island, Chernobyl Ukraine, Fukushima disaster), radioactive waste disposable

How are fuel rods stored?

submerging in water.

Half Life

the time it takes for half of a sample of radioactive decay

Biomass

stores energy from the sun, reflects the first law of thermodynamics (energy cannot be destroyed but changes from), used in developing nations. (wood, charcoal, peat, crop residue)

Biomass pros

renewable, easily accessible, inexpensive, carbon neutral

Biomass cons

Burning can release air pollutants like carbon monoxide and dioxide, burned indoors which causes respiratory issues, over harvesting trees causes deforestation, net energy is low.

Biofuels

liquid fuels made from plant matter used as substituted for conventional petroleum products. (ex: ethanol) comes from corn and mixed with gasoline.

photovoltaic energy

transforms sunlight directly into electricity using solar panels

Active Solar

uses mechanical and electrical equipment to transfer solar heated liquid to transfer heat or create electricity

Passive Solar

Heat is directly absorbed from the sun without mechanical or electrical equipment

Photovoltaic Cells

• the sunlight's energy activates and releases electrons from thin layers of semiconducting material (like silicon)

• Generates a low-voltage electric current

Photovoltaic Cells pros

generates electricity, no emissions during operation, can produce electricity during peak demand, economically feasible, can reduce habitat destruction, large and small scale applications

Photovoltaic Cells cons

limited by available sunlight, limited lifespan of nonrenewable PV cells, solar farms can disrupt habitats, very expensive to manufacture/install, with less solar radiation payback can take longer, manufacture of panels requires energy and water and can release toxic metals and chemical.

Active Solar

uses lenses and mirrors to focus on sunlight, evaporates water to steam

Active Solar pros

generates heat and electricity, large scale applications

Active Solar cons

expensive, requires maintenance, solar farms can disrupt ecosystems, requires high solar intensity.

Passive Solar Heating

Doesn’t require technology, rely on home design (Skylights)

Passive Solar Heating Pros

relatively inexpensive and low maintence

Passive Solar Heating Cons

Some aspects are difficult to implement retroactively, energy cannot be stored long- term

Hydroelectricity

power generated by the kinetic energy of moving water

Run of the river

retained behind a low dam no reservoirs, little flooding however smaller and unpredictable

Water Impoundment

typical dam

Water Impoundment Pros

allows for the generation of electricity on demand , minimal fossil fuel use, electricity is usually cheaper than made by nuclear or natural gas, reservoir can provide recreational and economic activities, downstream flood control. (three gorges dam)

Water Impoundment Cons

a naturally free flowing river must be held back, habitat destruction, large reservoirs of standing water hold more heat and less oxygen, more expensive, environmentally unfriendly, disruption of fish migration.

Tidal systems pro

efficient (80% can be converted)

Tidal Systems cons

does not have the potential for major energy source because tidal difference is not great enough in most places.

Geothermal

• doesn’t come from the sun

• convection currents bring mama towards the Crust, which heats groundwater

• largest producers: US, China, and Iceland

Geothermal Pros

Renewable, no combustion, very efficient and low maintenance, promotes national unity

Geothermal Cons

High initial cost, can release harmful gases, sustainability issues.

Hydrogen Fuel Cells

• produce energy by a chemical reaction that splits hydrogen molecules

• the reaction produces electricity, water, and a small amount of heat

Hydrogen Fuel Cells process

• Hydrogen fuel is added to one end of the fuel cell and oxygen to the other end

• hydrogen molecules are split into protons and electrons

• the flowing electrons create an electric current that can power devices and enfines

• the hydrogen protons are combines with oxygen to create water vapor, which is emitted from the fuel cell.

Hydrogen fuel cells pros

80 percent efficient, no harmful emission during operation

Hydrogen fuel cells cons

technology is still new (expensive), distribution network needs to be in place, vehicles and tanks are in more danger of fire and explosions, needs a constant supply of hydrogen, which may not be clean

Wind Energy

• recall the source of win

• fastest-growing source of electricity in the world

Wind Energy pros

renewable and clean, low cost after installation, allows for multiple land use (wind farms can share with agriculture or cattle)

wind Energy cons

locations must have consistent winds, blade disposal, Bird and bat incidents

Why is energy conservation important?

by using less energy and increasing energy efficiency of production and processes, we can reduce our dependence on energy resources and decrease out footprint on environment.

How to save energy at home?

change thermostat, shorter showers, energy-efficient appliances, larger laundry loads on cold cycle.

How to save energy in transportation?

fuel economy standards, electric vehicles, ride sharing/carpooling

how to save energy in building design?

green building design features, passive solar, green roof, heating systems, solar panel

Government conservation measures

Improve/increase public transportation, tax use of oil/electricity/natural gas.