APES Unit 6

Nonrenewable energy sources

Energy sources that exist in a fixed amount = can’t be easily replaced. Example: coal, oil, and other fossil fuels.

Renewable energy

Energy sources are those that can be replenished naturally and reused. Examples: Hydroelectric (dam) power, solar energy, wind energy.

Rate of Consumption

The rate at which we consume stuff. Rate of use must be at or below rate of regeneration = can use it. Negative effect: Fossils fuels take long to regenerate + the rate we use them = fossil fuels will run out.

Fossil fuels

Most widely used sources of energy globally. Developing countries rely on this as they become more developed.

Energy

Something we depend on for power. As the world becomes more industrialized, the demand for energy increases. Availability, price, and governmental regulations influence which energy sources people use and how they use them.

Wood

Commonly used as fuel in the forms of firewood and charcoal. It is often used in developing countries because it is easily accessible.

Peat

Partially decomposed organic material that can be burned for fuel. Found in wet ecosystems like bogs and moors.

Natural gas

This energy is the cleanest of thee fossil fuels and is mostly methane.

Crude oil

Can be recovered from tar sands, which are a combination of clay, sand, water, and bitumen. It is decaying organic matter trapped under rock layers and compressed into oil over time.

Cogeneration

Happens when a fuel source is used to generate both useful heat and electricity. Example: Excess heat from local power stations provides the surrounding community with heat via an extensive network of steam pipes.

Combustion of fossil fuels

Chemical reaction between the fuel and oxygen that yields carbon dioxide and water and releases energy. Burning fossil fuels → water is turn to steam → steam turns a turbine → spins generator → producing electricity.

Hydrologic fracturing (fracking)

This is a method of getting natural gas through drilling. This process can cause groundwater contamination and the release of volatile organic compounds. Can deplete ground or surface water for fracking fluid.

Nuclear power

Generated through the firing of a neutron into the nucleus of a radioactive element like Uranium = chain reaction (nucleus breaks apart, releasing more energy). A nonrenewable energy source. This is considered a cleaner energy source because it does not produce air pollutants, but it does release thermal pollution and hazardous solid waste. Same process as fossil fuels to generate electricity but uses uranium. Negative effects: Used fuel rods remain radioactive for millions of years = needed to be stored in lead containers, leftover rock and soil many have radioactive element = runoff = contaminate nearby water, and uses a lot of water.

Nuclear Fission

This releases a large amount of heat, which is used to generate steam, which powers a turbine and generates electricity.

Radioactivity

This occurs when the nucleus of a radioactive isotope loses energy by emitting radiation.

Uranium-235

Remains radioactive for a long time, which leads to the problems associated with the disposal of nuclear waste.

Accidental Incidents

Three Mile Island, Chernobyl, and Fukushima are three cases where accidents or natural disasters led to the release of radiation. These releases have had short- and long-term impacts on the environment.

Half-life

The amount of time it take for 50% of a radioactive substance to decay (breakdown). Can be used to calculate a variety of things, including the rate of decay and the radioactivity level at specific points in time.

Ethanol

Can be used as a substitute for gasoline. Burning this does not introduce additional carbon into the atmosphere via combustion, but the energy return on energy investment for this is low.

Photovoltaic solar cells

Also known as solar panels. Capture light energy from the sun and transform it directly into electrical energy. Their use is limited by the availability of sunlight.

Active solar energy systems

Use solar energy to heat a liquid through mechanical and electric equipment to collect and store the energy captured from the sun. Mnemonic - We are actively collecting that energy

Passive solar energy systems

Absorb heat directly from the sun without the use of mechanical and electric equipment, and energy cannot be collected or stored. Example: Using the sun’s heat to cook food in a solar oven. 

Solar energy systems

Have low environmental impact and produce clean energy, but they can be expensive. Large solar energy farms may negatively impact desert ecosystems, can disrupt habitats, and silicon is a limited resource.

Hydroelectric power

Moving water powers generator. Can be generated in several ways. Dams built across rivers collect water in reservoirs. The moving water can be used to spin a turbine. Turbines can also be placed in small rivers, where the flowing water spins the turbine. Does not generate air pollution or waste, but construction of the power plants can be expensive, and there may be a loss of or change in habitats following the construction of dams.

Tidal energy

Uses the energy produced by tidal flows to turn a turbine.

Geothermal Energy

Energy that is obtained by using the heat stored in the ground to heat up water, which is brought back to the surface as steam. The steam is used to drive an electric generator. Also expensive, as is not easily accessible in many parts of the world. In addition, it can cause the release of hydrogen sulfide.

Hydrogen fuel cells

This is an alternate to nonrenewable fuel sources. They use hydrogen as fuel, combining the hydrogen and oxygen in the air to form water and release energy (electricity) in the process. Water is the product (emission) of this. They also have have low environmental impact and produce no carbon dioxide when the hydrogen is produced from water. However, the technology is expensive and energy is still needed to create the hydrogen gas used in the fuel cell.

Wind turbines

They use the kinetic energy of moving air to spin a turbine, which spins a generator, producing electricity

Wind energy

This is a renewable, clean source of energy. However, birds and bats may be killed if they fly into the spinning turbine blades.

Ways to conserve energy

Adjusting the thermostat to reduce the heat and air conditioning, conserving water, use of energy efficient appliances, and conservation landscaping. Can also improve fuel eco for vehicles by using BEVs and hybrid vehicles and public transportation.

Coal formation

Pressure from overlying rock and sediment layers = compacts peat into coal over time. Lignite, bituminous, and anthracite are types of coal. Anthracite is the most valuable coal (highest quality).

Tar/Oil Sands

Deposits where crude oil can be recovered, but with higher and energy inputs. Negative effects: Habitat destruction to clear land for and water depletion (needed for steam and washing impurities from bitumen). Can cause water contaminations as holes storing waste water can runoff into other bodies of water.

Coal

The #1 source of electricity. Leads to habitat destruction b/c of mining and produce pollutants and releases CO2.

Heat

Much of the energy lost or not converted into electricity escapes as this.

Biomass

Organic matter (wood/charcoal, dried animal = waster or plants) burned to release heat . Releases mordern carbon stored in the air = doesn’t increase carbon dioxide levels as fossil fuels;. Negative effects: releases respiratory irritants and environmental consequences like deforestation and air pollutants. It also produces carbon dioxide, carbon monoxide, nitrogen oxides, particulates, and volatile organic compounds

Biofuels

Liquid fuels (ethanol, biodiesel) created from biomass (corn, sugar cane, palm oil). Used as a replacement for fuel sources. Negative effects: negative consequence of monocrop ag (soil erosion, habitat loss).

Biodiesel

Liquid fuels produced from plant oils. Negative effects: Palm oil biodiesel produces more GHGs than FFs bc of clearing forests.