AP Environmental Science Unit 6: Energy Resources and Consumption

Renewable energy source

Energy source naturally replenished faster than it’s used

Nonrenewable energy source

Resource that cannot be replenished at a rate that matches its consumption

Subsistence fuel

Fuels easily gathered or collected

• eg. wood, crop, animal waste

• very commonly used in less developed nations

Charcoal

Solid fuel created by burning wood, removing moisture and volatile compounds

Peat

Accumulation of partially decayed vegetation or organic matter

How can peat become anthracite coal?

Through coalification

• involves burial, increased temperature and pressure, and changes in carbon content

• intermediate coal forms are lignite, subbituminous, and bituminous coals

Petroleum

Primarily a mixture of carbon and hydrogen

• extracted from underground reservoirs through drilling

Fractional distillation

A process used to separate a mixture of liquids with slightly different boiling points, like those found in crude oil

• involves heating a mixture and allowing the components to evaporate and then condense at different points along a cooling column

Difference between extraction of petroleum from oil/tar sands and traditional petroleum extraction

Bitumen in oil sands is made of hydrocarbons, which are significantly more costly and more difficult to extract

How are fossil fuels used to generate energy?

Fossil fuel power plants burn coal or oil to create heat which is in turn used to generate steam to drive turbines which generate electricity

Benefits and drawbacks of coal

Advantages: being abundant and relatively cheap, with established infrastructure for its use

Drawbacks: environmental impacts, air pollution, and contributions to climate change

Benefits and drawbacks of petroleum/crude oil

Advantages: high power ratio and is easy to transport

Drawbacks: extraction process and the byproducts of the use of petroleum are toxic to the environment, may cause leaks, fracking can affect the water table

Benefits and drawbacks of natural gas

Advantages: relatively cleaner burning fossil fuel compared to coal and oil, offering lower emissions of pollutants and carbon dioxide

Drawbacks: releases methane

Fracking (natural gas extraction)

Natural gas extraction process that involves drilling deep wells into shale rock and then injecting a mixture of water, sand, and chemicals at high pressure

• pressure creates fractures in the shale, allowing trapped natural gas to flow out and be collected

• three components of fracking flowback fluid: water, volatile hydrocarbons (natural gas and other hydrocarbons), and chemicals/additives

Consequences of fracking

Habitat destruction, water and air pollution, increased earthquakes, and release of GHGs

Fracking flowback fluid

The wastewater which returns to the surface after hydraulic fracturing

• water, volatile hydrocarbons (natural gas and other hydrocarbons), and chemicals/additives

Fission reaction (nuclear energy)

A neutron slams into a larger atom, forcing it to excite and split into two smaller atoms

Advantages of nuclear energy

Produces no GHGs, doesn’t contribute to acid disposition, and is highly concentrated

Disadvantages of nuclear energy

High cost of construction and safety concerns about the operation or the plant and disposal of spent fuel rods

Ethanol

A renewable biofuel produced from plant matter (biomass) and used as a fuel additive, particularly in gasoline, to increase octane and reduce greenhouse gas emissions

• (+) reduces GHGs emissions, cleaner burning, and enhances energy independence

• (-) high land and water requirements, increased food prices, and not super energy efficient

• produced from the fermentation of glucose/sucrose sources, like sugar cane or corn

• combustion is carbon neutral because it takes carbon from the atmosphere

Active solar energy

Use mechanical and electrical devices to capture and utilize solar energy

Passive solar energy

Rely on building design and materials for energy capture and distribution

Photovoltaic (PV) cells

Electrical cells that allow the light energy of the sun to be directly converted into electricity

Concentrated solar thermal (CST) electricity generation

Uses mirrors or lenses to focus sunlight onto a receiver, converting it into heat

• heat/steam then drives a turbine connected to a generator, producing electricity

How is hydroelectricity generated?

Converting the kinetic energy of moving water into electricity

• using a dam to create a reservoir, then releasing the water to spin turbines connected to generators → moving water powers the turbines, which in turn drive the generators to produce electricity

Run of river energy system

Type of hydroelectric power generation that utilizes the natural flow of a river without creating a large dam or reservoir

• diverting a portion of the river's flow through a canal or penstock, which then powers turbines to generate electricity before returning the water to the river

Water impoundment system

Process where water is collected and stored, often for later use, like in hydropower plants or for irrigation

• involves creating a reservoir, usually behind a dam, to capture and store water from a river or other water source → captured water can then be released to generate electricity, irrigate crops, or be used for other purposes

Hydroelectric dam

Dams are built on rivers where the terrain will produce an artificial lake or reservoir

Geothermal energy

The heat energy derived from within the Earth, used for various applications like electricity generation and heating

Geothermal energy pros and cons

Pros: renewable and consistent nature, low greenhouse gas emissions, and potential for diverse applications

Cons: location specificity, high initial costs, and potential environmental impacts like minor earthquakes and emissions of some gases

Hydrogen fuel cell

Devices that convert hydrogen fuel into electricity, producing only water and heat as byproducts

Process of generating electricity using wind turbines

Wind turbines convert the kinetic energy of wind into electrical energy through a process involving blades, a rotor, a generator, and a gearbox → wind spins the turbine blades, which turn a rotor connected to a generator, which in turn produces electricity

Green roofs

Act as insulation and mitigating the urban heat island effect, thereby lowering the need for heating and cooling

Purpose of combustion of methane

To release heat energy to be used as a fuel source