Unit 4, AOS 2 - Energy

Energy types, energy sources, peak oil, impact of energy sources, electricity grids, and mine rehabilitation

Define Energy

The ability to do work.

Define Power

The rate at which energy is produced/consumed over time.

Define Joules

A measure of the amount of energy needed to do work.

(eg. 1 joule is the amount of energy needed to lift 100g of mass 1m, or raise the temperature of 1cm² of water 0.25^oC)

Define Watts

The unit that measures power.

Watt hours measure how much power is produce/consumed over time.

Define Amps (amperes)

Measure electric current - the strength of the electromagnetic force between two conductors carrying electrical current.

Define Volts

Measures the electrical potential difference (how much energy each unit carries when moving between too points)

Define Ohms

Measure electrical resistance, or how much power it takes to make electrons flow through an object.

Describe the Energy Conversion Equations Triangle

W on top, then A and V on the bottom

Define Potential Energy

Energy that is stored due to its position or configuration.

List 4 forms of Potential Energy with an example for each

• Chemical energy locked in the bonds of molecules (eg. food or fuels)

• Gravitational energy (eg. water in a dam)

• Elastic energy in a stretched or compressed object (eg. coiled spring)

• Nuclear energy in the nucleus holding protons and nuetrons together (eg. nuclear power plants, unstable or radioactive nuclei)

Define Kinetic Energy

The energy of a body in motion.

List 4 forms of Kinetic Energy with an example for each

• Thermal or the heat energy within a substance (eg. body heat or steam)

• Radiant energy transmitted as rays, waves or particles (eg. a torch or the sun)

• Electrical energy from the movement of charged particles (eg. powerlines)

• Sound energy transmitted in waves through a medium (eg. radio)

Define Mechanical Energy with an example

Energy associated with a mechanical device - the energy an object possesses due to its position or motion (it’s sum of kinetic and potential energy). 

For example, a hammer, bow and arrow or wind/generator turbine.

Describe the First Law of Thermodynamics

Energy is neither created nor destroyed, it can merely be changed from one form to another.

Describe the Second Law of Thermodynamics

The total amount of useful energy decreases with each transformation in the energy’s form.

Define what is meant by Peak Oil

The concept that the rate of oil extraction will increase until it reaches it’s highest level (or peak) after which the oil’s quality, amount and ease of extraction will decline.

Describe the process of Fracking

A extraction method for natural gas and oil from shale rock by drilling into the earth and injecting a high-pressure mix of water, sand and chemicals to fracture the rock and release the oil and gas.

Identify 3-4 environmental concerns around Fracking

• Groundwater and soil contamination from fracking chemicals

• Intensive water consumption

• Methane emissions from fractured rock

• Potential increases in seismic activity

Outline what is meant by the Electrical Grid

Electrical grids consist of power stations, electrical substations to step voltage up or down, transmission lines, local utilities and transformers. These components work to generate, transmit and distribute electricity.

Define the term Capacity

The maximum power output from an energy facility or electricity system (ie. if generators operated at 100%)

Define the term Capacity Factor

The ratio of actual energy produced and the capacity. 

(The actual output of a generator over time compared to the generator working at 100%)

Define the term Efficiency

How effectively input energy is converted into the output.

(eg. chemical energy in coal converted to electricity in a power plant)

Define the term Base Load Demand

The minimum level of demand for electricty over a span of time (eg. 24 hours)

Define the term Peak Demand

The highest demand consumed at any given time.

Define the term Dispatchable Energy

When an energy source has an adjustable output to help balance supply and demand.

Compare the reliability of fossil fuels and renenewable energy from solar and wind power

Fossil fuels are far more reliable because they can produce energy on demand, either continuously or when needed. Solar and wind produce energy intermittently, lowering their capacity factors and ability to consistently meet the base load.

List 3 Pros of Fossil Fuels

• Reliable and consistent

• Easy to transport and store

• Infrastructure already in place

• Easiest to use with current machinery and in many industrial processes, particularly those involving combustion (eg. cement)

List 3 Cons of Fossil Fuels

• Most significant source of GHG emissions

• Pollution from waste, runoff, particulate matter, combustion

• Relies on environmentally harmful extraction methods

• Finite, non-renewable and resources

• Increasingly damaging extractions as quality and quantity decline (peak oil)

List 3 Pros of Nuclear Power

• Reliable and constant power

• Very efficient energy production

• Expensive infrastructure

• Low carbon

• Lesser areas of land required for infrastructure

List 3 Cons of Nuclear Power

• Safe storage is extremely important

• Associated with development of nuclear weaponry

• Radioactive waste

• Extreme pollution/radiation risks

• Uranium, the fuel, is non-renewable

• Intensive water use

List 3 Pros of Hydro Power

• More reliable than renewables such as solar and wind

• Low carbon, renewable

• In the long term, it is cost-effective

• Dams can have multiple purposes (eg. irrigation, flood control)

• High efficiency

• Doesn’t rely on constant resource extraction

List 3 Cons of Hydro Power

• Impacts on waterways, peak flow and aquatic/interconnected ecosystems

• Interrupts fish migration routes

• Location can’t be chosen for convenience of transportation or storage

• Reservoir creation can displace people

List 3 Pros of Solar and Wind Power

• Low carbon, renewable

• Doesn’t rely on constant resource extraction

• Can be implemented in already cleared areas such as farmland

• Can be implemented on small scales

List 3 Cons of Solar and Wind Power

• Fluctuating ability to meet base load

• Inconsistent power supply, dependent on factors outside of control

• Batteries and the panels/turbines require mining for precious metals

• Large areas of land required

• Wind turbines can be loud, have disruptive shadows and pose a threat to high-flying birds

Identify 5-8 impacts of Fossil Fuel Mining

• Damage or destruction of natural environments and landforms with environmental, cultural and spiritual significance

• Permanent change to natural topography and landcover

• Losses of biodiversity

• Interruption, diversion, pollution and loss of waterways

• Toxic waste disposal and runoff

• Fire hazards of discarded low-quality coal

Define the term Ore

Natural rock or sediment that contains one or more valuable minerals.

Define the term Mine Void

The remaining area of excavation after mining is complete.

Define the term Overburden

The rock or soil layer that needs to be removed to access the ore being mined.

Define the term Tailings

The waste material after the target mineral has been extracted from the ore.

Define the Mechanical Rehabilitation

Rehabilitation efforts that involve physically moving components to, from and within the site.

Provide 3 examples of Mechanical Rehabilitation of a mining site

• Clearing out mining infrastructure

• Clearing out contaminate soil

• Reshaping the site to represent natural topography

• Backfilling of tunnels and shafts

Define Chemical Rehabilitation

Rehabilitation efforts that involve returning the chemical properties of the soil and water to safe, normal levels.

Provide 3 examples of Chemical Rehabilitation of a mining site

• Treating polluted water

• Treating soil and tailings

• Fertilising topsoil to encourage revegetation

Define Biological Rehabilitation

Rehabilitation efforts that involve reintroducing wildlife to the site.

Provide 3 examples of Biological Rehabilitation of a mining site

• Revegetation programs

• Reintroduction of fauna

• Creating and supporting habitats for native animals

Outline what is meant by the Cumulative Impacts of Mining

The collective impacts of mines across a region/country rather than individual mines, taking into account direct and indirect impacts.

Identify 3 sources of Indirect Mining Impacts

• Construction and maintenance

• Operatation of infrastructure

• Transportation

• Surrounding infrastructure (eg. pipes, roads, etc.)

Define and describe the purpose of Bioindicators

Living organisms used to judge the health of an ecosystem, often by measuring population trends in species vulnerable to physical or chemical change in their environments.

Define and describe the purpose of Benchmark/Reference Sites

Undisturbed sites in the region used to provide a specific, realistic and holistic goal of rehabilitation and measurement of comparitive success.