7.2

These flashcards cover the key vocabulary and concepts regarding global energy sources, including fossil fuels, renewable energy technologies, nuclear power, and energy management strategies.

Energy

The capacity to do work, which underpins every aspect of human civilisation including heating, transport, and industry.

Energy Resources

The natural sources from which usable energy is derived, broadly divided into fossil fuels, renewable sources, and nuclear energy.

Fossil Fuels

Coal, oil, and natural gas formed over millions of years and burned to release stored chemical energy.

Renewable Sources

Sources such as solar, wind, hydroelectric, geothermal, and tidal power that harness ongoing natural processes.

Nuclear Energy

A distinct category of energy released from atomic reactions like nuclear fission.

Primary Energy

The total energy consumption based on the substitution method and measured in terawatt-hours ($TWh$).

Turbine

A set of precisely engineered blades mounted on a shaft spun by a moving fluid, such as steam, water, or wind.

Generator

A device where a coil of wire spins within a magnetic field, inducing an electrical current through electromagnetic induction.

Michael Faraday

The nineteenth-century scientist who discovered the principle of electromagnetic induction used in generators.

Coal

A sedimentary rock formed over hundreds of millions of years from compressed remains of ancient forests and plant matter.

Coal Classifications

Includes high-grade Anthracite, Bituminous coal, and lower-grade Lignite, categorized by carbon content.

Oil (Crude Petroleum)

A liquid fossil fuel formed from the remains of marine organisms compressed under heat and pressure over millions of years.

Natural Gas

A fossil fuel composed primarily of methane, formed from ancient organic matter subjected to heat and pressure deep underground.

Hydraulic Fracturing (Fracking)

An extraction method for natural gas found in shale rock formations.

Transition Fuel

A term often used for natural gas because it produces approximately $50\%$ less $CO_2$ than coal when burned.

Nuclear Fission

A process that generates energy by splitting the atoms of heavy elements, typically uranium or plutonium.

Uranium Energy Density

A single kilogram of uranium fuel contains approximately $2 \times 10^6$ times the energy of a kilogram of coal.

Hydroelectric Power

The generation of electricity by harnessing the energy of moving water, typically using dams to create reservoirs.

Run-of-River Systems

A smaller-scale hydroelectric alternative that offers reduced ecological impact compared to large dams, though with less generating capacity.

Biomass

Organic material such as wood, agricultural residues, and waste that can be burned for heat or converted into biogas and liquid biofuels.

Solar Photovoltaic (PV) Cells

Cells made from semiconductor material (typically silicon) that generate electricity using the photovoltaic effect with no moving parts.

Photovoltaic Effect

The creation of electrical current when photons of light strike a semiconductor cell and knock electrons loose, first observed by Edmond Becquerel in 1839.

Inverter

A device used in solar systems to convert direct current ($DC$) into alternating current ($AC$) for use in homes and businesses.

Concentrated Solar Power (CSP)

A system using mirrors or lenses to focus sunlight onto a small point to generate heat, which then produces steam to drive a turbine.

Molten Salt

A thermal storage medium used in CSP systems to allow electricity generation to continue for hours after sunset.

Wind Energy

Harnesses the kinetic energy of moving air using aerodynamic blades that create lift to rotate a generator.

Tidal Energy

Energy harnessed from the predictable movement of ocean tides driven by the gravitational pull of the moon and sun.

Oscillating Water Column

A wave energy device that traps and compresses air as waves rise and fall to drive an air turbine.

Point Absorber Buoys

Wave energy devices that bob with wave motion to drive hydraulic pumps or linear generators.

Attenuator Devices

Wave energy machines, like the Pelamis, that flex with passing waves along their length to convert motion into electricity.

Geothermal Energy

Heat harnessed from within the Earth, originating from the planet's formation and radioactive decay in the crust.

Energy Poverty

A condition in regions like sub-Saharan Africa and South Asia where citizens lack reliable access to modern energy services, limiting education and healthcare.

Energy Security

The ability of a country to access reliable, affordable energy supplies without dangerous dependence on unstable sources.

Strategic Petroleum Reserve

A buffer maintained by the United States to protect against sudden supply shocks in the oil market.

Pumped Hydroelectric Storage

The largest form of grid storage globally, where surplus electricity is used to pump water uphill to be released through turbines later.

Hydrogen Energy Storage

A long-duration potential storage solution using electrolysis to split water into hydrogen with surplus renewable electricity.

Energy Conservation

The practice of using less energy through behavioral changes, such as turning off lights or lowering thermostats.

Energy Efficiency

Achieving the same outcome while consuming less energy through improved technology and design, such as using LED bulbs.

Negawatts

A principle stating that the most cost-effective unit of energy is the one that is never consumed.