Overview of Energy Resources and Their Uses

Energy demands

Primarily through fossil fuels (coal, oil, natural gas) and nuclear power, with increasing contributions from renewables (solar, wind, hydro).

Energy resources

Fossil fuels, nuclear fuels, solar, wind, hydroelectric, tidal, geothermal, biofuels.

Nuclear fuels in power stations

Uranium or plutonium undergoes nuclear fission in a reactor core, releasing heat to produce steam, which drives turbines and generators.

Other fuels in power stations

Coal, oil, natural gas (fossil fuels).

Other fuels to generate electricity

Biomass (e.g., wood, animal waste), biogas.

Wind turbine components

Blades, a rotor, a gearbox, a generator, and a tower. Wind turns the blades, driving the generator to produce electricity.

Waves generating electricity

Wave motion drives floating devices or turbines, converting kinetic energy into electrical energy.

Hydroelectric power station

Uses water running downhill to generate electricity (uses reservoirs and gravitational potential energy).

Tides generating electricity

Tidal barrages or underwater turbines capture energy from rising and falling tides.

Solar cells

Flat panels made of semiconductor materials (e.g., silicon) that convert sunlight directly into electricity.

Difference between solar cells and solar heating panels

Solar cells generate electricity from sunlight; solar heating panels absorb sunlight to heat water or air.

Geothermal energy

Energy from heat stored in the Earth's crust, released by radioactive decay in rocks.

Geothermal energy generating electricity

Steam or hot water from underground is piped to drive turbines connected to generators.

Fossil fuels and the environment

Release CO₂ (greenhouse gas), contributing to climate change, and produce pollutants (e.g., sulfur dioxide).

Concerns about nuclear power

Risks of radioactive leaks, nuclear waste disposal challenges, and potential for accidents (e.g., Chernobyl).

Advantages of renewable energy resources

Sustainable, low emissions, reduce reliance on fossil fuels.

Disadvantages of renewable energy resources

Intermittent supply (e.g., solar/wind), high initial costs, land use conflicts.

Evaluation of energy resources

Fossil fuels are reliable but polluting; renewables are clean but require infrastructure; nuclear is efficient but risky.

Using electricity supplies

Use peak-load power stations (e.g., gas turbines) for high demand and base-load stations (e.g., nuclear) for constant supply.

Economic costs of energy resources

Comparison of the economic costs of different energy resources.

Fossil fuels

Fuels formed from ancient organic matter (e.g., coal, oil, natural gas).

Renewables

Energy sources with high setup costs but low running costs.

Nuclear

Energy source with high safety/construction costs.

Biofuel

Fuel from living/recently living materials (e.g., animal waste, ethanol).

Carbon-neutral

A fuel that absorbs as much CO₂ during production as it emits when burned (e.g., biofuels from plants).

Climate change

Long-term shifts in global temperatures and weather patterns, often linked to human activities.

Hydroelectricity

Electricity generated by moving water (e.g., dams).

Non-renewable

Energy resources that cannot be replenished (e.g., fossil fuels, uranium).

Nuclear fuel

Material (e.g., uranium) used in nuclear reactors for fission.

Reactor core

The part of a nuclear reactor containing fuel rods, control rods, and moderator.

Tidal power

Electricity generation using tidal movements.

Conductors

Materials that allow the flow of electricity or heat (e.g., metals like copper, aluminum).

Insulators

Materials that resist the flow of electricity or heat (e.g., wood, plastic, fiberglass, foam).

Thermal conductivity

A measure of how quickly heat is transferred through a material.

Specific heat capacity

Energy required to raise 1kg of a substance by 1°C (unit: J/kg°C).

Energy transfer

The process of energy moving from one place or form to another.

Cavity wall insulation

Foam or fiberglass inserted between wall layers to reduce conduction and convection.

Central heating systems

Systems that heat homes using boilers, radiators, or geothermal pumps.

Double-glazed windows

Windows designed to reduce heat loss by having two layers of glass.

Draught excluders

Materials used to seal gaps around doors and windows to prevent heat loss.

Infrared Radiation

Electromagnetic waves emitted by hot objects, transferring heat energy.

Energy storage methods

Chemical, kinetic, gravitational potential, elastic potential, thermal, nuclear.

Energy transfer methods

Mechanically (work), electrically, by heating, or by radiation.

Energy transfers when an object falls

Gravitational potential energy → kinetic energy.

Energy transfers when a falling object hits the ground

Kinetic energy → sound, heat, and deformation energy (energy dissipates).

Conservation of energy

Energy cannot be created or destroyed, only transferred or stored.

Importance of conservation of energy

It underpins all energy calculations and sustainability efforts.

Closed system

A system where no energy is transferred to/from the surroundings.

Energy transfers in a closed system

Total energy remains constant; energy only changes form.

Work in science

Energy transferred by a force acting over a distance: W=F×s(J = N × m).

Relationship between work and energy

Work done = energy transferred.

Calculating work done

Example: 50N force moving an object 3m: W=50×3=150 J.

Work done to overcome friction

Energy is dissipated as heat.

Gravitational potential energy when moving up and down

Increases when moving up; decreases when moving down.

Increasing gravitational potential energy

Work is done against gravity, transferring energy to the GPE store.

Lifting objects on the Moon vs Earth

Moon's gravity is weaker → less force needed.

Change in gravitational potential energy

Example: 5kg object raised 10m (g = 10 N/kg): ΔEp=m×g×Δh=5×10×10=500 J.

Kinetic energy dependence

Mass and speed: Ek=12mv².

Calculating kinetic energy

Example: 10kg object moving at 5m/s: Ek=0.5×10×5²=125 J.

Elastic potential energy store

Energy stored in stretched/squashed objects (e.g., springs).

Calculating elastic potential energy

Example: Spring (k = 200 N/m) stretched 0.5m: Ee=0.5×200×(0.5)²=25 J.

Dissipated energy

Energy spread out into the environment (e.g., as heat).

Law of conservation of energy

Energy cannot be created/destroyed, only transferred or stored.

System in science

A group of interacting components (e.g., a kettle + water).