Uses of energy resources for transport, electricity and heating
Principles of energy • National and global energy resources
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Definition and overview of uses
An energy resource is any material or natural flow that provides usable energy by transfer from one store to another. Transport requires high energy density and controllable release, so chemical fuels and stored electricity dominate. Electricity generation requires continuous mechanical work on generators or conversion of natural flows into electrical energy. Heating requires direct thermal energy or electrical heating and often benefits from local, steady supplies. The suitability of a resource depends on cause→effect chains: resource availability causes selection of technology; technology converts stored energy into motion or heat; conversion losses and environmental effects limit use. Examples include burning coal (chemical energy → heat → steam → turbine → electricity) and solar cells (sunlight → electrical energy directly).
Fossil fuels: transport, electricity and heating
Fossil fuels (petrol, diesel, gas, coal) power transport by combustion in internal-combustion engines or turbines; combustion releases chemical energy that produces kinetic energy to move vehicles. High energy density and established infrastructure cause widespread use in cars, lorries and aeroplanes. Fossil fuels generate electricity when burned to heat water, create steam and drive turbines; coal and gas provide flexible and relatively cheap generation but cause carbon dioxide emissions and pollutants such as sulfur dioxide that cause acid rain. Fossil fuels also provide domestic and industrial heating by direct burning or in central boilers. Environmental impacts and finite supplies limit long-term use.
Nuclear energy: electricity and heat
Nuclear fuel provides large amounts of thermal energy through fission in reactor cores; heat produces steam that turns turbines and generates electricity. Nuclear generation causes low direct carbon emissions and provides large-scale, steady baseload power. Nuclear reactors can provide district heating in some cases by transferring reactor heat directly to water supplies, but safety concerns, radioactive waste and high capital costs limit widespread adoption for heating. Location and regulatory constraints also act as limiting factors.
Renewable electrical sources: wind, hydro, tidal and solar
Wind turbines convert kinetic energy of moving air into electricity using generators; hydropower uses falling or flowing water to turn turbines; tidal and wave installations convert predictable water movements into electrical energy. Cause→effect: natural flow (wind/water) causes turbine rotation → generator converts rotation to electricity. Intermittency, site-specific resources and upfront infrastructure costs limit continuous output. Solar cells convert sunlight directly into electricity on a small scale and feed local supplies or the grid. Low operational emissions and scalability cause increasing uptake, but weather and geographic location limit reliability and output.
Biomass, biofuels and geothermal uses
Biomass and biofuels release chemical energy through combustion or chemical conversion. Biofuels cause lower net carbon emissions when produced sustainably and fit familiar uses: liquid biofuels replace petrol/diesel in engines for transport; biomass burns in power stations or boilers for electricity and heating. Limiting factors include land use, production emissions and sustainability. Geothermal energy uses heat from beneath the Earth's surface directly for heating or to produce steam for electricity in suitable locations. Cause→effect: geological heat causes hot water or steam → direct heating systems transfer heat to buildings or steam drives turbines for generation. Geographic availability limits widespread use but provides clean, steady energy where accessible.
Electricity and transport: batteries and electric motors
Stored electrical energy in batteries or fuel cells drives electric motors to provide motion in transport. Batteries convert chemical energy to electrical energy; electric motors convert electrical energy to kinetic energy with higher efficiency than combustion engines. The cause→effect chain improves efficiency and reduces local emissions, but battery mass, charging infrastructure and energy source for electricity generation limit overall impact. Hydrogen used in fuel cells produces electricity on-board with water as the primary emission; storage and production of hydrogen act as limiting factors for widespread transport use. Overall transport electrification depends on the energy mix used to generate electricity and on charging/refueling infrastructure.
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