Geo 2026: Energy sources and a balanced energy mix

Fossil fuels: coal, oil and natural gas, plus shale gas and oil extracted by fracking. Nuclear power uses uranium.
They are finite: once used they cannot be replaced.
Advantages: reliable, available whatever the weather, and existing power stations and infrastructure use them.
Disadvantages: fossil fuels release carbon dioxide (climate change) and air pollution; mining and drilling damage landscapes; nuclear power produces radioactive waste and has accident risks; supplies will run out.

Solar, wind, hydroelectric power (HEP), geothermal (heat from inside the Earth) and biomass (plant material and waste), plus tidal and wave power.
They will not run out and give off little or no carbon dioxide when generating electricity.
Disadvantages: solar and wind vary with the weather; HEP dams flood valleys and move people; wind farms can be unpopular for their look and noise; geothermal works only in certain places (such as Iceland); biomass needs land that could grow food; set-up costs can be high.

An energy mix is the combination of sources a country uses.
A balanced mix uses several sources so the country is not dependent on one fuel or one supplier, improving energy security.
Countries balance it by keeping some reliable sources (gas, nuclear) while growing renewables, adding storage, importing from several partners and reducing demand.
In the exam, give a named source, an advantage and a disadvantage, and say who it affects: people or the environment.

Nuclear power splits the nucleus of uranium atoms (nuclear fission), releasing heat that makes steam to turn turbines.

No single energy source is perfect, which is why countries aim for a balanced energy mix.
Non-renewable sources (coal, oil, natural gas, shale gas and oil, and uranium) are finite, but they are reliable: a gas or nuclear station can run day and night in any weather. The cost is carbon dioxide and pollution (fossil fuels) or radioactive waste (nuclear).
Renewable sources (solar, wind, HEP, geothermal, biomass) will not run out and give little or no carbon dioxide, but solar and wind are intermittent: no sun at night, no power on a calm day. HEP and geothermal are steadier but only work in the right places.
A balanced mix combines them: renewables cut emissions, while reliable sources such as gas or nuclear fill the gaps. If one fuel or one supplier fails, the others keep the lights on, which improves energy security.
Example: the UK has grown offshore wind and phased out coal power, while still using gas and nuclear.

Calling nuclear renewable: uranium is finite, so nuclear is non-renewable even though it has very low carbon emissions.
Saying renewables have no disadvantages: give one, such as intermittency, flooded valleys (HEP) or land needed for biomass.
Saying biomass gives off no CO2: burning it does release CO2; it is renewable only if crops or trees are regrown.
Only naming the source: the checklist asks for impacts on people and the environment, so say who is affected.
Defining balanced mix too simply: say 'several sources so the country does not depend on one fuel or one supplier'.

How it works: the nucleus of an atom (usually uranium) is split in nuclear fission, releasing heat that boils water into steam, which spins turbines to generate electricity.
Advantages: a very large amount of energy from a very small amount of fuel (high energy density); plants run almost continuously, giving a steady base supply when solar or wind are not available; they take up less land than solar or wind farms; once built, running costs are relatively low; and they release no carbon dioxide while operating, so many countries see nuclear as part of tackling climate change.
Disadvantages: radioactive waste stays dangerous for thousands of years and must be stored safely deep underground; building and decommissioning (safely closing) plants is extremely expensive and takes many years; accidents are rare but can be devastating, as at Chernobyl (1986) and Fukushima (2011); uranium is non-renewable; there are security concerns because nuclear materials could be misused for weapons; and public opinion is often negative because of safety fears.
The future: your reading says new Generation IV reactors aim to reduce waste, improve efficiency and make nuclear power safer.
Compare with fossil fuels: both use a finite fuel to make steam that turns turbines and both are reliable; but nuclear releases no CO2 while operating, and its waste is radioactive rather than gases.

More detail from your class table: coal creates many jobs in mining; oil supports global industries; natural gas gives off fewer particulates (tiny pieces of soot) than coal or oil.
Renewables in your class mark scheme include wave power as well as solar, wind, HEP and biomass; a non-renewable answer of LNG (liquefied natural gas, natural gas cooled into a liquid for shipping) is also accepted.
Class challenge: how could countries reduce their dependence on fossil fuels?
1. Build more renewables (wind, solar, HEP) suited to their climate and relief.
2. Use nuclear for a steady low-carbon base supply.
3. Cut demand through efficiency (insulation, LED bulbs, efficient machines) and conservation.
4. Switch transport to public transport, cycling and electric vehicles.
5. Use taxes and grants to make fossil fuels more expensive and clean energy cheaper.