Renewables have been getting cheaper for twenty years, and yet the world still gets around four fifths of its energy from fossil fuels. That is not because nobody noticed. It is because energy choices are made under real constraints — cost, geography, politics and industries that electricity simply cannot run yet.
📘 What you need to know
Energy consumption is the total energy used by individuals, industries and countries.
Global consumption keeps rising because of population growth and rising per capita demand.
In 2022 about 80% of the world’s energy came from fossil fuels, with renewables at about 12.7%.
Energy use changes for two main reasons: economic development and environmental concerns.
Some industries are hard to run on renewables — especially steel, concrete and synthetic fertilisers.
Demand can be met by adding renewables and storage, or reduced through efficiency and behaviour change.
Energy choices are decided by economic cost, pollution, energy efficiency, availability and energy security.
Availability is what a country has; energy security is whether it can reliably meet demand. They are not the same.
Why demand keeps climbing
Global energy consumption rises for two reasons at once, and they multiply rather than add.
The demand equation
total demand = number of people × energy used per person
Population growth. More people need electricity, transport, heating and cooling.
Per capita demand. Each person uses more than they used to, particularly in developing countries where industrialisation is under way and living standards are improving.
Because both terms grow together, total demand climbs faster than either one alone. A country whose population grows by a quarter while energy use per person doubles ends up needing two and a half times as much energy, not one and a quarter times.
Do not treat rising per capita demand as a moral failing. It usually means fridges, hospitals, streetlights and school computers arriving in places that did not have them. The challenge in ESS is to meet that demand while managing the environmental and economic costs — not to wish the demand away.
What the world actually runs on
Renewable output is rising quickly, but it is still a thin slice. Growth in demand can swallow new renewable capacity before it replaces any coal.
Fossil fuels — coal, oil and natural gas — continue to supply the majority of the world’s energy. Renewables such as wind, solar and hydro are growing but still provide a much smaller share.
A trap worth avoiding. “Renewable use is rising” and “fossil fuel use is falling” are different claims. If total demand grows faster than renewable capacity is added, both can rise at the same time. Read data questions carefully: check whether the axis shows a share or an absolute amount.
Why the mix is changing
Driver
What happens
Example
Economic development
As countries get wealthier they use more energy for industrial processes, transport and technology
India’s consumption is rising quickly as its manufacturing sector and infrastructure grow
Environmental concerns
Worry about climate change pushes governments towards cleaner sources, with targets to cut carbon emissions and invest in renewables
The European Union is aiming for carbon neutrality by 2050, which needs a huge cut in fossil fuel use
The industries renewables cannot easily reach
Fossil fuels are not only burned for electricity. Some industries depend on them in ways that a wind farm cannot replace, and this is the part of the topic examiners most want you to understand.
When a question asks whether renewables can replace fossil fuels, the honest answer is “for most things, yes — for these, not yet”.
Steel and concrete. Both rely heavily on coal and natural gas, and renewable electricity is not yet suitable for these very high-energy processes. China is the world’s largest steel producer, and its steel industry accounts for a significant share of global coal consumption.
Synthetic fertilisers.Natural gas is essential for producing ammonia, the key ingredient in the fertilisers that support global agriculture. As food demand grows, so does the need for ammonia, and therefore for natural gas.
Meeting the demand, and reducing it
There are two directions of attack, and a sensible national plan uses both.
Approach
What it involves
Example
More renewable supply
Investing in renewable generation to meet rising demand while cutting reliance on fossil fuels
Expanding wind and solar capacity on the national grid
Energy storage
Storing surplus energy so that intermittent sources can supply power when they are not generating
Large battery systems in Australia store surplus solar for use at night or on low-wind days
Energy efficiency
Better appliances, vehicles and buildings, so the same task uses less energy
Stricter UK building regulations require more energy-efficient homes
Behavioural change
Encouraging individuals and industries to use less energy in the first place
Using less heating, driving less, switching things off
🧩
Efficiency versus reduction
Efficiency = the same task, less energy (an LED bulb lighting the same room). Reducing consumption = doing the task less often or at a lower level (turning the light off). Examiners treat these as different concepts, so never use the words as if they mean the same thing.
What decides a country’s energy choices
Energy choices are the decisions a country makes about how it generates and uses energy. Five factors do most of the deciding, and each pulls fossil fuels and renewables in different directions.
Factor
Fossil fuels
Renewables
Economic cost
Often cheaper to build at first, but carry high environmental and long-term costs
Higher upfront cost, then long-term savings; solar is now cost-competitive in many countries
Pollution
Emit large amounts of greenhouse gases and contribute to air pollution
Little or no pollution during operation
Energy efficiency
Often less efficient, with energy wasted as heat during burning
Can be efficient, but some depend on weather conditions
Availability
Countries with large reserves of coal, oil or gas tend to use them
Depend on geography — sunlight, wind or flowing water
Energy security
Importing oil or gas exposes a country to price swings and geopolitical risk
Usually produced locally, so less exposed to international market shocks
Availability is not security. Availability means the resource is physically present in the country. Energy security means being able to meet demand reliably, without depending too heavily on foreign supply. A country can sit on enormous reserves and still be insecure if it lacks the funding, the infrastructure or a stable supply chain to use them.
Worked examples
WE 1
Explain why global energy consumption continues to rise
Explain two reasons why global energy consumption continues to increase. (3 marks)
Reason 1: more people
Population growth means more people needing electricity, transport, heating and cooling.
Reason 2: more eachPer capita demand is rising, especially in developing countries where industrialisation and living standards are increasing.
Putting them together
Total demand is population multiplied by use per person, so the two effects compound rather than simply add.
More people, each using more — demand climbs steeplythe compounding point is what lifts this from a 2-mark answer to a 3-mark one
WE 2
Discuss whether renewables can replace fossil fuels entirely
Discuss the claim that renewable energy could completely replace fossil fuels. (4 marks)
Support: electricity
For lighting, appliances, heating and most transport, renewable electricity can do the same job with far less pollution, and costs are falling.
Support: security
Locally produced renewable energy also reduces exposure to fluctuating import prices and geopolitical risk.
Against: heat and chemistrySteel and concrete production needs coal and natural gas for very high-energy processes that renewables cannot yet supply.
Against: raw materials
Natural gas is the raw ingredient for ammonia, so synthetic fertiliser, and therefore global food supply, still depends on it.
Mostly, but not entirely — some industries have no substitute yetnaming steel, concrete and fertiliser is exactly what the examiner is looking for here
WE 3
Outline the factors influencing a country’s energy choices
Outline three factors that influence the energy sources a country chooses to use. (3 marks)
Factor 1: economic cost
The cost of building and maintaining the infrastructure; fossil fuels are often cheaper initially, renewables cheaper over time.
Factor 2: availability
What the country physically has — large coal reserves, or strong wind, sunlight and rivers.
Factor 3: energy security
Whether demand can be met reliably without depending too much on foreign supply, which is exposed to price swings and political disputes.
Cost, what is there, and how reliably it can be suppliedpollution and efficiency are the other two — pick whichever three fit the country in the question
💡 Exam tips
Quote the scale of the problem: roughly 80% fossil fuels, 12.7% renewables in 2022.
Give both drivers of rising demand: population growth and per capita demand.
Never claim renewables can replace fossil fuels everywhere — name steel, concrete and fertiliser.
Keep efficiency (same task, less energy) separate from reducing consumption (doing less).
Keep availability (what you have) separate from energy security (what you can rely on).
Learn the five choice factors: cost, pollution, efficiency, availability, security.
⚠ Common mix-ups
Assuming a rising renewable share means falling fossil fuel use. Growing demand can hide it.
Using efficiency and conservation interchangeably. One is technology, the other is behaviour.
Confusing availability with security. Having a resource is not the same as reliably supplying it.
Forgetting fossil fuels are raw materials too. Ammonia comes from natural gas, not from a power station.
Blaming rising demand on waste alone. Much of it is development and improving living standards.
Giving one-sided answers to “discuss”. You need arguments on both sides plus a conclusion.
Up next: Storing and Saving Energy. If the sun sets at six and everyone cooks dinner at seven, someone has to bridge that gap. The last page looks at how energy is stored, and at the cheapest energy of all — the energy you never use.
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