The Energy Transition

In short: Producing energy is the largest single cause of greenhouse gas emissions. Clean sources each have trade-offs: solar and wind are now among the cheapest electricity in most of the world but come and go with the weather; hydropower is steady but has limits; nuclear is low-carbon and steady but slow and expensive to build. In 2024, low-carbon sources produced just over 40% of the world’s electricity, with solar growing fastest. The switch is well under way, but electricity is only part of energy use, and fossil fuels still dominate transport, heating and industry.

The Question

Climate Change shows that burning coal, oil and gas is the main cause of global warming. This article asks: what can replace them, and how fast is the switch happening?

Why Energy Decisions Matter

Energy use causes about three quarters of greenhouse gas emissions. Switching to clean energy is therefore central to tackling climate change. It also means cleaner air, less dependence on imported fuel, and, more and more, lower costs.

The Main Clean Sources

Solar. Panels turn sunlight straight into electricity. The cost of large solar plants fell by about 90% between 2010 and 2023, making solar one of the cheapest sources of new electricity in most of the world.

• Strengths: no emissions while running, falling cost, works from a single roof to huge plants, long life.
• Challenges: produces only when the sun shines, so it needs storage or backup; large plants take up land.

Wind. Turbines turn moving air into electricity. Wind on land is among the cheapest electricity there is; wind at sea costs more but blows stronger and more steadily.

• Strengths: no emissions while running, competitive cost, long life.
• Challenges: comes and goes, visual and noise impact, care needed for birds and bats.

Hydropower. Electricity from moving water, and still the largest source of low-carbon electricity in the world.

• Strengths: reliable, can be turned up or down, helps keep the grid stable.
• Challenges: large dams have serious effects on rivers, nature and nearby communities; in many regions the best sites are already used.

Nuclear. Electricity from splitting atoms, with very low emissions over its whole life and steady output.

• Strengths: very low emissions, uses little land, runs day and night.
• Challenges: high building costs, long construction times, managing the waste, and public trust.

No source is perfect, which is why most plans combine several, with batteries and other storage, stronger grids linking regions, and using energy more flexibly.

How Far the Switch Has Come

• In 2024, low-carbon sources produced 40.9% of the world’s electricity: hydro 14.3%, nuclear 9.0%, wind 8.1%, solar 6.9%, and other renewables the rest.
• Solar was the fastest-growing source for the third year in a row, and wind and solar together now produce more than hydropower.
• But demand also grew, partly because of heatwaves and air conditioning, so emissions from electricity still reached a record high.
• Electricity is only about a fifth of the energy the world uses. Transport, heating and industry still run mostly on fossil fuels, which is why electric cars, heat pumps and clean industrial heat matter as much as clean power plants.

What You Can Do

As an individual:

• choose a renewable electricity contract where one is available;
• consider solar panels if you own your home;
• use less energy: insulation, efficient appliances, small habits;
• choose an electric car, public transport or cycling over petrol and diesel where possible.

As an organisation:

• measure where your energy goes and find the biggest uses;
• set targets for buying renewable power, or produce it on site;
• cut waste through efficiency, often the cheapest energy source of all;
• report progress openly.

Examples

• China: installed more solar capacity in 2023 alone than the United States has in its whole history, driving down the price of panels worldwide.
• Denmark: gets more than half of its electricity from wind, and the Danish grid stays stable by trading power with its neighbours.

The Human Side

Energy can feel abstract until the bill arrives. The 2022 price shock showed how much people’s sense of security depends on affordable heat and power. A fair transition means helping households insulate homes and switch heating, so that the people with the least are not left paying the most. See Mastering finance basics in the Personal Guide.

Open Questions

• What role should nuclear power play alongside renewables?
• Who should pay for new grids and storage: consumers, taxpayers or energy companies?
• How can poorer countries get clean energy fast enough without paying more than rich countries did for fossil fuels?

Where Next

• Previous: Climate Change
• Next: Managing Regional Migration
• Related: Nature and Water, From Inherited Wealth to a Fair Start, on returning fossil-fuel taxes to people

Sources

• Ember, Global Electricity Review 2025
• IRENA, Renewable Power Generation Costs in 2023 (2024)
• IEA, World Energy Outlook 2024
• IPCC, Sixth Assessment Report, Working Group III (2022), on emissions by sector
• Danish Energy Agency, annual energy statistics
• China National Energy Administration, 2023 national power industry statistics, and Carbon Brief analysis (2024)