Renewable vs Non-Renewable Energy

The world uses huge amounts of energy every day. Some of that energy comes from sources that will never run out: the Sun, wind, flowing water, the heat of Earths interior. These are called renewable sources. Other energy comes from sources we are using up much faster than they can be replaced: coal, oil and natural gas (fossil fuels) and uranium (nuclear). These are called non-renewable. The choice between them is one of the biggest issues of our time, because non-renewable fuels are the main cause of climate change.

• RenewablesWill not run outSun, wind, water, biomass
• Non-renewablesFinite supplyCoal, oil, gas, uranium
• Fossil fuels80% of world energy in 2024Main cause of climate change
• UK renewables shareAround 50% of electricityIn 2024
• World renewables shareAround 30%Of all electricity
• Cleanest renewablesSolar, wind, hydroVery low CO2 emissions

What makes an energy source renewable?

A renewable energy source is one that is constantly replenished by nature. Use as much as you like, there is always more on the way. Even if humans stopped tomorrow, these sources would keep being available.

The main renewable energy sources are:

• Solar: energy from sunlight. The Sun will keep shining for billions of years.
• Wind: caused by sunlight heating different parts of Earth differently. Wind will keep blowing as long as the Sun shines.
• Hydroelectric: from flowing water. The water cycle (evaporation, rain, rivers) is powered by sunlight, so it keeps refilling.
• Tidal and wave: from the rising and falling of the sea, powered by the Moons gravity.
• Geothermal: heat from Earths interior, mostly from radioactive decay deep underground. Effectively endless.
• Biomass: burning plant matter or biogas from waste. Renewable as long as plants grow back.

What about non-renewable?

A non-renewable source is one that we use much faster than nature can replace it. Once weve used up a deposit, we cannot just wait for more to grow back in a useful timeframe.

• Coal: formed from ancient swamps over hundreds of millions of years.
• Oil: formed from ancient marine plankton, similarly over hundreds of millions of years.
• Natural gas: mostly methane, formed alongside oil.
• Uranium: a metal mined for nuclear power, slowly formed in supernova explosions billions of years ago. Limited supplies in Earths crust.

Fact Most of the worlds coal formed during the Carboniferous period, about 360 to 300 million years ago. Back then, Earths atmosphere had less oxygen for fungi and bacteria to rot dead plants, so huge amounts of dead plant matter built up in swamps. Over millions of years, pressure and heat turned it into the coal we mine today. Once we burn that coal, it would take another 300 million years to make more.

The climate change problem

Burning fossil fuels releases carbon dioxide (CO2) into the atmosphere. CO2 is a greenhouse gas that traps heat, gradually warming the planet. Since the Industrial Revolution started around 1750, humans have raised atmospheric CO2 from about 280 to over 420 parts per million.

The result: global average temperatures have risen by about 1.2 degrees Celsius. Other effects include:

• Melting glaciers and polar ice.
• Rising sea levels.
• More intense storms, droughts, floods and heatwaves.
• Shifting wildlife habitats.
• Ocean acidification (extra CO2 dissolves in seawater).

Cutting CO2 emissions is therefore one of the biggest tasks facing the world. The main way is to switch from fossil fuels to renewable energy.

Comparing the sources

• Solar: low-CO2, falling cost, but only produces during the day. Needs storage or backup.
• Wind: low-CO2, cheap once built, but variable with weather. Big wind farms need lots of space.
• Hydroelectric: low-CO2, reliable, can store energy. But dams flood huge areas and affect wildlife.
• Tidal and wave: very predictable (tides come on schedule), but still expensive and only useful in coastal locations.
• Geothermal: works everywhere geology allows, very reliable, but only good in volcanic regions like Iceland.
• Biomass: can be carbon-neutral if managed well, but burning produces CO2 immediately. Some forms can cause deforestation.
• Nuclear: low-CO2, very reliable, but produces dangerous radioactive waste. Slow and expensive to build new ones. Non-renewable but very long-lasting fuel supply.
• Coal: very high CO2, also air pollution. The dirtiest fuel.
• Oil: high CO2, mostly used for transport (petrol, diesel).
• Natural gas: cleanest fossil fuel but still high CO2. Big methane leak risk during extraction.

Did you know? In 2024, the UK officially stopped burning coal for electricity, closing its last coal power station after 142 years. The UK is the first major industrial country to do so. Most coal-fired generation was replaced by gas and rapidly growing wind power (which now provides around 30 per cent of UK electricity).

Renewables on the rise

Costs of wind and solar have fallen dramatically over the past 15 years:

• Solar panels are about 90 per cent cheaper than in 2010.
• Wind turbines are about 70 per cent cheaper.
• Battery storage is around 80 per cent cheaper.

In many parts of the world, building new solar or wind is now cheaper than building new gas or coal stations. The global energy mix is shifting fast. The International Energy Agency expects renewables to overtake coal as the worlds biggest electricity source by 2025.

What can YOU do?

Saving energy at home helps reduce demand for fossil fuels.

• Turn off lights and devices when not in use.
• Replace old bulbs with LEDs.
• Walk, cycle or use public transport when you can.
• Eat less red meat (cattle farming produces lots of methane).
• Wear an extra jumper instead of turning the heating up.
• Recycle (saves energy compared to making things from scratch).
• If your parents are buying a new car, consider an electric one.
• If your home is being upgraded, ask about solar panels and insulation.

Try this Look at your home electricity bill or smart meter (with adult help) to see how much energy your family uses each month. Then find out where it comes from. UK electricity suppliers must publish their "fuel mix" showing the proportion from coal, gas, nuclear, renewables, and so on. Many suppliers now offer 100 per cent renewable tariffs. Could your home switch?

Deeper dive: the journey to net-zero by 2050

The UK was the first major economy to legally commit to net-zero greenhouse gas emissions by 2050. This means that, by 2050, the UK should not be adding any extra CO2 to the atmosphere overall. Any unavoidable emissions (such as from heavy industry or farming) have to be balanced by absorbing equal amounts elsewhere (planting trees, capturing CO2 from chimneys, ocean removal).

Net-zero is a huge challenge. To get there, the UK needs to:

• Decarbonise electricity: switch entirely to renewables, nuclear and low-carbon sources by around 2035.
• Electrify transport: replace petrol and diesel cars with electric vehicles. New petrol/diesel car sales stop in 2030 (or 2035 for hybrids).
• Electrify heating: replace gas boilers with heat pumps and hydrogen-ready boilers.
• Improve home insulation: make homes need less energy to heat.
• Decarbonise industry: switch steel, cement and chemicals to lower-carbon processes (often using hydrogen instead of gas).
• Restore nature: plant more trees, restore peatland, capture CO2 in the soil.
• Carbon capture: collect CO2 from chimneys and pump it underground into old oil wells.

Other countries have similar targets. The EU aims for net-zero by 2050. China by 2060. The USA by 2050. Whether all these targets are met depends on policy choices, technology breakthroughs and public support.

The good news is that progress has been faster than expected in some areas. Renewable electricity has overtaken fossil fuels in some countries. Electric car sales have boomed. Some new technologies (like green hydrogen) are advancing rapidly. The next 25 years will probably see one of the biggest transitions in human history.

For more, see electrical energy and conservation of energy.