What accounts for the largest percent of energy output?

November 19, 2025 •

2 min read

For decades, fossil fuels have been the dominant force powering the world's energy needs, historically accounting for the largest share of global energy output. While this remains true for total primary energy, the electricity sector is experiencing an unprecedented shift towards renewables.

Quick Summary

The world's energy output is primarily driven by fossil fuels, though the electricity landscape is rapidly changing. This article explains the composition of the global energy mix and the rise of clean energy.

Key Points

Fossil Fuels Remain Largest Source: Despite significant growth in clean energy, fossil fuels like coal, oil, and natural gas still account for the largest share of total primary global energy output.
Renewables' Unprecedented Growth: Solar and wind are the fastest-growing sources of electricity, with clean power (renewables and nuclear) surpassing 40% of global electricity generation in 2024.
Coal is the Single Largest Fuel (Historically): In 2024, coal was still the world's largest individual source of energy generation, though its dominance is waning and was surpassed by renewables in electricity generation in H1 2025.
Shift Led by Developing Nations: Countries like China and India are leading the charge in clean energy adoption, adding significant new solar and wind capacity.
Electrification is Key: Electrification of transport, residential heating, and industry is crucial for reducing emissions and will drive future electricity demand.
Economic and Environmental Drivers: Declining costs for renewable technology, coupled with increasing climate change concerns, are accelerating the energy transition globally.

The Enduring Dominance of Fossil Fuels

For generations, fossil fuels have been the backbone of the global energy system. Fossil fuels—specifically coal, oil, and natural gas—continue to account for the largest percentage of total primary energy output worldwide. This dominance stems from long-established infrastructure and their historical abundance.

Coal: A Historical Titan

Coal has been a cornerstone of industrial energy for centuries and remained the single largest individual source of energy generation globally in 2024. However, coal's share is declining in many regions due to its high carbon emissions.

Natural Gas and Petroleum: Powering Modern Life

Natural gas and petroleum are major contributors to global energy. Petroleum is essential for transportation, while natural gas is a significant source of electricity and heat. Existing infrastructure supports their continued role in the energy mix.

The Rise of Renewable Energy

While fossil fuels lead in total primary energy, the electricity sector shows a dramatic shift. Clean energy sources exceeded 40% of global electricity generation in 2024. This growth is fueled by rapid expansion in solar and wind power.

Solar and Wind: The Fastest Growing Sources

Solar and wind power are driving the energy transition. Solar generation doubled in the last three years to over 2000 TWh in 2024 and was the largest source of new electricity generation globally for the third consecutive year. Wind energy also continues strong growth, making clean energy an increasingly affordable power source.

Hydropower and Nuclear: Stable Low-Carbon Contributors

Hydropower remains the largest single source of low-carbon electricity, at 14.3% in 2024. Nuclear power also provides low-carbon electricity, contributing about 9% globally in 2024.

Emerging Renewables

Geothermal, biomass, and ocean energy also contribute to the global mix.

Comparison of Global Energy Sources

A comparison of global energy sources can be found on {Link: Ember website https://ember-energy.org/latest-insights/global-electricity-review-2025/2024-in-review/}.

Factors Driving the Energy Transition

Factors driving the energy transition are detailed on {Link: Ember website https://ember-energy.org/latest-insights/global-electricity-review-2025/2024-in-review/}.

Conclusion: An Era of Transition

While fossil fuels currently account for the largest percent of total primary energy output, the situation is evolving rapidly. The electricity sector is particularly seeing a significant shift with unprecedented growth in renewables like solar and wind. Renewables are set to play an increasingly dominant role in a cleaner, more sustainable energy future.

For more detailed analysis, refer to the Global Electricity Review 2025 by Ember.

Frequently Asked Questions

Historically and in recent years, coal has been the single largest source of electricity generation globally. However, the overall primary energy mix still relies heavily on a combination of fossil fuels, with recent data showing renewables surpassing coal specifically for electricity generation.

Renewables have recently overtaken coal as the biggest source of electricity generation. However, when considering total primary energy output, the combined share of fossil fuels (coal, oil, and natural gas) still currently represents the largest percentage globally.

Solar energy is the most abundant of all energy resources. The amount of solar energy that reaches Earth in just one hour is approximately 10,000 times greater than the rate at which humankind consumes energy annually.

The main fossil fuels used for energy are coal, natural gas, and petroleum. They are non-renewable energy sources that were formed over millions of years from the buried remains of ancient sea plants and animals.

In 2024, clean power (including renewables and nuclear) surpassed 40% of global electricity generation. While renewables are growing rapidly, their share of total primary energy output is still smaller than that of fossil fuels.

Primary energy output refers to energy from sources in their raw, unprocessed form, such as crude oil or unprocessed coal. Electricity output refers specifically to generated electrical power. For example, fossil fuels still dominate primary energy, but renewables are rapidly taking over in the electricity generation sector.

The global energy mix is shifting due to several factors, including heightened climate change concerns, the rapid decrease in renewable energy costs, and significant technological advancements in energy generation and storage.