Hydropower is a well-established renewable energy source that reduces carbon emissions worldwide. This technology delivers electricity with a remarkably low carbon footprint and supports the shift away from fossil fuel dependence. The ability of hydropower plants to provide stable, clean power day and night makes them essential for modern power grids. In contrast to non-renewable sources, hydropower contributes to environmental sustainability and is a fundamental element in reducing greenhouse gas emissions. Its widespread use and continual innovation make it a foundational pillar of the global movement toward cleaner energy.
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Hydropower’s Role in the Energy Landscape
Hydropower generates around 17% of the world’s electricity, representing the largest share of renewable power globally. The sector supplies clean energy to various economies, including China, Brazil, Canada, the United States, and emerging regions across Southeast Asia and Africa.
According to the International Hydropower Association, the displacement of fossil fuels by hydropower globally has helped avoid more than 100 billion tons of carbon emissions in the past 50 years. This immense reduction explains why hydropower is central to decarbonization pathways considered by the International Energy Agency (IEA) and Intergovernmental Panel on Climate Change (IPCC).1,2
The flexibility of hydropower plants enables them to stabilize power grids. This makes it easier to use other renewable sources such as wind and solar. Hydropower provides important services for balancing the grid and storing energy. These features make hydropower a low-carbon energy source and support the overall shift toward cleaner energy solutions.3
Southeast Asia as a Carbon-Cutting Case Study
A recent study published in Carbon Research examined five Southeast Asian countries—Vietnam, Malaysia, Indonesia, Thailand, and the Philippines. It analyzed how hydropower has affected carbon emissions over the past two decades.
The research found that increasing hydropower use leads to long-term reductions in CO2 emissions. On the other hand, reliance on fossil fuels, growing agriculture, and rising economic activity are linked to higher emissions. This suggests that expanding hydropower within a proper policy framework can effectively lower carbon emissions, while depending heavily on fossil fuels and uncontrolled industrial growth can worsen environmental issues.4
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The study’s diagnostic tests reinforce the robustness of these results and offer clear policy recommendations for Southeast Asia. It advocates for better integration of hydropower projects, gradually reducing fossil fuel subsidies, investment in clean energy infrastructure, and consistent policies across sectors. The research further identifies capital formation and labor productivity when channeled into the renewable energy sector, as additional levers for sustained emission mitigation.4
Perspectives from Other Global Regions
Confirmation of hydropower’s carbon-reduction potential does not end in Southeast Asia.
A study from Oak Ridge National Laboratory for the U.S. Department of Energy examined the carbon released from hydropower reservoirs. It was found that only a small portion of methane emissions from these reservoirs contribute to overall greenhouse gas increases, compared to what would naturally occur. In certain conditions, hydropower dams can act as carbon sinks, capturing more carbon than they emit. This characteristic makes hydropower a suitable energy and climate solution in various locations.3
A meta-analysis of hydropower's lifecycle carbon emissions indicates that its median emissions intensity is about 23-24 gCO2-eq/kWh, similar to wind and only slightly more than nuclear energy, while being much lower than coal and natural gas, which emit around 490 gCO2-eq/kWh.
Another study published in Renewable Energy found that hydroelectric plants in Turkey reduce greenhouse gas emissions by about 96.2% compared to natural gas, and even more than coal. In China, the scale of hydropower projects shows that larger and longer-lasting installations have a smaller carbon footprint per unit of electricity produced.5-7
Strengths Beyond Carbon Emissions
Hydropower not only curbs carbon but also increases energy reliability. It can quickly adjust to changes in demand, making it valuable as energy grids rely more on wind and solar power.
While hydropower generally maintains stable energy production throughout the seasons, changing rainfall patterns or droughts can impact its output. Moreover, hydropower operates more efficiently than other renewable sources, with a capacity factor exceeding 40%, far above wind or solar, further emphasizing its carbon-saving potential.1,3
Concerns and Nuances
Hydropower provides substantial advantages, but it also has drawbacks that need to be considered. Large projects, particularly those involving big dams, can harm ecosystems and change river patterns. This disruption can affect fish migration and local habitats. Therefore, conducting thorough environmental assessments and developing strategies to reduce these impacts is important. Solutions may include building fish ladders, restoring ecosystems, or using run-of-river designs that limit flooding and preserve habitats.1,8
Another concern is the carbon footprint associated with some hydropower projects. If large areas of forest or organic soil are flooded, especially in tropical regions, methane emissions may increase due to faster decomposition. Small and medium-sized projects might seem beneficial for local energy needs, but they often have higher emissions per unit because of shorter operational lifetimes and less efficient use of resources.3,5,7
Hydropower’s climate resilience presents another challenge: pronounced changes in rainfall and runoff patterns render some installations less predictable.
A recent global review warns of the vulnerability of hydropower assets to climate variability. It highlights the need to integrate climate risk into planning and expansion in regions like Africa, Latin America, and parts of Asia. To address these challenges, planning should include climate risk management, adapting reservoir levels, coordinating with other energy sources, and investing in efficient turbine technologies.9
The Path Forward
Global research shows that decision-makers have similar priorities. Hydropower remains crucial where deep carbon reduction is a principal policy driver, and grid reliability must be preserved.
To maximize its benefits, policymakers should focus on long-lasting projects in suitable areas, plan at a basin level to protect local ecosystems, and regularly update methods for measuring emissions.3-5
Investing in research and technology can further address hydropower’s limitations. New ways to measure greenhouse gas emissions, improved environmental assessment tools, and better integration with wind and solar energy can enhance climate and ecological results. Initiatives like the International Hydropower Association promote sharing effective practices and setting standards for environmental protection.2
Conclusion
Hydropower’s cumulative global impact positions it at the center of carbon-reduction strategies. Its scalable, renewable, and dispatchable nature makes it the backbone of efforts to cut emissions in industrialized and developing economies.
Recent research and studies cement these conclusions with rigorous econometric evidence and outline a model for others to follow. While the ecological and climate impacts of hydropower need to be assessed on a case-by-case basis, global experience highlights its essential status as a “key carbon-cutter.”
References and Further Reading
- Lai, O. (2023). Examining the Pros and Cons of Hydroelectric Energy. earth.org. https://earth.org/pros-and-cons-of-hydroelectric-energy/
- Hydropower's carbon footprint. International Hydropower Association. https://www.hydropower.org/factsheets/greenhouse-gas-emissions
- Tracking the Carbon Footprint of Hydropower. US DOE. https://www.energy.gov/eere/water/tracking-carbon-footprint-hydropower
- Idroes, G.M. et al. (2025). Investigating hydropower energy consumption's effect on Southeast Asia's path to achieving environmental sustainability and carbon neutrality. Carbon Research. 4, 57. DOI:10.1007/s44246-025-00218-4. https://link.springer.com/article/10.1007/s44246-025-00218-4
- Carbon emissions from hydropower reservoirs: facts and myths. (2021). International Hydropower Association. https://www.hydropower.org/blog/carbon-emissions-from-hydropower-reservoirs-facts-and-myths
- Bayazit, Y. (2021). The effect of hydroelectric power plants on the carbon emission: An example of Gokcekaya dam, Turkey. Renewable Energy, 170, 181-187. DOI:10.1016/j.renene.2021.01.130. https://www.sciencedirect.com/science/article/abs/pii/S0960148121001439
- Tang, C. et al. (2024). Study on carbon emissions of a small hydropower plant in Southwest China. Frontiers in Environmental Science, 12, 1462571. DOI:10.3389/fenvs.2024.1462571. https://www.frontiersin.org/journals/environmental-science/articles/10.3389/fenvs.2024.1462571/full
- Silva, S. N., & Castillo, J. Á. d. (2021). An Approach of the Hydropower: Advantages and Impacts. A Review. Journal of Energy Research and Reviews, 10–20. DOI:10.9734/jenrr/2021/v8i130201. https://journaljenrr.com/index.php/JENRR/article/view/134
- Travers, J. (2022). Global Review Assesses Hydropower’s Vulnerability to Climate Change. Columbia Climate School. https://news.climate.columbia.edu/2022/07/28/global-review-assesses-hydropowers-vulnerability-to-climate-change/
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