This blog is updated from one written on August 9, 2022.

“There is only one thing in the world worse than being talked about, and that is not being talked about” said Oscar Wilde.  We should therefore take it as a compliment that so many people talk incorrectly about hydropower. It shows that we are relevant. Eddie Rich, CEO of the International Hydropower Association, writes about the most common misconceptions and myths about hydropower that the organisation deals with daily.

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‍Myth 1: Renewable energy is all about wind and solar.

Reality: Hydropower, as the "forgotten giant of renewables", is the world's largest source of low-carbon electricity.

In 2023, hydropower generated around 14% of the world’s electricity (~4,185TWh) – about the same as all other renewables combined. Recent growth, which has been overwhelmingly led by China, who has added around 100GW installed capacity in the last decade.  

See the 2024 World Hydropower Outlook for the full picture on hydropower development worldwide.

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Myth 2: Wind and solar can power the planet alone.

Reality: Variable renewables like wind and solar need a reliable backup and storage.

Wind and solar are growing faster than hydropower. It is beyond doubt that both technologies are crucial to making progress on climate change. But what happens when the wind doesn’t blow, and the sun doesn’t shine?

Do we fall back on fossil fuels? Do we face blackouts? Or do we look towards reliable, dispatchable, firm energy in the form of hydropower?

For this reason, both IEA and IRENA say we will need to double hydropower capacity in the next 30 years to stay on track with net zero pathways. Hydropower’s role will increasingly shift to enhancing system flexibility and supporting variable wind and solar.

In other words, hydropower is ready to fill the hole left by coal.

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Myth 3: All the available hydropower has already been built.

Reality: Potential hydropower capacity exists in abundance in all regions of the world.

Academic studies indicate there is more than enough global potential to achieve 1,200 GW more hydropower by 2050, even allowing for economic, social and environmental constraints. Tapping into this will be key to unlocking our net zero ambitions.

IHA's Hydropower 2050 report reviewed potential capacity in all regions. It found large potential in areas where hydropower is relatively underdeveloped; for example, 90% of Africa’s hydropower capacity is untapped. And these figures do not include pumped storage, where there is almost potential for additional expansion.

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Myth 4: We need new technology to deliver net zero.

Reality: We have the technology; we are just not deploying it.

When addressing climate change, there is often lazy talk about needing new technologies and future innovations to achieve net zero.  

Don’t believe a word of it. While innovation should always be encouraged, our net zero ambitions do not rely upon it. We already have the tools we need, variable renewable energy in the form of wind and solar, supported by storage – batteries, pumped storage hydropower (PSH) and green hydrogen – can lead us to a zero-emission energy world.

Pumped storage, as the “world’s water battery”, is the perfect natural complement to wind and solar. It already accounts for over 90% long duration storage capacity and stored energy in grid scale applications globally.

New technologies, and refinements to existing ones, will of course emerge – whether it is bigger and better batteries and electrolysers, smarter turbines, or the creation of virtual power plants to name just a few.

But right now, the single most important priority should be the planning and construction of long duration electricity storage (LDES) in the form of pumped hydro.

By using excess wind and solar at zero or low cost to pump water to an upper reservoir and dropping it down through turbines when there is a shortage of wind and solar, pumped storage is a brilliant example of renewables working together. PSH has grown by 6.5GW in 2023 to 179GW overall.

Batteries will be important, but they currently amount to just 7-8 GWh. 40 countries have PSH capacity, but China, Japan and the United States alone are home to over 50% of the world’s installed capacity.

We can do more. A study by Australia National University has identified over 600,000 potential off-river PSH sites globally. That’s 23,000 TWh of potential storage. Without these tools, the energy transition risks stalling when it should be accelerating.

For more insights on PSH, visit the International Forum on Pumped Storage Hydropower (IFPSH)  

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Myth 5: Old hydropower plants need decommissioning and removal.

Reality: Hydropower is a forever resource.

There is over 600 GW of aging hydropower around the globe. While a few plants should be decommissioned and/or removed, the vast majority can be modernised.

IHA has undertaken studies on the potential for modernisation in Africa, Asia and Latin America.

Upgrading our existing fleet is a massive opportunity for low-impact green electricity, showing we do not need new technology to make progress towards our net zero targets.

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‍Myth 6: All dams are hydroelectric.

Reality: Less than one in five reservoirs worldwide are powered.

Most of the world’s hydroelectric dams provide a range of multi-purpose services, such as flood and drought control, irrigation and water supply.

Conversely, 80% of unpowered dams around the world represent a significant potential for retrofitting.

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Myth 7: Hydropower is unsustainable.

Reality: Demonstrable sustainability is not just possible; it is an expectation of the sector.

IHA members – who represent one third of the world’s installed hydropower capacity – adhere to, and monitored against, the San José Declaration on Sustainable Hydropower which says that “Going forward, the only acceptable hydropower is sustainable hydropower.”

New projects are to be independently certified by the multi-stakeholder designed and governed Hydropower Sustainability Standard, which is the first standard of its kind in the renewables sector. The Standard is managed by the independent Hydropower Sustainability Alliance of governments, companies, civil society and banks. In this way, projects should enable healthy ecosystems, prosperous communities, resilient infrastructure and good governance.

The Standard is aligned with the World Bank and IFC Sustainability Frameworks, with Renewable Energy Certificates, and with the Climate Bonds Initiative requirements for green bonds.

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Myth 8: Drought will render hydropower unusable.

Reality: To mitigate against drought and floods we need more hydropower, not less.

Isn’t it funny how we only notice hydropower's massive role in providing green electricity when we don't have it? With volatile weather conditions becoming more frequent, water management and multi-purpose reservoirs will be more important than ever in the future. Countries like Spain are only able to cope with drought today because of massive investments in water infrastructure in the 1970s.

Hydropower is the answer. While coal and nuclear use up vast volumes of water, hydropower can use the same drop repeatedly.  

In fact, hydropower is among the best ways to mitigate droughts. IHA estimates that through the water storage function of its reservoirs, the hydropower industry prevents over US$130bn in annual GDP losses from drought incidents.  

The IHA Climate Resilience Guide provides a blueprint for hydropower operators to withstand the growing volatility in weather patterns.

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‍Myth 9: Hydropower is expensive.

Reality: Hydropower is, over its full life cycle, the second cheapest form of renewable energy.

The IRENA'S 2022 Renewable Power Generation Costs Report states that in 2022, 96% of the newly deployed capacity of hydropower projects had a levelized cost of electricity (LCOE) lower than the weighted average cost of newly commissioned fossil fuel-fired capacity in the respective country or region.

IPCC reported that for a lifetime of 40–80 years for a hydropower project, the costs for operation and maintenance were found to be 2–2.5% of the investment costs per kW yr-1.

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‍Myth 10: Hydropower causes excessive greenhouse gas emissions.

Reality: Only wind and nuclear power have lower median lifecycle greenhouse gas emissions than hydropower.

Independent research suggests that use of hydropower instead of fossil fuels for electricity generation has helped to avoid more than 100 billion tonnes of carbon dioxide in the past 50 years alone. That’s roughly equivalent to the total annual carbon footprint of the United States for 20 years.

Nonetheless, all energy sources, even renewables, produce carbon emissions in their lifecycle, due to the emissions caused by their manufacture, construction or operation. The IPCC report noted that only wind and nuclear power have lower median lifecycle greenhouse gas emissions than hydropower. It states that hydropower has a median greenhouse gas (GHG) emission intensity of 24 gCO₂-eq/kWh. By comparison, the median figure for gas is 490 gCO₂-eq/kWh.

The G-res Tool, the reservoir emissions calculator, can help hydropower developers and operators to measure their emissions.

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‍Myth 11: Hydropower is yesterday’s technology.

Reality: Hydropower technology has been developing at fast pace.

Hydropower may be the oldest of the renewable technologies, but it is also one that is evolving swiftly with the times and delivering important climate innovations.

The changing energy mix places increased demands on hydropower to provide flexible, reliable power services in order to adapt to supply and demand. New advancements in hydropower technology are helping to integrate variable renewables such as wind and solar power and batteries into the energy system.

XFLEX HYDRO is an ambitious €18m energy innovation project demonstrating how more flexible hydropower assets can help countries and regions to meet their renewable energy targets.  

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Myth 12: The market will deliver for hydropower.

Reality: The future of the sustainable hydropower sector is a matter of political will and choice.

Markets do not naturally reward electricity beyond generation. Hydropower does not get compensated for its wider system and other roles, such as flexibility, reliability, storage, floods and drought control, water supply and irrigation. Energy markets need to be adapted to reflect this, especially to allow pumped storage to become mainstream in the market.

Furthermore, proportionate, streamlined license/permit processes are needed to rapidly scale up hydropower to deliver on net zero.

Governments must also act to enable investment into maximising their existing infrastructure through modernisation, the retrofitting of non-powered dams, and the integration of floating solar panels into hydropower reservoirs.

And all parties – governments, financiers, operators and NGOs – should advocate for widespread adoption of the Hydropower Sustainability Standard.

The San José Declaration says that “sustainable hydropower is a clean, green, modern and affordable solution to climate change”. I believe that we can make net zero a reality #WithHydropower.

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