You are here

Facts about hydropower


Renewable hydropower is a clean, reliable, versatile and low-cost source of electricity generation and water management.

In a world in which a billion people still do not have access to electricity and two billion are without safely managed water, demand for hydropower is on the increase.

Hydropower plants are helping to decarbonise the global economy by aiding the adoption of complementary renewables and reducing dependence on fossil fuels which emit greenhouse gas emissions and pollutants.

Types of hydropower 

There are four broad types of hydropower plants:

  • Run-of-river hydropower: a facility that channels flowing water from a river through a canal or penstock to spin a turbine. 
  • Storage hydropower: typically a large system that uses a dam to store water in a reservoir. 
  • Pumped-storage hydropower: provides peak-load supply, harnessing water which is cycled between a lower and upper reservoir. Learn more.
  • Offshore hydropower: a less established but growing group of technologies that generate electricity from seawater. 

Safely managed water 

Hydropower infrastructure and reservoirs can meet our basic needs for water management, providing clean water for homes, industry and agriculture, as well as transportation and recreation services.

In addition, hydropower projects can mitigate the devastating impacts of extreme weather events such as floods and drought, which are on the rise due to climate change. Learn more.

Low-carbon and pollution-free

Hydropower is among the cleanest sources of electricity, with an estimated median greenhouse gas emission intensity of 18.5 gCO2-eq/kWh. Learn more.

If hydropower was replaced by coal, up to 4 billion tonnes of additional greenhouse gases would be emitted annually, increasing global emissions from fossil fuels and industry by 10 per cent each year. There would also be an additional 150 million tonnes of air polluting particulates emitted annually. Learn more.

Charging up variable renewables

No country has come close to achieving 100% renewable electricity without hydropower in the energy mix.

Thanks to its flexibility in dispatch and energy storage, hydropower is helping to accelerate the clean energy transition by working in concert with variable renewables like wind and solar.

Hydropower can meet demand when intermittment renewable sources are unavailable. Pumped storage hydropower, operating like a rechargable battery, absorbs energy from variable renewables when supply exceeds demand.

Low-cost over the long-term

Hydropower provides very low-cost electricity over its long lifetime, despite relatively high upfront construction costs.

The global weighted average cost of electricity from hydropower projects in 2018 was US$0.047 per kWh, making it the lowest-cost source of electricity in many markets (IRENA 2019).

In addition, hydropower provides an opportunity to generate significant revenue from exports to neighbouring countries.

The hydropower industry directly employs more than 2 million people worldwide, and many more in connected supply chains (IRENA 2019)

Sustainability in hydropower

Hydropower projects of all sizes can result in net-benefits to communities and the environment, provided they have a strategic fit in a river basin and are responsibly developed and operated.

Internationally recognised Hydropower Sustainability Tools exist to ensure that hydropower projects can be developed and operated in accordance with good practice.  Learn more.

The sustainability tools were developed by a multi-stakeholder group of civil society, industry, governments and financial institutions, and are aligned with safeguards and frameworks developed by the World Bank and other organisations.

The International Hydropower Association (IHA) is committed to advancing sustainable hydropower. Learn more about IHA.