Clean energy can help to ease the water crisis

Energy is thirsty

The world has a water problem – and the energy sector needs to contend with it. About a quarter of the global population does not have access to safe drinking water and almost half lack proper sanitation services. Nearly two-thirds of the world’s population experiences severe water scarcity for at least one month each year, and climate change will make water flows more erratic.

At the same time, the global energy system used around 370 billion cubic metres (bcm) of freshwater in 2021, or roughly 10% of total global freshwater withdrawals. Water is essential for almost every aspect of energy supply, from electricity generation to fossil fuel production to biofuels cultivation.

World Water Day is an annual event aimed at bringing attention to sustainable water management and this year’s theme is “accelerating change”. This commentary explores how an acceleration in clean energy development can help ease the world’s water crisis. The choices we make for future energy pathways will have a major impact on our ability to achieve Sustainable Development Goals, including access to clean water and sanitation for all.

In the Stated Policies Scenario (STEPS) – our most conservative scenario which only takes into account energy transition measures that have been implemented or are under development – energy’s thirst for water continues to rise and reaches nearly 400 bcm by 2030. This is mostly driven by a growth in withdrawals for cooling nuclear power plants and to irrigate bioenergy feedstocks. Some of this increase is offset by the shift from fossil fuels to solar PV and wind in the power sector.

Energy uses less water in a net zero emissions pathway

In the Net Zero Emissions by 2050 Scenario (NZE) – our most ambitious scenario – water withdrawals by the energy sector decline by almost 20 bcm by 2030. The biggest reductions happen in the power sector, where withdrawals fall nearly 15% as coal-fired power generation is quickly replaced by solar PV and wind. Greater energy efficiency also plays an important role in reducing the volume of water needed to meet global energy demand.

Different pathways towards a low-emissions future have different implications for water use. Some low-emissions technologies such as biofuels, concentrated solar power, carbon capture or nuclear have high water requirements. Without efforts to reduce water use in these technologies as well as in fossil energy supply, a pathway to lower emissions could exacerbate water stress or be limited by it.

In the NZE Scenario, water consumption (a subset of withdrawals, which indicates water no longer available for other uses) increases by nearly 5 bcm from 2021 to 2030. Diminishing water needs for fossil energy are more than offset by higher water use for bioenergy production. While bioenergy supply increases by around 85%, related water consumption grows a slower 70%, mostly due to increasing use of organic waste and forest and wood residues, which have lower water requirements.

Water is also an important consideration for hydrogen. We estimate that current hydrogen supply consumes around 1.5 bcm of freshwater, less than 5% of the total consumed by the energy sector. In the NZE Scenario, a rapid growth in hydrogen production doubles this to about 3 bcm by 2030 (around 5% of the total). Meanwhile, the average volume of water consumed per tonne of hydrogen made from electricity decreases by over 25% due to a growth in wind and solar PV generation. The production of electrolytic hydrogen in renewable-rich but water-stressed regions requires careful assessment, and in these places the use of desalination plants could help to limit the depletion of freshwater resources. 

Water stewardship is critical for energy security

The power sector is particularly vulnerable to growing water stress, and increasing water shortages in dry regions are a major source of concern for energy security. Hydropower generation could decline significantly in regions where water flows are likely to decrease, such as southern Europe, North Africa and the Middle East. Fluctuations in hydropower output have already exacerbated the global energy crisis: lower hydropower availability in Latin America in 2021 led to increased demand for liquified natural gas, contributing to early pressure on natural gas prices. In 2022, a very poor year for hydropower in southern Europe added to the strains on gas and electricity markets caused by Russia’s invasion of Ukraine and the related cuts to pipeline gas deliveries.

Thermal power plants often require water for cooling. France’s Chooz nuclear power plant was closed for around two months when a severe drought hit in 2020, and several other plants had to reduce output in 2022 due to lack of cooling water.

Water stress also poses risks to the transport of fuels and materials. In 2022, droughts and severe heatwaves led to low water levels in key European rivers such as the Rhine, limiting barge transport of coal, chemicals and other materials.

Water availability is an increasingly important measure for assessing the physical, economic and environmental viability of energy projects. Some energy producers are turning to alternative water sources and water recycling to help reduce freshwater constraints. There is also significant scope to lower water use by improving the efficiency of the power plant fleet and deploying more advanced cooling systems for thermal generation.

An integrated approach to energy and water management can help reduce risks on both fronts. Many of the clean technologies being deployed to provide electricity can also be used to provide access to water. Decentralised solar PV water pumps can replace more expensive diesel pumps and mini-grids can power filtration technologies, such as reverse osmosis systems, to produce clean drinking water. Also, water services can provide an “anchor load” for power generation and assist with balancing and storage. For example, irrigation can be shifted to periods of low electricity demand, while pumping to storage facilities can be reduced during demand peaks. Energy and water stewardship should go hand in hand.