The Colorado River Basin has recently been wracked by an extended drought, which brought to the fore major concerns regarding hydroelectricity production. The iconic Hoover Dam sits on the Colorado, which transforms water into enough electricity to power 1.3 million people in Nevada, Arizona and California. Although an agreement was reached by the three dependent Western states to cut water use, it served as a reminder of how energy production is dependent on water — a dependency that is being subjected to greater uncertainties because of climate change. 

This phenomenon is not only impacting citizens dependent on the Colorado River but stretches across the United States and the world. Over the past two years, Europe, China, Brazil, Iraq and the Horn of Africa have experienced the worst droughts in (sometimes hundreds of) years.

Importantly, the water-to-energy relationship also runs the other way: Water production and delivery are themselves dependent on energy. Moreover, the need for water services for energy is likely to increase, driven by growing populations, rising prosperity (notably in developing countries) and novel uses of energy for water in desalination plants and elsewhere.  

As we feel the impact of increasingly intense heat waves and droughts, the time has come to revisit the challenges of the water-energy nexus.

The dependence of energy production on water has long been recognized by energy experts but has surprised many others. Beyond very visible hydropower plants, like the Hoover Dam, water is used to cool down nuclear power plants (through the cooling towers emitting steam that many may have noticed, without perhaps always identifying the purpose), as well as in natural gas and coal-fired plants. Water is also used in various stages of the energy supply chain, including for production and processing.

Climate change is expected, through its impact on water supply and availability, to increase vulnerabilities in energy production. For example, changing rain patterns will create uncertainties for hydropower production, which represents about 15 percent of global power generation, even if the overall level of rainfall doesn’t change. Heat waves have reduced water levels and raised water temperature above the levels at which water can be discharged back into rivers, restricting the operation of many nuclear power plants. And in a completely different dynamic, various coal power plants dependent on barge transport for resupply have seen their operations imperiled by low water levels. These are aspects that have received some, but altogether inadequate, attention to date.

Both hydroelectricity and nuclear generation, two low-carbon sources of electricity, are expected to increase significantly over decades to come under various government programs to reduce greenhouse gas emissions. Moreover, even as the need for water to cool down coal-fired plants is eventually expected to drop as countries transition from this carbon-intensive fuel source, new uses for water are emerging, including the production of hydrogen through electrolysis.

What has attracted less attention is the impact of the growing demand for energy from developments in water systems. The United Nations projects that the world’s population will increase by more than 1.2 billion by 2040, with most of that increase occurring in emerging economies and other developing countries. These nations are also projected to see rising income levels, increasing the ability of their populations to access water services, at home, at the office or for pleasure. Moreover, the demand for food is also similarly projected to increase, and with that, the need for more water irrigation services that are inevitably powered by energy.

These factors are helping to drive an increase in the demand for energy. For example, the International Energy Agency (IEA) projects that the amount of energy required by the water sector will more than double within 20 years. The major driver under the IEA’s modeling is the demand created by desalination plants. These are no longer confined to the dryer climates of the Middle East and North Africa, but also in regions that once thought that their water supplies were ample, such as  Europe and Asia. Another important growing demand for water is coming from wastewater treatment plants and the supply of clean drinking water and sanitation services to both the billions of poor who currently lack it and the other more prosperous billions across the developing world whose consumption is projected to increase.

Unfortunately, efforts to meet this demand will be exacerbated by climate change. For example, droughts are likely to require the transport of water over greater distances to satisfy the needs of populations suffering from water scarcity, an effort that will require more energy. Similarly, over the past year, droughts have heightened the possibility of water restrictions for millions of people in Southern Europe, including drinking water, which might in turn require more desalination.

But though tensions are inevitable, actions can be taken to, if not avoid the problems, dampen their impact. Actions lie in the water or energy sectors and, often, at the intersection of the two. In the water sector, these include reducing water losses, allowing the construction of rainwater collection tanks for agricultural use, increasing wastewater facilities and fast-tracking the installation of desalination plants. In energy, transitioning to solar irrigation pumps is something that can help everywhere, in rich and poor countries alike. At the intersection, actions include hydropower plant design and management that are better adapted to the changing rainfall patterns of the future, building more efficient water-based cooling systems for other plants, and even greater use of artificial intelligence.

The energy-for-water dimension will become increasingly fraught, driven by climate change, growing populations and increasing prosperity. Not only do we need to redouble our efforts to reduce greenhouse gas emissions, we also require stronger concerted actions on adaptation and resilience. Much like energy, we need to be more efficient at using water, whether for household needs, industrial processes, agriculture or energy; meanwhile, concerted action and discussion between those sectors will be needed. 

The recent events along the Colorado River serve as an important wake-up call. Water is at the essence of our quality of life, and energy is an integral part of that story. We need to do a better job of managing our thirst for water and the energy required to satisfy that demand, and we need to do this in the face of a changing climate.