Flexible Desalination: A Renewable Energy Twist on the Energy-Water Nexus

A dire new report from the United Nations warns of a looming world water and sanitation crisis. Businesses can help alleviate the problem by supporting work on new desalination technologies that leverage renewable energy, with broader implications for grid reliability and stability as well.

The world water crisis continues to loom...

The new U.N. 2023 Water Development Report follows decades of tracking global water resources and sanitation issues. It was released in advance of the U.N.’s first conference on water resources in almost 50 years, held last week.

The report was prepared by the U.N. Educational, Scientific and Cultural Organization (UNESCO), which warned: “The accelerating pace of change to water systems is creating new and ever-greater risks to society.”

“In parallel, demand for water is intensifying not only when it comes to domestic use but also in other sectors such as agriculture, energy and industry,” UNESCO added in the report. Even as demand is rising, climate change and pollution are adding new stressors, raising new obstacles to progress.

Overall, the report notes that the water and sanitation access described in U.N. Sustainability Goal 6 is off track. “According to the latest figures from 2020, 26 percent of the world’s population (2 billion people) did not have access to safely managed drinking water services…and an estimated 46 percent (3.6 billion) lacked access to safely managed sanitation,” the report reads.

…but businesses can contribute to progress

While the overall situation is dire, the report does take note of progress in the area of global water use efficiency, an element of SDG 6. Improvements in that area can cover a wide range, from repairing leaky pipes to planting different crops and investing in new technologies.

“Water savings are also often associated with energy savings, as less water needs to be extracted, treated, transported and heated,” UNESCO noted.

The report cites a three-year period from 2015 to 2018 in which water use efficiency rose by an average of 9 percent overall. The global industrial sector over-performed the average by a wide margin, achieving a 15 percent improvement during that period.

New technologies for the energy-water nexus

While past performance does not necessarily indicate future progress, all indications are that the technology factor will provide the force needed to sustain and accelerate progress on water use efficiency. 

One emerging example is the deployment of new, more efficient technologies to collect water vapor from the air. Desalination is another pathway. The expense and energy intensity of desalination facilities has been an obstacle to widespread use, but technology improvements can help overcome those challenges. That includes improvements to renewable energy technologies that have allowed for a sharp drop in the cost of wind and solar power in recent years.

A new twist on the energy-water nexus

A drop in the cost of energy for desalination is just one water efficiency factor related to renewable energy. Another factor is the potential value of desalination facilities in contributing to the stability and reliability of a grid that depends heavily on wind and solar power.

In past years, the use of wind and solar power was limited by weather and time-of-day factors. However, new grid management and energy storage technologies are smoothing out those intermittent bumps, and the U.S. Department of Energy has spotted an opportunity to add desalination facilities to the mix.

On March 22, the Energy Department announced funding for a suite of 12 new projects aimed at increasing the efficiency of water desalination and reuse technologies. Three of the projects are focused specifically on balancing the energy use of industrial-scale desalination facilities with the availability of intermittent resources on the grid.

The basic idea is to time the operation of desalination facilities to take advantage of excess wind or solar power. Having a dedicated, industrial-scale electricity consumer taking up the slack during periods of low demand could also help motivate additional renewable energy development.

“Desalination plants can draw large amounts of electricity from the grid and have the potential to become flexible or intermittent power users to increase grid stability and reliability,” the Energy Department explained in its announcement.

The University of California will lead one of the projects in partnership with the Chino Basin Desalter Authority in San Bernardino County and the water engineering firm Irvine, Hazen and Sawyer. As described by the Energy Department, the partners are tasked with developing a framework for estimating the value of deploying desalination plants as flexible power users. The partners will also spot potential obstacles that could impede flexibility.

Stanford University will head up a second project in partnership with the SLAC National Accelerator Laboratory, the National Energy Technology Laboratory and the city of Santa Barbara in California. This project takes note of an existing degree of flexibility in operating desalination plants.

“In some parts of the U.S., operators of desalination facilities can participate in demand-response energy supply contracts where they pay lower electric rates but are also required to lower energy use during periods of high grid demand,” the Energy Department observes. The team will use an assessment platform developed by the public-private National Alliance for Water Innovation research program to identify opportunities for upgrading desalination plants and optimizing their schedules around the use of low-cost, low-carbon energy resources.

A third project pairs the Electric Power Research Institute with Colorado State University, the National Renewable Energy Laboratory and the not-for-profit Salt River Project utility district in Arizona. The team will take a broad look at energy availability and water management to identify high-impact opportunities for desalination flexibility in the context of the electrification trend.

The desalination fight has only just begun

The other nine Energy Department projects involve advanced technology improvements in other areas of desalination plant operations, including the treatment of brine left over from the process.

One example is a new treatment system that deploys three different electrochemical processes — electroosmosis, electrophoresis and electrodialysis — to treat a range of contaminants in desalination brine, including pesticides, boron, heavy metals and PFAS (per- and polyfluoroalkyl substances, often called “forever” chemicals).

New solutions and public-private partnerships like these dovetail with the new United Nations report, which calls for a renewed focus on collaboration, partnerships, new technologies, and the sharing of data and information.

U.S. businesses can help accelerate progress by lending their voices in support of federal resources for tackling the water crisis, including more resources for electrification and renewable energy development.