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But electric utilities’ overall exposure to power plant water stress risks could diminish as they pursue decarbonization strategies and replace water-dependent plants with wind and solar generation that require little to no water. Some companies are also implementing water management and related investment strategies to reduce their exposure. ……..

According to projections from the World Resources Institute’s Aqueduct Water Risk Atlas, water stress — when humanity’s competition for water exceeds the rate at which nature can replenish its stocks — could grow materially by 2030 in the drought-prone Western U.S., as well as the upper Midwest and portions of the Northeast and Florida, due to climate change.

About 61.8% of existing fossil-fueled and nuclear power plants in the Lower 48, or a combined 535 GW of operating capacity, is in areas that could face medium-high to extremely high water stress in 2030, based on an analysis of Market Intelligence’s power plant data paired with the Aqueduct water stress projections.

Moreover, 68.6% of the Lower 48’s natural gas-fired fleet, 73.3% of its oil-fueled fleet, 61.0% of its nuclear fleet, and 44.6% of its coal-fired fleet are in areas expected to face medium-high to extremely-high water stress that year.

“As we’re seeing snowpack decline — a natural mountainous reservoir of water — and as we’re getting lower amounts of total precipitation and available water in the U.S. West, this is going to be a really serious issue for the power sector,” said Betsy Otto, director of the Global Water Program at the World Resource Institute, or WRI. Moreover, scientists have said the West is entering a megadrought that could last more than 20 years.

Otto also noted that several other U.S. regions not normally thought of as facing water supply issues are already experiencing chronic water challenges that, if left unchecked, could become a problem if extended droughts, heatwaves, and other major extreme weather events should occur.

A number of utilities use WRI’s Aqueduct tool to assess their water risks in their annual reports to the CDP, formerly known as the Carbon Disclosure Project, and other organizations. But those reports typically focus on the WRI’s current water stress models and not the tool’s future climate projections.

WRI’s current water stress models show a number of regions that are facing water stress will be in the same situation, or worse, at the end of the decade.

Along those lines, Moody’s Investors Service in August reported that about 48 GW of nuclear capacity across the U.S. face elevated exposure to combined heat and water stress, including plants owned by Exelon Corp., Vistra Corp., Entergy Corp., and the Arizona Public Service Co.

In hot water

A plant’s location is not the only factor that will determine its vulnerability to water stress. A plant’s water source, cooling technology and the temperature of the water when it is withdrawn are also key factors, according to scientific reports. The Market Intelligence analysis using the WRI tool does not account for those three factors.

In addition, rising ambient air and water temperatures can also create operational and legal issues for plants. Because plants primarily use water to cool their systems, “if that water is hot or warmer to start with, that’s not so good. That makes the power plant less efficient” and it also means the plant risks violating federal restrictions on how hot water can be when it is discharged, said Auroop Ganguly, director of the Northeastern University College of Engineering Sustainability and Data Sciences Laboratory.

Ganguly co-authored a study that found that by the 2030s, climate-induced water stress in the form of increased water temperatures and limited freshwater supplies will hurt the power production of thermoelectric plants in the South, Southwest, West and West North Central regions of the U.S. According to the 2017 study, U.S. nuclear and fossil-fueled plants at that time used about 161 billion gallons per day, or 45% of the nation’s daily freshwater usage, 90% of which was for cooling.

The technologies used by a power plant can also make a big difference in how much water it needs. Dry-cooling technology uses very little water but is costlier and less efficient than alternatives. And while once-through cooling systems withdraw more water than recirculating systems, once-through cooling returns nearly all of the water to the source while recirculating systems consume more water due to evaporation………. https://www.spglobal.com/marketintelligence/en/news-insights/blog/street-talk-episode-69-banks-left-with-pockets-full-of-cash-and-few-places-to-go