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California energy companies are asking for permission to take in more revenue. Consumer advocates are having none of it.

There’s a seemingly obvious solution to expensive electricity bills: Cut utility profits.
Investor-owned utilities have to deliver profits to their shareholders to be able to raise capital for grid projects. That profit comes in the form of a markup you and I pay on our electricity bills. State regulators decide how much that mark-up is. What if they made it lower?
A growing body of evidence suggests they should at least consider it. In principle, the rate of return on equity, or ROE, that regulators allow utilities to charge should reflect the risk that equity investors are taking by putting their money in those utilities, but that relationship seems to have gotten out of whack. Among the first to draw attention to the issue was a 2019 paper by Carnegie Mellon researchers which found that since the 1990s, the average “risk premium” exhibited by utility ROEs as compared to relatively risk-free U.S. Treasury bonds has grown from 3% to nearly 8%.
“An error or bias of merely one percentage point in the allowed return would imply tens of billions of dollars in additional cost for ratepayers in the form of higher retail power prices,” the authors wrote.
Subsequent research reproduced and built on those findings, showing that a generous ROE creates a perverse incentive for utilities to increase their capital investments, leading to excess costs for consumers of $3 billion to $11 billion per year. Now, the ex-chief economist of a major U.S. utility company, Mark Ellis, is putting his own analysis out there, arguing that unreasonably high ROEs are costing U.S. energy customers $50 billion per year, or over $300 per household.
Not only does this hurt consumers, it also makes the energy transition more expensive and less politically palatable.
That’s what environmental and consumer advocates are worried about in California, where the Public Utility Commission is currently considering requests by the state’s four largest energy companies to raise each of their ROE. Utilities in the state have reported record profits amid a worsening affordability crisis. On Friday, the commission signaled that it would instead lower the companies’ ROE — although not nearly as much as advocates have recommended. A final decision is expected in December.
“It’s a joke,” Ellis, the former utility executive, told me of the commission proceedings. “If you read the proposed decision, they don’t address any of the facts or evidence in the case at all.” His own analysis, which he submitted to the California commission on behalf of the Sierra Club, proposes that an average ROE of 6%, down from about 10%, would be justified and has the potential to save California energy customers more than $6 billion per year.
Utilities, of course, disagree, and have brought their own analysis and warnings about the risks of lowering their ROE. Regulators are left to sort through it all to figure out the magic number — one large enough to appeal to investors, but not so large as to throw ratepayers under the bus.
How does the ROE work its way into your bill? Let’s say your local utility, The Electric Company, has a regulated return on equity of 10%, and it plans to spend $100 million to build new substations. Utilities typically finance these kinds of capital projects with a mix of debt (loans they will have to pay interest on) and equity (shares sold to investors). Then they recover that money from ratepayers over the course of decades. If The Electric Company raises half of the capital, or $50 million, via equity, an ROE of 10% means it will be able to charge ratepayers $5 million on top of the cost of the project. That additional $5 million is factored into the per-killowatt-hour rates that customers pay. The profit can then be reinvested into future projects, issued to shareholders as dividends, paid out to executives as bonuses — the list goes on.
The energy research group RMI, which agrees that the average utility ROE is much too high, estimates the surcharge currently makes up between 15% and 20%% of the average customer’s utility bill. “Setting ROEs at the right level is necessary to bring forward a rapid, just, and equitable transition,” RMI wrote.
Utilities, however, say the “right level” is likely higher, not lower. They warn that in reality, lowering their ROE would trigger a cascade of negative effects — credit downgrades, higher borrowing costs, lower stock prices, investors taking their money elsewhere — that would push energy rates up, not down. These effects would also make it more difficult for utilities to invest in projects to clean up and expand the electric grid.
Timothy Winter, the portfolio manager of a utility-focused fund at the investment firm Gabelli, told me this “virtuous cycle” runs in both directions. Higher ROEs lead to a lower cost of capital, which leads to more investment, better reliability, and lower rates, he argued. Winter said that if California regulators reduced utility ROEs to 6%, investors would flee the state.
Between growing wildfire risk and the bankruptcy of California’s largest utility, PG&E, California energy providers are too exposed to warrant such low returns, he said. As a comparison, he noted that U.S. Treasury bonds, which are generally viewed as risk-free, yield about 4%. “If it’s a 6% return with an equity risk, they’re not going to do it,” he said of investors.
I probed Winter a bit more on this. Is that really true given that utilities are still, in many ways, the opposite of risky investments? They have captive customers, stable income, and are seeing skyrocketing growth in demand for their product.
This caused him to spiral down into an investor’s worst nightmare scenario. “Yes, there is a risk,” he said. “If a regulator is willing to give a 6% return and they used to give 11%, how do I know they’re not going to decide, okay, rates keep going up, next rate case it’s going to be 4%?” After that, he said, how can investors be sure the government won’t end up taking over the utility altogether?
Travis Miller, a senior equity analyst at Morningstar, was more measured. He hesitated to tell me whether a 6% ROE would hurt utilities’ ability to raise capital. “What usually happens” when regulators lower the ROE, he said, “is the utilities just decide not to invest very much, so then they don’t have to raise capital.” He would expect the California utilities to “invest to maintain reliability and that’s about it,” meaning that “a lot of new data center build that is planned in California would have to go elsewhere.”
Return on equity also isn’t the only thing investors look at, Miller added. They consider the overall regulatory environment. Is it predictable? Is it transparent? He said there have been cases where regulators cut a utility’s ROE but the overall regulatory environment remained strong, and other instances where the cut to ROE was “another sign of a deteriorating relationship” — a phrase that brings to mind Winter’s panic about government takeovers. (I should note, advocates for public takeovers of utilities cite this whole dynamic around the need to woo investors and the perverse incentives it creates as a key justification for their cause. Publicly-owned utilities — which serve about 1 in 7 electricity customers in the U.S., including in large cities like Sacramento, Los Angeles, and Seattle — don’t charge an ROE.)
When I spoke to Ellis about his proposal, I fired off all of the utility arguments I could think of. Won’t utilities stop building stuff and making the investments we need them to make if they can’t earn as much? “They have a legal obligation to continue to invest,” he said. But will they be able to raise equity? They don’t necessarily need to raise new equity, he responded, suggesting that utilities could reinvest more of their profits rather than distributing the money as dividends. This is not how utilities traditionally operate, he admitted, but it’s an option.
Prior to taking up the consumer cause, Ellis spent 15 years in leadership and executive roles at Sempra Energy, the parent company of San Diego Gas and Electric and SoCal Gas — two of the companies that petitioned for higher ROE. “I know how they think about this issue,” he told me, asserting that the arguments the companies make to regulators do not match how they think about ROE internally.
During our interview, Ellis described the current state of utility regulation of ROE in California as “reprehensible,” “egregious,” “heartbreaking,” and “a huge injustice.”
In the analysis he submitted to the utility commission, Ellis not only makes the case that the average U.S. utility’s ROE is much higher than is necessary to attract capital, but also that the potential impacts to consumers of lowering it — i.e. the potential to hurt a utility’s credit rating and increase its cost of debt — would be outweighed by customer savings.
He argues that to justify their requests for higher ROEs, the utilities use forecasts from biased sources, cherry-pick and manipulate data, and make economically impossible assumptions, like that earnings will grow faster than GDP.
Stephen Jarvis, an assistant professor at the London School of Economics who has conducted research on ROE rates, has reached similar conclusions about them being excessively high. Nonetheless, he told me he sympathized with the challenge regulators face. He said there was no “right” answer for how to calculate the appropriate ROE. “Depending on the assumptions that you use, you can come up with quite different numbers for what a fair rate of return should be,” he said.
The sentiment echoes the preliminary decision the California Public Utilities Commission issued last week, when it observed that all of the proposals submitted in the proceeding were “dependent on subjective inputs and assumptions.”
Ellis said the decision contained a “smoking gun,” however, proving that the commission didn’t really do its job. Changes in ROE are supposed to reflect changes to a company’s risk profile, he said. The risk profile for Southern California Edison, which is facing lawsuits related to the Eaton Fire and already paying out hundreds of millions of dollars to survivors, has certainly changed in a different way than its peers. Regardless, the commission made the exact same recommendation for each utility to reduce ROE by 0.35%. “The Commission clearly is not looking at the evidence.”
There is likely some truth to that. “It’s more art than science,” Cliff Rechtschaffen, who served for six years on the California Public Utilities Commission, told me when I asked how the people in those seats attempt to calibrate ROE. He acknowledged there was a self-reinforcing element to the process — regulators look at where investors might go if the rate of return is too low, and use that to determine what the rate should be. “But the rates of return that are set in other jurisdictions are, in turn, influenced by the national utility market, which includes your own utility market,” he said.
Similarly, regulators rely on market analysts, investment advisors, investment bankers, and so on, who have an inherent interest in building up the market and ensuring healthy rates of return, he said. “That makes it harder to discern and do true price discovery.”
Rechtschaffen said he was glad that environmental and consumer advocates were bringing greater scrutiny to ROE, adding that it was the “right time” to do so. “Particularly in this environment where utilities have forecast that they’re going to be spending tens of billions of dollars on capital upgrades, do we need the same rates of return that we’ve seen?”
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Plus SAF, another SPAC, and more of the week’s biggest money moves.
With SpaceX’s historic IPO dominating headlines this week, Heatmap turned its attention to the impact Elon Musk’s protégés have had on the climate tech landscape. Right after we published the story, an underwater geothermal startup founded and staffed by SpaceX alumni announced a sizable Series A, with its founder telling TechCrunch that his “experience at a very hardcore company like SpaceX” helped shape his approach to this new endeavor.
In other news, one of the biggest players in the sustainable aviation space, Twelve, opened its first commercial fuels plant and is preparing to begin supplying low-carbon jet fuel to Alaska Airlines later this month. Meanwhile, the battery sector saw two SPAC announcements: In a bid for survival, Factorial Energy officially went public this week through a SPAC merger, while ZincFive announced plans to do the same later this year. And finally there was some positive news for Germany’s heat pump market, as the startup Galvany raised fresh funding to simplify the end-to-end process of buying, installing, and operating a heat pump.
Drawing from an increasingly familiar playbook for Musk alumni, Endurance Energy founder and former SpaceX engineer Andrew Redd applied the lessons he learned from the rocket company’s notoriously “hardcore” culture and rapid pace of development to something completely different. Now that he’s pivoted away from rocket tech, Redd wants to harness geothermal energy from underwater volcanic activity, and his startup just raised a $54 million Series A to make it happen While a growing crop of geothermal startups including Fervo and Zanskar are focused on tapping into the heat beneath our feet, no other company in the sector has sought to develop the resource beneath the ocean floor.
There are good reasons for that, of course. Offshore infrastructure is notoriously difficult and expensive to build, maintain, and repair, and saltwater is corrosive. But if Endurance can crack the code, Redd told TechCrunch he thinks the company could unlock about 6 terawatts of geothermal energy in the coming decade.
Investors seem to be convinced: Peter Thiel’s Founders Fund led the startup’s latest funding roundSeries A, its second capital raise since launching less than two years ago. Other backers include First Round Capital, Felicis Ventures, and Voyager Ventures. EnduranceThe startup is initially targeting remote islands, where electricity costs are often far higher than on the mainland. It’s already launched an initial pilot off the coast of Tonga, which still gets about 80% of its electricity from imported diesel.
Twelve, one of the best capitalized sustainable aviation fuel startups, opened its first e-fuel facility in Washington State this week. The demo plant has officially started production, and the company’s strategic partner and investor, Alaska Airlines, expects to begin using it on commercial flights as soon as this month. The plant’s launch comes roughly two years later than originally planned, a delay that’s hardly unusual for first-of-a-kind industrial projects like this. Last September, Twelve raised $645 million to complete buildout of the facility, as well as to jumpstart development of future plants, which it says will be orders of magnitude larger.
The company’s process begins with renewable-powered electrolysis. Using a proprietary catalyst, Twelve’s electrolyzer splits apart CO2 captured from a nearby ethanol plant at a lower temperature than conventional approaches, making it better suited to running on renewable energy. The company combines the resulting carbon monoxide with hydrogen to create a syngas, which gets refined into sustainable jet fuel. Airlines can blend the resulting product with conventional jet fuel (the Federal Aviation Administration allows a maximum 50% blend) to create a drop-in replacement that requires no engine modifications.
To cover the cost premium of SAF, Twelve and Alaska partnered with Microsoft. The tech giant is buying SAF certificates — essentially carbon credits — from the project to help offset Scope 3 emissions associated with employee travel. “We are seeing strong demand from the corporate offtake side, not only for employee travel, but also for freight and logistics,” Twelve’s CEO, Nicholas Flanders, told me. “Everything from pharmaceuticals to data centers use a lot of air travel.” There are also some policy tailwinds — the European Union now has a sustainable fuels mandate that requires the use of synthetic e-fuels like Twelve’s beginning in 2030.
The plant also comes online at a moment of heightened volatility in the jet fuel market. As my colleague Alexander C. Kaufman noted in Wednesday’s morning newsletter, the closure of the Strait of Hormuz has led to soaring fuel prices, prompting domestic refiners to ramp production to record highs. By contrast, Flanders argues that SAF offers customers greater price certainty via long-term offtake agreements. “You can fix the cost of our key inputs like electricity and CO2 and so that actually makes it a more attractive project from a project financing perspective,” he explained.
SPACs are back. But this week, it’s not just another pre-revenue nuclear company that’s looking to get to market as quickly as possible. Solid-state battery startup Factorial Energy, which has yet to develop a commercial product, has merged with the blank check company Cartesian Growth Corporation III, netting it $100 billion at a $1.3 billion valuation.
The company was upfront about needing the SPAC to stay afloat after racking up losses since its founding in 2013. Factorial’s SEC filing states that prior to this new capital, “its liquidity wasn’t sufficient to fund twelve months of operations.” Yet it does have real traction in the industry — Mercedes-Benz, Stellantis, Hyundai, and Kia have all made strategic investments, looking to use Factorial’s tech in their electric vehicles to achieve higher energy density, longer range, and faster charging.
Solid state batteries typically use a solid electrolyte in place of the flammable liquid electrolytes found in conventional lithium-ion cells, but Factorial is starting with more of a hybrid approach. Its initial design relies on a “quasi-solid” gel-like electrolyte, which allows it to use an energy dense lithium metal anode while preventing the needle-like dendrite growth that predisposes solid-state batteries to short circuit. Factorial is manufacturing these cells at a pilot plant in Massachusetts, while working on a prototype with a fully solid electrolyte that could offer even greater performance gains.
Factorial isn’t the only battery company with SPAC news this week. ZincFive, a nickel-zinc battery producer, also announced plans to go public via SPAC in a deal expected to close in the second half of this year. Unlike Factorial, however, ZincFive is already making money, selling its batteries to hyperscalers and other data center operators as a backup power solution to bridge the gap in between when the power goes out and when the backup generator turns on. As the company’s CEO Tod Higinbotham told Bloomberg, “We have the backlog. We have the capacity. We have the demand. We really need capital.”
Navigating the maze of consumer clean energy incentives and coordinating home energy upgrades is hardly a U.S.-specific challenge. Just a few years ago, heat pump sales in Germany were falling precipitously despite generous subsidies and proven tech. One startup, Galvany, theorized the problem wasn’t the heat pumps themselves, but rather the unnecessary complexity of the surrounding ecosystem. Now it’s raised roughly $11.5 million to help streamline the process of getting heat pumps into consumers’ homes and apartments.
“In Germany, heat pumps do not fail because of the technology, but because of the gap between subsidy bureaucracy, installation capacity, and economic viability for the end customer,” the company’s CEO, Raik Belka, said in a press release. This is exactly the gap we are closing.” The approach is already paying off — Galvany has installed more than 2,500 heat pumps to date and became profitable last year after increasing its revenue sevenfold.
The startup produces its heat pump in partnership with Panasonic, but its real innovation lies in the way it streamlines sales, procurement, installation, and ongoing heat pump operations into a single platform. Potential customers enter their building data online and, after a feasibility check, get a quick quote that factors in subsidies. They can then purchase a standardized kit that’s simple for installers to assemble. Once operational, the heat pump’s energy management system, which launches this summer, will automatically adjust heating loads based on the cost of electricity, saving customers money without them having to actively manage the system.
The administration filed to dismiss an appeal of a December ruling that overturned its wind permitting freeze.
Trump’s Department of Justice is giving up on defending the president’s wind permitting moratorium.
The DOJ filed a motion on Wednesday to dismiss its appeal of a federal court’s December decision vacating the order to halt wind energy approvals. The plaintiffs in the case — New York and 16 other states, as well as the Alliance for Clean Energy New York, a trade group — did not oppose the motion. The case will not be officially dismissed, however, until the First Circuit Court of Appeals approves the request, which typically happens quickly when both parties support the dismissal.
The case stems from an executive order President Trump issued on the first day of his current term temporarily withdrawing all areas of the outer continental shelf from offshore wind leasing and pausing all federal authorizations for onshore and offshore wind projects while the administration conducted a review of leasing and permitting practices.
States took the administration to court last May, arguing that the order was arbitrary and capricious and violated the Administrative Procedures Act. They claimed it harmed their ability to source reliable and affordable energy and threatened billions of dollars in investment in supply chains, workforce development, and wind industry-related infrastructure.
On December 8, Judge Patti B. Saris of the U.S. District Court for the District of Massachusetts ruled in the states’ favor and vacated the wind order. More specifically, the judge vacated the portion of the order directing agencies to pause permits and other authorizations. The withdrawal of areas eligible for new leases remains in effect.
What it means is that federal agencies will now have to proceed with permitting wind projects using the existing statutory and regulatory framework, Kit Kennedy, the managing director for power, climate, and energy at the Natural Resources Defense Council, told me in an email. “The door to federal permitting is now unlocked again and each developer will be able to make the case for permitting their individual project based on the facts and the law,” she said.
The Trump administration appealed the ruling to the First Circuit in February, but never submitted an opening brief. The initial deadline was May 11, but on May 4, the DOJ requested additional time to file the brief. The judge gave the defendants until June 10. On that date, the defendants filed the motion to dismiss.
This is a developing story and we’ll update it as we learn more about the administration’s actions and their effects.
Editor’s note: This story has been updated to reflect that the freeze and ruling apply to onshore as well as offshore wind. It also adds a quote from Kit Kennedy.
The data center water issues are real – but they aren’t what you think.
Too often, I hear people say the number one reason they’re against data center development is water use. Heatmap’s data shows water consumption is historically the reason cited most often by activists when opposing projects. This complaint, they often say, is rooted in the fear that this nascent buildout of AI infrastructure will simply draw so much H2O it will leave little liquid left for the rest of us.
I spent weeks trying to understand how real the water use problem is when it comes to data centers, reading research and speaking to some of the world’s leading academics, large tech firms, and environmental advocates to make my best attempt at answering some of the most important questions being asked about data centers.
Before I jump into this thicket, a few caveats. I’m not going to address the host of water pollution concerns many have raised about data centers because that is for a future article. If you want me to dissect how Rep. Alexandria Ocasio-Cortez got a jar of dirty water near a Meta data center, that was poor construction practices – not a data center’s water demand. By that same token, if you're itching for me to find out how much PFAS is in data center water, I’m not delving into that here, though I’ll just say PFAS is everywhere and isn’t a data center-specific issue.
So are there problems with AI data centers’ water use? Yes. Are data centers using too much water for society to handle? It depends on what “too much” means to you. Is the AI data center boom going to usher in a new era of drought across the United States? Probably not, but there’s a few places we should be mindful of.

Researchers told me data center water use is a painfully understudied topic rendered more obscure by a lack of public information about individual H2O consumption at the project level. Those I spoke to were split on how seriously to take the topic.
Some analyses insist the sector’s water use should be regulated and tackled head-on by the sector. I spoke with Yi Ding, an assistant professor at Purdue University, who co-authored a paper laying out a framework for evaluating the water impact of computing weighted specifically for water stress. Ding told me there is currently no set of industry-led best practices for sustainable water-conscious data center operation and her work aims to fill that gap.
When I asked Ding if data centers are actually threatening individual towns’ water supplies, she didn’t hesitate: “Yes, it’s significant.”
Others in this field have the opposite view.
“Water is often brought up as the primary concern when it’s less important,” David Mytton, a sustainable computing researcher at Oxford University, told me. “The more important thing is going to be how you bring more clean energy onto the grid, and nuclear power, so that we can generate sufficient energy to build these centers.”
Large tech companies are starting to spend less time debating the extent of the problem and more bandwidth addressing the PR crisis surrounding data center and AI water use.
Ben Townsend, Google’s head of infrastructure and sustainability, told me he believes that “from a comms and PR perspective” he has “no doubt” it would be easier to build data centers without the debate over water. “Data centers operators are not explaining why they’re using water or how much water they use. There’s a complete lack of transparency or discussion.”
Google has been getting splashy around this topic, a public relations strategy that reminds me of Meta’s recent workforce training investments. Last week, Google announced five fresh “commitments” towards its “climate-conscious approach” to water use, including a pledge to “replenish more water than we consume at our sites” by 2030.
This week, Amazon made a similar declaration and claimed its operations are 75% of the way to accomplishing this goal, which it’s calling “water positive.” Brandon Oyer, director of energy and water at Amazon Web Services, told me he thinks the industry “could’ve done better” and “come out earlier” to address its water use.
“There’s just been a lot of misinformation that has led people to [be] a little bit alarmist. And rightfully so. I would get alarmed if I thought that water was going to be impacted in my community,” Oyer said.
The basics of data center water use
Data centers need water to cool large server racks whizzing away to power AI and most other internet practices, from streaming to online banking. Normally, you don’t want computers to get too hot because then they can crash causing potentially catastrophic harm to the machine.
This water use presents a number of environmental challenges. Often, server farms rely on clean, fresh water, or filtered drinking water, a need largely for functionality reasons. They’re competing for this resource at a time when supply is dwindling amidst the crisis of global warming.
Making matters worse, much of the U.S. has faced drought conditions over the past year, including states that are typically water abundant, like Virginia and Georgia, that are at the center of the data center boom. On Monday, The Guardian reported that more than half of all planned data centers in the U.S. are in “locations that have been in drought conditions throughout the past year,” citing data center site information from federal agencies and the energy data firm Cleanview.
In the top data center destination of Texas, where peak electricity demand could more than quadruple in the near future, analysis from state university researchers released in May found data centers could wind up between 3% to 9% of water demand by 2040. Projects are being developed near cities like Corpus Christi and El Paso that were already fearful their drinking water supplies would dry up before the AI infrastructure boom came to town.
“The impact of building a data center in Arizona versus Wyoming is very different,” said Ding, the Purdue University researcher. “[Companies] will say different things because of their position. The problem is substantial and sometimes it’s not that they don’t want to use water – it means they don’t have water to use.”
The most water intensive version of data center cooling is called “evaporative cooling,” which mixes water evaporation and ventilation air flow to cool rooms in ways industry compares to human sweat. Evaporative cooling uses a lot of water and regular fresh supply because, well, the water goes away once it evaporates.
One Google data center using evaporative cooling in Council Bluffs, Iowa used more than 1 billion gallons of water in 2024, a stat that made the project a poster child for perceived excesses in water use. Somewhat ironically, we know this because Google is one of the few large tech companies to voluntarily disclose direct water consumption from individual data centers on an annual basis.
But cooling tech is becoming much more water efficient. You may have heard of “closed loop cooling” – that’s when a chilling system is supposedly self-contained. These systems as designed typically rely on loops of pipes filled with coolant flowing through them. This means they should not expel much liquid. If the modern trend in data center development skewed towards closed-loop systems, it would theoretically mean very little new water supply drawn on the average day.
“If you’re using a closed loop system, the water goes into the data center and then it doesn’t really require a refill every so often. It’s a one-time thing,” Mytton said. “If you’re using evaporative cooling, the water is continuously evaporating into the atmosphere. That’s when it’s being drawn from water sources.”
Closed-loop systems aren’t perfect because of ordinary issues like leaks. These flaws have meant this innovation has done little to assuage the loudest local concerns about water use. Critics of the sector have pointed to estimates pegging a closed-loop failure rate up to 25%. But Mytton said this criticism against closed-loop cooling systems is a little misguided. “They’re just wrong. They just don’t understand how data centers work.”
Closed loop systems and water-free cooling processes (like simple air vent-based cooling) also have trade-offs, particularly the extra energy and chemicals required to make these loops work to spec. Given data center developers are often choosing gas-fired power, which also requires water and produces greenhouse gas emissions, more power for less water is hardly a comfortable trade-off from an environmental perspective.
“‘Closed-loop cooling’ is a marketing gimmick,” proclaimed anti-data center group Food and Water Watch in an April blog post, calling the practice “greenwashing” and “just clever advertising.”
We do not know right now how much water most data centers are actually using, sans a handful of companies reporting individual facility use like Google. The data center development space – Big Tech, their subsidiaries, start ups, real estate firms – is mostly keeping their individual facility water usage private, and there isn’t really any regulation at any level of government to compel this information to be released in the United States, despite it being the number one destination for data center development. Corporations often consider these figures proprietary and municipal governments often consider this confidential business information, making it likely to be redacted or withheld from public records requests.
For example, in Wisconsin, an environmental group sued the city of Racine when officials refused to give water use projections for Microsoft’s data center campus in the nearby village of Mount Pleasant, about five miles from the shores of Lake Michigan. The projections were ultimately released under court order, showing Microsoft’s data center campus was projected to use up to 234,000 gallons of water on peak days or up to 2.8 million per year; eventually those numbers could almost triple to 702,000 gallons on peak days, or almost 8.5 million gallons a year.
These projections, according to Microsoft, are for a facility where more than 90% of the facility will rely on closed-loop cooling. The rest of the data center campus “will use outside air for cooling, switching to water only on the hottest days.” The company has called this design a “technological milestone” that’ll use “roughly the amount of water a typical restaurant uses annually.”
Microsoft is accurate here: the average eatery uses roughly 250,000-to-300,000 gallons of water a year according to restaurant sustainability advocates, a level of consumption that’s led restaurants to be roughly 15 percent of total water use in commercial facilities in the United States.
Personally I think it is easier and more useful to compare a data center to a farm, especially given how many are fighting to stop these projects to preserve prime farmland. Agriculture doesn’t measure water consumption by the gallon; farms use far too much water for those stats to work here. Instead farms use acre-feet, which is calculated using the volume of water necessary to entirely cover an acre of land with one foot of water. For posterity, one acre-foot is almost 326,000 gallons of water, which is about the maximum daily water consumption of that Microsoft data center in Mount Pleasant, Wisconsin. In 2023, the average amount of water applied to a single acre of farmland for irrigation was 1.5 acre-feet, rendering this figure comparable to a large Microsoft data center. This is still a lot of water and not a 1:1 comparison, since different crops require water at different times. But even if a data center consumed that much water every day for a full year, that’s 365 days. An average large farm is a little more than 1,400 acres and many farms span far more acreage. That’s the sort of relative scale we’re working with. So, for instance, a large family farm in Stafford County, Kansas, might use something like 420 million gallons of water over roughly 1,000 irrigated acres of corn in an average year.
I’m no farming expert – there might be things about farmland irrigation I don’t necessarily understand. But it's hard for me to look at these numbers and not long for some sort of rethinking about how we’re doing water math with data centers, especially given the environmental trade-offs around using less water.
Honestly I don’t think trying to explain this math helps anymore because secrecy may have spoiled the well in Racine, pun intended. In September, a peer-reviewed study by University of Wisconsin researchers found the Mount Pleasant datacenter had become “a microcosm of a macro problem with secrecy.” The paper stated that while closed-loop systems at the Mount Pleasant facility “may significantly reduce water use during some of the year, there is still a question of transparency and why it has been so difficult to obtain clear answers about water use.” Full transparency around water use, as well as the energy required for water-lite cooling practices, would be “essential” for any future research into industry practices “to have credibility,” the study stated.
Asked for comment on the study, a Microsoft spokesperson said via email: “Our datacenter campus in Mount Pleasant leverages the latest and most innovative cooling technology available. In past datacenter designs, water has played a key role in datacenter cooling and humidification, but our new designs aim to eliminate this continuous need for municipal water for cooling. The bottom line is that this data center, and others we build in the future, will not require massive amounts of water.”
When you zoom out further, water use by sector shows that U.S. data centers are not the leading driver of water use and its scarcity to date. Thermal power (fossil energy) and agriculture are by far the largest users of water in the U.S. economy, and it would be challenging for the data center industry to ever catch up. Industry figures collected in 2015 found thermo-electric power used roughly 132.4 billion gallons of water per day. Irrigation was a close second at 118 billion gallons of water daily. By comparison, researchers have noted International Energy Agency estimates that the entire global data center sector consumed a comparable amount of water during all of 2023. These are pre-AI boom numbers, but they tell us a lot about relative scale.
However, once again, researchers, tech companies, and advocates alike all told me they believe this macro picture elides individual communities and transparency issues are rendering these comparisons unhelpful for calming concerns down. The data center conflicts are local matters felt acutely, especially in places where drinking water is either hard to come by or expensive. Your average rural desert town or midwestern farming district cares little about the world; they want to know if their own wells will run dry. As Amazon’s Oyer told me, “The hyperlocal influence you can have on a water supply is why it becomes top of mind for people.”
One way to measure data center water impacts in aggregate may be to quantify the potential infrastructure upgrades necessary to meet the industry’s demand. A new study by researchers at University of California-Riverside and CalTech found that new water infrastructure spending for data centers alone could total as much as $58 billion in only four years time. These upgrades will be necessary in order for municipal water supplies to withstand peak demand on the hottest days of the year, a need akin to grid resilience upgrades. Not to mention our nation’s sewer systems are in desperate need of upgrades.
“If a data center was able to show they weren’t stripping our water resources and convinced a community they have mitigation strategies at the local level, that’s a theoretical path,” said Kathryn Hoffman, executive director of the Minnesota Center for Environmental Advocacy. Her organization has successfully stalled data center projects in the state with lawsuits arguing city and county environmental reviews are failing to account for the full extent of local resource usage, including water.
“Unfortunately, we’re a long way from that,” Hoffman added.