NERC Predicting Blackouts Over Winter

From a NERC Press Release:

NERC’s 2025–2026 Winter Reliability Assessment (WRA) finds that much of North America is again at an elevated risk of having insufficient energy supplies to meet demand in extreme operating conditions. Although resources are adequate for normal winter peak demand, any prolonged, wide-area cold snaps will be challenging and may result in blackouts. This is largely due to rising electricity demand, which has grown by 20 GW since last winter, significantly outpacing winter on-peak capacity. This, coupled with the changing resource mix, is affecting the winter outlook.

“Electricity demand continues to grow faster than the resources being added to the grid, especially during the most extreme winter conditions where actual demand can topple forecasts by as much as 25%--as we saw in 2021 in ERCOT and SPP,” said John Moura, NERC’s director of Reliability Assessments and Performance Analysis. “This latest assessment highlights progress on cold weather readiness but underscores that more work remains to ensure energy and fuel supplies can be reliably delivered even during the harshest conditions.”

Although evidence from the past two winters indicates notable improvement in the delivery of natural gas to bulk power system generators, natural gas availability for generators remains precarious during extreme winter conditions due to the uneven application of voluntary freeze protection mitigations impacting production and transportation.

“Natural gas is an essential fuel for electricity generation in winter. Winter fuel supplies for thermal generators must be readily available during the periods of high demand for both electricity and natural gas that accompany extreme cold weather,” said Mark Olson, NERC’s manager of Reliability Assessment. “Although we are seeing evidence of improved performance, grid operators in areas that rely on single-fuel gas-fired generators are exposed to unanticipated generator loss during cold snaps when gas supply interruptions are more prevalent,” said Mark Olson, NERC’s manager of Reliability Assessment. 

NERC’s cold weather Reliability Standards address recommendations from winter storms Elliott and Uri reviews. The most recent standard, EOP-012-3, became effective on October 1, 2025, among the improvements in the new version are enhanced and expanded requirements to ensure that Generator Owners (GO) implement corrective actions to address known issues affecting their ability to operate in cold weather in a timely manner.

This year’s assessment, previewed in the 2025-2026 WRA video and summarized in the WRA infographic, makes a series of recommendations to reduce the risks of energy shortfalls on the bulk power system this winter:

• Cold Weather Preparations: GOs should complete winter readiness plans and checklists prior to December, deploy weatherization packages well in advance of approaching winter storms, and frequently check and maintain cold weather mitigations while conditions persist. 
  
  
• Load Forecasting: Be cognizant of the potential for short-term load forecasts to underestimate load in extreme cold weather events and be prepared to take early action to implement protocols and procedures for managing potential reserve deficiencies. .
  
  
• Fuel: They should prepare their operating plans to manage potential supply shortfalls and take proactive steps fand should maintain awareness of potential extreme cold weather developing over holiday weekends and the implications for fuel planning and procurement that may result over long, holiday weekends.  
  
  
• Regulation and Policy: State and provincial regulators can assist grid owners and operators in advance of and during extreme cold weather by amplifying public appeals for electricity and natural gas conservation, and supporting requested environmental and transportation waivers.

Undertaken annually in coordination with the Regional Entities, NERC’s WRA examines multiple factors that collectively provide deep and unique insights into reliability risk. These factors include resource adequacy, encompassing reserve margins and scenarios to identify operational risk; fuel assurance; and preparations to mitigate reliability concerns.

 

DEQ Proposes Changes to Backup Generator Rules

 The Virginia Department of Environmental Quality (DEQ) regulates backup generators primarily through air quality permits and rules governing their operation, particularly in the context of data centers. The regulations specify when generators can be used, their emission standards, and permit requirements, with a general emphasis on non-emergency use limitations. 

The data centers that increasingly fuel our interactions need to run 24 hours a day to keep the internet going. So, these facilities include backup power generators, often fueled by diesel or natural gas, and intended to run only during emergencies. Each data center is equipped with sometimes dozens, sometimes hundreds of tractor trailer-sized generators. Running generators burns fossil fuels for power emits pollutants such as particulate matter, nitrogen oxides, sulfur dioxides and carbon dioxide. 

In the summer of 2022 Virginia regulators proposed allowing Northern Virginia data centers to use backup generators in a more continuous manner for a five-month period during which energy “transmission problems” were anticipated. Homeowners’ associations that were already opposing data center projects in their backyards quickly coalesced to contest the proposal. The data center industry ended up asking regulators to rescind it.

But the outsized power demands have only grown since then, especially as more hyperscale data centers enabling AI come online. This past summer, the region faced another test of its grid when power demand for cooling reached record highs during heat waves in June and July. PJM Interconnection, which manages the grid for the northeastern U.S., issued permission in late June for places with high power consumption to use backup systems instead of the grid to prevent blackouts.

Electricity demand continues to grow faster than the generation being added to the grid. An extreme period of cold when the ubiquitous air heat exchanges cannot make the temperature gap and are forced to operate on the les efficient electric heat resistance to warm the homes could topple the grid.

The Virginia Department of Environmental Quality (DEQ) is currently accepting comments (until December 4th ) on a proposed change that would allow data centers to run backup diesel generators during planned outage events. Until now, these generators could only be used in the case of “sudden and reasonably unforeseeable events” or maintenance. In other words, these diesel generators–one of the most polluting forms of energy generation–were only ever meant to serve as backup power in emergency situations.

Below are the comments from the Piedmont Environmental Council:

“Utilities want the flexibility for the data centers to be able to run their existing backup diesel generators during planned outage events. This is driven by a desire to expedite timelines and avoid paying for more expensive options better equipped to protect public health."

"Planned outages, such as while transmission lines are built or worked on, are considered foreseeable, meaning data center operators have sufficient time — and are expected to — seek alternative options. Options typically used include: a) renting mobile Tier IV gas generators with higher pollution controls, or b) retrofitting Tier II generators with SCRs (selective catalytic reduction systems) to protect the public from pollution."

"But DEQ's proposal would allow data centers to potentially turn on hundreds to thousands of diesel generators, putting public health at greater risk. We believe this change should not be allowed or, at the very least, should be strictly limited and regulated."

The Public Comment Period ends on Thursday. Until then you can provide your comment at the following link: Guidance Document Public Comment Forum

DEQ Proposes to Allow more Frequent Operation of Backup Generators

A bad idea is once more being considered. The Virginia Department of Environmental Quality (DEQ) proposes to allow backup diesel generators to operate more often, particularly at data centers in Northern Virginia. This would lead to significant increases in air pollution, noise, and environmental impacts in the region, especially to residential communities and schools.

There are 4,000 MW of backup generation (primarily diesel) in the Potomac River Basin is concentrated in Northern Virginia, with an estimated 9,000 permitted diesel generators across the state, many of which serve data centers in Loudoun and Prince William counties (Source 1,2,8).

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Air and Health Impacts

The core issue is that these generators are generally Tier II or unrated diesel engines (designed only for emergency use) and are a highly polluting energy source (Source 1.2, 3.3). Increased operation would directly increase the emission of harmful air pollutants, posing a significant public health burden.

• Particulate Matter (PM): Diesel generators emit diesel particulate matter (DPM), a known carcinogen (Source 1.1). Increased use would raise the concentration of PM2.5 (fine particulate matter), which can penetrate deeply into the lungs and bloodstream, exacerbating asthma, bronchitis, and other respiratory and cardiovascular diseases (Source 1.8).
• Ozone Precursors (NOx): The generators emit large amounts of nitrogen oxides, which react with volatile organic compounds (VOCs) to form ground-level ozone (smog) (Source 3.3). Allowing generators to run during anticipated disruptions often coincides with peak summer heat and grid stress, which are already the highest ozone-forming conditions (Source 1.2).
• Cumulative Health Costs: The Joint Legislative Audit and Review Commission (JLARC) and related studies estimate that even a fraction of the permitted emissions could result in an annual public health cost of $190–260 million in Virginia and surrounding states (Source 1,8).

Impact on Schools and Residential Areas:

Children are especially vulnerable to air quality impacts. Proximity of generator clusters to sensitive receptors—such as schools, hospitals, and residential areas—is a key concern, as increased operation would directly expose these communities to higher levels of toxic emissions (Source 1,2).

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Noise Impacts

The allowance for more frequent operation, especially for non-emergency reasons like planned maintenance or grid support, would lead to chronic noise pollution in adjacent communities.

• Disruptive Decibel Levels: Diesel generators are extremely loud. When multiple units run simultaneously, they produce a constant, industrial-grade humming and droning noise (Source 3,2).
• Quality of Life: Residents near data centers already report that the noise from cooling equipment and routine testing disrupts sleep, conversation, and the ability to use outdoor spaces (Source 3,2). Extending the permitted operating time beyond brief emergency tests would make this noise pollution a pervasive, ongoing issue.
• Increased Frequency: The proposal is designed to allow use during "planned outage events" or grid constraints (Source 1,2). This shifts the use from unpredictable, rare emergencies to foreseeable, planned operations, increasing the overall frequency and duration of loud generator operation (Source 3,2).

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Environmental and Regulatory Impacts

• Climate Change (GHG): Increased burning of diesel fuel for non-emergency grid support directly increases greenhouse gas emissions, making it more difficult for Virginia to meet its climate goals, such as the Virginia Clean Economy Act (VCEA) targets (Source 1,1).
• Cumulative Emissions: The total number of permitted generators is enormous (nearly 9,000 across the state, with thousands concentrated in Northern Virginia) (Source 1.8). The concern is that DEQ has not publicly estimated the potential cumulative impact of thousands of these generators operating together for extended periods, effectively using them as a temporary, polluting power plant (Source 1,2).
• Regulatory Precedent: Environmental groups oppose the change, fearing it sets a "slippery slope" precedent that allows generators, which are permitted only for emergency use, to be used for demand response—where data centers are paid to reduce grid usage by running their polluting backup power (Source 1,2).

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Sources

1. PEC Web Map, "Data Centers, Diesel Generators and Air Quality"
2. PEC Virginia, "Proposed Increase to Data Center Diesel Generator Use"
3. Bay Journal, "Virginia regulators consider letting data centers regularly use fossil-fuel power for part of the year"
4. Trinity Consultants, "Virginia Department of Environmental Quality Releases Three Air Permitting Guidance Documents for Data Centers"
5. Virginia Conservation Network, "ADDRESSING DATA CENTER IMPACTS & ENSURING TRANSPARENCY"
6. JLARC, "Data Centers in Virginia"
7. McGuireWoods, "Virginia DEQ Withdraws Proposed Rule Allowing Extended Backup Generator Use"
8. Virginia Regulatory Town Hall, View Comments on Proposed Rule

COP 30 Ends

COP30 that was held  in the rainforest in Belém, Brazil, in November 2025, closed declaring that it achieved agreements on tripling adaptation finance and launched initiatives to protect forests and scale up climate finance. However, it failed to adopt a formal roadmap to transition away from fossil fuels, leading to disappointment among many nations and civil society groups. The United States did not send an official delegation though California Governor Galvin Newsome made an appearance.

What was decided:

• Finance at scale: Mobilise $1.3 trillion annually by 2035 for climate action.
• Adaptation boost: Double adaptation finance by 2025 and triple by 2035.
• New initiatives: Launch of the Global Implementation Accelerator and Belém Mission to 1.5°C to drive ambition and implementation.
• Climate disinformation: Commitment to promote information integrity and counter false narratives.

COPs continue to operate around consensus. Many compromises are made, but just one country can veto a proposal. At the conference Brazilian scientist Carlos Nobre issued a stark warning: fossil fuel use must fall to zero by 2040 – 2045 at the latest to avoid temperature rises of up to 2.5°C by mid-century. That trajectory, he said, would spell the near-total loss of coral reefs, the collapse of the Amazon rainforest and an accelerated melt of the Greenland ice sheet.

The world is in a critical state is supported by scientific data released at the conference: 

• CO2 emissions are projected to reach a new record high in 2025 (38.1 billion tonnes), an increase of 1.1% over 2024 levels.
• 1.5°C Goal is beyond reach: The remaining carbon budget to limit warming to 1.5°C is "virtually exhausted" and expected to be gone before 2030 at the current emission rate which is still rising. Keeping warming below 1.5°C is "no longer plausible".
• Warming and Water Stress: Global temperatures will continue to rise with 2024 likely the first year to temporarily exceed the 1.5°C threshold. The accompanying impacts, including droughts and water stress, are intensifying. 

Expectations were high that COP30's final decision would include explicit reference to phasing out fossil fuels. More than 80 countries backed Brazil’s proposal for a formal ‘roadmap.’ However, more nations did not.

The Tropical Forests Forever Facility was launched. The goal is to raise $125 billion to pay countries to conserve forests. There were  $5.5 billion in initial pledges. Brazil also committed to creating new Indigenous territories.

• Methane Reductions: Seven countries (including the UK, Canada, and Germany) signed a separate statement to achieve "near zero" methane emissions from the fossil fuel sector.
• Renewable Energy: Public utility companies in various countries pledged nearly $150 billion for new grids and energy storage to accelerate the global clean energy transition. 

COP30 fell short of the decisive action on fossil fuels that many scientists say is necessary to "correct course" and keep the 1.5°C limit within reach.

  

Drought Expands

The Virginia Department of Environmental Quality (DEQ), in coordination with the Virginia Drought Monitoring Task Force, has expanded the drought watch advisory to now include 50 counties and 23 cities. Virginia has endured three dry years and this water year (October 1 2025 -September 30 2026) has started off very dry.

from DEQ

The drought advisory is intended to help Virginians prepare for a potential drought and now includes the following areas:

• Middle James: Albemarle, Amelia, Amherst, Appomattox, Buckingham, Chesterfield, Cumberland, Fluvanna, Goochland, Hanover, Henrico, Nelson, Powhatan, Prince Edward counties; and the cities of Charlottesville, Colonial Heights, Hopewell, Lynchburg, Petersburg, and Richmond
• Northern Virginia:  Arlington, Fairfax, Fauquier, Loudoun, and Prince William counties; and the cities of Arlington, Fairfax, Falls Church, Manassas, and Manassas Park 
• Northern Piedmont: Culpeper, Greene, Louisa, Madison, Orange, Rappahannock, Spotsylvania, and Stafford counties; and the city of Fredericksburg
• Roanoke River: Bedford, Campbell, Charlotte, Franklin, Patrick, Halifax, Henry, Mecklenburg, Pittsylvania, and Roanoke counties; and the cities of Bedford, Martinsville, Salem, and Roanoke
• Upper James: Alleghany, Bath, Craig, Botetourt, Highland, and Rockbridge counties; and the city of Covington
• Shenandoah: Augusta, Clarke, Frederick, Page, Rockingham, Shenandoah, and Warren counties; and the cities of Buena Vista, Harrisonburg, Lexington, Staunton, Waynesboro, and Winchester

Recent lack of precipitation has resulted in continued below normal or declines in streamflow and groundwater levels throughout northern, central, and south-central regions of the state. The forecast for the next week suggests limited precipitation east of the Blue Ridge Mountains (0.10 to 0.25”) with slightly higher, but still below normal, totals forecasted in western portions of the Commonwealth (0.25 to 0.5”). Above normal temperatures are predicted over all the Commonwealth for the next two weeks. Below normal water levels are present in Smith Mountain Lake and Switzer Lake with storage at all other major water supply reservoirs at normal levels.

Groundwater monitoring wells along the Blue Ridge Mountains and throughout northern portions of the state continue to exhibit moderate declines and were generally below or much below normal levels in these areas. Groundwater levels in three indicator wells were below the 5th percentile, one in the Roanoke and two in the Northern Virginia drought evaluation regions. Groundwater levels in three indicator wells were between the 5th and 10th percentiles, one in each of the Roanoke, Northern Virginia, and Upper James drought evaluation regions.

from USGS

DEQ is working with local governments, public water works, and water users in the affected areas to ensure that conservation and drought response plans and ordinances are followed. Localities and residents that are supplied water from the Potomac River should consult the Metropolitan Washington Water Supply and Drought Awareness Response Plan for specific triggers and actions to be taken. All Virginians are encouraged to protect water supplies by minimizing water use, monitoring drought conditions, and detecting and repairing leaks.

Water Impacts of Data Centers in the Potomac River Basin

The following is a summary of a recent presentation by Alimatou Seck, PhD Senior Water Resources Scientist Interstate Commission on the Potomac River Basin (ICPRB). All points, and data are hers. The video of the presentation is worth watching if want to know more.

Webinar: Water Impacts from Data Centers in the Potomac River Basin - YouTube

Water Supply System Overview

The Washington Metropolitan Area (WMA) water supply system provides water to approximately 6.1 million residents across three states. On average, the system meets a demand of 400 million gallons per day (MGD), with peak demand escalating to 600 MGD during the month of August. Upstream, consumptive water use averages 107 MGD annually, but reaches 125 MGD in the summer. This upstream use has a noticeable effect on the overall flow of the Potomac River.

 
Data Center Water Use

Data centers play a critical role in supporting digital infrastructure, and their growth has accelerated rapidly due to advancements in artificial intelligence (AI) and the expansion of cloud computing services. In the United States, water consumption had been stable for a extended period of time then water consumption specifically by data centers increased from 15 MGD in 2014 to 48 MGD in 2023. In Virginia alone, data centers used an estimated 2.1 billion gallons of water in 2023, averaging about 6 MGD.

 
Cooling Technologies

Data centers utilize various cooling methods to manage heat and maintain operational efficiency. These include air cooling, evaporative cooling, and direct liquid cooling. Among these, direct liquid cooling is recognized for its lower water footprint compared to traditional cooling techniques. Additionally, hybrid cooling systems are being adopted to further minimize water losses by recirculating water within the system.

 
Water Use Estimates

On average, each data center facility uses between 38,000 and 42,000 gallons of water per day, though this data includes the older and smaller data centers built earlier and few of the new hyperscale data centers that are currently being built. Data centers do not disclose their power usage nor water usage. Dr. Seck used power consumption as derived from backup generator permits and disclosure from the ICPRB water utility partner to determine the relationship between power consumption and water use. Then she used the projections from the JLARC report to project a range of water use. Projections indicate that water use by data centers will increase substantially by 2050. The extent of growth will largely dependent on the adoption of efficient cooling technologies.

 
Future Projections

Looking ahead, the water consumption of data centers is expected to rise markedly. Under medium-growth scenarios, peak day water use could reach as high as 80 MGD by 2050 (that's 13% of summer water use). Water use also displays seasonal variability, using the most water in the summers when temperatures are highest. Combining the drought experience in the summer of 2023 with the projected growth in summer water demand it appears that there will not be enough storage and reserves in the system to meet the forecast demand during dry / drought periods.

 
Key Takeaways

• Currently, data centers have a modest impact on overall water use in the region, but they represent a rapidly growing sector.
• Future water use will be shaped by technology choices and trends in energy demand.
• Building resilience in the system will require effective management of both water and energy needs, especially in the face of uncertainty.

Further Considerations

• Transparency in water and energy usage data is essential for managing future demand effectively.
• There is potential for state-level regulations to restrict water withdrawals by data centers in the future.
• Ongoing innovations in technology and operational practices can improve water use efficiency across the sector.

Iran’s Teaters on the Edge

 Iran has begun water rationing due to a severe drought and decades of mismanagement, leading to critically low levels in reservoirs. In response to the crisis, authorities have lowered water pressure, implemented nightly cuts in Tehran (before it was announced), and have already started rationing in some cities.

The authorities have also called on people to curb consumption during the day. Water rationing has not yet been reported in other parts of Iran. The Iranian President, Masoud Pezeshkian, has warned that Tehran could face more severe rationing or even evacuation if rainfall does not increase soon, a scenario that could affect the almost 10 million people of Tehran.

The five main reservoirs supplying water to Tehran are at historically low levels, currently holding just 11% of overall capacity. In Mashhad, Iran's second-largest city with 4 million residents, reservoirs have fallen below 3% of their capacity, with three of the four dams supplying the city now out of operation due to lack of water. Nationwide, 10% percent of Iran's reservoirs have run completely dry, and more than 20 dams are holding under 5% of their capacity.

Short-term fixes exist, but experts say fundamental reforms and tough policy decisions are needed to avert a catastrophe. Without rain and swift and effective action it is hard to see how the regime will survive. Attempts at seeding the rain clouds have failed because there was not enough moisture. Iranian officials have not yet presented a concrete plan to tackle the emergency but suggest prayer.

Water scarcity is already fueling local tensions and protests, which could escalate into broader social conflict, especially as rising inflation, unemployment, housing issues, and the high cost of living further erode people’s capacity to cope with yet one more crisis.

Conspiracy theories are once more rampant usually accusing Israel and the U.S. of stealing Iran’s rain clouds. Most recently the Middle East Media Research Institute (MEMRI), Mohsen Arbabian claimed in an interview on the Iranian YouTube channel that the U.S. and Israel have been "deliberately diverting clouds" away from Iran for over four decades, alleging that satellite imagery shows altered cloud trajectories. He contrasted the low water levels of Iran’s Lake Urmia now nearly dry with the relatively stable levels of Turkey’s Lake Van as supposed evidence of this manipulation.

This echo’s Brigadier General Gholam Reza Jalali, head of Iran's Civil Defense Organization, 2018 claim that "Israel and another country in the region have joint teams which work to ensure clouds entering Iranian skies are unable to release rain". Similar claims were made by other officials and experts in the past two years as the drought in Iran worsened. 

However, Reza Haji-Karim, head of Iran’s Water Industry Federation, told the website Didban Iran that the city’s water resources are in decline. “Water rationing should have started much earlier. Right now, 62% of Tehran’s water comes from underground sources, and the level of these aquifers has dropped sharply.”

The crisis, he said, is the result of years of neglecting scientific warnings about groundwater depletion and climate change. “The only way to save Tehran is through a chain of measures – from wastewater recycling and consumption reform to cutting agricultural water use,” he added. Unfortunately for them, despite a decade of warnings they have waited too long.

More than 90% of Iran’s water supply is used for irrigation. Iranian law requires that 85% of food be produced domestically. However, Iran does not have the water and soil resources for that, and nearly 30% of agricultural produce is wasted due to a lack of infrastructure, outdated irrigation practices and misguided crop selection according to Morad Kaviani, Professor of geography and hydro- politics at Kharazmi University.

Iran has been using groundwater reserves at unchecked rates; leading to widespread land subsidence and ecosystem collapse in central Iran and Sistan and Baluchestan to the southeast. Tehran and many other cities have outgrown their supplies, forcing reliance on water transfers from distant aquifers via outdated and poorly maintained infrastructure.

We are going to see unfolding in real time the fate that awaits governments that mismanage water resources. Not just dictatorships, it is common under all forms of government to ignore water resource management when there are competing concerns. However, even in water resource rich areas our cities are running up against the true limits of freshwater on earth.

Lake  Urmia, Iran from NASA