Why California's Climate Policies Are Causing Electricity Blackouts


california blackouts

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California Rolling Blackouts expose grid reliability risks amid a heatwave, as CAISO curtails power while solar output fades at sunset, wind stalls, and scarce natural gas and nuclear capacity plus PG&E issues strain imports.

 

Key Points

Grid outages during heatwaves from low reserves, fading solar, weak wind, and limited firm capacity.

✅ Heatwave demand rose as solar output dropped at sunset

✅ Limited imports and gas, nuclear shortfalls cut reserves

✅ Policy, pricing, and maintenance gaps increased outage risk

 

Millions of Californians were denied electrical power and thus air conditioning during a heatwave, raising the risk of heatstroke and death, particularly among the elderly and sick. 

The blackouts come at a time when people, particularly the elderly, are forced to remain indoors due to Covid-19, and as later heat waves would test the grid again statewide.

At first, the state’s electrical grid operator last night asked customers to voluntarily reduce electricity use. But after lapses in power supply pushed reserves to dangerous levels it declared a “Stage 3 emergency” cutting off power to people across the state at 6:30 pm.

The immediate reason for the black-outs was the failure of a 500-megawatt power plant and an out-of-service 750-megawatt unit not being available. “There is nothing nefarious going on here,” said a spokeswoman for California Independent System Operator (CAISO). “We are just trying to run the grid.”

But the underlying reasons that California is experiencing rolling black-outs for the second time in less than a year stem from the state’s climate policies, which California policymakers have justified as necessary to prevent deaths from heatwaves, and which it is increasingly exporting to Western states as a model.

In October, Pacific Gas and Electric cut off power to homes across California to avoid starting forest fires after reports that its power lines may have started fires in recent seasons. The utility and California’s leaders had over the previous decade diverted billions meant for grid maintenance to renewables. 

And yesterday, California had to impose rolling blackouts because it had failed to maintain sufficient reliable power from natural gas and nuclear plants, or pay in advance for enough guaranteed electricity imports from other states.

It may be that California’s utilities and their regulator, the California Public Utilities Commission, which is also controlled by Gov. Newsom, didn’t want to spend the extra money to guarantee the additional electricity out of fears of raising California’s electricity prices even more than they had already raised them.

California saw its electricity prices rise six times more than the rest of the United States from 2011 to 2019, helping explain why electricity prices are soaring across the state, due to its huge expansion of renewables. Republicans in the U.S. Congress point to that massive increase to challenge justifications by Democrats to spend $2 trillion on renewables in the name of climate change.

Even though the cost of solar panels declined dramatically between 2011 and 2019, their unreliable and weather-dependent nature meant that they imposed large new costs in the form of storage and transmission to keep electricity as reliable. California’s solar panels and farms were all turning off as the blackouts began, with no help available from the states to the East already in nightfall.

Electricity from solar goes away at the very moment when the demand for electricity rises. “The peak demand was steady in late hours,” said the spokesperson for CAISO, which is controlled by Gov. Gavin Newsom, “and we had thousands of megawatts of solar reducing their output as the sunset.”

The two blackouts in less than a year are strong evidence that the tens of billions that Californians have spent on renewables come with high human, economic, and environmental costs.

Last December, a report by done for PG&E concluded that the utility’s customers could see blackouts double over the next 15 years and quadruple over the next 30.

California’s anti-nuclear policies also contributed to the blackouts. In 2013, Gov. Jerry Brown forced a nuclear power plant, San Onofre, in southern California to close.

Had San Onofre still been operating, there almost certainly would not have been blackouts on Friday as the reserve margin would have been significantly larger. The capacity of San Onofre was double that of the lost generation capacity that triggered the blackout.

California's current and former large nuclear plants are located on the coast, which allows for their electricity to travel shorter distances, and through less-constrained transmission lines than the state’s industrial solar farms, to get to the coastal cities where electricity is in highest demand.

There has been very little electricity from wind during the summer heatwave in California and the broader western U.S., further driving up demand. In fact, the same weather pattern, a stable high-pressure bubble, is the cause of heatwaves, since it brought very low wind for days on end along with very high temperatures.

Things won’t be any better, and may be worse, in the winter, with a looming shortage as it produces far less solar electricity than the summer. Solar plus storage, an expensive attempt to fix problems like what led to this blackout, cannot help through long winters of low output.

California’s electricity prices will continue to rise if it continues to add more renewables to its grid, and goes forward with plans to shut down its last nuclear plant, Diablo Canyon, in 2025.

Had California spent an estimated $100 billion on nuclear instead of on wind and solar, it would have had enough energy to replace all fossil fuels in its in-state electricity mix.

To manage the increasingly unreliable grid, California will either need to keep its nuclear plant operating, build more natural gas plants, underscoring its reliance on fossil fuels for reliability, or pay ever more money annually to reserve emergency electricity supplies from its neighbors.

After the blackouts last October, Gov. Newsom attacked PG&E Corp. for “greed and mismanagement” and named a top aide, Ana Matosantos, to be his “energy czar.” 

“This is not the new normal, and this does not take 10 years to solve,” Newsom said. “The entire system needs to be reimagined.”

 

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Neste increases the use of wind power at its Finnish production sites to nearly 30%

Neste wind power agreement boosts renewable electricity in Finland, partnering with Ilmatar and Fortum to supply Porvoo and Naantali sites, cutting Scope 2 emissions and advancing a 2035 carbon-neutral production target via long-term PPAs.

 

Key Points

A PPA to source wind power for sites, cutting Scope 2 emissions and supporting Neste's 2035 carbon-neutral goal.

✅ 10-year PPA with Ilmatar; + Fortum boosts renewable electricity share.

✅ Supplies ~7% of Porvoo-Naantali electricity; capacity >20 MW.

✅ Cuts Scope 2 emissions by ~55 kt CO2e per year toward 2035 neutrality.

 

Neste is committed to reaching carbon neutral production by 2035, mirroring efforts such as Olympus 100% renewable electricity commitments across industry.

As part of this effort, the company is increasing the use of renewable electricity at its production sites in Finland, reflecting trends such as Ireland's green electricity targets across Europe, and has signed a wind power agreement with Ilmatar, a wind power company. The agreement has been made together with Borealis, Neste's long-term partner in the Kilpilahti area in Porvoo, Finland.

As a result of the agreement with Ilmatar, as well as that signed with Fortum at the end of 2019, and in line with global growth such as Enel's 450 MW wind project in the U.S., nearly 30% of the energy used at Neste's production sites in Porvoo and Naantali will be renewable wind power in 2022.

'Neste's purpose is to create a healthier planet for our children. Our two climate commitments play an important role in living up to this ambition, and one of them is to reach carbon neutral production by 2035. It is an enormous challenge and requires several concrete measures and investments, including innovations like offshore green hydrogen initiatives. Wind power, including advances like UK offshore wind projects, is one of the over 70 measures we have identified to reduce our production's greenhouse gas emissions,' Neste's President and CEO Peter Vanacker says.

With the ten year contract, Neste is committed to purchase about one-third of the production of Ilmatar's two wind farms, reflecting broader market moves such as BC Hydro wind deals in Canada. The total capacity of the agreement is more than 20 MW, and the energy produced will correspond to around 7% of the electricity consumption at Neste's sites in Porvoo and Naantali. The wind power deliveries are expected to begin in 2022.

The two wind power agreements help Neste to reduce the indirect greenhouse gas emissions (Scope 2 emissions defined by the Greenhouse Gas Protocol) of electricity purchases at its Finnish production sites, a trend mirrored by Dutch green electricity growth across Europe, annually by approximately 55 kilotons. 55 kt/a CO2e equals annual carbon footprint of more than 8,500 EU citizens.

 

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Energy experts: US electric grid not designed to withstand the impacts of climate change

Summer Power Grid Reliability and Climate Risk drives urgent planning as extreme heat, peak demand, drought, and aging infrastructure strain ERCOT, NERC regions, risking outages without renewables integration and climate-informed grid modeling.

 

Key Points

Assessment of how extreme weather and demand stress the US grid, informing climate-smart planning to reduce outages.

✅ Many operators rely on historical weather, not climate projections

✅ NERC flags elevated blackout risk amid extreme heat and drought

✅ Renewables and storage can boost capacity and cut emissions

 

As heat ramps up ahead of what forecasters say will be a hotter than normal summer, electricity experts and officials are warning that states may not have enough power to meet demand in the coming months. And many of the nation's grid operators are also not taking climate change into account in their planning, despite available grid resilience guidance that could inform upgrades, even as extreme weather becomes more frequent and more severe.

Power operators in the Central US, in their summer readiness report, have already predicted "insufficient firm resources to cover summer peak forecasts." That assessment accounted for historical weather and the latest NOAA outlook that projects for more extreme weather this summer.

But energy experts say that some power grid operators are not considering how the climate crisis is changing our weather — including more frequent extreme events — and that is a problem if the intent is to build a reliable power grid while accelerating investing in carbon-free electricity across markets.

"The reality is the electricity system is old and a lot of the infrastructure was built before we started thinking about climate change," said Romany Webb, a researcher at Columbia University's Sabin Center for Climate Change Law. "It's not designed to withstand the impacts of climate change."

Webb says many power grid operators use historical weather to make investment decisions, rather than the more dire climate projections, simply because they want to avoid the possibility of financial loss, even as climate-related credit risks for nuclear plants are being flagged, for investing in what might happen versus what has already happened. She said it's the wrong approach and it makes the grid vulnerable.

"We have seen a reluctance on the part of many utilities to factor climate change into their planning processes because they say the science around climate change is too uncertain," Webb said. "The reality is we know climate change is happening, we know the impact it has in terms of more severe heatwaves, hurricanes, drought, with recent hydropower constraints in British Columbia illustrating the risks, and we know that all of those things affect the electricity system so ignoring those impacts just makes the problems worse."

An early heatwave knocked six power plants offline in Texas earlier this month. Residents were asked to limit electricity use, keeping thermostats at 78 degrees or higher and, as extreme heat boosts electricity bills for consumers, avoid using large appliances at peak times. The Electric Reliability Council of Texas, or ERCOT, in its seasonal reliability report, said the state's power grid is prepared for the summer and has "sufficient" power for "normal" summer conditions, based on average weather from 2006 to 2020.

But NOAA's recently released summer outlook forecasts above average temperatures for every county in the nation.

"We are continuing to design and site facilities based on historical weather patterns that we know in the age of climate change are not a good proxy for future conditions," Webb said.

When asked if the agency is creating a blind spot for itself by not accounting for extreme weather predictions, an ERCOT spokesperson said the report "uses a scenario approach to illustrate a range of resource adequacy outcomes based on extreme system conditions, including some extreme weather scenarios."

The North American Electric Reliability Corporation, or NERC — a regulating authority that oversees the health of the nation's electrical infrastructure — has a less optimistic projection.

In a recent seasonal reliability report, NERC placed Texas at "elevated risk" for blackouts this summer. It also reported that while much of the nation will have adequate electricity this summer, several markets are at risk of energy emergencies.

California grid operators, who recently avoided widespread rolling blackouts as heat strained the grid, in its summer reliability report also based its readiness analysis on "the most recent 20 years of historical weather data." The report also notes the assessment "does not fully reflect more extreme climate induced load and supply uncertainties."

Compounding the US power grid's supply and demand problem is drought: NERC says there's been a 2% loss of reliable hydropower from the nation's power-producing dams. Add to that the rapid retirement of many coal power plants — all while nearly everything from toothbrushes to cars are now electrified. Energy experts say adding more renewables into the mix will have the dual impact of cutting climate change inducing greenhouse gas emissions but also increasing the nation's power supply, aligning with efforts such as California's 100% carbon-free mandate that aim to speed the transition.
 

 

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Trump Is Seen Replacing Obama’s Power Plant Overhaul With a Tune-Up

Clean Power Plan Rollback signals EPA's shift to inside-the-fence efficiency at coal plants, emphasizing heat-rate improvements over sector-wide decarbonization, renewables, natural gas switching, demand-side efficiency, and carbon capture under Clean Air Act constraints.

 

Key Points

A policy shift by the EPA to replace broad emissions rules with plant-level efficiency standards, limiting CO2 cuts.

✅ Inside-the-fence heat-rate improvements at coal units

✅ Potential CO2 cuts limited to about 6% per plant

✅ Alternatives: fuel switching, renewables, carbon capture

 

President Barack Obama’s signature plan to reduce carbon dioxide emissions from electrical generation took years to develop and touched every aspect of power production and use, from smokestacks to home insulation.

The Trump administration is moving to scrap that plan and has signaled that any alternative it might adopt would take a much less expansive approach, possibly just telling utilities to operate their plants more efficiently.

That’s a strategy environmentalists say is almost certain to fall short of what’s needed.

The Trump administration is making "a wholesale retreat from EPA’s legal, scientific and moral obligation to address the threats of climate change," said former Environmental Protection Agency head Gina McCarthy, the architect of Obama’s Clean Power Plan.

President Donald Trump promised to rip up the initiative, echoing an end to the 'war on coal' message from his campaign, which mandated that states change their overall power mix, displacing coal-fired electricity with that from wind, solar and natural gas. The EPA is about to make it official, arguing the prior administration violated the Clean Air Act by requiring those broad changes to the electricity sector, according to a draft obtained by Bloomberg.

 

Possible Replacements

Later, the agency will also ask the public to weigh in on possible replacements. The administration will ask whether the EPA can or should develop a replacement rule -- and, if so, what actions can be mandated at individual power plants, though some policymakers favor a clean electricity standard to drive broader decarbonization.

 

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Such changes -- such as adding automation or replacing worn turbine seals -- would yield at most a 6 percent gain in efficiency, along with a corresponding fall in greenhouse gas emissions, according to earlier modeling by the Environmental Protection Agency and other analysts. That compares to the 32 percent drop in emissions by 2030 under Obama’s Clean Power Plan.

"In these existing plants, there’s only so many places to look for savings," said John Larsen, a director of the Rhodium Group, a research firm. "There’s only so many opportunities within a big spinning machine like that."

EPA Administrator Scott Pruitt outlined such an "inside-the-fence-line" approach in 2014, later embodied in the Affordable Clean Energy rule that industry groups backed, when he served as Oklahoma’s attorney general. Under his blueprint, states would set emissions standards after a detailed unit-by-unit analysis, looking at what reductions are possible given "the engineering limits of each facility."

The EPA has not decided whether it will promulgate a new rule at all, though it has also proposed new pollution limits for coal and gas plants in separate actions. In a forthcoming advanced notice of proposed rulemaking, the EPA will ask "what inside-the-fence-line options are legal, feasible and appropriate," according to a document obtained by Bloomberg.

Increased efficiency at a coal plant -- known as heat-rate improvement -- translates into fewer carbon-dioxide emissions per unit of electric power generated.

Under Obama, the EPA envisioned utilities would make some straightforward efficiency improvements at coal-fired power plants as the first step to comply with the Clean Power Plan. But that was expected to coincide with bigger, broader changes -- such as using more cleaner-burning natural gas, adding more renewable power projects and simply encouraging customers to do a better job turning down their thermostats and turning off their lights.

Obama’s EPA didn’t ask utilities to wring every ounce of efficiency they could out of coal-fired power plants because they saw the other options as cheaper. A plant-specific approach "would be grossly insufficient to address the public health and environmental impacts from CO2 emissions," Obama’s EPA said.

That approach might yield modest emissions reductions and, in a perverse twist, might event have the opposite effect. If utilities make coal plants more efficient -- thereby driving down operating costs -- they also make them more competitive with natural gas and renewables, "so they might run more and pollute more," said Conrad Schneider, advocacy director for the Clean Air Task Force.  

In a competitive market, any improvement in emissions produced for each unit of energy could be overwhelmed by an increase in electrical output, and debates over changes to electricity pricing under Trump and Perry added further uncertainty.

"A very minor heat rate improvement program would very likely result in increased emissions," Schneider said. "It might be worse than nothing."

Power companies want to get as much electricity as possible from every pound of coal, so they already have an incentive to keep efficiency high, said Jeff Holmstead, a former assistant EPA administrator now at Bracewell LLP. But an EPA regulation known as “new source review” has discouraged some from making those changes, for fear of triggering other pollution-control requirements, he said.

"If EPA’s replacement rule allows companies to improve efficiency without triggering new source review, it would make a real difference in terms of reducing carbon-dioxide emissions," Holmstead said.

 

Modest Impact

A plant-specific approach doesn’t have to mean modest impact.

"If you’re thinking about what can be done at the power plants by themselves, you don’t stop at efficiency tune-ups," said David Doniger, director of the Natural Resources Defense Council’s climate and clean air program. "You look at things like switching to natural gas or installing carbon capture and storage."

Requirements that facilities use carbon capture technology or swap in natural gas for coal could actually come close to hitting the same goals as in Obama’s Clean Power Plan -- if not go even further, Schneider said. They just would cost more.

The benefit of the Clean Power Plan "is that it enabled states to create programs and enabled companies to find a reduction strategy that was the most efficient and made the most sense for their own content," said Kathryn Zyla, deputy director of the Georgetown Climate Center. "And that flexibility was really important for the states and companies."

Some utilities, including Houston-based Calpine Corp., PG&E Corp. and Dominion Resources Inc., backed the Obama-era approach. And they are still pushing the Trump administration to be creative now.

"The Clean Power Plan achieved a thoughtful, balanced approach that gave companies and states considerable flexibility on how best to pursue that goal," said Melissa Lavinson, vice president of federal affairs and policy for PG&E’s Pacific Gas and Electric utility. “We look forward to working with the administration to devise an alternative plan for decarbonizing the U.S. economy."

 

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Key Ontario power system staff may end up locked down at work sites due to COVID-19, operator says

Ontario IESO COVID-19 Control Room Measures detail how essential operators safeguard the electricity grid with split shifts, backup control centres, real-time balancing, deep cleaning, social distancing, and shelter-in-place readiness to maintain reliable power.

 

Key Points

Measures that protect essential grid operators with split shifts, backup sites, and hygiene to keep power reliable.

✅ Split teams across primary and backup control centres

✅ 12-hour shifts with remote handoffs and deep cleaning

✅ Real-time grid modeling to balance demand and supply

 

A group of personnel key to keeping Ontario's electricity system functioning may end up locked down in their control centres due to the COVID-19 crisis, according to the head of the province's power operator.

But that has so far proven unnecessary with a change-up in routine, Independent Electricity System Operator CEO Peter Gregg said.

While about 90 per cent of staff were sent to work from home on March 13, another 48 control-room operators deemed essential are still going into work, Gregg said in an interview.

"We identified a smaller cohort of critical operations room staff that need to go in to operate the system out of our control centres," Gregg said. "My biggest concern is to maintain their health, their safety as we rely on them to do this critical work."

Some of the operators manage power demand and supply in real time as Ontario electricity demand shifts, by calling for more or less generation and keeping an eye on the distribution grid, which also allows power to flow to and from Ontario's neighbours. Others do scenario planning and modelling to prepare for changes.

The essential operators have been split into eight teams of six each working 12-hour shifts. The day crew works out of a control centre near Toronto and the night shift out of a backup centre in the city's west end, Gregg said.

"That means that we're not having physical hand-off between control room operators on shift change -- we can do it remotely -- and it also allows us to do deep cleansing," Gregg said. "We're fortunate that the way the room is set up allows us to practice good social distancing."

Should it become necessary, he said, bed, food and other on-site arrangements have been made to allow the operators to stay at their workplaces as a similar agency in New York has done.

"If we do need to shelter these critical employees in place, we've got the ability to do so."

IESO is responsible for ensuring a balance between supply and demand for electricity across the province. Because power cannot be stored, the IESO ensures generators produce enough power to meet peak demand while making sure they don't produce too much.

"You're seeing, obviously, commercial demand drop, some industrial demand drop," Gregg said. "But you're also seeing a shift in the demand curve as well, where normally you have people heading off to work and so residential demand would go down. But obviously with them staying home, you're seeing an increase in residential electricity use across the province."

Some utilities have indicated no cuts to peak rates for self-isolating customers, with Hydro One peak pricing remaining in place for now.

IESO also runs and settles the wholesale electricity markets. Market prices are set based on accepted offers to supply electricity, while programs supporting stable electricity pricing for industrial and commercial users can affect costs against forecast demand.

With the pandemic forcing many businesses to close and people to stay home, and provincial electricity relief for families and small businesses in place, typical power needs fallen about seven per cent at a time of year that would normally see demand soften anyway. It remains to be seen whether, and how much, power needs shift further amid stringent isolation measures and the ongoing economic impact of the outbreak.

Gregg said the operator is constantly modeling different possibilities.

"What we do normally is prepare for all of these sort of emergency scenarios, as reflected in the U.S. grid response coverage, and test and drill for these," he said. "What we're experiencing over the last few weeks is that those drills come in handy because they help us prepare for when the real-time situation actually happens."

 

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Relief for power bills in B.C. offered to only part of province

BC Hydro COVID-19 Relief offers electricity bill credits for laid-off workers and small business support, announced by Premier John Horgan, while FortisBC customers face deferrals and billing arrangements across Kelowna, Okanagan, and West Kootenay.

 

Key Points

BC Hydro COVID-19 Relief gives bill credits to laid-off residents; FortisBC offers deferrals and payment plans.

✅ Credit equals 3x average monthly bill for laid-off BC Hydro users

✅ Small businesses on BC Hydro get three months bill forgiveness

✅ FortisBC waives late fees, no disconnections, offers deferrals

 

On April 1, B.C. Premier John Horgan announced relief for BC Hydro customers who are facing bills after being laid-off during the economic shutdown due to the COVID-19 epidemic, while the utility also explores time-of-use rates to manage demand.

“Giving people relief on their power bills lets them focus on the essentials, while helping businesses and encouraging critical industry to keep operating,” he said.

BC Hydro residential customers in the province who have been laid off due to the pandemic will see a credit for three times their average monthly bill and, similar to Ontario's pandemic relief fund, small businesses forced to close will have power bills forgiven for three months.

But a large region of the province which gets its power from FortisBC will not have the same bail out.

FortisBC is the electricity provider to the tens of thousands who live and work in the Silmikameen Valley on Highway 3, the city of Kelowna, the Okanagan Valley south from Penticton, the Boundary region along the U.S. border. as well as West Kootenay communities.

“We want to make sure our customers are not worried about their FortisBC bill,” spokesperson Nicole Brown said.

FortisBC customers will still be on the hook for bills despite measures being taken to keep the lights on, even as winter disconnection pressures have been reported elsewhere.

Recent storm response by BC Hydro also highlights how crews have kept electricity service reliable during recent atypical events.

“We’ve adjusted our billing practices so we can do more,” she said. “We’ve discontinued our late fees for the time being and no customer will be disconnected for any financial reason.”

Brown said they will work one-on-one with customers to help find a billing arrangement that best suits their needs, aligning with disconnection moratoriums seen in other jurisdictions.

Those arrangement, she said, could include a “deferral, an equal payment plan or other billing options,” similar to FortisAlberta's precautions announced in Alberta.

Global News inquired with the Premier’s office why FortisBC customers were left out of Wednesday’s announcement and were deferred to the Ministry of Energy, Mines and Petroleum Resources.

The Ministry referred us back to FortisBC on the issue and offered no other comment, even as peak rates for self-isolating customers remained unchanged in parts of Ontario.

“We’re examining all options of how we can further help our customers and look forward to learning more about the program that BC Hydro is offering,” Brown said.

Disappointed FortisBC customers took to social media to vent about the disparity.

 

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Potent greenhouse gas declines in the US, confirming success of control efforts

US SF6 Emissions Decline as NOAA analysis and EPA mitigation show progress, with atmospheric measurements and Greenhouse Gas Reporting verifying reductions from the electric power grid; sulfur hexafluoride's extreme global warming potential underscores inventory improvements.

 

Key Points

A documented drop in US sulfur hexafluoride emissions, confirmed by NOAA atmospheric data and EPA reporting reforms.

✅ NOAA towers and aircraft show 2007-2018 decline

✅ EPA reporting and utility mitigation narrowed inventory gaps

✅ Winter leaks and servicing signal further reduction options

 

A new NOAA analysis shows U.S. emissions of the super-potent greenhouse gas sulfur hexafluoride (SF6) have declined between 2007-2018, likely due to successful mitigation efforts by the Environmental Protection Agency (EPA) and the electric power industry, with attention to SF6 in the power industry across global markets. 

At the same time, significant disparities that existed previously between NOAA’s estimates, which are based on atmospheric measurements, and EPA’s estimates, which are based on a combination of reported emissions and industrial activity, have narrowed following the establishment of the EPA's Greenhouse Gas Reporting Program. The findings, published in the journal Atmospheric Chemistry and Physics, also suggest how additional emissions reductions might be achieved. 

SF6 is most commonly used as an electrical insulator in high-voltage equipment that transmits and distributes electricity, and its emissions have been increasing worldwide as electric power systems expand, even as regions hit milestones like California clean energy surpluses in recent years. Smaller amounts of SF6 are used in semiconductor manufacturing and in magnesium production. 

SF6 traps 25,000 times more heat than carbon dioxide over a 100-year time scale for equal amounts of emissions, and while CO2 emissions flatlined in 2019 globally, that comparison underscores the potency of SF6. That means a relatively small amount of the gas can have a significant impact on climate warming. Because of its extremely large global warming potential and long atmospheric lifetime, SF6 emissions will influence Earth’s climate for thousands of years.

In this study, researchers from NOAA’s Global Monitoring Laboratory, as record greenhouse gas concentrations drive demand for better data, working with colleagues at EPA, CIRES, and the University of Maryland, estimated U.S. SF6 emissions for the first time from atmospheric measurements collected at a network of tall towers and aircraft in NOAA’s Global Greenhouse Gas Reference Network. The researchers provided an estimate of SF6 emissions independent from the EPA’s estimate, which is based on reported SF6 emissions for some industrial facilities and on estimated SF6 emissions for others.

“We observed differences between our atmospheric estimates and the EPA’s activity-based estimates,” said study lead author Lei Hu, a Global Monitoring Laboratory researcher who was a CIRES scientist at the time of the study. “But by closely collaborating with the EPA, we were able to identify processes potentially responsible for a significant portion of this difference, highlighting ways to improve emission inventories and suggesting additional emission mitigation opportunities, such as forthcoming EPA carbon capture rules for power plants, in the future.” 

In the 1990s, the EPA launched voluntary partnerships with the electric power, where power-sector carbon emissions are falling as generation shifts, magnesium, and semiconductor industries to reduce SF6 emissions after the United States recognized that its emissions were significant. In 2011, large SF6 -emitting facilities were required to begin tracking and reporting their emissions under the EPA Greenhouse Gas Reporting Program. 

Hu and her colleagues documented a decline of about 60 percent in U.S. SF6 emissions between 2007-2018, amid global declines in coal-fired power in some years—equivalent to a reduction of between 6 and 20 million metric tons of CO2 emissions during that time period—likely due in part to the voluntary emission reduction partnerships and the EPA reporting requirement. A more modest declining trend has also been reported in the EPA’s national inventories submitted annually under the United Nations Framework Convention on Climate Change. 

Examining the differences between the NOAA and EPA independent estimates, the researchers found that the EPA’s past inventory analyses likely underestimated SF6 emissions from electrical power transmission and distribution facilities, and from a single SF6 production plant in Illinois. According to Hu, the research collaboration has likely improved the accuracy of the EPA inventories. The 2023 draft of the EPA’s U.S. Greenhouse Gas Emissions and Sinks: 1990-2021 used the results of this study to support revisions to its estimates of SF6 emissions from electrical transmission and distribution. 

The collaboration may also lead to improvements in the atmosphere-based estimates, helping NOAA identify how to expand or rework its network to better capture emitting industries or areas with significant emissions, according to Steve Montzka, senior scientist at GML and one of the paper’s authors.

Hu and her colleagues also found a seasonal variation in SF6 emissions from the atmosphere-based analysis, with higher emissions in winter than in summer. Industry representatives identified increased servicing of electrical power equipment in the southern states and leakage from aging brittle sealing materials in the equipment in northern states during winter as likely explanations for the enhanced wintertime emissions—findings that suggest opportunities for further emissions reductions.

“This is a great example of the future of greenhouse gas emission tracking, where inventory compilers and atmospheric scientists work together to better understand emissions and shed light on ways to further reduce them,” said Montzka.

 

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