NRC seeks input on new nuclear design

Hourly Electricity Emissions Tracking maps grid balancing areas, embodied emissions, and imports/exports, revealing carbon intensity shifts across PJM, ERCOT, and California ISO, and clarifying renewable energy versus coal impacts on health and climate.

Key Points

An hourly method tracing generation, flows, and embodied emissions to quantify carbon intensity across US balancing areas.

✅ Hourly traces of imports/exports and generation mix

✅ Consumption-based carbon intensity by balancing area

✅ Policy insights for renewables, coal, health costs

In the United States, electricity generation accounts for nearly 30% of our carbon emissions. Some states have responded to that by setting aggressive renewable energy standards; others are hoping to see coal propped up even as its economics get worse. Complicating matters further is the fact that many regional grids are integrated, and as America goes electric the stakes grow, meaning power generated in one location may be exported and used in a different state entirely.

Tracking these electricity exports is critical for understanding how to lower our national carbon emissions. In addition, power from a dirty source like coal has health and environment impacts where it's produced, and the costs of these aren't always paid by the parties using the electricity. Unfortunately, getting reliable figures on how electricity is produced and where it's used is challenging, even for consumers trying to find where their electricity comes from in the first place, leaving some of the best estimates with a time resolution of only a month.

Now, three Stanford researchers—Jacques A. de Chalendar, John Taggart, and Sally M. Benson—have greatly improved on that standard, and they have managed to track power generation and use on an hourly basis. The researchers found that, of the 66 grid balancing areas within the United States, only three have carbon emissions equivalent to our national average, and they have found that imports and exports of electricity have both seasonal and daily changes. de Chalendar et al. discovered that the net results can be substantial, with imported electricity increasing California's emissions/power by 20%.

Hour by hour
To figure out the US energy trading landscape, the researchers obtained 2016 data for grid features called balancing areas. The continental US has 66 of these, providing much better spatial resolution on the data than the larger grid subdivisions. This doesn't cover everything—several balancing areas in Canada and Mexico are tied in to the US grid—and some of these balancing areas are much larger than others. The PJM grid, serving Pennsylvania, New Jersey, and Maryland, for example, is more than twice as large as Texas' ERCOT, in a state that produces and consumes the most electricity in the US.

Despite these limitations, it's possible to get hourly figures on how much electricity was generated, what was used to produce it, and whether it was used locally or exported to another balancing area. Information on the generating sources allowed the researchers to attach an emissions figure to each unit of electricity produced. Coal, for example, produces double the emissions of natural gas, which in turn produces more than an order of magnitude more carbon dioxide than the manufacturing of solar, wind, or hydro facilities. These figures were turned into what the authors call "embodied emissions" that can be traced to where they're eventually used.

Similar figures were also generated for sulfur dioxide and nitrogen oxides. Released by the burning of fossil fuels, these can both influence the global climate and produce local health problems.

Huge variation
The results were striking. "The consumption-based carbon intensity of electricity varies by almost an order of magnitude across the different regions in the US electricity system," the authors conclude. The low is the Bonneville Power grid region, which is largely supplied by hydropower; it has typical emissions below 100kg of carbon dioxide per megawatt-hour. The highest emissions come in the Ohio Valley Electric region, where emissions clear 900kg/MW-hr. Only three regional grids match the overall grid emissions intensity, although that includes the very large PJM (where capacity auction payouts recently fell), ERCOT, and Southern Co balancing areas.

Most of the low-emissions power that's exported comes from the Pacific Northwest's abundant hydropower, while the Rocky Mountains area exports electricity with the highest associated emissions. That leads to some striking asymmetries. Local generation in the hydro-rich Idaho Power Company has embodied emissions of only 71kg/MW-hr, while its imports, coming primarily from Rocky Mountain states, have a carbon content of 625kg/MW-hr.

The reliance on hydropower also makes the asymmetry seasonal. Local generation is highest in the spring as snow melts, but imports become a larger source outside this time of year. As solar and wind can also have pronounced seasonal shifts, similar changes will likely be seen as these become larger contributors to many of these regional grids. Similar things occur daily, as both demand and solar production (and, to a lesser extent, wind) have distinct daily profiles.

The Golden State
California's CISO provides another instructive case. Imports represent less than 30% of its total electric use in 2016, yet California electricity imports provided 40% of its embodied emissions. Some of these, however, come internally from California, provided by the Los Angeles Department of Water and Power. The state itself, however, has only had limited tracking of imported emissions, lumping many of its sources as "other," and has been exporting its energy policies to Western states in ways that shape regional markets.

Overall, the 2016 inventory provides a narrow picture of the US grid, as plenty of trends are rapidly changing our country's emissions profile, including the rise of renewables and the widespread adoption of efficiency measures and other utility trends in 2017 that continue to evolve. The method developed here can, however, allow for annual updates, providing us with a much better picture of trends. That could be quite valuable to track things like how the rapid rise in solar power is altering the daily production of clean power.

More significantly, it provides a basis for more informed policymaking. States that wish to promote low-emissions power can use the information here to either alter the source of their imports or to encourage the sites where they're produced to adopt more renewable power. And those states that are exporting electricity produced primarily through fossil fuels could ensure that the locations where the power is used pay a price that includes the health costs of its production.

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Central Asia power shortages strain grids across Kazakhstan, Uzbekistan, Kyrgyzstan, Tajikistan, and Turkmenistan, driven by drought-hit hydropower, aging coal and gas plants, rising demand, cryptomining loads, and winter peak consumption risks.

Key Points

Regionwide blackouts from drought, aging plants and grids, rising demand, and winter peaks stressing Central Asia.

✅ Drought slashes hydropower in Kyrgyzstan, Tajikistan, Uzbekistan

✅ Aging coal and gas TPPs and weak grids cause frequent outages

✅ Cryptomining loads and winter heating spike demand and stress supply

Central Asians from western Kazakhstan to southern Tajikistan are suffering from power and energy shortages that have caused hardship and emergency situations affecting the lives of millions of people.

On October 14, several units at three power plants in northeastern Kazakhstan were shut down in an emergency that resulted in a loss of more than 1,000 megawatts (MW) of electricity.

It serves as an example of the kind of power failures that plague the region 30 years after the Central Asian countries gained independence and despite hundreds of millions of dollars being invested in energy infrastructure and power grids, and echo risks seen in other advanced markets such as Japan's near-blackouts during recent cold snaps.

Some of the reasons for these problems are clear, but with all the money these countries have allocated to their energy sectors and financial help they have received from international financial institutions, it is curious the situation is already so desperate with winter officially still weeks away.

The Current Problems
Three power plants were affected in the October 14 shutdowns of units: Ekibastuz-1, Ekibastuz-2, and the Aksu power plant.

Ekibastuz-1 is the largest power plant in Kazakhstan, capable of generating some 4,000 MW, roughly 13 percent of Kazakhstan’s total power output.

The Kazakhstan Electricity Grid Operating Company (KEGOC) explained the problems resulted partially from malfunctions and repair work, but also from overuse of the system that the government would later say was due to cryptominers, a large number of whom have moved to Kazakhstan recently from China after Beijing banned the mining needed by Bitcoin and other cryptocurrencies, amid its own China's power cuts across several provinces in 2021.

But between November 8 and 9, rolling blackouts were reported in the East Kazakhstan, North Kazakhstan, and Kyzylorda provinces, as well as the area around Almaty, Kazakhstan’s biggest city, and Shymkent, its third largest city.

People in Uzbekistan say they, too, are facing blackouts that the Energy Ministry described as “short-term outages,” even as authorities have looked to export electricity to Afghanistan to support regional demand, though it has been clear for several weeks that the country will have problems with natural gas supplies this winter.

Power lines in Uzbekistan
Kyrgyz President Sadyr Japarov continues to say there won't be any power rationing in Kyrgyzstan this winter, but at the end of September the National Energy Holding Company ordered “restrictions on the lighting of secondary streets, advertisements, and facades of shops, cafes, and other nonresidential customers.”

Many parts of Tajikistan are already experiencing intermittent supplies of electricity.

Even in Turkmenistan, a country with the fourth-largest reserves of natural gas in the world, there were reports of problems with electricity and heating in the capital, Ashgabat.

What Is Going On?
The causes of some of these problems are easy to see.

The population of the region has grown significantly, with the population of Central Asia when the Soviet Union collapsed in late 1991 being some 50 million and today about 75 million.

Kyrgyzstan and Tajikistan are mountainous countries that have long been touted for their hydropower potential and some 90 percent of Kyrgyzstan’s domestically produced electricity and 98 percent of Tajikistan’s come from hydropower.

But a severe drought that struck Central Asia this year has resulted in less hydropower and, in general, less energy for the region, similar to constraints seen in Europe's reduced hydro and nuclear output this year.

Tajik authorities have not reported how low the water in the country’s key reservoirs is, but Kyrgyzstan has reported the water level in the reservoir at its Toktogul hydropower plant (HPP) is 11.8 billion cubic meters (bcm), the lowest level in years and far less than the 14.7 bcm of water it had in November 2020.

The Toktogul HPP, with an installed capacity of 1,200 MW, provides some 40 percent of the country's domestically produced electricity, but operating the HPP this winter to generate desperately needed energy brings the risk of leaving water levels at the reservoir critically low next spring and summer when the water is also needed for agricultural purposes.

This year’s drought is something Kyrgyzstan and Tajikistan will have to take into consideration as they plan how to provide power for their growing populations in the future. Hydropower is a desirable option but may be less reliable with the onset of climate change, prompting interest in alternatives such as Ukraine's wind power to diversify generation.

Uzbekistan is also feeling the effects of this year’s drought, and, like the South Caucasus where Georgia's electricity imports have increased, supply shortfalls are testing grids.

According to the International Energy Agency, HPPs account for some 12 percent of Uzbekistan’s generating capacity.

Uzbekistan’s Energy Ministry attributed low water levels at HPPs that have caused a 23 percent decrease in hydropower generation this year.

A reservoir in Kyrgyzstan
Kazakhstan and Uzbekistan are the most populous Central Asian countries, and both depend on thermal power plants (TPP) for generating most of their electricity.

Most of the TPPs in Kazakhstan are coal-fired, while most of the TPPs in Uzbekistan are gas-fired.

Kazakhstan has 68 power plants, 80 percent of which are coal-fired TPPs, and most are in the northern part of the country where the largest deposits of coal are located. Kazakhstan has the world's 10th largest reserves of coal.

About 88 percent of Uzbekistan’s electricity comes from TTPs, most of which use natural gas.

Uzbekistan’s proven reserves are some 800 billion cubic meters, but gas production in Uzbekistan has been decreasing.

In December 2020, Uzbek President Shavkat Mirziyoev ordered a halt to the country’s gas exports and instructed that gas to be redirected for domestic use. Mirziyoev has already given similar instructions for this coming winter.

How Did It Come To This?
The biggest problem with the energy infrastructure in Central Asia is that it is generally very old. Nearly all of its power plants date back to the Soviet era -- and some well back into the Soviet period.

The use of power plants and transmission lines that some describe as “obsolete” and a few call “decrepit” has unfortunately been a necessity in Central Asia, even as regional players pursue new interconnections like Iran's plan to transmit electricity to Europe as a power hub.

Reporting on Kazakhstan in September 2016, the Asian Development Bank (ADB) said, “70 percent of the power generation infrastructure is in need of rehabilitation.”

The Ekibastuz-1 TPP is relatively new by the power-plant standards of Central Asia. The first unit of the eight units of the TPP was commissioned in 1980.

The first unit at the AKSU TPP was commissioned in 1968, and the first unit of the gas- and fuel-fired TPP in southern Kazakhstan’s Zhambyl Province was commissioned in 1967.

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Ukraine Energy Grid Attacks intensify as missile strikes and drone raids hit power plants, substations, and transmission lines, causing blackouts, disrupted logistics, and humanitarian strain during winter, despite repairs, air defense, and allied aid.

Key Points

Missile and drone strikes on Ukraine's power grid to force blackouts, strain civilians, and disrupt military logistics.

✅ Targets: power plants, substations, transmission lines

✅ Impacts: blackouts, heating loss, hospital strain

✅ Goals: erode morale, disrupt logistics, force aid burdens

Russia’s continued strikes on Ukraine have taken a severe toll on the country’s critical infrastructure, particularly its energy grid, as Ukraine continues to keep the lights on despite sustained bombardment. In recent months, Western Ukraine has increasingly become a target of missile and drone attacks, leading to widespread power outages and compounding the challenges faced by the civilian population. These strikes aim to cripple Ukraine's resilience during a harsh winter season and disrupt its wartime operations.

Targeting Energy Infrastructure

Russian missile and drone assaults on Ukraine’s energy grid are part of a broader strategy to weaken the country’s morale and capacity to sustain the war effort. The attacks have primarily focused on power plants, transmission lines, and substations. Western Ukraine, previously considered a relative safe haven due to its distance from front-line combat zones, is now experiencing the brunt of this campaign.

The consequences of these strikes are severe. Rolling blackouts and unplanned outages have disrupted daily life for millions of Ukrainians, though authorities say there are electricity reserves that could stabilize supply if no new strikes occur, leaving homes without heating during freezing temperatures, hospitals operating on emergency power, and businesses struggling to maintain operations. The infrastructure damage has also affected water supplies and public transportation, further straining civilian life.

Aimed at Civilian and Military Impact

Russia’s targeting of Ukraine’s power grid has dual purposes. On one hand, it aims to undermine civilian morale by creating hardships during the cold winter months, even as Ukraine works to keep the lights on this winter through contingency measures. On the other, it seeks to hinder Ukraine’s military logistics and operations, which heavily rely on a stable energy supply for transportation, communications, and manufacturing of military equipment.

These attacks coincide with a broader strategy of attritional warfare, where Moscow hopes to exhaust Ukraine’s resources and diminish its ability to continue its counteroffensive operations. By disrupting critical infrastructure, Russia increases pressure on Ukraine's allies to step up humanitarian and military aid, stretching their capacities.

Humanitarian Consequences

The impact of these power cuts on the civilian population is profound. Millions of Ukrainians are enduring freezing temperatures without consistent access to electricity or heating. Vulnerable populations, such as the elderly, children, and those with disabilities, face heightened risks of hypothermia and other health issues.

Hospitals and healthcare facilities are under immense strain, relying on backup generators that cannot sustain prolonged use. In rural areas, where infrastructure is already weaker, the effects are even more pronounced, leaving many communities isolated and unable to access essential services.

Humanitarian organizations have ramped up efforts to provide aid, including distributing generators, warm clothing, and food supplies, while many households pursue new energy solutions to weather blackouts. However, the scale of the crisis often outpaces the resources available, leaving many Ukrainians to rely on their resilience and community networks.

Ukraine's Response

Despite the challenges, Ukraine has demonstrated remarkable resilience in the face of these attacks. The government and utility companies are working around the clock to repair damaged infrastructure and restore power to affected areas. Mobile repair teams and international assistance have played crucial roles in mitigating the impact of these strikes.

Ukraine’s Western allies have also stepped in to provide support. The European Union, the United States, and other countries have supplied Ukraine with energy equipment, financial aid, and technical expertise to help rebuild its energy grid, though recent decisions like the U.S. ending support for grid restoration complicate planning and procurement. Additionally, advanced air defense systems provided by Western nations have helped intercept some of the incoming missiles and drones, though not all attacks can be thwarted.

Russia’s Escalation Strategy

Russia’s focus on Western Ukraine reflects a shift in its strategy. Previously, attacks were concentrated on front-line areas and major urban centers in the east and south. However, by targeting the western regions, Moscow seeks to disrupt the relatively stable zones where displaced Ukrainians and critical supply chains are located.

Western Ukraine is also a hub for receiving and distributing international aid and military supplies. Striking this region not only undermines Ukraine’s internal stability but also sends a message to its allies about Russia’s willingness to escalate the conflict further.

Broader Implications

The attacks on Ukraine’s energy grid have broader geopolitical implications. By targeting infrastructure, Russia intensifies the pressure on Ukraine’s allies to continue providing support, even as Kyiv has at times helped Spain amid blackouts when capacity allowed, testing their unity and resolve. The destruction also poses long-term challenges for Ukraine’s post-war recovery, as rebuilding a modern and resilient energy system will require significant investments and time.

Moreover, these attacks highlight the vulnerability of civilian infrastructure in modern warfare, echoing that electricity is civilization amid winter conditions. The deliberate targeting of non-combatant assets underscores the need for international efforts to strengthen the protection of critical infrastructure and address the humanitarian consequences of such tactics.

The Russian attacks on Western Ukraine's power grid are a stark reminder of the devastating human and economic costs of the ongoing conflict. While Ukraine continues to demonstrate resilience and adaptability, the scale of destruction underscores the need for sustained international support. As the war drags on, the focus must remain on mitigating civilian suffering, rebuilding critical infrastructure, and pursuing a resolution that ends the violence and stabilizes the region.

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Nova Scotia Power solar charge proposes an $8/kW monthly system access fee on net metering customers, citing grid costs. UARB review, carbon credits, rate hikes, and solar industry impacts fuel political and consumer backlash.

Key Points

A proposed $8/kW monthly grid access fee on net metered solar customers, delayed to Feb 1, 2023, pending UARB review.

✅ $8/kW monthly system access fee on net metering

✅ Delay to Feb 1, 2023 after industry and political pushback

✅ UARB review; debate over grid costs and carbon credits

Nova Scotia Power has pushed back by a year the start date of a proposed new charge for customers who generate electricity and sell it back to the grid, following days of concern from the solar industry and politicians worried that it will damage the sector.

The company applied to the Nova Scotia Utility and Review Board (UARB) last week for various changes, including a "system access charge" of $8 per kilowatt monthly on net metered installations, and the province cannot order the utility to lower rates under current law. The vast majority of the province's 4,100 net metering customers are residential customers with solar power, according to the application. 

The proposed charge would have come into effect Tuesday if approved, but Nova Scotia Power said in a news release Tuesday it will change the date in its filing from Feb. 1, 2022, to Feb. 1, 2023.

"We understand that the solar industry was taken off guard," utility CEO Peter Gregg said in an interview.

"There could have been an opportunity to have more conversations in advance."

Gregg said the utility will meet with members of the solar industry over the next year to work on finding solutions that support the sector's growth, while addressing what NSP sees as an inequity in the net metering system.

NSP recognized that customers who choose solar invest a significant amount and pay for the electricity they use, but they don't pay for costs associated with accessing the electrical grid when they need energy, such as on cold winter evenings when the sun is not shining.

"I know that's hit a nerve, but it doesn't take away the fact that it is an issue," Gregg said.

He said this is an issue utilities are navigating around North America, where seasonal rate designs have sparked consumer backlash in New Brunswick, and NSP is open to hearing ideas for other models of charges or fees.

The utility's suggested system access charge closely resembles one proposed in California, which has also raised major concerns from the solar industry and been criticized by the likes of Elon Musk, and has parallels to Massachusetts solar demand charges as well.

Although the "solar profile" of Nova Scotia and California is very different, with far more solar customers in that state, and in other provinces such as Saskatchewan, NDP criticism of 8% hikes has intensified affordability debates, Gregg said the fundamental issues are the same.

For those with a typical 10-kilowatt solar system, which generates around $1,800 of electricity a year, the new charge would mean those customers would be required to pay $960 back to NSP. That would roughly double the length of time it takes for those customers to pay off their investment for the panels.

David Brushett, chair of Solar Nova Scotia, said he relayed concerns from solar installers and others in the industry to Gregg on Monday. 

Brushett said the year delay is a positive first step, but he is still calling on the province to take a strong stance against the application, which has led to customers cancelling their panel installations and companies considering layoffs.

"There's still an urgency to this situation that hasn't been addressed, and we need to kind of protect the industry," he said Tuesday.

NSP's original application proposed exempting net metering customers who enrolled before Feb. 1, 2022, from the charge for 25 years after they sign up. But any benefit would be lost if those customers sold their home, and the exemption wouldn't extend to the new buyers, said Brushett.

Carbon offsets missing from equation: industry
Brushett said NSP "completely ignored" the fact that it's getting free carbon offset credits from homeowners who use solar energy under the provincial cap and trade program.

If the net metering system continues as is, NSP has said non-solar customers would pay about $55 million between now and 2030. That number assumes about 2,000 people sign up for net metering each year over the next nine years.

When asked whether those carbon emission credits were factored into the calculations for the proposed charge, Gregg said, "I don't believe in the current structure it is, but it's something that certainly we'd be open to hearing about."

Brushett said his group is finalizing a legal response to NSP's proposal and has already filed an official complaint against the company with the UARB.

Base charge on actual electrical output: customer
At least one shareholder in NSP parent company Emera is considering selling his shares in response to the application.

Joe Hood, a shareholder from Middle Sackville, said the proposed charge won't apply to his existing 11.16-kilowatt solar system, but if it did, it would cost him $1,071 a year.

"I am offended that a company I would invest in would do this to the solar industry in Nova Scotia," he said.

According to his meter, Hood said he pushed 9,600 kilowatt hours of solar electricity to the grid last year— some only for a brief period, and all of which was used by his home by the end of the year.

Under the proposed charge, someone with one solar panel who goes away on vacation in the summer would push all their electricity to the grid, and be charged far less than someone with 10 panels who has used all their own power and hasn't pushed anything.

"Nova Scotia Power's argument is that it's an issue with the grid. Well, then it should be based on what touches the grid," Hood said.

Far from actually making the system fair for everyone, Hood said this charge places solar only in the hands of the super-rich or NSP, with projects like its community solar gardens in Amherst, N.S.

Green Party suggests legislation update
Nova Scotia's Green Party also said Tuesday that Gregg's arguments of fairness are misleading, echoing earlier premier opposition to a 14% hike on rates.

The party is calling for an update to the Electricity Act that would "prevent penalizing any activity that helps Nova Scotia reach its emissions target," aligning with calls to make the electricity system more accountable to residents.

In its application, NSP has also asked to increase electricity rates for residential customers by at least 10 per cent over the next three years, amid debate that culminated in a 14% rate hike approval by regulators. 

The company wants to maintain its nine per cent rate of return.

NSP expects to earn $153 million this year, $192 million in 2023, and $213 million in 2024 from its rate of return. 

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Costa Rica Renewable Energy Record highlights 99.99% clean power in May 2019, driven by hydropower, wind, solar, geothermal, and biomass, enabling ICE REM electricity exports and reduced rates from optimized generation totaling 984.19 GWh.

Key Points

May 2019 benchmark: Costa Rica generated 99.99% of 984.19 GWh from renewables, shifting from imports to regional exports.

✅ 99.99% renewable share across hydro, wind, solar, geothermal, biomass

✅ 984.19 GWh generated; ICE suspended imports and exported via REM

✅ Geothermal output increased to offset dry-season hydropower variability

During the whole month of May 2019, Costa Rica generated a total of 984.19 gigawatt hours of electricity, the highest in the country’s history. What makes this feat even more impressive is the fact that 99.99% of this energy came from a portfolio of renewable sources such as hydropower, wind, biomass, solar, and geothermal.

With such a high generation rate, the state power company Instituto Costariccense de Electricidad (ICE) were able to suspend energy imports from the first week of May and shifted to exports, while U.S. renewable electricity surpassed coal in 2022 domestically. To date, the power company continues to sell electricity to the Regional Electricity Market (REM) which generates revenues and is likely to reduce local electricity rates, a trend echoed in places like Idaho where a vast majority of electricity comes from renewables.

The record-breaking power generation was made possible by optimization of the country’s renewable sources, much as U.S. wind capacity surpassed hydro capacity at the end of 2016 to reshape portfolios. As the period coincided with the tail end of the dry season, the geothermal quota had to be increased.

Costa Rica remains a leader in renewable power generation, whereas U.S. wind generation has become the most-used renewable source in recent years. In 2015, more than 98% of the country’s electrical generation came from renewable sources, while U.S. renewables hit a record 28% in April in one recent benchmark. Through the years, this figure has remained fairly constant despite dry bouts caused by the El Niño phenomenon, and U.S. solar generation also continued to rise.

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PG&E Wind Shutdown and Renewable Reliability examines PSPS strategy, wildfire risk, transmission line exposure, wind turbine cut-out speeds, grid stability, and California's energy mix amid historic high-wind events and supply constraints across service areas.

Key Points

An overview of PG&E's PSPS decisions, wildfire mitigation, and how wind cut-out limits influence grid reliability.

✅ Wind turbines reach cut-out near 55 mph, reducing generation.

✅ PSPS mitigates ignition from damaged transmission infrastructure.

✅ Baseload diversity improves resilience during high-wind events.

According to the official, widely reported story, Pacific Gas & Electric (PG&E) initiated power shutoffs across substantial portions of its electric transmission system in northern California as a precautionary measure.

Citing high wind speeds they described as “historic,” the utility claims that if it didn’t turn off the grid, wind-caused damage to its infrastructure could start more wildfires.

Perhaps that’s true. Perhaps. This tale presumes that the folks who designed and maintain PG&E’s transmission system are unaware of or ignored the need to design it to withstand severe weather events, and that the Federal Energy Regulatory Commission (FERC) and North American Electric Reliability Corp. (NERC) allowed the utility to do so.

Ignorance and incompetence happens, to be sure, but there’s much about this story that doesn’t smell right—and it’s disappointing that most journalists and elected officials are apparently accepting it without question.

Take, for example, this statement from a Fox News story about the Kincade Fires: “A PG&E meteorologist said it’s ‘likely that many trees will fall, branches will break,’ which could damage utility infrastructure and start a fire.”

Did you ever notice how utilities cut wide swaths of trees away when transmission lines pass through forests? There’s a reason for that: When trees fall and branches break, the grid can still function, and even as the electric rhythms of New York City shifted during COVID-19, operators planned for variability.

So, if badly designed and poorly maintained infrastructure isn’t the reason PG&E cut power to millions of Californians, what might have prompted them to do so? Could it be that PG&E’s heavy reliance on renewable energy means they don’t have the power to send when a “historic” weather event occurs, especially as policymakers weigh the postponed closure of three power plants elsewhere in California?

Wind Speed Limits

The two most popular forms of renewable energy come with operating limitations, which is why some energy leaders urge us to keep electricity options open when planning the grid. With solar power, the constraint is obvious: the availability of sunlight. One doesn’t generate solar power at night and energy generation drops off with increasing degrees of cloud cover during the day.

The main operating constraint of wind power is, of course, wind speed, and even in markets undergoing 'transformative change' in wind generation, operators adhere to these technical limits. At the low end of the scale, you need about a 6 or 7 miles-per-hour wind to get a turbine moving. This is called the “cut-in speed.” To generate maximum power, about a 30 mph wind is typically required. But, if the wind speed is too high, the wind turbine will shut down. This is called the “cut-out speed,” and it’s about 55 miles per hour for most modern wind turbines.

It may seem odd that wind turbines have a cut-out speed, but there’s a very good reason for it. Each wind turbine rotor is connected to an electric generator housed in the turbine nacelle. The connection is made through a gearbox that is sized to turn the generator at the precise speed required to produce 60 Hertz AC power.

The blades of the wind turbine are airfoils, just like the wings of an airplane. Adjusting the pitch (angle) of the blades allows the rotor to maintain constant speed, which, in turn, allows the generator to maintain the constant speed it needs to safely deliver power to the grid. However, there’s a limit to blade pitch adjustment. When the wind is blowing so hard that pitch adjustment is no longer possible, the turbine shuts down. That’s the cut-out speed.

Now consider how California’s power generation profile has changed. According to Energy Information Administration data, the state generated 74.3 percent of its electricity from traditional sources—fossil fuels and nuclear, amid debates over whether to classify nuclear as renewable—in 2001. Hydroelectric, geothermal, and biomass-generated power accounted for most of the remaining 25.7 percent, with wind and solar providing only 1.98 percent of the total.

By 2018, the state’s renewable portfolio had jumped to 43.8 percent of total generation, with clean power increasing and wind and solar now accounting for 17.9 percent of total generation. That’s a lot of power to depend on from inherently unreliable sources. Thus, it wouldn’t be at all surprising to learn that PG&E didn’t stop delivering power out of fear of starting fires, but because it knew it wouldn’t have power to deliver once high winds shut down all those wind turbines

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