Energy recycled by using sound to convert heat into electricity

By Electricity Forum


Electrical Testing & Commissioning of Power Systems

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Physicists have developed a way to turn heat into sound and then electricity, suggesting a new way to effectively recycle waste energy.

“We are converting waste heat to electricity in an efficient, simple way by using sound,” said the scientist who led the effort, Orest Symko of the University of Utah. “It is a new source of renewable energy from waste heat.”

Symko’s recycling devices are cylinder-shaped “resonators” that fit in the palm of your hand. Each cylinder contains a stack of material with a large surface area — such as metal or plastic plates, or fibers made of glass, cotton or steel wool — placed between cold and hot heat exchangers.

When heat is applied, the heat builds to a particular threshold where hot, moving air produces sound at a single frequency — like air blown into a flute.

“You have heat, which is so disorderly and chaotic, and all of a sudden you have sound coming out at one frequency,” Symko said.

The sound waves then squeeze what is called a piezoelectric device (“piezo” means pressure or squeezing). The pressure created produces an electric voltage. Symko says it is similar to when you hit your "funnybone" or the nerve on outside of your elbow, thereby generating  that weird, painful pinch, which is actually an electrical nerve impulse.

Symko plans to test the devices within a year at a military radar facility and the University of UtahÂ’s hot-water-generating plant. (The U.S. Army funded the study in hopes the technology can be used to create a portable source of energy.)

Symko expects these devices could be used within two years as an alternative to the photovoltaic cells that currently convert sunlight into electricity, and could also provide a new way to cool laptops and other computers, and a to generate electricity from the heat released by nuclear power plant cooling towers.

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Nonstop Records For U.S. Natural-Gas-Based Electricity

U.S. Natural Gas Power Demand is surging for electricity generation amid summer heat, with ERCOT, Texas grid reserves tight, EIA reporting coal and nuclear retirements, renewables intermittency, and pipeline expansions supporting combined-cycle capacity and prices.

 

Key Points

It is rising use of natural gas for power, driven by summer heat, plant retirements, and new combined-cycle capacity.

✅ ERCOT reserve margin 9%, below 14% target in Texas

✅ Gas share of U.S. power near 40-43% this summer

✅ Coal and nuclear retirements shift capacity to combined cycle

 

As the hot months linger, it will be natural gas that is leaned on most to supply the electricity that we need to run our air conditioning loads on the grid and keep us cool.

And this is surely a great and important thing: "Heat causes most weather-related deaths, National Weather Service says."

Generally, U.S. gas demand for power in summer is 35-40% higher than what it was five years ago, with so much more coming (see Figure).

The good news is regions across the country are expected to have plenty of reserves to keep up with power demand.

The only exception is ERCOT, covering 90% of the electric load in Texas, where a 9% reserve margin is expected, below the desired 14%.

Last summer, however, ERCOT’s reserve margin also was below the desired level, yet the grid operator maintained system reliability with no load curtailments.

Simply put, other states are very lucky that Texas has been able to maintain gas at 50% of its generation, despite being more than justified to drastically increase that.

At about 1,600 Bcf per year, the flatness of gas for power demand in Texas since 2000 has been truly remarkable, especially since Lone Star State production is up 50% since then.

Increasingly, other U.S. states (and even countries) are wanting to import huge amounts of gas from Texas, a state that yields over 25% of all U.S. output.

Yet if Texas justifiably ever wants to utilize more of its own gas, others would be significantly impacted.

At ~480 TWh per year, if Texas was a country, it would be 9th globally for power use, even ahead of Brazil, a fast growing economy with 212 million people, and France, a developed economy with 68 million people.

In the near-term, this explains why a sweltering prolonged heat wave in July in Texas, with a hot Houston summer setting new electricity records, is the critical factor that could push up still very low gas prices.

But for California, our second highest gas using state, above-average snowpack should provide a stronger hydropower for this summer season relative to 2018.

Combined, Texas and California consume about 25% of U.S. gas, with Texas' use double that of California.

 

Across the U.S., gas could supply a record 40-43% of U.S. electricity this summer even as the EIA expects solar and wind to be larger sources of generation across the mix

Our gas used for power has increased 35-40% over the past five years, and January power generation also jumped on the year, highlighting broad momentum.

Our gas used for power has increased 35-40% over the past five years. DATA SOURCE: EIA; JTC

Indeed, U.S. natural gas for electricity has continued to soar, even as overall electricity consumption has trended lower in some years, at nearly 10,700 Bcf last year, a 16% rise from 2017 and easily the highest ever.

Gas is expected to supply 37% of U.S. power this year, even as coal-fired generation saw a brief uptick in 2021 in EIA data, versus 27% just five years ago (see Figure).

Capacity wise, gas is sure to continue to surge its share 45% share of the U.S. power system.

"More than 60% of electric generating capacity installed in 2018 was fueled by natural gas."

We know that natural gas will continue to be the go-to power source: coal and nuclear plants are retiring, and while growing, wind and solar are too intermittent, geography limited, and transmission short to compensate like natural gas can.

"U.S. coal power capacity has fallen by a third since 2010," and last year "16 gigawatts (16,000 MW) of U.S. coal-fired power plants retired."

This year, some 2,000 MW of coal was retired in February alone, with 7,420 MW expected to be closed in 2019.

Ditto for nuclear.

Nuclear retirements this year include Pilgrim, Massachusetts’s only nuclear plant, and Three Mile Island in Pennsylvania.

This will take a combined ~1,600 MW of nuclear capacity offline.

Another 2,500 MW and 4,300 MW of nuclear are expected to be leaving the U.S. power system in 2020 and 2021, respectively.

As more nuclear plants close, EIA projects that net electricity generation from U.S. nuclear power reactors will fall by 17% by 2025.

From 2019-2025 alone, EIA expects U.S. coal capacity to plummet nearly 25% to 176,000 MW, with nuclear falling 15% to 83,000 MW.

In contrast, new combined cycle gas plants will grow capacity almost 30% to around 310,000 MW.

Lower and lower projected commodity prices for gas encourage this immense gas build-out, not to mention non-stop increases in efficiency for gas-based units.

Remember that these are official U.S. Department of Energy estimates, not coming from the industry itself.

In other words, our Department of Energy concludes that gas is the future.

Our hotter and hotter summers are therefore more and more becoming: "summers for natural gas"

Ultimately, this shows why the anti-pipeline movement is so dangerous.

"Affordable Energy Coalition Highlights Ripple Effect of Natural Gas Moratorium."

In April, President Trump signed two executive orders to promote energy infrastructure by directing federal agencies to remove bottlenecks for gas transport into the Northeast in particular, where New England oil-fired generation has spiked, and to streamline federal reviews of border-crossing pipelines and other infrastructure.

Builders, however, are not relying on outside help: all they know is that more U.S. gas demand is a constant, so more infrastructure is mandatory.

They are moving forward diligently: for example, there are now some 27 pipelines worth $33 billion already in the works in Appalachia.

 

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3 Reasons Why Cheap Abundant Electricity Is Getting Closer To Reality

Renewable Energy Breakthroughs drive quantum dots solar efficiency, Air-gen protein nanowires harvesting humidity, and cellulose membranes for flow batteries, enabling printable photovoltaics, 24/7 clean power, and low-cost grid storage at commercial scale.

 

Key Points

Advances like quantum dot solar, Air-gen, and cellulose flow battery membranes that improve clean power and storage.

✅ Quantum dots raise solar conversion efficiency, are printable

✅ Air-gen harvests electricity from humidity with protein nanowires

✅ Cellulose membranes cut flow battery costs, aid grid storage

 

Science never sleeps. The quest to find new and better ways to do things continues in thousands of laboratories around the world. Today, the global economy is based on the use of electricity, and one analysis shows wind and solar potential could meet 80% of US demand, underscoring what is possible. If there was a way to harness all the energy from the sun that falls on the Earth every day, there would be enough of electricity available to meet the needs of every man, woman, and child on the planet with plenty left over. That day is getting closer all the time. Here are three reasons why.

Quantum Dots Make Better Solar Panels
According to Science Daily, researchers at the University of Queensland have set a new world record for the conversion of solar energy to electricity using quantum dots — which pass electrons between one another and generate electrical current when exposed to solar energy in a solar cell device. The solar devices they developed have beaten the existing solar conversion record by 25%.

“Conventional solar technologies use rigid, expensive materials. The new class of quantum dots the university has developed are flexible and printable,” says professor Lianzhou Wang, who leads the research team. “This opens up a huge range of potential applications, including the possibility to use it as a transparent skin to power cars, planes, homes and wearable technology. Eventually it could play a major part in meeting the United Nations’ goal to increase the share of renewable energy in the global energy mix.”

“This new generation of quantum dots is compatible with more affordable and large-scale printable technologies,” he adds. “The near 25% improvement in efficiency we have achieved over the previous world record is important. It is effectively the difference between quantum dot solar cell technology being an exciting prospect and being commercially viable.” The research was published on January 20 in the journal Nature Energy.

Electricity From Thin Air
Science Daily also reports that researchers at UMass Amherst also have interesting news. They claim they created a device called an Air-gen, short for air powered generator. (Note: recently we reported on other research that makes electricity from rainwater.) The device uses protein nanowires created by a microbe called Geobacter. Those nanowires can generate electricity from thin air by tapping the water vapor present naturally in the atmosphere. “We are literally making electricity out of thin air. The Air-gen generates clean energy 24/7. It’s the most amazing and exciting application of protein nanowires yet,” researchers Jun Yao and Derek Lovely say. There work was published February 17 in the journal Nature.

The new technology developed in Yao’s lab is non-polluting, renewable, and low-cost. It can generate power even in areas with extremely low humidity such as the Sahara Desert. It has significant advantages over other forms of renewable energy including solar and wind, Lovley says, because unlike these other renewable energy sources, the Air-gen does not require sunlight or wind, and “it even works indoors,” a point underscored by ongoing grid challenges that slow full renewable adoption.

Yao says, “The ultimate goal is to make large-scale systems. For example, the technology might be incorporated into wall paint that could help power your home. Or, we may develop stand-alone air-powered generators that supply electricity off the grid, and in parallel others are advancing bio-inspired fuel cells that could complement such devices. Once we get to an industrial scale for wire production, I fully expect that we can make large systems that will make a major contribution to sustainable energy production. This is just the beginning of a new era of protein based electronic devices.”

Improved Membranes For Flow Batteries From Cellulose
Storing energy is almost as important to decarbonizing the environment as making it in the first place, with the rise of affordable solar batteries improving integration.  There are dozens if not hundreds of ways to store electricity and they all work to one degree or another. The difference between which ones are commercially viable and ones that are not often comes down to money.

Flow batteries — one approach among many, including fuel cells for renewable storage — use two liquid electrolytes — one positively charged and one negatively charged — separated by a membrane that allows electrons to pass back and forth between them. The problem is, the liquids are highly corrosive. The membranes used today are expensive — more than $1,300 per square meter.

Phys.org reports that Hongli Zhu, an assistant professor of mechanical and industrial engineering at Northeastern University, has successfully created a membrane for use in flow batteries that is made from cellulose and costs just $147.68 per square meter. Reducing the cost of something by 90% is the kind of news that gets people knocking on your door.

The membrane uses nanocrystals derived from cellulose in combination with a polymer known as polyvinylidene fluoride-hexafluoropropylene.  The naturally derived membrane is especially efficient because its cellular structure contains thousands of hydroxyl groups, which involve bonds of hydrogen and oxygen that make it easy for water to be transported in plants and trees.

In flow batteries, that molecular makeup speeds the transport of protons as they flow through the membrane. “For these materials, one of the challenges is that it is difficult to find a polymer that is proton conductive and that is also a material that is very stable in the flowing acid,” Zhu says.

Cellulose can be extracted from natural sources including algae, solid waste, and bacteria. “A lot of material in nature is a composite, and if we disintegrate its components, we can use it to extract cellulose,” Zhu says. “Like waste from our yard, and a lot of solid waste that we don’t always know what to do with.”

Flow batteries can store large amounts of electricity over long periods of time — provided the membrane between the storage tanks doesn’t break down. To store more electricity, simply make the tanks larger, which makes them ideal for grid storage applications where there is often plenty of room to install them. Slashing the cost of the membrane will make them much more attractive to renewable energy developers and help move the clean energy revolution forward.

The Takeaway
The fossil fuel crazies won’t give up easily. They have too much to lose and couldn’t care less if life on Earth ceases to exist for a few million years, just so long as they get to profit from their investments. But they are experiencing a death of a thousand cuts. None of the breakthroughs discussed above will end thermal power generation all by itself, but all of them, together with hundreds more just like them happening every day, every week, and every month, even as we confront clean energy's hidden costs across supply chains, are slowly writing the epitaph for fossil fuels.

And here’s a further note. A person of Chinese ancestry is the leader of all three research efforts reported on above. These are precisely the people being targeted by the United States government at the moment as it ratchets up its war on immigrants and anybody who cannot trace their ancestry to northern Europe. Imagine for a moment what will happen to America when researchers like them depart for countries where they are welcome instead of despised. 

 

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Indian government takes steps to get nuclear back on track

India Nuclear Generation Shortfall highlights missed five-year plan targets due to uranium fuel scarcity, commissioning delays at Kudankulam, PFBR slippage, and PHWR equipment bottlenecks under IAEA safeguards and domestic supply constraints.

 

Key Points

A gap between planned and actual nuclear output due to fuel shortages, reactor delays, and first-of-a-kind hurdles.

✅ Fuel scarcity pre-2009-10 constrained unsafeguarded reactors.

✅ Kudankulam delays from protests, litigation, and remobilisation.

✅ FOAK PHWR equipment bottlenecks and PFBR slippage.

 

A lack of available domestically produced nuclear fuel and delays in constructing and commissioning nuclear power plants, including first-of-a-kind plants and the Prototype Fast Breeder Reactor (PFBR), meant that India failed to meet its nuclear generation targets under the governmental plans over the decade to 2017, even as global project milestones were being recorded elsewhere.

India's nuclear generation target under its 11th five-year plan, covering the period 2007-2012, was 163,395 million units (MUs) and the 12th five-year Plan (2012-17) was 241,748 MUs, Minister of state for the Department of Atomic Energy and the Prime Minister's Office Jitendra Singh told parliament on 6 February. Actual nuclear generation in those periods was 109,642 MUs and 183,488 MUs respectively, Singh said in a written answer to questions in the Lok Sabah.

Singh attributed the shortfall in generation to a lack of availability of the necessary quantities of domestically produced fuel during the three years before 2009-2010; delays to the commissioning of two 1000 MWe nuclear power plants at Kudankulam due to local protests and legal challenges; and delays in the completion of two indigenously designed pressurised heavy water reactors and the PFBR.

Kudankulam 1 and 2 are VVER-1000 pressurised water reactors (PWRs) supplied by Russia's Atomstroyexport under a Russian-financed contract. The units were built by Nuclear Power Corporation of India Ltd (NPCIL) and were commissioned and are operated by NPCIL under International Atomic Energy Agency (IAEA) safeguards, with supervision from Russian specialists, while China's nuclear program advanced on a steady development track in the same period. Construction of the units - the first PWRs to enter operation in India - began in 2002.

Singh said local protests resulted in the halt of commissioning work at Kudankulam for nine months from September 2011 to March 2012, when he said project commissioning had been at its peak. As a consequence, additional time was needed to remobilise the workforce and contractors, he said. Litigation by anti-nuclear groups, and compliance with supreme court directives, impacted commissioning in 2013, he said. Unit 1 entered commercial operation in December 2014 and unit 2 in April 2017.

Delays in the manufacture and supply by domestic industry of critical equipment for first-of-a-kind 700 MWe pressurised heavy water reactors -  Kakrapar units 3 and 4, and Rajasthan units 7 and 8 - has led to delays in the completion of those units, the minister said, as well as noting the delay in completion of the PFBR, which is being built at Kalpakkam by Bhavini. In answer to a separate question, Singh said the PFBR is in an "advance stage of integrated commissioning" and is "expected to approach first criticality by the year 2020."

Eight of India's operating nuclear power plants are not under IAEA safeguards and can therefore only use indigenously-sourced uranium. The other 14 units operate under IAEA safeguards and can use imported uranium. The Indian government has taken several measures to secure fuel supplies for reactors in operation and under construction, amid coal supply rationing pressures elsewhere in the power sector, concluding fuel supply contracts with several countries for existing and future reactors under IAEA Safeguards and by "augmentation" of fuel supplies from domestic sources, Singh said.

Kakrapar 3 and 4, with Kakrapar 3 criticality already reported, and Rajasthan 7 and 8 are all currently expected to enter service in 2022, according to World Nuclear Association information.

 

Joint venture discussions

In February 2016 the government amended the Atomic Energy Act to allow NPCIL to form joint venture companies with other public sector undertakings (PSUs) for involvement in nuclear power generation and possibly other aspects of the fuel cycle, reflecting green industrial strategies shaping future reactor waves globally. In answer to another question, Singh confirmed that NPCIL has entered into joint ventures with NTPC Limited (National Thermal Power Corporation, India's largest power company) and Indian Oil Corporation Limited. Two joint venture companies - Anushakti Vidhyut Nigam Limited and NPCIL-Indian Oil Nuclear Energy Corporation Limited - have been incorporated, and discussions on possible projects to be set up by the joint venture companies are in progress.

An exploratory discussion had also been held with Oil & Natural Gas Corporation, Singh said. Indian Railways - which has in the past been identified as a potential joint venture partner for NPCIL - had "conveyed that they were not contemplating entering into an MoU for setting up of nuclear power plants," Singh said.

 

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Entergy Creates COVID-19 Emergency Relief Fund to Help Customers in Need

Entergy COVID-19 Emergency Relief Fund provides financial assistance to ALICE households, low-income seniors, and disabled customers via United Way grants for rent, mortgage, utilities, food, and bill payment support during COVID-19, alongside a disconnect moratorium.

 

Key Points

A shareholder-funded program offering essential grants and bill support to Entergy customers affected by COVID-19.

✅ Shareholders commit $700,000; grants distributed via United Way partners.

✅ Focus on ALICE families, low-income seniors, and disabled customers.

✅ Disconnects suspended; bill tools and LIHEAP advocacy underway.

 

In an effort to help working families experiencing financial hardships as a result of the coronavirus pandemic, the Entergy Charitable Foundation has established the COVID-19 Emergency Relief Fund, recognizing the need for electricity across communities.

"The health and safety of our customers, employees and communities is Entergy's top priority," said Leo Denault, chairman and CEO of Entergy Corporation. "For more than 100 years, Entergy has never wavered in our commitment to supporting our customers and the communities we serve. This pandemic is no different. During this challenging time, we are helping lessen the impact of this crisis on the most vulnerable in our communities. I strongly encourage our business partners to join us in this effort."

As devastating and disruptive as this crisis is for everyone, we know from past experience that those most heavily impacted are ALICE households (low-wage working families) and low-income elderly and disabled customers, who often face energy insecurity during such events - roughly 40%-50% of Entergy's customer base.

"We know from experience that working families and low-income elderly and disabled customers are hardest hit during times of crisis," said Patty Riddlebarger, vice president of Entergy's corporate social responsibility. "We are working quickly to make funds available to community partners that serve vulnerable households to lessen the economic impact of the COVID-19 crisis and ensure that families have the resources they need to get by during this time of uncertainty."

To support our most vulnerable customers, Entergy shareholders are committing $700,000 to the COVID-19 Emergency Relief Fund to help qualifying customers with basic needs such as food and nutrition, rent and mortgage assistance, and other critical needs, alongside measures like Texas utilities waiving fees that ease household costs, until financial situations become more stable. Grants from the fund will be provided to United Way organizations and other nonprofit partners across Entergy's service area that are providing services to impacted households.

Company shareholders will also match employee contributions to the COVID-19 relief efforts of local United Way organizations up to $100,000 to maximize impact.

In addition to establishing the COVID-19 Emergency Relief Fund, Entergy is taking additional steps to support and protect our customers during this crisis, similar to PG&E's pandemic response measures, including:

With support from our regulators, we are temporarily suspending customer disconnects, as seen in New Jersey and New York policies, as we continue to monitor the situation.

We are working with our network of community advocates, as the industry coordination with federal partners continues, to request a funding increase of the Low Income Home Energy Assistance Program to help alleviate financial hardships caused by COVID-19 on vulnerable households.

We are developing bill payment solutions and tools to help customers pay their accumulated balances once the disconnect moratorium is lifted.

Already in place to support vulnerable customers is Entergy's The Power to Care program, which provides emergency bill payment assistance to seniors and disabled individuals. To mark the 20th anniversary of Entergy's low-income customer initiative, the limit of shareholders' dollar for dollar match of customer donations was increased from $500,000 to $1 million per year. Shareholders continue to match employee donations dollar for dollar with no limit.

 

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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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Was there another reason for electricity shutdowns in California?

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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