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Spread & Containment

What is curtailment? An electricity market expert explains

Sometimes wind and solar power produce more electricity than the local grid can handle. Better energy storage and transmission could move extra energy…

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The control room of the California Independent System Operator, which manages the flow of electricity on the state's power grid. Rolf Schulten/ullstein bild via Getty Images

Curtailment has a special meaning in electric power systems. It describes any action that reduces the amount of electricity generated to maintain the balance between supply and demand – which is critical for avoiding blackouts.

Recently, curtailment has made news in states like California and Texas that are adding a lot of wind and solar power. On very windy or sunny days, these sources may produce more electricity than the grid can take. So grid managers reduce production to manage that oversupply.

This can be a lost opportunity. Electricity from solar and wind, as well as existing nuclear plants, is inexpensive and emits less greenhouse gases than fossil fuels, so it may be in society’s interest to keep these generators running.

A special kind of surplus

Consumers know about shortages and surpluses in the goods they buy. Shortages mean that shoppers can’t get that PlayStation 5 for Christmas – or, more critically, the bread, water or baby formula they need.

Surpluses look different, like unsold books classified as remainders or Easter candy discounted 80% at local drug stores on Monday morning.

But electricity is not like these goods. On today’s electric grid, shortages and surpluses can both result in the exact same thing – a blackout.

The North American grid transmits electricity as alternating current that changes direction back and forth, like water ebbing and flowing from a vintage hand pump as the handle is pushed up and down. Modern electricity grids require precise levels of frequency – the back-and-forth motion of power – to function properly.

The grid is designed to function at 60 hertz, which means that the flow of electric current shifts back and forth 60 times per second. This is achieved, in part, by ensuring that the amount of electricity produced at any given time is equal to the amount of electricity being used. If too little electricity is produced, frequency on the system drops. If too much electricity is produced, then frequency increases.

Modern power plants are designed to operate within a relatively narrow range around 60 hertz. If the actual frequency on the grid is outside that range, the plant can disconnect itself from the system. If enough plants do that, it causes a blackout.

As the U.S. electric power industry shifts increasingly to renewable sources, the national power grid will require major updates.

Managing the flow

In some parts of the U.S., mostly the Southeast and the West, the same companies generate electricity and deliver it to customers. When power plants in a utility’s territory generate more electricity than customers are using, the company will simply produce less electricity from its most expensive power plant, or temporarily shut it off altogether.

But other states have restructured their electricity markets so that some companies produce power and others deliver it to customers. In these competitive markets, curtailment raises complex issues. Power generators stay in business by generating and selling power, so when demand drops, grid operators need a system to ensure that they make curtailment decisions fairly.

Often the first tool for choosing which plants to curtail is the prices that generators are paid. When supply grows or demand falls, the price of electricity falls. Some generators may decide that they are unwilling to produce electricity below a certain price and drop off if it hits that level.

If there’s still a power surplus, the organization that operates the grid steps in to manually curtail generators. They can either do this through signals in the grid’s data system or by contacting generators directly through phone calls. Power may be curtailed for five minutes or five hours, depending on how quickly the system returns to normal.

Overall, the U.S. needs more low-emissions electricity to help reduce air pollution and slow climate change. So curtailment isn’t a sound long-term strategy for managing power surpluses. It’s somewhat comparable to the early days of the COVID-19 pandemic when supply chain disruptions forced producers to throw away huge quantities of food even as grocery stores struggled to fill their shelves.

One solution is to expand energy storage so that generators can save excess power for a few hours instead of sending it straight into the grid. Another option is building more transmission to carry power to areas that need it. Both types of investments can reduce the need to curtail generation and forgo making clean, affordable electricity.

Theodore Kury is the Director of Energy Studies at the University of Florida’s Public Utility Research Center, which is sponsored in part by the Florida electric and gas utilities and the Florida Public Service Commission, none of which has editorial control of any of the content the Center produces.

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Spread & Containment

TJ Maxx and Marshalls follow Costco and Target on upcoming closures

Many of these stores have information customers need to know.

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U.S. consumers have come to increasingly rely on the near ubiquity of convenience stores and big-box retailers. 

Many of us depend on these stores being open practically all day, every day, even during some of the biggest holidays. After all, Black Friday beckons retail stores to open just hours after a Thanksgiving Day dinner in hopes of attracting huge crowds of shoppers in search of early holiday sales. 

Related: Walmart announces more store closures for 2024

And it's largely true that before the covid pandemic most of our favorite stores were open all the time. Practically nothing — from inclement weather to bad news to holidays — could shut down a major operation like Walmart  (WMT)  or Target  (TGT)

Then the pandemic hit, and it turned everything we thought we knew about retail operations upside down. 

Everything from grocery stores to shopping malls shut down in an effort to contain potential spread. And when they finally reopened to the public, different stores took different precautionary measures. Some monitored how many shoppers were inside at once, while others implemented foot-traffic rules dictating where one could enter and exit an aisle. And almost every one of them mandated wearing masks at one point or another. 

Though these safety measures seem like a distant memory, one relic from the early 2020s remains firmly a part of our new American retail life. 

A woman in a face mask shopping in the HomeGoods kitchen aisle.

Jeff Greenberg/Getty Images

Store closures announced for spring 2024

Many retailers have learned to adapt after a volatile start to this third decade, and in many ways this requires serving customers better and treating employees better to retain a workforce. 

In some cases, the changes also reflect a change in shopping behavior, as more customers order online and leave more breathing room for brick-and-mortar operations. This also means more time for employees. 

Thanks to this, big retailers have recently changed how they operate, especially during holiday hours, with Walmart recently saying it would close during Thanksgiving to give employees more time to spend with loved ones.

"I am delighted to share that once again, we'll be closing our doors for Thanksgiving this year," Walmart U.S. CEO John Furner told associates in a video posted to Twitter in November. "Thanksgiving is such a special day during a very busy season. We want you to spend that day at home with family and loved ones." 

Other retailers have now followed suit, with Costco  (COST) , Aldi, and Target all saying they would close their doors for 24 hours on Easter Sunday, March 31. 

Now, the stores that operate under TJX Cos.  (TJX)  will also shut down during the holiday, including HomeGoods, TJ Maxx and Marshalls

Though it closed on Thanksgiving, Walmart says it will remain open for shoppers on Easter. 

Here's a list of stores that are closing for Easter 2024: 

  • Target
  • Costco
  • Aldi
  • TJ Maxx
  • Marshalls
  • HomeGoods
  • Publix
  • Macy's
  • Best Buy
  • Apple
  • ACE Hardware

Others are expected to remain open, including:

  • Walmart
  • Ikea
  • Petco
  • Home Depot

Most of the stores closing on Sunday will reopen for regular business hours on Monday. 

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International

Gates-backed PhIII study tuberculosis vaccine study gets underway

A large study of an experimental vaccine for the world’s biggest infectious disease has finally kicked off in South Africa.
The Bill & Melinda Gates…

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A large study of an experimental vaccine for the world’s biggest infectious disease has finally kicked off in South Africa.

The Bill & Melinda Gates Medical Research Institute (MRI) will test a tuberculosis vaccine’s ability to prevent latent infections from causing potentially deadly lung disease. Last summer the nonprofit said it would foot $400 million of the estimated $550 million cost of running the 20,000-person Phase III trial.

It’s a pivotal moment for a vaccine whose origins date back 25 years when scientists identified two proteins that triggered strong immunity to the bacterium that causes tuberculosis. A fusion of those proteins, paired with the tree bark-derived adjuvant that helps power GSK’s shingles shot, comprise the so-called M72 vaccine.

Thomas Scriba

After decades of failures in the field, the vaccine impressed scientists in 2018 when GSK found that it was 54% efficacious at preventing lung disease in a 3,600-person Phase IIb study.

But the Big Pharma decided that a full-blown trial was too expensive to conduct on its own. Gates MRI stepped in to license the vaccine in early 2020, right before the Covid pandemic shifted global vaccine priorities towards the coronavirus, further stalling the tuberculosis shot.

“There’s been frustration that it’s taken so long to get this trial up and running,” Thomas Scriba, deputy director of immunology for the South African Tuberculosis Vaccine Initiative, told Endpoints News last summer.

At last, the vaccine is getting a chance to prove itself in a bigger study. If successful, it could lead to the first new shot for tuberculosis in over a century.

Emilio Emini, CEO of the Gates MRI, told Endpoints that the initial results may come in roughly four to six years. “Hopefully this will galvanize a refocus on TB,” he said. “It’s been ignored for many, many years. We can’t ignore it anymore.”

A substantial impact

Even though an existing vaccine helps protect babies and children against severe tuberculosis, the bacterium responsible for the disease still causes roughly 10 million new cases and 500,000 deaths each year.

Emilio Emini

By vaccinating adolescents and adults who test positive for infections but don’t have symptoms of lung disease, the Gates MRI hopes the shot will help prevent mild infections from becoming severe ones, curtail transmission of the bug, which is predominantly driven by people with lung disease, and reduce deaths.

“The impact would be substantial,” Emini said. But he cautioned that the biology behind mild and severe diseases is still mysterious. “The reality is that no one really knows what keeps it under control.”

The study, which will take place at 60 sites across seven countries, will include some people who are not infected with tuberculosis to ensure that the vaccine is safe in that broader population.

“Having to pre-test everybody is not going to make the vaccine easy to deliver,” Emini said. If the vaccine is ultimately approved, it will likely be used in targeted communities with high tuberculosis, rather than across a whole country, he added. “In practice, you would immunize everybody in those populations.”

Emini described the Gates MRI’s rights to the vaccine as “close to a worldwide license.” GSK retained rights to commercialize the vaccine in certain countries but declined to specify which ones.

A spokesperson for GSK said that the company “has around 30 assets under development specifically for global health … none of which are expected to generate significant return on investment.”

“It is not sustainable or practical in the longer term for GSK to deliver all of these alone. So we continue to work on M72, but in partnership with others,” the spokesperson added.

If the shot works, Emini said that the Gates MRI will sublicense it to a manufacturer that will be responsible for making and marketing the vaccine. The details are still being worked out, he noted.

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Government

Choosing over the counter drugs for COVID 19? It’s complicated

COVID-19 illness may include symptoms such as a sore throat, fever, cough and fatigue. In January, the United States Centers for Disease Control and Prevention…

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COVID-19 illness may include symptoms such as a sore throat, fever, cough and fatigue. In January, the United States Centers for Disease Control and Prevention (CDC) issued its most recent guidelines for the use of over the counter (OTC) drugs for COVID-19. Specifically, its guidelines state that most people with COVID-19 have mild illness and can recover at home while treating symptoms with OTC medicines such as acetaminophen (Tylenol) or ibuprofen (Motrin, Advil). 

Credit: Florida Atlantic University

COVID-19 illness may include symptoms such as a sore throat, fever, cough and fatigue. In January, the United States Centers for Disease Control and Prevention (CDC) issued its most recent guidelines for the use of over the counter (OTC) drugs for COVID-19. Specifically, its guidelines state that most people with COVID-19 have mild illness and can recover at home while treating symptoms with OTC medicines such as acetaminophen (Tylenol) or ibuprofen (Motrin, Advil). 

Researchers from Florida Atlantic University’s Schmidt College of Medicine and academic colleagues say it’s more complicated. They suggest that selecting an OTC medication to alleviate mild symptoms of COVID-19 should be based on the entire benefit-to-risk profile of the patient. Moreover, they say clinical decisions should be made by the health care provider for each of his or her patients.

In a review, published in The American Journal of Medicine, researchers take a closer look at both the potential benefits and risks of acetaminophen, non-steroidal anti-inflammatory drugs (NSAIDs) – such as ibuprofen, as well as aspirin for the selection of OTC drugs to treat mild symptoms of COVID-19.

Traditional nonspecific NSAIDs such as the shorter acting ibuprofen and longer acting naproxen have been used to treat COVID-19. These widely used OTC drugs reversibly and non-specifically inhibit both cyclooxygenase enzyme isoforms. This results in systematic reduction in the synthesis of prostaglandins resulting in anti-inflammatory and fever-reducing effects. The researchers caution, however, that both ibuprofen and naproxen have similar but greater side effect profiles than aspirin, such as gastroenteritis and peptic ulcers.

Acetaminophen is one of the most frequently used OTC drugs in the U.S. and worldwide as a treatment for fever, allergic symptoms, headaches, myalgia, symptoms of the common cold, and most recently COVID-19. Acetaminophen was originally marketed as an alternative to aspirin for treatment of mild to moderate pain based on reduced mucosal gastrointestinal side effects. The authors caution that even at daily doses of 4,000 milligrams per day, generally accepted as safe for adults, acetaminophen can be toxic to the liver and may result in the onset of acute liver failure. In the U.S., acetaminophen is the leading reason for calls to Poison Control Centers with more than 100,000 cases per year. These circumstances account for more than 2,600 hospitalizations and 450 deaths in the U.S. due to acute liver failure. 

Aspirin, or acetylsalicylic acid, inhibits the production of prostaglandins, which are responsible for mediating pain, inflammation and fever. The authors say that the beneficial effects of aspirin include anti-platelet, analgesic, antipyretic or anti-fever and anti-inflammatory properties. Aspirin is rapidly absorbed when taken orally and has a half-life of around four hours, after which it is mostly metabolized by the kidneys.

The researchers note that the anti-inflammatory benefits of aspirin should provide symptomatic relief of fever and body aches in COVID-19. They underscore, however, that health providers should view these in the context of the increased risks of bleeding, principally gastrointestinal. Further, COVID-19 itself may already predispose individuals to bleeding as well as to clotting abnormalities.

“We believe that health care providers should make individual clinical judgments for each of his or her patients in the selection of OTC drugs to treat symptoms of COVID-19. This judgement should be based on the entire benefit to risk profile of the patient,” said Charles H. Hennekens, M.D., Dr.PH, senior author, first Sir Richard Doll Professor and senior academic advisor in FAU’s Schmidt College of Medicine. “It is our belief that the individual health care provider knows far more about each of his or her patients than anyone, including expert members of guideline committees.”

The authors conclude that when the totality of evidence is complete, health care providers can make the most rational individual clinical judgements for their patients and policymakers for the health of the general public.

The authors believe that, at present, the totality of evidence is incomplete and requires reliable evidence from large- scale randomized trials designed a priori to do so, which is necessary to develop rational guidelines. They also believe that any guidelines should provide only guidance to health care providers. Currently, these considerations pose new clinical challenges for health care providers in prescribing OTC drugs to treat COVID-19. 

“The astute and judicious individual clinical decision making of health care providers for each individual patient based on all these considerations has the potential to do far more good than harm. Finally, guidelines should provide guidance to individual health care providers,” said Hennekens.

Study co-authors are Gage Collamore, a second-year medical student; Mark J. DiCorcia, Ph.D., an associate professor and associate dean for educational affairs and admissions; Yash Nagpal, a second-year medical student; and Larry Fiedler, M.D., a board certified gastroenterologist and an affiliate associate professor, all within FAU’s Schmidt College of Medicine; Michael A. Garone, M.D., a board-certified gastroenterologist and clinical assistant professor at George Washington University Hospital; and David L. DeMets, Ph.D., emeritus Halperin Professor and founding chair of biostatistics and informatics; and Dennis G. Maki, M.D., the Ovid O. Meyer Professor of Medicine; both at the University of Wisconsin School of Medicine and Public Health.

Hennekens and Maki served for two years as lieutenant commanders in the U.S. Public Health Service as epidemic intelligence service (EIS) officers with the CDC. They served under Alexander D. Langmuir, M.D., who created the EIS and directed the epidemiology program at the CDC, as well as Donald A. Henderson, M.D., chief of the Virus Disease Surveillance Program at the CDC. Langmuir and Henderson made significant contributions to the eradication of polio and smallpox using widespread vaccinations and public health strategies of proven benefit and had extraordinary collaborations with local, state, federal and international health authorities.   

– FAU –

About the Charles E. Schmidt College of Medicine:

FAU’s Charles E. Schmidt College of Medicine is one of approximately 157 accredited medical schools in the U.S. The college was launched in 2010, when the Florida Board of Governors made a landmark decision authorizing FAU to award the M.D. degree. After receiving approval from the Florida legislature and the governor, it became the 134th allopathic medical school in North America. With more than 70 full and part-time faculty and more than 1,300 affiliate faculty, the college matriculates 64 medical students each year and has been nationally recognized for its innovative curriculum. To further FAU’s commitment to increase much needed medical residency positions in Palm Beach County and to ensure that the region will continue to have an adequate and well-trained physician workforce, the FAU Charles E. Schmidt College of Medicine Consortium for Graduate Medical Education (GME) was formed in fall 2011 with five leading hospitals in Palm Beach County. The Consortium currently has five Accreditation Council for Graduate Medical Education (ACGME) accredited residencies including internal medicine, surgery, emergency medicine, psychiatry, and neurology.

 

About Florida Atlantic University:
Florida Atlantic University, established in 1961, officially opened its doors in 1964 as the fifth public university in Florida. Today, the University serves more than 30,000 undergraduate and graduate students across six campuses located along the southeast Florida coast. In recent years, the University has doubled its research expenditures and outpaced its peers in student achievement rates. Through the coexistence of access and excellence, FAU embodies an innovative model where traditional achievement gaps vanish. FAU is designated a Hispanic-serving institution, ranked as a top public university by U.S. News & World Report and a High Research Activity institution by the Carnegie Foundation for the Advancement of Teaching. For more information, visit www.fau.edu.


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