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Nature, Published online: 07 February 2024; doi:10.1038/d41586-024-00229-y
In lithium-metal batteries, grains of lithium can become electrically isolated from the anode, lowering battery performance. Experiments reveal that rest periods after battery discharge might help to solve this problem.
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Applying an electric potential causes a proton to transfer from a hydronium ion (at right) to an electrode’s surface. Using electrodes with molecularly defined proton binding sites, MIT researchers developed a general model for these interfacial proton-coupled electron transfer reactions. Credit: MIT
A key chemical reaction — in which the movement of protons between the surface of an electrode and an electrolyte drives an electric current — is a critical step in many energy technologies, including fuel cells and the electrolyzers used to produce hydrogen gas.
For the first time, MIT chemists have mapped out in detail how these proton-coupled electron transfers happen at an electrode surface. Their results could help researchers design more efficient fuel cells, batteries, or other energy technologies.
“Our advance in this paper was studying and understanding the nature of how these electrons and protons couple at a surface site, which is relevant for catalytic reactions that are important in the context of energy conversion devices or catalytic reactions,” says Yogesh Surendranath, a professor of chemistry and chemical engineering at MIT and the senior author of the study.
Among their findings, the researchers were able to trace exactly how changes in the pH of the electrolyte solution surrounding an electrode affect the rate of proton motion and electron flow within the electrode.
MIT graduate student Noah Lewis is the lead author of the paper, which was recently published in Nature Chemistry. Ryan Bisbey, a former MIT postdoc; Karl Westendorff, an MIT graduate student; and Alexander Soudackov, a research scientist at Yale University, are also authors of the paper.
Proton-coupled electron transfer occurs when a molecule, often water or an acid, transfers a proton to another molecule or to an electrode surface, which stimulates the proton acceptor to also take up an electron. This kind of reaction has been harnessed for many energy applications.
“These proton-coupled electron transfer reactions are ubiquitous. They are often key steps in catalytic mechanisms, and are particularly important for energy conversion processes such as hydrogen generation or fuel cell catalysis,” Surendranath says.
In a hydrogen-generating electrolyzer, this approach is used to remove protons from water and add electrons to the protons to form hydrogen gas. In a fuel cell, electricity is generated when protons and electrons are removed from hydrogen gas and added to oxygen to form water.
Proton-coupled electron transfer is common in many other types of chemical reactions, for example, carbon dioxide reduction (the conversion of carbon dioxide into chemical fuels by adding electrons and protons). Scientists have learned a great deal about how these reactions occur when the proton acceptors are molecules, because they can precisely control the structure of each molecule and observe how electrons and protons pass between them. However, when proton-coupled electron transfer occurs at the surface of an electrode, the process is much more difficult to study because electrode surfaces are usually very heterogeneous, with many different sites that a proton could potentially bind to.
To overcome that obstacle, the MIT team developed a way to design electrode surfaces that gives them much more precise control over the composition of the electrode surface. Their electrodes consist of sheets of graphene with organic, ring-containing compounds attached to the surface. At the end of each of these organic molecules is a negatively charged oxygen ion that can accept protons from the surrounding solution, which causes an electron to flow from the circuit into the graphitic surface.
“We can create an electrode that doesn’t consist of a wide diversity of sites but is a uniform array of a single type of very well-defined sites that can each bind a proton with the same affinity,” Surendranath says. “Since we have these very well-defined sites, what this allowed us to do was really unravel the kinetics of these processes.”
Using this system, the researchers were able to measure the flow of electrical current to the electrodes, which allowed them to calculate the rate of proton transfer to the oxygen ion at the surface at equilibrium — the state when the rates of proton donation to the surface and proton transfer back to solution from the surface are equal. They found that the pH of the surrounding solution has a significant effect on this rate: The highest rates occurred at the extreme ends of the pH scale — pH 0, the most acidic, and pH 14, the most basic.
To explain these results, researchers developed a model based on two possible reactions that can occur at the electrode. In the first, hydronium ions (H3O+), which are in high concentration in strongly acidic solutions, deliver protons to the surface oxygen ions, generating water. In the second, water delivers protons to the surface oxygen ions, generating hydroxide ions (OH–), which are in high concentration in strongly basic solutions.
However, the rate at pH 0 is about four times faster than the rate at pH 14, in part because hydronium gives up protons at a faster rate than water.
The researchers also discovered, to their surprise, that the two reactions have equal rates not at neutral pH 7, where hydronium and hydroxide concentrations are equal, but at pH 10, where the concentration of hydroxide ions is 1 million times that of hydronium. The model suggests this is because the forward reaction involving proton donation from hydronium or water contributes more to the overall rate than the backward reaction involving proton removal by water or hydroxide.
Existing models of how these reactions occur at electrode surfaces assume that the forward and backward reactions contribute equally to the overall rate, so the new findings suggest that those models may need to be reconsidered, the researchers say.
“That’s the default assumption, that the forward and reverse reactions contribute equally to the reaction rate,” Surendranath says. “Our finding is really eye-opening because it means that the assumption that people are using to analyze everything from fuel cell catalysis to hydrogen evolution may be something we need to revisit.”
The researchers are now using their experimental setup to study how adding different types of ions to the electrolyte solution surrounding the electrode may speed up or slow down the rate of proton-coupled electron flow.
“With our system, we know that our sites are constant and not affecting each other, so we can read out what the change in the solution is doing to the reaction at the surface,” Lewis says.
Reference: “A molecular-level mechanistic framework for interfacial proton-coupled electron transfer kinetics” by Noah B. Lewis, Ryan P. Bisbey, Karl S. Westendorff, Alexander V. Soudackov and Yogesh Surendranath, 16 January 2024, Nature Chemistry.
DOI: 10.1038/s41557-023-01400-0
The study was funded by the U.S. Department of Energy Office of Basic Energy Sciences.
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With an agreement in place between the EU and Canada, the University of Calgary (UCalgary) research community can now collaborate as a formal partner on Horizon Europe’s Pillar II opportunities addressing Global Challenges and European Industrial Competitiveness.
Located in the foothills of the Alberta Rocky Mountains, UCalgary is Canada’s youngest top ten research university. It has been the number one research-based startup creator in Canada for three years.
UCalgary currently has active educational and training agreements with 52 countries, including a campus in Qatar, and since 2018, has been a collaborator in over 2,900 completed and ongoing research and non-research agreements with international partners from 60 countries, including a Strategic Alliance with the University of Aberdeen in Scotland and Curtin University in Australia.
Dr William Ghali, Vice-President (Research), said: “The University of Calgary, as an international research hub, is excited about the prospective collaborations made possible by the agreement between the EU and Canada. We have a demonstrated track record of international research collaboration and partnerships contributing to global community impact.”
UCalgary has established itself globally as the world’s first United Nations University (UNU) Hub on Empowering Communities to Adapt Environmental Change in collaboration with the UNU Institute for Water, Environment and Health. In addition, UCalgary’s Centre for Health Informatics is a designated World Health Organization Family of International Classification Collaborating Centre.
UCalgary’s Arctic Institute of North America is home to the Kluane Lake Research Station, where the environmental and geographical attributes of the region and location provide unique research opportunities to support climatology, natural resources and environmental research. Meanwhile, the current development of Quantum City, an ecosystem of quantum science and technology in partnership with Mphasis and the Government of Alberta, is an exciting UCalgary initiative attracting global talent.
Dr Ghali said: “Horizon Europe opportunities present a promising avenue for our researchers to impact communities beyond Alberta. Our researchers bring entrepreneurial thinking, transdisciplinary scholarship, and access to unique research infrastructure to the table. We are eager to start something impactful through these potential partnerships and continue contributing to the global research landscape to make a real impact on our communities.”
Pre-clinical and clinical health research is enabled through UCalgary research infrastructure embedded within two hospital campuses and a singular health-care system in Alberta, allowing for the translation of findings from bench to bedside. UCalgary leads the REBX Exchange, a unique-in-Canada platform to simplify and expedite research ethics administration processes for multi-site clinical trials and non-health research studies between jurisdictions.
Examples of this work include the UCalgary-led ESCAPE international randomised clinical trial for stroke intervention, which involved research partnerships with 22 sites from North America, Europe, the UK, and Asia. Results found that a clot retrieval procedure, known as endovascular treatment, can dramatically improve patient outcomes after an acute ischemic stroke.
The current HEMO clinical trial for an implantable therapeutic to improve blood pressure regulation after spinal cord injury is led by UCalgary’s RESTORE Network in partnership with the Lausanne University Hospital in Switzerland and Dutch company ONWARD.
Leading-edge health research infrastructure unique to UCalgary includes the International Microbiome Centre, designed to investigate the microbiome of humans, plants, animals, and the physical environment. The Centre for Mobility and Joint Health features state-of-the-art imaging, movement assessment and diagnostic equipment, with some imaging equipment only available in this lab and one or two other facilities worldwide.
For the past two decades, UCalgary has been ranked a top institution globally in paediatric concussion research, with more than 30 experts focused on this area of research, including five Canada Research Chairs, and is ranked top-four for total publications and citations in concussions worldwide.
UCalgary’s is leading the One Health Consortium, a pan-collaborative transdisciplinary platform focused on antimicrobial use and resistance research, policy, training, outreach, and commercialisation. This research initiative is complemented by UCalgary’s W.A. Ranches, a working cow-calf ranch with 19,000 acres for cattle, farmland for feed production, and wildlife habitat provides a unique living lab for agriculture research and technology development, and Advancing Canadian Water Assets, a fully integrated, fully contained university research facility located within an operating industrial wastewater treatment plant.
In addition to vast expertise in health, UCalgary has long been a world leader in navigation and positioning technologies, with faculty regularly participating in international space missions, including the European Space Agency’s ROARS mission and the CASSIOPE satellite project, which was conceived, researched, and operated by UCalgary.
The Microsystems Hub at UCalgary is one of about 20 in Canada. This open-access facility provides a high-level cleanroom with CAD$8m in specialised equipment for micro- and nanofabrication, characterisation, and prototyping.
UCalgary is also a leader in developing the ground-breaking energy innovations the world urgently needs, with more than 300 UCalgary interdisciplinary scholars researching to transform the energy landscape for a cleaner, more efficient energy future. UCalgary is one of three universities leading the Canadian Government’s Energy Modelling Hub.
In the last six years, UCalgary researchers have published over 40,000 scientific articles, half of which are in collaboration with international researchers, and it is currently the academic home for 311 international postdoctoral scholars.
UCalgary is not just a local institution but a truly international university, deeply invested in the exchange of knowledge across borders. UCalgary is embracing its role as a prospective global partner for research advancement and industrial competitiveness.
Please note, this article will also appear in the seventeenth edition of our quarterly publication.
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The European Commission has unveiled an ambitious climate target for 2040 — aiming to cut net greenhouse-gas emissions by 90% compared to 1990 levels. Researchers say that the target, while admirable, risks relying too much on technologies such as carbon removal — which is largely unproven — rather than prioritizing the cutting of fossil fuels. Political shifts to the right, with many European Union member states electing governments that are unlikely to prioritize climate policy, might also make the goal difficult to achieve.
“It’s going to be very difficult to reach a 90% or 95% emissions reduction without cutting very strongly on fossil fuels,” says Richard Klein, a climate researcher at the Stockholm Environment Institute. “Carbon capture and storage is great if it works,” says Klein. “But it simply hasn’t been shown to work at the scale that would be needed — it remains a pipe dream.”
The target was revealed in a ‘communication’ report on 6 February. It is not yet legally binding, but the communication will now form the basis of legislation designed to take the EU beyond its existing targets for 2030, and onto its goal for 2050.
The commission’s current targets, which were set in 2021 and are law, are to reduce net greenhouse-gas emissions by at least 55% compared with 1990 level by 2030. The other goal commits bloc to achieving ‘climate neutrality’ by 2050. That means ensuring that greenhouse-gas emissions are equal to or less than the emissions absorbed from the atmosphere by natural processes. In 2022, the EU had decreased emissions by 32.5% compared with 1990 levels.
The 2040 target focuses on a ‘net cut’, meaning that the goal can be met by actual cuts to emissions alongside technologies such as carbon capture and storage (CCS) that lock emissions underground. The commission also wants to phase out coal-fired power by 2040, as well as fossil fuel subsidies, which it says “do not address energy poverty or just transition”.
The latest target has taken into account scientists’ recommendations, says Joeri Rogelj, a climate scientist at Imperial College London who is a board member of the European Scientific Advisory Board on Climate Change, which includes climate scientists from across the EU and advises the commission. Rogelj says that the board advised the commission to aim for a target of reducing greenhouse-gas emissions by 90% to 95% by 2040. “With this communication, of aiming for a reduction of 90% — it definitely falls in that range,” Rogelj says. “It’s positive to see that the advice was taken up.”
But the finer details of the strategy — in particular the inclusion of targets for carbon removal — have attracted criticism. CCS has not yet been proven on a large scale. “It’d be very dangerous to rely strongly on carbon capture and storage, because it would give the signal that you can basically continue to invest in fossil fuels, and that will go very much against the idea of what was agreed in Dubai at COP28,” he adds, referring to the last year’s United Nations climate summit. The focus on removal echos a bold target proposed by the administration of US President Joe Biden, which also focused on CCS technologies.
Rogelj is pleased that the communication explicitly separates out emissions reductions from carbon removal — meaning member states can’t just rely on removing carbon, they must also reduce emissions in parallel. “Carbon dioxide removal definitely comes with this kind of risk of obfuscating what actually needs to happen, by expecting that indeed carbon dioxide will be removed,” he says.
Although the commission’s 2040 target provides a more detailed plan towards achieving net zero — meaning greenhouse-gas emissions are zero or completely balanced by removal mechanisms — it will be important to ensure that it doesn’t detract from efforts to meet the 2030 goals, says Klein. Countries already aren’t on track to meet 2030 targets, and a political shift to the right in many EU nations makes it less likely that the bloc will meet the existing goal, says Klein.
“We’ve got several countries with governments either just installed or in the making, like in the Netherlands, where the governments are likely to be led by parties who either don’t believe in climate change or don’t consider climate policy to be particularly the priority,” he says.
Researchers also say that although reducing carbon emissions is crucial, there needs to be more focus on adaptation — lessening the current or future impacts of climate change, such as by building flood barriers. “We can’t effectively mitigate climate change without more ambitious finance for adapting to the impacts it’s already having,” says climate-policy researcher Mikael Allan Mikaelsson, who is also at the Stockholm Environment Institute.
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A new method for green hydrogen production, introduced by Technion researchers, leverages renewable energy for a cleaner, efficient, and cost-effective alternative to fossil fuels, marking a significant advancement in the fight against global warming. Credit: SciTechDaily.com
Professor Avner Rothschild’s research group at the Technion – Israel Institute of Technology developed a new green technology for producing hydrogen.
A group of researchers from the Technion Faculty of Materials Science and Engineering is presenting a new technology for producing green hydrogen using renewable energy. Their breakthrough was recently published in Nature Materials. The novel technology embodies significant advantages compared to other processes for producing green hydrogen, and its development into a commercial technology is likely to reduce the costs and accelerate the use of green hydrogen as a clean, sustainable alternative to fossil fuels.
Using hydrogen as a fuel instead of coal, gasoline, and “natural” gas will reduce the use of these fuels and greenhouse gas emissions from various sources, including transportation, the production of materials and chemicals, and industrial heating. Unlike these fuels, which emit carbon dioxide into the atmosphere when they combust in the air, using hydrogen produces water and is therefore considered a clean fuel.
However, the most common way to produce hydrogen involves using natural gas (or coal) and the process emits large amounts of carbon dioxide into the atmosphere – thereby canceling out its advantages as a green, sustainable alternative to fossil fuels. In 2022, global consumption of hydrogen stood at approximately 95 million tons – a quantity suitable for improving various fuel products, and especially to produce ammonia, which is needed for manufacturing agricultural fertilizers.
From right to left: Dr. Anna Breytus, Matan Sananis, Dr. Yelena Davidova, and Ilya Slobodkin. Credit: Technion
Nearly all of the hydrogen that is consumed today is produced from fossil fuels, which is why it is called “gray hydrogen” (made from methane) or “black hydrogen” (made from coal). Hydrogen production using these methods is responsible for around 2.5% of the annual global carbon dioxide emissions into the atmosphere as a result of human actions. Replacing gray hydrogen with green hydrogen is necessary in order to reduce this significant source of emissions and replace polluting fossil fuels with clean, sustainable hydrogen.
Various estimates predict that green hydrogen is likely to account for around 10% of the global energy market at net zero emissions – the current target for mitigating climate change and global warming as a result of the greenhouse effect due to increased concentration of carbon dioxide in the atmosphere. That is the reason for the enormous importance of green hydrogen in combatting global warming.
Green hydrogen is produced through electrolysis – electrochemical decomposition of water into oxygen and hydrogen using energy from renewable sources such as wind and sun. Electrolysis was discovered more than 200 years ago, and since then it has undergone many developments and improvements. However, it is still too expensive for producing green hydrogen at a competitive price.
One of the technological challenges that limit the use of electrolysis for producing large amounts of green hydrogen – amounts that would help achieve plans to attain net zero carbon emissions – is the need for expensive membranes, gaskets, and sealing components to separate the cathodic and anodic compartments.
Professor Avner Rothschild. Credit: Technion
Several years ago, Technion researchers presented an innovative and efficient electrolysis technique that doesn’t require a membrane and sealing to separate the two parts of the cell, since the hydrogen and the oxygen are produced at different stages of the process, unlike in regular electrolysis where they are created simultaneously.
This novel process, called E-TAC, was developed by Dr. Hen Dotan and Dr. Avigail Landman under the supervision of Prof. Avner Rothschild and Prof. Gideon Grader. They partnered with the entrepreneur Talmon Marco to fulfill the process’s potential and develop commercial applications.
The researchers from Prof. Rothschild’s group at the Technion are now presenting a new process whereby hydrogen and oxygen are produced simultaneously in two separate cells, unlike the E-TAC process where they are produced in the same cell but at different stages. The new process was developed by Ilia Slobodkin as part of his master’s thesis, with the help of Senior Researcher Dr. Elena Davydova and Dr. Anna Breytus and master’s student Matan Sananis.
This novel process bypasses operational challenges and limitations of the solid electrode where the oxygen is produced in the E-TAC technique by replacing it with NaBr aqueous electrolyte in water. This replacement paves the way for a continuous process (as opposed to a batch process with E-TAC) and repeals the need to swing cold and hot electrolytes alternately through the cell.
The bromide anions in the electrolyte are oxidized to bromate while producing hydrogen in a cathode, and they then flow with the aqueous electrolyte to a different cell, where they are turned back into their original state while at the same time producing oxygen, and this process keeps repeating itself. In this way, hydrogen and oxygen are produced at the same time in two separate cells in a continuous process without any temperature changes, unlike with E-TAC.
Moreover, the oxygen is produced in the aqueous electrolyte and not in the solid electrode as in E-TAC, and it is therefore not dependent on the rate and capacity limitations typical of those types of electrodes, such as chargeable batteries.
In the article published in Nature Materials, the researchers describe their basic experiments which prove the preliminary feasibility of the proposed process, and present results that demonstrate its high efficiency and ability to work at high electric current, meaning that hydrogen can be produced at a high rate.
At the same time, there is still a long way ahead for developing a new technology based on the scientific breakthrough depicted in the article. Such a technology is likely to get past the many obstacles on the way to industrial production of green hydrogen as a sustainable alternative to fossil fuels.
eference: “Electrochemical and chemical cycle for high-efficiency decoupled water splitting in a near-neutral electrolyte” by Ilya Slobodkin, Elena Davydova, Matan Sananis, Anna Breytus and Avner Rothschild, 9 January 2024, Nature Materials.
DOI: 10.1038/s41563-023-01767-y
Prof. Rothschild is a member of the Nancy and Stephen Grand Technion Energy Program, the Stewart and Lynda Resnick Sustainability Center for Catalysis, and the National Research Institute for Energy Storage. The research was supported by the Ministry of Innovation, Science and Technology and JNF-KKL’s Climate Solution Prize.
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Excitement is growing over hints Earth has vast reserves of carbon-free natural hydrogen that we could extract and burn to power our economies, but it is way too soon to declare it a climate saviour
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Prospectors around the world are scrambling to find reserves of “gold hydrogen”, a naturally occurring fuel that burns without producing carbon dioxide. But how much is really out there and how easy is it to tap into?
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Carbon emissions from fossil fuels could finally start to fall in 2024
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Planet-warming greenhouse gas emissions have been on the rise since the industrial revolution, and 2023 appears to have been no different. This year saw a more than 1 per cent increase in emissions from burning fossil fuels compared with 2022, according to the Global Carbon Budget compiled by Pierre Friedlingstein at the University of Exeter in the UK and his colleagues.
But 2024 could see these emissions begin to decline for the first time, driven mainly by the unprecedented…
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A groundbreaking study has identified molecular photoswitches that can improve solar energy storage. Using quantum computing, researchers analyzed a large database to find molecules best suited for this technology, marking a significant step in emission-free solar energy utilization. Credit: SciTechDaily.com
Molecular photoswitches that can both convert and store energy could be used to make solar energy harvesting more efficient. A team of researchers has used a quantum computing method to find a particularly efficient molecular structure for this purpose. As the team described in the journal Angewandte Chemie, their procedure was based on a dataset of more than 400,000 molecules, which they screened to find the optimum molecular structure for solar energy storage materials.
At present, solar energy is either used directly to generate electricity, or indirectly via the energy stored in heat reservoirs. A third route could involve first storing the energy from the sun in light-sensitive materials and then releasing it as needed. The EU-backed project MOST (“Molecular Solar Thermal Energy Storage”) is exploring molecules such as photoswitches that can absorb and store solar energy at room temperature to create entirely emission-free utilization of solar energy a reality.
The research teams of Kurt V. Mikkelsen at the University of Copenhagen, (Denmark) and Kasper Moth–Poulsen at the Technical University of Catalonia, Barcelona (Spain), have taken a closer look at the photoswitches best suited for this task. They studied molecules known as bicyclic dienes, which switch to a high-energy state when illuminated. The most prominent example of this bicyclic diene system is known as norbornadiene quadricyclane, but a vast number of similar candidates exist. The researchers explain: “The resulting chemical space consists of approximately 466,000 bicyclic dienes that we have screened for their potential applicability in MOST technology.”
Screening a database of this size is typically done by machine learning, but this requires large amounts of training data based on real-world experiments, which the team did not have. Using a previously developed algorithm and a novel evaluation score, “eta,” the screening and evaluation of the database molecules yielded a clear result: all six of the top scoring molecules differed from the original norbornadiene quadricyclane system at a crucial point in the structure. The researchers concluded that this structural change, an expansion of the molecular bridge between the two carbon rings in the bicyclic part, allowed the new molecules to store more energy than the original norbornadiene.
The researchers’ work demonstrates the potential for optimizing solar energy storage molecules. However, the new molecules must first be synthesized and tested under real conditions. “Even though the systems can be synthetically prepared, there is no guarantee that they are soluble in relevant solvents and that they will actually photoswitch in high yield or at all, as we have assumed in eta,” the authors caution.
Despite this, the team has developed a new, large set of training data for machine learning algorithms and has thus shortened the arduous research step prior to synthesis for chemists tackling such systems in the future. The authors envision this much larger repository of bicyclic dienes coming into its own for research into photoswitches for a variety of applications, potentially making it easier for molecules to be tailored to specific requirements.
Reference: “Searching the Chemical Space of Bicyclic Dienes for Molecular Solar Thermal Energy Storage Candidates” by Andreas Erbs Hillers-Bendtsen, Jacob Lynge Elholm, Oscar Berlin Obel, Helen Hölzel, Kasper Moth-Poulsen and Kurt V. Mikkelsen, 25 July 2023, Angewandte Chemie International Edition.
DOI: 10.1002/anie.202309543
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Power outages could come to many regions of North America in the coming years
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More than 300 million people in the US and Canada face the growing possibility of electricity shortages beginning as early as 2024 and continuing to 2028.
In a recent report, the North American Electric Reliability Corporation (NERC) – an international regulatory authority overseeing the North American power grid – projected that a majority of regions in the US and Canada will have insufficient electricity supply to reliably meet demand during extreme weather conditions. A few may even see…
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