EPRI, Entergy validate voltage stability monitoring

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The Electric Power Research Institute (EPRI) and Entergy Corporation (Entergy) have validated a method developed by EPRI for continuously calculating the voltage stability margin on transmission networks using measured voltage and current waveforms at the transmission substation level.

The method promises to overcome limitations of traditional methods that rely primarily on simulation-based methods and promises to help power system operators prevent voltage collapse.

The offline validation was conducted on the western region of EntergyÂ’s power system and demonstrated how voltage instability margins can be calculated in real time using data from selected transmission substations. The calculated voltage stability margins provide important indices for power system operators to monitor and control voltage stability.

“It is extremely challenging to assess voltage stability in a continuously changing electric system,” said Sharma Kolluri, manager, transmission planning at Entergy. “Utilities and system operators need dependable tools to accurately predict voltage stability margins in order to come up with mitigation plans.”

Voltage stability assessment (VSA) is important in helping power system operators anticipate potential system-wide instability problems. Although computer simulation tools are available to help monitor and control system voltage stability, their accuracy depends primarily on computer modeling of generation, load, and transmission facilities.

“As transmission networks operate closer to their limits, maintaining voltage stability is more important than ever,” said Arshad Mansoor, vice president for power delivery and utilization at EPRI. “During conditions of high transmission loading or a power system disturbance, progressive drops in voltage can jeopardize system integrity. If the voltage drops were not corrected, voltage instability could lead to voltage collapse and wide-area blackouts. Having the capability to assess the stability margins online is an important step in improving reliability.”

“The results of the validation study have shown us here at Entergy that this is promising for enhancing the security of our transmission system,” says Sujit Mandal, senior staff engineer at Entergy.

Mansoor also said that this research has established a solid technical foundation for the next steps in the technology’s development — demonstration and validation at the control center level and implementation as an online tool.

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Elon Musk could help rebuild Puerto Rico with solar-powered electricity grid

Puerto Rico Tesla Solar Power enables resilient microgrids using batteries, renewable energy, and energy storage to rebuild the hurricane-damaged grid, reduce fossil fuels, cut costs, and accelerate recovery with scalable solar-plus-storage solutions.

 

Key Points

A solar-plus-storage plan using Tesla microgrids and batteries to restore Puerto Rico's cleaner, resilient power.

✅ Microgrids cut diesel reliance and harden critical facilities.

✅ Batteries stabilize the grid and shave peak demand costs.

✅ Scalable solar enables faster, modular disaster recovery.

 

Puerto Rico’s governor Ricardo Rossello has said that he will speak to Elon Musk after the Tesla inventor said his innovative solar and battery systems could be used to restore electricity on the island.

Mr Musk was mentioned in a tweet, referencing an article discussing ways to restore Puerto Rico’s power grid, which was knocked out by Hurricane Maria on September 20.

Restoring the ageing and already-weakened network has proved slow: as of Friday 90 per cent of the island remained without power. The island’s electricity company was declared bankrupt in July.

Mr Musk was asked: “Could @ElonMusk go in and rebuild #PuertoRico’s electricity system with independent solar & battery systems?”

The South African entrepreneur replied: “The Tesla team has done this for many smaller islands around the world, but there is no scalability limit, so it can be done for Puerto Rico too.

“Such a decision would be in the hands of the PR govt, PUC, any commercial stakeholders and, most importantly, the people of PR.”

His suggestion was seized upon by Mr Rossello, who then tweeted: “@ElonMusk Let's talk. Do you want to show the world the power and scalability of your #TeslaTechnologies?

“PR could be that flagship project.”

Mr Musk replied that he was happy to talk.

Restoring power to the battered island is a priority for the government, and improving grid resilience remains critical, with hospitals still running on generators and the 3.5 million people struggling with a lack of refrigeration or air conditioning.

Radios broadcast messages advising people how to keep their insulin cool, and doctors are concerned about people not being able to access dialysis.

And, with its power grid wiped out, the Caribbean island could totally rethink the way it meets its energy needs, drawing on examples like a resilient school microgrid built locally. 

“This is an opportunity to completely transform the way electricity is generated in Puerto Rico and the federal government should support this,” said Judith Enck, the former administrator for the region with the environmental protection agency.

“They need a clean energy renewables plan and not spending hurricane money propping up the old fossil fuel infrastructure.”

Forty-seven per cent of Puerto Rico’s power needs were met by burning oil last year - a very expensive and outdated method of electricity generation. For the US as a whole, petroleum accounted for just 0.3 per cent of all electricity generated in 2016 even as the grid isn’t yet running on 100% renewable energy nationwide.

The majority of the rest of Puerto Rico’s energy came courtesy of coal and natural gas, with renewables, which later faced pandemic-related setbacks, accounting for only two per cent of electricity generation.

“In that time of extreme petroleum prices, the utility was borrowing money and buying oil in order to keep those plants operating,” said Luis Martinez, a lawyer at natural resources defense council and former special aide to the president of Puerto Rico’s environmental quality board.

“That precipitated the bankruptcy that followed. It was in pretty poor shape before the storm. Once the storm got there, it finished the job.”

But Mr Martinez told the website Earther that it might be difficult to secure the financing for rebuilding Puerto Rico with renewables from FEMA (Federal Emergency Management Agency) funds.

“A lot of distribution lines were on wood poles,” he said.

“Concrete would make them more resistant to winds, but that would potentially not be authorized under the use of FEMA funds.

"We’re looking into if some of those requirements can be waived so rebuilding can be more resilient.”

 

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China's nuclear energy on steady development track, say experts

China Nuclear Power Expansion accelerates with reactor approvals, Hualong One and CAP1400 deployments, rising gigawatts, clean energy targets, carbon neutrality goals, and grid reliability benefits to meet coastal demand and reduce emissions.

 

Key Points

An accelerated reactor buildout to add clean capacity, curb emissions, and improve grid reliability nationwide.

✅ Approvals surge for Hualong One and CAP1400 third-gen reactors

✅ Capacity targets approach 100 GW installed by 2030

✅ Supports carbon neutrality, energy security, and lower costs

 

While China has failed to accomplish its 2020 nuclear target of 58 gigawatts under operation and 30 GW under construction, insiders are optimistic about prospects for the nonpolluting energy resource in China over the next five years as the country has stepped up nuclear approvals and construction since 2020.

China expects to record 49 operating nuclear facilities and capacity of more than 51 GW as of the end of 2020. Nuclear power currently makes up around 2.4 percent of the country's total installed energy capacity, said the China Nuclear Energy Association. There are 19 facilities that have received approval and are under construction, with capacity exceeding 20 GW, ranking top globally as nuclear project milestones worldwide continue, it said.

"With surging power demand from coastal regions, more domestic technology, including next-gen nuclear, will be adopted with installations likely nearing 100 GW by the end of 2030," said Wei Hanyang, a power market analyst at Bloomberg New Energy.

Following the Fukushima nuclear reactor disaster in 2011 in Japan, China has, like many countries including Japan, Germany and Switzerland, suspended nuclear power project approvals for a period, including construction of the pilot project of Shidaowan nuclear power plant in Shandong province that uses CAP1400 technology, based on third-generation Westinghouse AP1000 reactor technology.

As China promotes greener development and prioritizes safety and security of nuclear power plant construction, it has pledged to hit peak emissions before 2030 and achieve carbon neutrality by 2060, with electricity meeting 60% of energy use by 2060 according to Shell, the Shidaowan plant, originally scheduled to launch construction in 2014 and enter service in 2018, is expected to start fuel loading and begin operations this year.

Joseph Jacobelli, an independent energy analyst and executive vice-president for Asia business at Cenfura Ltd, a smart energy services company, said recent developments confirm China's ongoing commitment to further boost the country's nuclear sector.

"The nuclear plants can help meet China's goal of reducing greenhouse gas emissions as the country reduces coal power production and provide air pollution-free energy at a lower cost to consumers. China's need for clean energy means that nuclear power generation definitely has an important place in the long-term energy mix," Jacobelli said.

He added that Chinese companies' cost control capabilities and technological advancements, and operational performance improvements such as the AP1000 refueling outage record, are also likely to continue providing domestic companies with advantages, as the cost per kilowatt-hour is very important, especially as solar, wind and other clean energy solutions become even cheaper over the next few years.

China approved two nuclear projects in 2020- Hainan Changjiang nuclear power plant unit 2 and Zhejiang San'ao nuclear power plant unit 1. This is after the country launched three new nuclear power plants in 2019 in the provinces of Shandong, Fujian and Guangdong, which marked the end of a moratorium on new projects.

The Zhejiang San'ao nuclear power plant saw concrete poured for unit 1 on Dec 31, according to its operator China General Nuclear. It will be the first of six Hualong One pressurized water reactors to be built at the site as well as the first Chinese nuclear power plant project to involve private capital.

Jointly invested, constructed and operated by CGN, Zheneng Electric Power, Wenzhou Nuclear Energy Development, Cangnan County Haixi Construction Development and Geely Maijie Investment, the project creates a new model of mixed ownership of nuclear power enterprises, said CGN.

The world's first Hualong One reactor at unit 5 of China National Nuclear Corp's Fuqing nuclear plant in Fujian province was connected to the grid in November. With the start of work on San'ao unit 1, China now has further seven Hualong One units under construction, including Fuqing 6, which is scheduled to go online this year.

CNNC is also constructing one unit at Taipingling in Guangdong and two at Zhangzhou in Fujian province. CGN is building two at its Fangchenggang site in Guangxi Zhuang autonomous region. In addition, two Hualong One units are under construction at Karachi in Pakistan, while CGN proposes to use a UK version of the Hualong One at Bradwell in the United Kingdom, aligning with the country's green industrial revolution strategy.

 

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Japan opens part of last town off-limits since nuclear leaks

Futaba Partial Reopening marks limited access to the Fukushima exclusion zone, highlighting radiation decontamination progress, the train station restart, and regional recovery ahead of the Tokyo Olympics after the 2011 nuclear disaster and evacuation.

 

Key Points

A lift of entry bans in Futaba, signaling Fukushima recovery, decontamination progress, and a train station restart.

✅ Unrestricted access to 2.4 km² around Futaba Station

✅ Symbolic step ahead of Tokyo Olympics torch relay

✅ Decommissioning and decontamination to span decades

 

Japan's government on Wednesday opened part of the last town that had been off-limits due to radiation since the Fukushima nuclear disaster nine years ago, in a symbolic move to show the region's recovery ahead of the Tokyo Olympics, even as grid blackout risks have drawn scrutiny nationwide.

The entire population of 7,000 was forced to evacuate Futaba after three reactors melted down due to damage at the town's nuclear plant caused by a magnitude 9. 0 quake and tsunami March 11, 2011.

The partial lifting of the entry ban comes weeks before the Olympic torch starts from another town in Fukushima, as new energy projects like a large hydrogen system move forward in the prefecture. The torch could also arrive in Futaba, about 4 kilometres (2.4 miles) from the wrecked nuclear plant.

Unrestricted access, however, is only being allowed to a 2.4 square-kilometre (less than 1 square-mile) area near the main Futaba train station, which will reopen later this month to reconnect it with the rest of the region for the first time since the accident. The vast majority of Futaba is restricted to those who get permission for a day visit.

The three reactor meltdowns at the town's Fukushima Dai-ichi nuclear power plant spewed massive amounts of radiation that contaminated the surrounding area and at its peak, forced more than 160,000 people to flee, even as regulators later granted TEPCO restart approval for a separate Niigata plant elsewhere in Japan.

The gate at a checkpoint was opened at midnight Tuesday, and Futaba officials placed a signboard at their new town office, at a time when the shutdown of Germany's last reactors has reshaped energy debates abroad.

“I'm overwhelmed with emotion as we finally bring part of our town operations back to our home town," said Futaba Mayor Shiro Izawa. “I pledge to steadily push forward our recovery and reconstruction."

Town officials say they hope to see Futaba’s former residents return, but prospects are grim because of lingering concern about radiation, and as Germany's nuclear exit underscores shifting policies abroad. Many residents also found new jobs and ties to communities after evacuating, and only about 10% say they plan to return.

Futaba's registered residents already has decreased by 1,000 from its pre-disaster population of 7,000. Many evacuees ended up in Kazo City, north of Tokyo, after long bus trips, various stopovers and stays in shelters at an athletic arena and an abandoned high school. The town's government reopened in a makeshift office in another Fukushima town of Iwaki, while abroad projects like the Bruce reactor refurbishment illustrate long-term nuclear maintenance efforts.

Even after radiation levels declined to safe levels, the region's farming and fishing are hurt by lingering concerns among consumers and retailers. The nuclear plant is being decommission in a process that will take decades, with spent fuel removal delays extending timelines, and it is building temporary storage for massive amounts of debris and soil from ongoing decontamination efforts.

 

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UK price cap on household energy bills expected to cost 89bn

UK Energy Price Guarantee Cost forecasts from Cornwall Insight suggest an £89bn bill, tied to wholesale gas prices, OBR projections, and fiscal policy, to shield households amid the cost of living crisis.

 

Key Points

It is the projected government spend to cap household bills, driven by wholesale gas prices and OBR market forecasts.

✅ Base case: £89bn over two years, per Cornwall Insight

✅ Range: £72bn to £140bn, volatile wholesale gas costs

✅ Excludes 6-month business support estimated at £22bn-£48bn

 

Liz Truss’s intervention to freeze energy prices for households for two years is expected to cost the government £89bn, according to the first major costing of the policy by the sector’s leading consultancy.

The analysis from Cornwall Insight, seen exclusively by the Guardian, shows the prime minister’s plan to tackle the cost of living crisis could cost as much as £140bn in a worst-case scenario.

Truss announced in early September that the average annual bill for a typical household would be capped at £2,500 to protect consumers from the intensifying cost of living crisis amid high winter energy costs and a scheduled 80% rise in the cap to £3,549.

The ultimate cost of the policy is uncertain as it is highly dependent on the wholesale cost of gas, including UK natural gas prices which have soared since Russia’s invasion of Ukraine put a squeeze on already-volatile international markets. Ballpark projections had put the cost anywhere from £100bn to £150bn.

The Office for Budget Responsibility is expected to give its forecast for the bill when it provides its independent assessment of Kwasi Kwarteng’s medium-term fiscal plan, which the chancellor said on Tuesday would still happen on 23 November despite previous reports that it would be brought forward.

Cornwall Insight analysed projections of wholesale market moves to cost the intervention. In its base case scenario, analysts expect the policy to cost £89bn. That assumes the cost of supporting each household would be just over £1,000 in the first year, and about £2,000 in the second year.

The study’s authors said the wholesale price of gas would be influenced by energy demand, the severity of weather, “geo-political uncertainty” and prices for liquified natural gas as Europe seeks to refill storage facilities, which countries have rushed to fill up this winter but which could be relatively empty by next spring.

In the best-case outcome, the policy would cost £72bn, with some projections pointing to a 16% decrease in energy bills in April for households, while the “extreme high” outlook would see the government shell out £140bn to protect 29m UK households.

Gas prices are expected to push even higher if the Kremlin decides to completely cut off Russian gas exports into Europe.

Cornwall Insight’s projection does not include a separate six-month initiative to cap costs for companies, charities and public sector organisations, which is forecast to cost £22bn to £48bn.

The consultancy’s chief executive, Gareth Miller, said the £70bn range in its forecasts reflected “a febrile wholesale market continuing to be beset by geopolitical instability, sensitivity to demand, weather and infrastructure resilience”.

He said: “Fortune befriends the bold, but it also favours the prepared. The large uncertainties around commodity markets over the next two years means that the government could get lucky with costs coming out at the low end of the range, but the opposite could also be true.

“In each case, the government may find itself passengers to circumstances outside its control, having made policy that is a hostage to surprises, events and volatile factors. That’s a difficult position to be in.”

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The government has faced criticism, as some British MPs urge tighter limits on prices, that the policy is effectively a “blank cheque” and is not targeted at the most vulnerable in society.

Concerns over how Truss and Kwarteng intend to fund a series of measures, including the price guarantee, have spooked financial markets.

The EU, which has outlined possible gas price cap strategies in recent proposals, said last week it planned to cap the revenues of low-carbon electricity generators at €180 a megawatt hour, which is less than half current market prices. Truss has so far resisted calls to extend a levy on North Sea oil and gas operators to electricity generators, who have benefited from a link between gas and electricity prices in Britain.

Truss hopes to strike voluntary long-term deals with generators including Centrica and EDF, alongside the government’s Energy Security Bill measures, to bring down wholesale prices.

The Financial Times reported on Tuesday that the government has threatened companies with legislation to cap their revenues if voluntary deals cannot be agreed.

 

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Scientists generate 'electricity from thin air.' Humidity could be a boundless source of energy.

Air Humidity Energy Harvesting converts thin air into clean electricity using air-gen devices with nanopores, delivering continuous renewable energy from ambient moisture, as demonstrated by UMass Amherst researchers in Advanced Materials.

 

Key Points

A method using nanoporous air-gen devices to harvest continuous clean electricity from ambient atmospheric moisture.

✅ Nanopores drive charge separation from ambient water molecules

✅ Works across materials: silicon, wood, bacterial films

✅ Predictable, continuous power unlike intermittent solar or wind

 

Sure, we all complain about the humidity on a sweltering summer day. But it turns out that same humidity could be a source of clean, pollution-free energy, aligning with efforts toward cheap, abundant electricity worldwide, a new study shows.

"Air humidity is a vast, sustainable reservoir of energy that, unlike wind and solar power resources, is continuously available," said the study, which was published recently in the journal Advanced Materials.

While humidity harvesting promises constant output, advances like a new fuel cell could help fix renewable energy storage challenges, researchers suggest.

“This is very exciting,” said Xiaomeng Liu, a graduate student at the University of Massachusetts-Amherst, and the paper’s lead author. “We are opening up a wide door for harvesting clean electricity from thin air.”

In fact, researchers say, nearly any material can be turned into a device that continuously harvests electricity from humidity in the air, a concept echoed by raindrop electricity demonstrations in other contexts.

“The air contains an enormous amount of electricity,” said Jun Yao, assistant professor of electrical and computer engineering at the University of Massachusetts-Amherst and the paper’s senior author. “Think of a cloud, which is nothing more than a mass of water droplets. Each of those droplets contains a charge, and when conditions are right, the cloud can produce a lightning bolt – but we don’t know how to reliably capture electricity from lightning.

"What we’ve done is to create a human-built, small-scale cloud that produces electricity for us predictably and continuously so that we can harvest it.”

The heart of the human-made cloud depends on what Yao and his colleagues refer to as an air-powered generator, or the "air-gen" effect, which relates to other atmospheric power concepts like night-sky electricity studies in the field.

In broader renewable systems, flexible resources such as West African hydropower can support variable wind and solar output, complementing atmospheric harvesting concepts as they mature.

The study builds on research from a study published in 2020. That year, scientists said this new technology "could have significant implications for the future of renewable energy, climate change and in the future of medicine." That study indicated that energy was able to be pulled from humidity by material that came from bacteria; related bio-inspired fuel cell design research explores better electricity generation, the new study finds that almost any material, such as silicon or wood, also could be used.

The device mentioned in the study is the size of a fingernail and thinner than a single hair. It is dotted with tiny holes known as nanopores, it was reported. "The holes have a diameter smaller than 100 nanometers, or less than a thousandth of the width of a strand of human hair."

 

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Turning thermal energy into electricity

Near-Field Thermophotovoltaics captures radiated energy across a nanoscale gap, using thin-film photovoltaic cells and indium gallium arsenide to boost power density and efficiency, enabling compact Army portable power from emitters via radiative heat transfer.

 

Key Points

A nanoscale TPV method capturing near-field photons for higher power density at lower emitter temperatures.

✅ Nanoscale gap boosts radiative transfer and usable photon flux

✅ Thin-film InGaAs cells recycle sub-band-gap photons via reflector

✅ Achieved ~5 kW/m2 power density with higher efficiency

 

With the addition of sensors and enhanced communication tools, providing lightweight, portable power has become even more challenging, with concepts such as power from falling snow illustrating how diverse new energy-harvesting approaches are. Army-funded research demonstrated a new approach to turning thermal energy into electricity that could provide compact and efficient power for Soldiers on future battlefields.

Hot objects radiate light in the form of photons into their surroundings. The emitted photons can be captured by a photovoltaic cell and converted to useful electric energy. This approach to energy conversion is called far-field thermophotovoltaics, or FF-TPVs, and has been under development for many years; however, it suffers from low power density and therefore requires high operating temperatures of the emitter.

The research, conducted at the University of Michigan and published in Nature Communications, demonstrates a new approach, where the separation between the emitter and the photovoltaic cell is reduced to the nanoscale, enabling much greater power output than what is possible with FF-TPVs for the same emitter temperature.

This approach, which enables capture of energy that is otherwise trapped in the near-field of the emitter is called near-field thermophotovoltaics or NF-TPV and uses custom-built photovoltaic cells and emitter designs ideal for near-field operating conditions, alongside emerging smart solar inverters that help manage conversion and delivery.

This technique exhibited a power density almost an order of magnitude higher than that for the best-reported near-field-TPV systems, while also operating at six-times higher efficiency, paving the way for future near-field-TPV applications, including remote microgrid deployments in extreme environments, according to Dr. Edgar Meyhofer, professor of mechanical engineering, University of Michigan.

"The Army uses large amounts of power during deployments and battlefield operations and must be carried by the Soldier or a weight constrained system," said Dr. Mike Waits, U.S. Army Combat Capabilities Development Command's Army Research Laboratory. "If successful, in the future near-field-TPVs could serve as more compact and higher efficiency power sources for Soldiers as these devices can function at lower operating temperatures than conventional TPVs."

The efficiency of a TPV device is characterized by how much of the total energy transfer between the emitter and the photovoltaic cell is used to excite the electron-hole pairs in the photovoltaic cell, where insights from near-light-speed conduction research help contextualize performance limits in semiconductors. While increasing the temperature of the emitter increases the number of photons above the band-gap of the cell, the number of sub band-gap photons that can heat up the photovoltaic cell need to be minimized.

"This was achieved by fabricating thin-film TPV cells with ultra-flat surfaces, and with a metal back reflector," said Dr. Stephen Forrest, professor of electrical and computer engineering, University of Michigan. "The photons above the band-gap of the cell are efficiently absorbed in the micron-thick semiconductor, while those below the band-gap are reflected back to the silicon emitter and recycled."

The team grew thin-film indium gallium arsenide photovoltaic cells on thick semiconductor substrates, and then peeled off the very thin semiconductor active region of the cell and transferred it to a silicon substrate, informing potential interfaces with home battery systems for distributed use.

All these innovations in device design and experimental approach resulted in a novel near-field TPV system that could complement distributed resources in virtual power plants for resilient operations.

"The team has achieved a record ~5 kW/m2 power output, which is an order of magnitude larger than systems previously reported in the literature," said Dr. Pramod Reddy, professor of mechanical engineering, University of Michigan.

Researchers also performed state-of-the-art theoretical calculations to estimate the performance of the photovoltaic cell at each temperature and gap size, informing hybrid designs with backup fuel cell solutions that extend battery life, and showed good agreement between the experiments and computational predictions.

"This current demonstration meets theoretical predictions of radiative heat transfer at the nanoscale, and directly shows the potential for developing future near-field TPV devices for Army applications in power and energy, communication and sensors," said Dr. Pani Varanasi, program manager, DEVCOM ARL that funded this work.

 

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