Utility, wind farmer reach deal: No upgrade required for wind farm

TEPCO Kashiwazaki-Kariwa restart plan clears NRA fitness review, anchored by a seven-point safety code, Niigata consent, Fukushima lessons, seismic risk analysis, and upgrades to No. 6 and No. 7 reactors, each rated 1.35 GW.

Key Points

TEPCO's plan to restart Kashiwazaki-Kariwa under NRA rules, pending Niigata consent and upgrades to Units 6 and 7.

✅ NRA deems TEPCO fit; legally binding seven-point safety code

✅ Local consent required: Niigata review of evacuation and health impacts

✅ Initial focus on Units 6 and 7; 1.35 GW each, seismic upgrades

Tokyo Electric Power Co. cleared a major regulatory hurdle toward restarting a nuclear power plant in Niigata Prefecture, but the utility’s bid to resume its operations still hangs in the balance of a series of political approvals.

The government’s nuclear watchdog concluded Sept. 23 that the utility is fit to operate the plant, based on new legally binding safety rules TEPCO drafted and pledged to follow, even as nuclear projects worldwide mark milestones across different regulatory environments today. If TEPCO is found to be in breach of those regulations, it could be ordered to halt the plant’s operations.

The Nuclear Regulation Authority’s green light now shifts the focus over to whether local governments will agree in the coming months to restart the Kashiwazaki-Kariwa plant.

TEPCO is keen to get the plant back up and running. It has been financially reeling from the closure of its nuclear plants in Fukushima Prefecture following the triple meltdown at the Fukushima No. 1 nuclear plant in 2011 triggered by the earthquake and tsunami disaster.

In parallel, Japan is investing in clean energy innovations such as a large hydrogen system being developed by Toshiba, Tohoku Electric Power and Iwatani.

The company plans to bring the No. 6 and No. 7 reactors back online at the Kashiwazaki-Kariwa nuclear complex, which is among the world’s largest nuclear plants, amid China’s nuclear energy continuing on a steady development track in the region.

The two reactors each boast 1.35 gigawatts in output capacity, while Kenya’s nuclear plant aims to power industry as part of that country’s expansion. They are the newest of the seven reactors there, first put into service between 1996 and 1997.

TEPCO has not revealed specific plans yet on what to do with the older five reactors.

In 2017, the NRA cleared the No. 6 and No. 7 reactors under the tougher new reactor regulations established in 2013 in response to the Fukushima nuclear disaster, while jurisdictions such as Ontario support continued operation at Pickering under strict oversight.

It also closely scrutinized the operator’s ability to run the Niigata Prefecture plant safely, given its history as the entity responsible for the nation’s most serious nuclear accident.

After several rounds of meetings with top TEPCO managers, the NRA managed to hold the utility’s feet to the fire enough to make it pledge, in writing, to abide by a new seven-point safety code for the Kashiwazaki-Kariwa plant.

The creation of the new code, which is legally binding, is meant to hold the company accountable for safety measures at the facility.

“As the top executive, the president of TEPCO will take responsibility for the safety of nuclear power,” one of the points reads. “TEPCO will not put the facility’s economic performance above its safety,” reads another.

The company promised to abide by the points set out in writing during the NRA’s examination of its safety regulations.

TEPCO also vowed to set up a system where the president is directly briefed on risks to the nuclear complex, including the likelihood of earthquakes more powerful than what the plant is designed to withstand. It must also draft safeguard measures to deal with those kinds of earthquakes and confirm whether precautionary steps are in place.

The utility additionally pledged to promptly release public records on the decision-making process concerning crucial matters related to nuclear safety, and to preserve the documents until the facility is decommissioned.

TEPCO plans to complete its work to reinforce the safety of the No. 7 reactor in December. It has not set a definite deadline for similar work for the No. 6 reactor.

To restart the Kashiwazki-Kariwa plant, TEPCO needs to obtain consent from local governments, including the Niigata prefectural government.

The prefectural government is studying the plant’s safety through a panel of experts, which is reviewing whether evacuation plans are adequate as off-limits areas reopen and the health impact on residents from the Fukushima nuclear disaster.

Niigata Governor Hideyo Hanazumi said he will not decide on the restart until the panel completes its review.

The nuclear complex suffered damage, including from fire at an electric transformer, when an earthquake it deemed able to withstand hit in 2007.

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Manitoba NDP Energy Financing Strategy outlines public ownership of renewables, halts private wind farms, stabilizes hydroelectric rates, and addresses Manitoba Hydro deficits amid drought, export revenue declines, and rising demand for grid reliability.

Key Points

A plan to fund public renewables, pause private wind, and stabilize Manitoba Hydro rates, improving utility finances.

✅ Public ownership favored over private wind contracts

✅ Focus on rate freeze and Manitoba Hydro debt management

✅ Addresses drought impacts, export revenue declines, rising demand

Manitoba's NDP administration has declared its intention to formulate a strategy for financing new energy ventures, following a decision to halt the development of additional private-sector wind farms and to extend a pause on new cryptocurrency connections amid grid pressures. This plan will accompany efforts to stabilize hydroelectric rates and manage the financial obligations of the province's state-operated energy company.

Finance Minister Adrien Sala, overseeing Manitoba Hydro, shared these insights during a legislative committee meeting on Thursday, emphasizing the government's desire for future energy expansions to remain under public ownership, even as Ontario moves to reintroduce renewable energy projects after prior cancellations, and expressing trust in Manitoba Hydro's governance to realize these goals.

This announcement was concurrent with Manitoba Hydro unveiling increased financial losses in its latest quarterly report. The utility anticipates a $190-million deficit for the fiscal year ending in March, marking a $29 million increase from its previous forecast and a significant deviation from an initial $450 million profit expectation announced last spring. Contributing factors to this financial downturn include reduced hydroelectric power generation due to drought conditions, diminished export revenues, and a mild fall season impacting heating demand.

The recent financial update aligns with a period of significant changes at Manitoba Hydro, initiated by the NDP government's board overhaul following its victory over the former Progressive Conservative administration in the October 3 election, and comes as wind projects are scrapped in Alberta across the broader Canadian energy landscape.

Subsequently, the NDP-aligned board discharged CEO Jay Grewal, who had advocated for integrating wind energy from third-party sources, citing competitive wind power trends, to promptly address the province's escalating energy requirements. Grewal's approach, though not unprecedented, sought to offer a quicker, more cost-efficient alternative to constructing new Manitoba Hydro dams, highlighting an imminent energy production shortfall projected for as early as 2029.

The opposition Progressive Conservatives have criticized the NDP for dismissing the wind power initiative without presenting an alternate solution, warning about costly cancellation fees seen in Ontario when projects are halted, and emphasizing the urgency of addressing the predicted energy gap.

In response, Sala reassured that the government is in the early stages of policy formulation, reflecting broader electricity policy debates in Ontario about how to fix the power system, and criticized the previous administration for its inaction on enhancing generation capacity during its tenure.

Manitoba Hydro has named Hal Turner as the acting CEO while it searches for Grewal's successor, following controversies such as Solar Energy Program mismanagement raised by a private developer. Turner informed the committee that the utility is still deliberating on its approach to new energy production and is exploring ways to curb rising demand.

Expressing optimism about collaborating with the new board, Turner is confident in finding a viable strategy to fulfill Manitoba's energy needs in a safe and affordable manner.

Additionally, the NDP's campaign pledge to freeze consumer rates for a year remains a priority, with Sala committing to implement this freeze before the next provincial election slated for 2027.

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New York Green New Deal accelerates clean energy and climate action, targeting carbon neutrality with renewable energy, offshore wind, solar, energy storage, and green jobs while advancing environmental justice and economy-wide decarbonization.

Key Points

New York's plan for 100% clean power by 2040 and 70% renewables by 2030, with a just transition and green jobs.

✅ 100% carbon-free electricity by 2040; 70% renewables by 2030

✅ 9,000 MW offshore wind and 3,000 MW energy storage targets

✅ Just transition focuses on jobs, equity, and affordability

New York Governor Andrew M. Cuomo announced the Green New Deal, a nation-leading clean energy and jobs agenda that will aggressively put New York State on a path to net-zero electricity and economy-wide carbon neutrality, is included in the 2019 Executive Budget. The landmark plan provides for a just transition to clean energy that spurs growth of the green economy and prioritizes the needs of low- to moderate-income New Yorkers.

"Climate change is a reality, and the consequences of delay are a matter of life and death. We know what we must do. Now we have to have the vision, the courage, and the competence to get it done," Governor Cuomo said. "While the federal government shamefully ignores the reality of climate change and fails to take meaningful action, we are launching the first-in-the-nation Green New Deal to seize the potential of the clean energy economy, set nation's most ambitious goal for carbon-free power, and ultimately eliminate our entire carbon footprint."

During Governor Cuomo's first two terms, New York banned fracking of natural gas, committed to phasing out coal power by 2020, mandated 50 percent renewable power by 2030, and established the U.S. Climate Alliance to uphold the Paris Agreement, reflecting the view that decarbonization is irreversible under a clean energy economy. Under the Reforming the Energy Vision agenda, New York has held the largest renewable energy procurements in U.S. history, solar has increased nearly 1,500 percent, and offshore wind is poised to transform the State's electricity supply to be cleaner and more sustainable. Through Governor Cuomo's Green New Deal, New York will take the bold next steps to secure a clean energy future that protects the environment for generations to come while growing the clean energy economy.

100 Percent Clean Power by 2040 Coupled with New Nation-leading Renewable Energy Mandates

The Green New Deal will statutorily mandate New York's power be 100 percent carbon-free by 2040, the most aggressive goal in the United States and five years ahead of a target recently adopted by California state policymakers. The cornerstone of this new mandate is a significant increase of New York's successful Clean Energy Standard mandate from 50 percent to 70 percent renewable electricity by 2030. This globally unprecedented ramp-up of renewable energy will include:

• Quadrupling New York's offshore wind target to 9,000 megawatts by 2035, up from 2,400 megawatts by 2030
• Doubling distributed solar deployment to 6,000 megawatts by 2025, up from 3,000 megawatts by 2023
• More than doubling new large-scale land-based wind and solar resources through the Clean Energy Standard
• Maximizing the contributions and potential of New York's existing renewable resources
• Deploying 3,000 megawatts of energy storage by 2030, up from 1,500 megawatts by 2025
• Develop an Implementation Plan to Make New York Carbon Neutral

The Green New Deal will create the State's first statutory Climate Action Council, comprised of the heads of relevant State agencies and other workforce, environmental justice, and clean energy experts to develop a comprehensive plan to make New York carbon neutral by significantly and cost-effectively reducing emissions from all major sources, including electricity, transportation, buildings, industry, commercial activity, and agriculture. The Climate Action Council will consider a range of possible options, including the feasibility of working with the U.S. Climate Alliance to create a new multistate emissions reduction program that covers all sectors of the economy, including transportation and industry, and exploring ways to leverage the successful Regional Greenhouse Gas Initiative to drive transformational investment in the clean energy economy and support a just transition.

At the national level, a historic climate deal is reshaping incentives and standards for clean energy deployment across the country.

The Green New Deal will also include an ambitious strategy to move New York's statewide building stock to carbon neutrality. The agenda includes:

Advancing legislative changes to strengthen building energy codes and establish appliance efficiency standards

Directing State agencies to ensure that their facilities uphold the strongest energy efficiency and sustainability standards

Developing a Net Zero Roadmap to chart a course to statewide carbon neutrality in buildings

A Multibillion Dollar Green New Deal Investment in the Clean Tech Economy that will Reduce Greenhouse Gas Emissions

Demonstrating New York's immediate commitment to implementing the nation's most ambitious clean energy agenda and creating high-quality clean energy jobs, Governor Cuomo is announcing $1.5 billion in competitive awards to support 20 large-scale solar, wind and energy storage projects across upstate New York. These investments will add over 1,650 megawatts of capacity and generate over 3,800,000 megawatt-hours of renewable energy annually - enough to power nearly 550,000 homes and create over 2,600 short and long-term jobs. Combined with the renewable energy projects previously announced under the Clean Energy Standard, New York has now awarded more than $2.9 billion to 46 projects statewide, enough to power over one million households.

The Green New Deal also includes new investments to jumpstart New York's offshore wind energy industry and support the State's world-leading target of 9,000 megawatts by 2035. New York will invest up to $200 million in port infrastructure to match private sector investment in regional development of offshore wind. This multi-location investment represents the nation's largest infrastructure commitment to offshore wind and solidifies New York's position as the hub of the burgeoning U.S. offshore wind industry.

These new investments build upon a $250 million commitment to electric vehicle infrastructure by the New York Power Authority's EVolve program, $3.5 billion in private investment in distributed solar driven by NYSERDA's NY-Sun program, and NY Green Bank transactions mobilizing nearly $1.75 billion in private capital for clean energy projects.

A Just Transition to a Clean Energy Economy

Deliver Climate Justice for Underserved Communities: The Green New Deal will help historically underserved communities prepare for a clean energy future and adapt to climate change by:

Giving communities a seat at the table by codifying the Environmental Justice and Just Transition Working Group into law and incorporating it into the planning process for the Green New Deal's implementation.

Directing the State's low-income energy task force to identify reforms to achieve greater impact of the public energy funds expended each year in order to increase the effect of funds and initiatives that target energy affordability to underserved communities.

Directing each of the State's ten Regional Economic Development Councils to develop an environmental justice strategy for their region.

Finance a Property Tax Compensation Fund to Help Communities Transition to the Clean Energy Economy: Governor Cuomo is introducing legislation to finance the State's $70 million Property Tax Compensation Fund to continue helping communities directly affected by the transition away from dirty and obsolete energy industries and toward the new clean energy economy. Specifically, this funding will protect communities impacted by the retirement of conventional power generation facilities.

Protect Labor Rights: To ensure creation of high-quality clean energy jobs, large-scale renewable energy projects supported by the Green New Deal will require prevailing wage, and the State's offshore wind projects will be supported by a requirement for a Project Labor Agreement.

Develop the Clean Tech Workforce: To prepare New York's workforce for the transition, New York State will take new steps to support workforce development, including establishing a New York State Advisory Council on Offshore Wind Economic and Workforce Development, as well as investing in an offshore wind training center that will provide New Yorkers with the skills and safety training required to construct this clean energy technology in New York.   

Richard Kauffman, Chairman of Energy and Finance for New York, said, "Governor Cuomo's Green New Deal will advance New York State further into the clean energy future, and we won't let the Trump Administration push us backwards. Governor Cuomo's new commitments ensure New York is the undisputed national clean energy and climate leader, and we will continue to build upon the foundations of the REV agenda to achieve a sustainable economy and healthy environment for generations of New Yorkers to come."

Alicia Barton, President and CEO, NYSERDA, said, "Climate scientists have made frighteningly clear that averting the worst effects of climate change will require bold action, not incremental steps, and Governor Cuomo's Green New Deal boldly goes where no others have before. His unwavering climate agenda includes the most aggressive clean energy target in U.S. history, the largest commitments to renewable energy and to offshore wind in the nation, a massive mobilization of clean energy jobs and an unprecedented investment in offshore wind port infrastructure. Together these actions make New York the clear national leader in the fight against climate change, and will show the world that New York can and will achieve a clean energy future for the sake of future generations."

DEC Commissioner Basil Seggos said, "The threat of climate change calls for bold action like Governor Cuomo's comprehensive agenda to make New York State carbon neutral. The Green New Deal ensures New York is continuing our nation-leading efforts to capitalize on the economic potential of the clean energy economy, while making sure those most vulnerable to climate change are benefitting from the state's efforts and investments. I look forward to working with my agency and authority partners on the Climate Action Council to develop and implement meaningful solutions to reduce greenhouse gas emissions from all sectors of our economy."  

John B. Rhodes, CEO, Department of Public Service, said, "With this nation-leading Green New Deal, Governor Cuomo puts New York on the path to fully clean electricity and to carbon neutrality with the strongest renewable energy goals in the nation. This will deliver the energy system that New York needs - cost-effective, reliable, and 100% clean.”

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HVDC-WISE Project accelerates HVDC technology integration across the European transmission system, delivering a planning toolkit to boost grid reliability, resilience, and interconnectors for renewables and offshore wind amid climate, cyber, and physical threats.

Key Points

EU-funded project delivering tools to integrate HVDC into Europe's grid, improving reliability, resilience, and security.

✅ EU Horizon Europe-backed consortium of 14 partners

✅ Toolkit to assess extreme events and grid operability

✅ Supports interconnectors, offshore wind, and renewables

A partnership of 14 leading European energy industry companies, research organizations and universities has launched a new project to identify opportunities to increase integration of HVDC technology into the European transmission system, echoing calls to invest in smarter electricity infrastructure from abroad.

The HVDC-WISE project, in which the University of Strathclyde is the UK’s only academic partner, is supported by the European Union’s Horizon Europe programme.

The project’s goal is to develop a toolkit for grid developers to evaluate the grid’s performance under extreme conditions and to plan systems, leveraging a digital grid approach that supports coordination to realise the full range of potential benefits from deep integration of HVDC technology into the European transmission system.

The project is focused on enhancing electric grid reliability and resilience while navigating the energy transition. Building and maintaining network infrastructure to move power across Europe is an urgent and complex task, and reducing losses with superconducting cables can play a role, particularly with the continuing growth of wind and solar generation. At the same time, threats to the integrity of the power system are on the rise from multiple sources, including climate, cyber, and physical hazards.

Mutual support

At a time of increasing worries about energy security and as Europe’s electricity systems decarbonise, connections between them to provide mutual support and routes to market for energy from renewables, a dynamic also highlighted in discussions of the western Canadian electricity grid in North America, become ever more important.

In modern power systems, this means making use of High Voltage Direct Current (HVDC) technology.

The earliest forms of technology have been around since the 1960s, but the impact of increasing reliance on HVDC and its ability to enhance a power system’s operability and resilience are not yet fully understood.

Professor Keith Bell, Scottish Power Professor of Future Power Systems at the University of Strathclyde, said:

As an island, HVDC is the only practical way for us to build connections to other countries’ electricity systems. We’re also making use of it within our system, with one existing and more planned Scotland-England subsea link projects connecting one part of Britain to another.

“These links allow us to maximise our use of wind energy. New links to other countries will also help us when it’s not windy and, together with assets like the 2GW substation now in service, to recover from any major disturbances that might occur.

“The system is always vulnerable to weather and things like lightning strikes or short circuits caused by high winds. As dependency on electricity increases, insights from electricity prediction specialists can inform planning as we enhance the resilience of the system.”

Dr Agusti Egea-Alvarez, Senior Lecturer at Strathclyde, said: “HVDC systems are becoming the backbone of the British and European electric power network, either interconnecting countries, or connecting offshore wind farms.

“The tools, procedures and guides that will be developed during HVDC-WISE will define the security, resilience and reliability standards of the electric network for the upcoming decades in Europe.”

Other project participants include Scottish Hydro Electric Transmission, the Supergrid Institute, the Electric Power Research Institute (EPRI) Europe, Tennet TSO, Universidad Pontificia Comillas, TU Delft, Tractebel Impact and the University of Cyprus.

Climate change

Eamonn Lannoye, Managing Director of EPRI Europe, said: “The European electricity grid is remarkably reliable by any standard. But as the climate changes and the grid becomes exposed to more extreme conditions, energy interdependence between regions intensifies and threats from external actors emerge. The new grid needs to be robust to those challenges.”

Juan Carlos Gonzalez, a senior researcher with the SuperGrid Institute which leads the project said: “The HVDC-WISE project is intended to provide planners with the tools and know-how to understand how grid development options perform in the context of changing threats and to ensure reliability.”

HVDC-WISE is supported by the European Union’s Horizon Europe programme under agreement 101075424 and by the UK Research and Innovation Horizon Europe Guarantee scheme.

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Pickering Nuclear False Alert Investigation probes Ontario's emergency alert system after a provincewide cellphone, radio, and TV warning, assessing human error, Pelmorex safeguards, Emergency Management Ontario oversight, and communication delays.

Key Points

An Ontario probe into the erroneous Pickering nuclear alert, focusing on human error, system safeguards, and oversight.

✅ Human error during routine testing suspected

✅ Pelmorex safeguards and EMO protocols under review

✅ Two-hour all-clear delay prompts communication fixes

An investigation into a mistaken Pickering alert warning of an incident at the Pickering Nuclear Generating Station will be completed fairly quickly, Ontario's solicitor general said.

Sylvia Jones tapped the chief of Emergency Management Ontario to investigate how the alert warning of an unspecified problem at the facility was sent in error to cellphones, radios and TVs across the province at about 7:30 a.m. Sunday.

"It's very important for me, for the people of Ontario, to know exactly what happened on Sunday morning," said Jones. "Having said that, I do not anticipate this is going to be a long, drawn-out investigation. I want to know what happened and equally important, I want some recommendations on insurances and changes we can make to the system to make sure it doesn't happen again."

Initial observations suggest human error was responsible for the alert that was sent out during routine tests of the emergency alert, Jones said.

"This has never happened in the history of the tests that they do every day, twice a day, but I do want to know exactly all of the issues related to it, whether it was one human error or whether it was a series of things."

Martin Belanger, the director of public alerting for Pelmorex, a company that operates the alert system, said there are a number of safeguards built in, including having two separate platforms for training and live alerts.

"The software has some steps and some features built in to minimize that risk and to make sure that users will be able to know whether or not they're sending an alert through the...training platform or whether they're accessing the live system in the case of a real emergency," he said.

Only authorized users have access to the system and the province manages that, Belanger said. Once in the live system, features make the user aware of which platform they are using, with various prompts and messages requiring the user's confirmation. There is a final step that also requires the user to confirm their intent of issuing an alert to cellphones, radio and TVs, Belanger said.

On Sunday, a follow-up alert was sent to cellphones nearly two hours after the original notification, and similar grid alerts in Alberta underscore timing and public expectations.

NDP energy critic Peter Tabuns is critical of that delay, noting that ongoing utility scam warnings can further erode public trust.

"That's a long time for people to be waiting to find out what's really going on," he said. "If people lose confidence in this system, the ability to use it when there is a real emergency will be impaired. That's dangerous."

Treasury Board President Peter Bethlenfalvy, who represents the riding of Pickering-Uxbridge, said getting that alert Sunday morning was "a shock to the system," and he too wants the investigation to address the reason for the all-clear delay.

"We all have a lot of questions," he said. "I think the public has every right to know exactly what went on and we feel exactly the same way."

People in the community know the facility is safe, Bethlenfalvy said.

"We have some of the safest nuclear assets in the world -- the safest -- at 60 per cent of Ontario's electricity," he said.

A poll released Monday found that 82 per cent of Canadians are concerned about spills from nuclear reactors contaminating drinking water and 77 per cent are concerned about neighbourhood safety and security risks for those living close to nuclear plants. Oraclepoll Research surveyed 2,094 people across the country on behalf of Friends of the Earth between Jan. 2 and 12, the day of the false alert. The have a margin of error of plus or minus 2.1 per cent, 19 times out of 20.

The wording of Sunday's alert caused much initial confusion, and events like a power outage in London show how morning disruptions can amplify concern, warning residents within 10 kilometres of the plant of "an incident," though there was no "abnormal" release of radioactivity and residents didn't need to take protective steps, but emergency crews were responding.

In the event of a real emergency, the wording would be different, Jones said.

"There are a number of different alerts that are already prepared and are ready to go," she said. "We have the ability to localize it to the communities that are impacted, but because this was a test, it went provincewide."

Jones said she expects the results of the probe to be made public.

The Pickering nuclear plant has been operating since 1971, and had been scheduled to be decommissioned this year, but the former Liberal government -- and the current Progressive Conservative government -- committed to keeping it open until 2024. Decommissioning is now set to start in 2028.

It operates six CANDU reactors, generates 14 per cent of Ontario's electricity and is responsible for 4,500 jobs across the region, according to OPG, and OPG's credit rating remains stable.

During the COVID-19 pandemic, Hydro One employees supported the Province of Ontario in the fight against COVID-19.

The Green party is calling on the province to use this opportunity to review its nuclear emergency response plan, including pandemic staffing contingencies, last updated in 2017 and subject to review every five years.

Toronto Mayor John Tory praised Ontario for swiftly launching an investigation, but said communication between city and provincial officials wasn't what it should have been under the circumstances.

"It was a poor showing and I think everybody involved knows that," he said. "We've got to make sure it's not repeated."

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Polycrystalline Tin Selenide Thermoelectrics enable waste heat recovery with ZT 3.1, matching single crystals while cutting costs, powering greener car engines, industrial furnaces, and thermoelectric generators via p-type and emerging n-type designs.

Key Points

Low-cost tin selenide devices that turn waste heat into power, achieving ZT 3.1 and enabling p-type and n-type modules.

✅ Oxygen removal prevents heat-leaking tin oxide grain skins.

✅ Polycrystalline ingots match single-crystal ZT 3.1 at lower cost.

✅ N-type tin selenide in development to pair with p-type.

So-called thermoelectric generators turn waste heat into electricity without producing greenhouse gas emissions, providing what seems like a free lunch. But despite helping power the Mars rovers, the high cost of these devices has prevented their widespread use. Now, researchers have found a way to make cheap thermoelectrics that work just as well as the pricey kind. The work could pave the way for a new generation of greener car engines, industrial furnaces, and other energy-generating devices.

“This looks like a very smart way to realize high performance,” says Li-Dong Zhao, a materials scientist at Beihang University who was not involved with the work. He notes there are still a few more steps to take before these materials can become high-performing thermoelectric generators. However, he says, “I think this will be used in the not too far future.”

Thermoelectrics are semiconductor devices placed on a hot surface, like a gas-powered car engine or on heat-generating electronics using thin-film converters to capture waste heat. That gives them a hot side and a cool side, away from the hot surface. They work by using the heat to push electrical charges from one to the other, a process of turning thermal energy into electricity that depends on the temperature gradient. If a device allows the hot side to warm up the cool side, the electricity stops flowing. A device’s success at preventing this, as well as its ability to conduct electrons, feeds into a score known as the figure of merit, or ZT.

 Over the past 2 decades, researchers have produced thermoelectric materials with increasing ZTs, while related advances such as nighttime solar cells have broadened thermal-to-electric concepts. The record came in 2014 when Mercouri Kanatzidis, a materials scientist at Northwestern University, and his colleagues came up with a single crystal of tin selenide with a ZT of 3.1. Yet the material was difficult to make and too fragile to work with. “For practical applications, it’s a non-starter,” Kanatzidis says.

So, his team decided to make its thermoelectrics from readily available tin and selenium powders, an approach that, once processed, makes grains of polycrystalline tin selenide instead of the single crystals. The polycrystalline grains are cheap and can be heated and compressed into ingots that are 3 to 5 centimeters long, which can be made into devices. The polycrystalline ingots are also more robust, and Kanatzidis expected the boundaries between the individual grains to slow the passage of heat. But when his team tested the polycrystalline materials, the thermal conductivity shot up, dropping their ZT scores as low as 1.2.

In 2016, the Northwestern team discovered the source of the problem: an ultrathin skin of tin oxide was forming around individual grains of polycrystalline tin selenide before they were pressed into ingots. And that skin acted as an express lane for the heat to travel from grain to grain through the material. So, in their current study, Kanatzidis and his colleagues came up with a way to use heat to drive any oxygen away from the powdery precursors, leaving pristine polycrystalline tin selenide, whereas other devices can generate electricity from thin air using ambient moisture.

The result, which they report today in Nature Materials, was not only a thermal conductivity below that of single-crystal tin selenide but also a ZT of 3.1, a development that echoes nighttime renewable devices showing electricity from cold conditions. “This opens the door for new devices to be built from polycrystalline tin selenide pellets and their applications to be explored,” Kanatzidis says.

Getting through that door will still take some time. The polycrystalline tin selenide the team makes is spiked with sodium atoms, creating what is known as a “p-type” material that conducts positive charges. To make working devices, researchers also need an “n-type” version to conduct negative charges.

Zhao’s team recently reported making an n-type single-crystal tin selenide by spiking it with bromine atoms. And Kanatzidis says his team is now working on making an n-type polycrystalline version. Once n-type and p-type tin selenide devices are paired, researchers should have a clear path to making a new generation of ultra-efficient thermoelectric generators. Those could be installed everywhere from automobile exhaust pipes to water heaters and industrial furnaces to scavenge energy from some of the 65% of fossil fuel energy that winds up as waste heat. 

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