Clean-coal dream remains elusive for west

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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Ontario Clean Grid Plan outlines emissions-free electricity growth, renewable energy procurement, nuclear expansion at Bruce and Darlington, reduced natural gas, grid reliability, and net-zero alignment to meet IESO demand forecasts and EV manufacturing loads.

Key Points

A plan to expand emissions-free power via renewables and nuclear, cut natural gas use, and meet growing demand.

✅ Targets renewables, hydro, and nuclear capacity growth

✅ Aims to reduce reliance on gas for grid reliability

✅ Aligns with IESO demand forecasts and EV manufacturing loads

Ontario is working toward filling all of the province’s quickly growing electricity needs with emissions-free sources, including a plan to secure new renewable generation and clean power options, but isn’t quite ready to commit to a moratorium on natural gas.

Energy Minister Todd Smith announced Monday a plan to address growing energy needs for 2030 to 2050 — the Independent Electricity System Operator projects Ontario’s electricity demand could double by mid-century — and next steps involve looking for new wind, solar and hydroelectric power.

“While we may not need to start building today, government and those in the energy sector need to start planning immediately, so we have new clean, zero-emissions projects ready to go when we need them,” Smith said in Windsor, Ont.

The strategy also includes two nuclear projects announced last week — a new large-scale nuclear plant at Bruce Power on the shore of Lake Huron and three new small modular reactors at the site of the Darlington nuclear plant east of Toronto.

Those projects, enough to power six million homes, will help Ontario end its reliance on natural gas to generate electricity, said Smith, but committing to a natural gas moratorium in 2027 and eliminating natural gas by 2050 is contingent on the federal government helping to speed up the new nuclear facilities.

“Today’s report, the Powering Ontario’s Growth plan, commits us to working towards a 100 per cent clean grid,” Smith said in an interview.

“Hopefully the federal government can get on board with our intentions to build this clean generation as quickly as possible … That will put us in a much better position to use our natural gas facilities less in the future, if we can get those new projects online.”

The IESO has said that natural gas is required to ensure supply and stability in the short to medium term, as Ontario works on balancing demand and emissions across the grid, but that it will also increase greenhouse gas emissions from the electricity sector.

The province is expected to face increased demand for electricity from expanded electric vehicle use and manufacturing in the coming years, even as a $400-billion cost estimate for greening the grid is debated.

Keith Brooks, programs director for Environmental Defence, said the provincial plan could have been much more robust, containing firm timelines and commitments.

“This plan does not commit to getting emissions out of the system,” he said.

“It doesn’t commit to net zero, doesn’t set a timeline for a net zero goal or have any projection around emissions from Ontario’s electricity sector going forward. In fact, it’s not really a plan. It doesn’t set out any real goals and it doesn’t it doesn’t project what Ontario’s supply mix might look like.”

The Canadian Climate Institute applauded the plan’s focus on reducing reliance on gas-fired generation and emphasizing non-emitting generation, but also said there are still some question marks.

“The plan is silent on whether the province intends to construct new gas-fired generation facilities,” even as new gas plant expansions are proposed, senior research director Jason Dion wrote in a statement.

“The province should avoid building new gas plants since cost-effective alternatives are available, and such facilities are likely to end up as stranded assets. The province’s timeline for reaching net zero generation is also unclear. Canada and other G7 countries have set a target for 2035, something Ontario will need to address if it wants to remain competitive.”

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Covid-19 Energy Transition and Machine Learning reshape climate change policy, electricity planning, and grid operations, from demand forecasting and decarbonization strategies in Europe to scalable electrification modeling and renewable integration across Africa.

Key Points

How the pandemic reshapes energy policy and how ML improves planning, demand forecasts, and grid reliability in Africa.

✅ Pandemic-driven demand shifts strain grid operations and markets

✅ Policy momentum risks rollback; favor future-oriented decarbonization

✅ ML boosts demand prediction, electrification, and grid reliability in Africa

The impact of Covid-19 on the energy system was discussed in an online climate change workshop that also considered how machine learning can help electricity planning in Africa.

This year’s International Conference on Learning Representations event included a workshop held by the Climate Change AI group of academics and artificial intelligence industry representatives, which considered how machine learning can help tackle climate change and highlighted advances by European electricity prediction specialists working in this field.

Bjarne Steffen, senior researcher at the energy politics group at ETH Zürich, shared his insights at the workshop on how Covid-19 and the accompanying economic crisis are affecting recently introduced ‘green’ policies. “The crisis hit at a time when energy policies were experiencing increasing momentum towards climate action, especially in Europe, and in proposals to invest in smarter electricity infrastructure for long-term resilience,” said Steffen, who added the coronavirus pandemic has cast into doubt the implementation of such progressive policies.

The academic said there was a risk of overreacting to the public health crisis, as far as progress towards climate change goals was concerned.

Lobbying

“Many interest groups from carbon-intensive industries are pushing to remove the emissions trading system and other green policies,” said Steffen. “In cases where those policies are having a serious impact on carbon-emitting industries, governments should offer temporary waivers during this temporary crisis, instead of overhauling the regulatory structure.”

However, the ETH Zürich researcher said any temptation to impose environmental conditions to bail-outs for carbon-intensive industries should be resisted. “While it is tempting to push a green agenda in the relief packages, tying short-term environmental conditions to bail-outs is impractical, given the uncertainty in how long this crisis will last,” he said. “It is better to include provisions that will give more control over future decisions to decarbonize industries, such as the government taking equity shares in companies.”

Steffen shared with pv magazine readers an article published in Joule which can be accessed here, and which articulates his arguments about how Covid-19 could affect the energy transition.

Covid-19 in the U.K.

The electricity system in the U.K. is also being affected by Covid-19, even as the U.S. electric grid grapples with climate risks, according to Jack Kelly, founder of London-based, not-for-profit, greenhouse gas emission reduction research laboratory Open Climate Fix.

“The crisis has reduced overall electricity use in the U.K.,” said Kelly. “Residential use has increased but this has not offset reductions in commercial and industrial loads.”

Steve Wallace, a power system manager at British electricity system operator National Grid ESO recently told U.K. broadcaster the BBC electricity demand has fallen 15-20% across the U.K. The National Grid ESO blog has stated the fall-off makes managing grid functions such as voltage regulation more challenging.

Open Climate Fix’s Kelly noted even events such as a nationally-coordinated round of applause for key workers was followed by a dramatic surge in demand, stating: “On April 16, the National Grid saw a nearly 1 GW spike in electricity demand over 10 minutes after everyone finished clapping for healthcare workers and went about the rest of their evenings.”

Climate Change AI workshop panelists also discussed the impact machine learning could have on improving electricity planning in Africa. The Electricity Growth and Use in Developing Economies (e-Guide) initiative funded by fossil fuel philanthropic organization the Rockefeller Foundation aims to use data to improve the planning and operation of electricity systems in developing countries.

E-Guide members Nathan Williams, an assistant professor at the Rochester Institute of Technology (RIT) in New York state, and Simone Fobi, a PhD student at Columbia University in NYC, spoke about their work at the Climate Change AI workshop, which closed on Thursday. Williams emphasized the importance of demand prediction, saying: “Uncertainty around current and future electricity consumption leads to inefficient planning. The weak link for energy planning tools is the poor quality of demand data.”

Fobi said: “We are trying to use machine learning to make use of lower-quality data and still be able to make strong predictions.”

The market maturity of individual solar home systems and PV mini-grids in Africa mean more complex electrification plan modeling is required, similar to integrating AI data centers into Canada's grids at scale.

Modeling

“When we are doing [electricity] access planning, we are trying to figure out where the demand will be and how much demand will exist so we can propose the right technology,” added Fobi. “This makes demand estimation crucial to efficient planning.”

Unlike many traditional modeling approaches, machine learning is scalable and transferable. Rochester’s Williams has been using data from nations such as Kenya, which are more advanced in their electrification efforts, to train machine learning models to make predictions to guide electrification efforts in countries which are not as far down the track.

Williams also discussed work being undertaken by e-Guide members at the Colorado School of Mines, which uses nighttime satellite imagery and machine learning to assess the reliability of grid infrastructure in India, where new algorithms to prevent ransomware-induced blackouts are also advancing.

Rural power

Another e-Guide project, led by Jay Taneja at the University of Massachusetts, Amherst – and co-funded by the Energy and Economic Growth program on development spending based at Berkeley – uses satellite imagery to identify productive uses of electricity in rural areas by detecting pollution signals from diesel irrigation pumps.

Though good quality data is often not readily available for Africa, Williams added, it does exist.

“We have spent years developing trusting relationships with utilities,” said the RIT academic. “Once our partners realize the value proposition we can offer, they are enthusiastic about sharing their data … We can’t do machine learning without high-quality data and this requires that organizations can effectively collect, organize, store and work with data. Data can transform the electricity sector, as shown by Canadian projects to use AI for energy savings, but capacity building is crucial.”

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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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Iran Electricity Grid Synchronization enables regional interconnection, cross-border transmission, and Caspian-Europe energy corridors, linking Iraq, Azerbaijan, Russia, and Qatar to West Asia and European markets with reliable, flexible power exchange.

Key Points

Iran's initiative to link West Asian and European power grids for trade, transit, reliability, and regional influence.

✅ Synchronizes grids with Iraq, Azerbaijan, Russia, and potential Qatar link

✅ Enables east-to-Europe electricity transit via Caspian energy corridors

✅ Backed by gas-fueled and combined-cycle generation capacity

Following a plan for becoming West Asia’s electricity hub, Iran has been taking serious steps for joining its electricity network with neighbors in the past few years.

The Iranian Energy Ministry has been negotiating with the neighboring countries including Iraq for the connection of their power networks with Iran, discussing Iran-Iraq energy cooperation as well as ties with Russia, Afghanistan, Azerbaijan, and Qatar to make them enable to import or transmit their electricity to new destination markets through Iran.

The synchronization of power grids with the neighboring countries, not only enhances Iran’s electricity exchanges with them, but it will also increase the political stance of the country in the region.

So far, Iran’s electricity network has been synchronized with Iraq, where Iran is supplying 40% of Iraq's power today, and back in September, the Energy Minister Reza Ardakanian announced that the electricity networks of Russia and Azerbaijan are the next in line for becoming linked with the Iranian grid in the coming months.

“Within the next few months, the study project of synchronization of the electricity networks of Iran, Azerbaijan, and Russia will be completed and then the executive operations will begin,” the minister said.

Meanwhile, Ardakanian and Qatari Minister of State for Energy Affairs Saad Sherida Al-Kaabi held an online meeting in late September to discuss joining the two countries' electricity networks via sea.

During the online meeting, Al-Kaabi said: "Electricity transfer between the two countries is possible and this proposal should be worked on.”

Now, taking a new step toward becoming the region’s power hub, Iran has suggested becoming a bridge between East and Europe for transmitting electricity.

In a virtual conference dubbed 1st Caspian Europe Forum hosted by Berlin on Thursday, the Iranian energy minister has expressed the country’s readiness for joining its electricity network with Europe.

"We are ready to connect Iran's electricity network, as the largest power generation power in West Asia, with the European countries and to provide the ground for the exchange of electricity with Europe," Ardakanian said addressing the online event.

Iran's energy infrastructure in the oil, gas, and electricity sectors can be used as good platforms for the transfer of energy from east to Europe, he noted.

In the event, which was aimed to study issues related to the development of economic cooperation, especially energy, between the countries of the Caspian Sea region, the official added that Iran, with its huge energy resources and having skilled manpower and advanced facilities in the field of energy, can pave the ground for the prosperity of international transport and energy corridors.

"In order to help promote communication between our landlocked neighbors with international markets, as Uzbekistan aims to export power to Afghanistan across the region, we have created a huge transit infrastructure in our country and have demonstrated in practice our commitment to regional development and peace and stability," Ardakanian said.

He pointed out that having a major percentage of proven oil and gas resources in the world, regional states need to strengthen relations in a bid to regulate production and export policies of these huge resources and potentially play a role in determining the price and supply of these resources worldwide.

“EU countries can join our regional cooperation in the framework of bilateral or multilateral mechanisms such as ECO,” he said.

Given the growing regional and global energy needs and the insufficient investment in the field, with parts of Central Asia facing severe electricity shortages today, as well as Europe's increasing needs, this area can become a sustainable area of cooperation, he noted.

Ardakanian also said that by investing in energy production in Iran, Europe can meet part of its future energy needs on a sustainable basis.

In Iraq, plans for nuclear power plants are being pursued to tackle chronic electricity shortages, reflecting parallel efforts to diversify generation.

Iran currently has electricity exchange with Armenia, Azerbaijan, Iraq, where grid rehabilitation deals have been finalized, Turkmenistan, and Afghanistan.

The country’s total electricity exports vary depending on the hot and cold seasons of the year, since during the hot season which is the peak consumption period, the country’s electricity exports decreases, however electrical communication with neighboring countries continues.

Enjoying abundant gas resources, which is the main fuel for the majority of the country’s power plants, Iran has the capacity to produce about 85,500 megawatts [85.5 gigawatts (GW)] of electricity.

Currently, combined cycle power plants account for the biggest share in the country’s total power generation capacity as Iran is turning thermal plants to combined cycle to save energy, followed by gas power plants.

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Nighttime Thermoelectric Generator converts radiative cooling into renewable energy, leveraging outer space cold; a Stanford-UCLA prototype complements solar, serving off-grid loads with low-power output during peak evening demand, using simple materials on a rooftop.

Key Points

A device converting nighttime radiative cooling into electricity, complementing solar for low-power evening needs.

✅ Uses thermocouples to convert temperature gradients to voltage.

✅ Exploits radiative cooling to outer space for night power.

✅ Complements solar; low-cost parts suit off-grid applications.

Two years ago, one freezing December night on a California rooftop, a tiny light shone weakly with a little help from the freezing night air. It wasn't a very bright glow. But it was enough to demonstrate the possibility of generating renewable power after the Sun goes down.

Working with Stanford University engineers Wei Li and Shanhui Fan, University of California Los Angeles materials scientist Aaswath Raman put together a device that produces a voltage by channelling the day's residual warmth into cooling air, effectively generating electricity from thin air with passive heat exchange.

"Our work highlights the many remaining opportunities for energy by taking advantage of the cold of outer space as a renewable energy resource," says Raman.

"We think this forms the basis of a complementary technology to solar. While the power output will always be substantially lower, it can operate at hours when solar cells cannot."

For all the merits of solar energy, it's just not a 24-7 source of power, although research into nighttime solar cells suggests new possibilities for after-dark generation. Sure, we can store it in a giant battery or use it to pump water up into a reservoir for later, but until we have more economical solutions, nighttime is going to be a quiet time for renewable solar power. 

Most of us return home from work as the Sun is setting, and that's when energy demands spike to meet our needs for heating, cooking, entertaining, and lighting.

Unfortunately, we often turn to fossil fuels to make up the shortfall. For those living off the grid, it could require limiting options and going without a few luxuries.

Shanhui Fan understands the need for a night time renewable power source well. He's worked on a number of similar devices, including carbon nanotube generators that scavenge ambient energy, and a recent piece of technology that flipped photovoltaics on its head by squeezing electricity from the glow of heat radiating out of the planet's Sun-warmed surface.

While that clever item relied on the optical qualities of a warm object, this alternative device makes use of the good old thermoelectric effect, similar to thin-film waste-heat harvesting approaches now explored.

Using a material called a thermocouple, engineers can convert a change in temperature into a difference in voltage, effectively turning thermal energy into electricity with a measurable voltage. This demands something relatively toasty on one side and a place for that heat energy to escape to on the other.

The theory is the easy part – the real challenge is in arranging the right thermoelectric materials in such a way that they'll generate a voltage from our cooling surrounds that makes it worthwhile.

To keep costs down, the team used simple, off-the-shelf items that pretty much any of us could easily get our hands on.

They put together a cheap thermoelectric generator and linked it with a black aluminium disk to shed heat in the night air as it faced the sky. The generator was placed inside a polystyrene enclosure sealed with a window transparent to infrared light, and linked to a single tiny LED.

For six hours one evening, the box was left to cool on a roof-top in Stanford as the temperature fell just below freezing. As the heat flowed from the ground into the sky, the small generator produced just enough current to make the light flicker to life.

At its best, the device generated around 0.8 milliwatts of power, corresponding to 25 milliwatts of power per square metre.

That might just be enough to keep a hearing aid working. String several together and you might just be able to keep your cat amused with a simple laser pointer. So we're not talking massive amounts of power.

But as far as prototypes go, it's a fantastic starting point. The team suggests that with the right tweaks and the right conditions, 500 milliwatts per square metre isn't out of the question.

"Beyond lighting, we believe this could be a broadly enabling approach to power generation suitable for remote locations, and anywhere where power generation at night is needed," says Raman.

While we search for big, bright ideas to drive the revolution for renewables, it's important to make sure we don't let the smaller, simpler solutions like these slip away quietly into the night.

This research was published in Joule.

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