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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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Electric Field-Induced Glass Softening reveals a Joule heating anomaly in silicate glass, where anode-side nanoscale alkali depletion drives ionic conduction, localized thermal runaway, melting, and evaporation, challenging homogeneity assumptions and refining materials processing models.

Key Points

An effect where electric fields lower glass softening temperature via nanoscale ionic migration and structural change.

✅ Anode-side alkali depletion creates extreme, localized heating

✅ Thermal runaway melts glass near the anode despite uniform bulk

✅ Findings refine Joule heating models and enable new glass processing

A team of scientists working with electrical currents and silicate glass have been left gobsmacked after the glass appeared to defy a basic physical law, in a field that also explores electricity-from-air devices for novel energy harvesting.

If you pass an electrical current through a material, the way that current generates heat can be described by Joule's first law. It's been observed time and time again, with the temperature always evenly distributed when the material is homogeneous (or uniform).

But not in this recent experiment. A section - and only a section - of silicate glass became so hot that it melted, and even evaporated. Moreover, it did so at a much lower temperature than the boiling point of the material.

The boiling point of pure silicate glass is 2,230 degrees Celsius (4,046 degrees Fahrenheit). The hottest temperature the researchers recorded in a homogeneous piece of silicate glass during the experiment was 1,868.7 degrees Celsius.

Say whaaaat.

"The calculations did not add up to explain what we were seeing as simply standard Joule heating," said engineer and materials scientist Himanshu Jain of Lehigh University.

"Even under very moderate conditions, we observed fumes of glass that would require thousands of degrees higher temperature than Joule's law could predict!"

Jain and his colleagues from materials science company Corning Incorporated were investigating a phenomenon they had described in a previous paper. In 2015, they reported that an electric field could reduce the temperature at which glass softens, by as much as a few hundred degrees, a line of inquiry that parallels work on low-cost heat-to-electricity materials in energy research. They called this "electric field-induced softening."

It was certainly a peculiar phenomenon, so they set up another experiment. They put pieces of glass in a furnace, and applied 100 to 200 volts in the form of both alternating and direct currents.

Next, a thin wisp of vapour emanated from the spot where the anode conveying the current contacted the glass.

"In our experiments, the glass became more than a thousand degrees Celsius hotter near the positive side than in the rest of the glass, which was very surprising considering that the glass was totally homogeneous to begin with," Jain said.

This seems to fly in the face of Joule's first law, so the team investigated more closely - and found that the glass wasn't remaining as homogeneous as it started out. The electric field changed the chemistry and the structure of the glass on nanoscale, in just a small section close to the anode.

This region heats faster than the rest of the glass, to the point of becoming a thermal runaway - where an increase in temperature further increases temperature in a blistering feedback loop.

As it turned out, that spot of structural change and dramatic heat resulted in a small area of glass reaching melting point while the rest of the material remained solid.

"Unlike electronically conducting metals and semiconductors, with time the heating of ionically conducting glass becomes extremely inhomogeneous with the formation of a nanoscale alkali-depletion region, such that the glass melts near the anode, even evaporates, while remaining solid elsewhere," the researchers wrote in their paper.

In other words, the material wasn't homogeneous any more, which means the glass heating experiment doesn't exactly change how we apply Joule's first law.

But it's an exciting result, since until now we didn't know a material could actually lose its homogeneity with the application of an electrical current, with possible implications for thin-film heat harvesters in electronics. (The thing is, no one had tried electrically heating glass to these extreme temperatures before.)

So the physical laws of the Universe are still okay, as a piece of glass hasn't broken them. But Joule's first law may need a bit of tweaking to take this effect into account, a reminder that unconventional energy concepts like nighttime solar cells also challenge our intuitions.

And, of course, it's another piece of understanding that could help us in other ways too, including advances in thermoelectric materials that turn waste heat into electricity.

"Besides demonstrating the need to qualify Joule's law," Jain said, "the results are critical to developing new technology for the fabrication and manufacturing of glass and ceramic materials."

The research has been published in Scientific Reports.

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Maritime Link HVDC Transmission connects Newfoundland and Nova Scotia to the North American grid, enabling renewable energy imports, subsea cable interconnection, Muskrat Falls hydro power delivery, and lower carbon emissions across Atlantic Canada.

Key Points

A 500 MW HVDC intertie linking Newfoundland and Nova Scotia to deliver Muskrat Falls hydro power.

✅ 500 MW capacity using twin 170 km subsea HVDC cables

✅ Interconnects Newfoundland and Nova Scotia to the North American grid

✅ Enables Muskrat Falls hydro imports, cutting CO2 and costs

For the first time, electricity has been sent between Newfoundland and Nova Scotia through the new Maritime Link.

The 500-megawatt transmission line — which connects Newfoundland to the North American energy grid for the first time and echoes projects like the New England Clean Power Link underway — was tested Friday.

"This changes not only the energy options for Newfoundland and Labrador but also for Nova Scotia and Atlantic Canada," said Rick Janega, the CEO of Emera Newfoundland and Labrador, which owns the link.

"It's an historic event in our eyes, one that transforms the electricity system in our region forever."

'On time and on budget'

It will eventually carry power from the Muskrat Falls hydro project in Labrador, where construction is running two years behind schedule and $4 billion over budget, a context in which the Manitoba Hydro line to Minnesota has also faced delay, to Nova Scotia consumers. It was supposed to start producing power later this year, but the new deadline is 2020 at the earliest.

The project includes two 170-kilometre subsea cables across the Cabot Strait between Cape Ray in southwestern Newfoundland and Point Aconi in Cape Breton.

The two cables, each the width of a two-litre pop bottle, can carry 250 megawatts of high voltage direct current, and rest on the ocean floor at depths up to 470 metres.

This reel of cable arrived in St. John's back in April aboard the Norwegian vessel Nexans Skagerrak, after the first power cable reached Nova Scotia earlier in the project. (Submitted by Emera NL)

The Maritime Link also includes almost 50 kilometres of overland transmission in Nova Scotia and more than 300 kilometres of overland transmission in Newfoundland, paralleling milestones on Site C transmission work in British Columbia.

The link won't go into commercial operation until January 1.

Janega said the $1.6-billion project is on time and on budget.

"We're very pleased to be in a position to be able to say that after seven years of working on this. It's quite an accomplishment," he said.

This Norwegian vessel was used to transport the 5,500 tonne subsea cable. (Submitted by Emera NL)

Once in service, the link will improve electrical interconnections between the Atlantic provinces, aligning with climate adaptation guidance for Canadian utilities.

"For Nova Scotia it will allow it to achieve its 40 per cent renewable energy target in 2020. For Newfoundland it will allow them to shut off the Holyrood generating station, in fact using the Maritime Link in advance of the balance of the project coming into service," Janega said.

Karen Hutt, president and CEO of Nova Scotia Power, which is owned by Emera Inc., calls it a great day for Nova Scotia.

"When it goes into operation in January, the Maritime Link will benefit Nova Scotia Power customers by creating a more stable and secure system, helping reduce carbon emissions, and enabling NSP to purchase power from new sources," Hutt said in a statement.

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Duke Energy Net Metering Proposal updates rooftop solar compensation with time-of-use rates, lower grid credits, and a minimum charge, aligning payments with electricity demand in North Carolina pending regulators' approval.

Key Points

A plan to swap flat credits for time-of-use rates and a minimum charge for rooftop solar customers in North Carolina.

✅ Time-of-use credits vary by grid demand

✅ $10 minimum use charge plus $14 basic fee

✅ Aims to align solar payouts with actual electricity value

Duke Energy has proposed new rules for how owners of rooftop solar panels are paid for electricity they send to the electric grid. It could mean more complexity and lower payments, but the utility says rates would be fairer.

State legislators have called for changes in the payment rules — known as "net metering" policies that allow households to sell power back to energy firms.

Right now, solar panel owners who produce more electricity than they need get credits on their bills, equal to whatever they pay for electricity. Under the proposed changes, the credit would be lower and would vary according to electricity demand, said Duke spokesperson Randy Wheeless.

"So in a cold winter morning, like now, you would get more, but maybe in a mild spring day, you would get less," Wheeless said Tuesday. "So, it better reflects what the price of electricity is."

Besides setting rates by time of use, solar owners also would have to pay a minimum of $10 a month for electricity, even if they don't use any from the grid. That's on top of Duke's $14 basic charge. Duke said it needs the extra revenue to pay for grid infrastructure to serve solar customers.

The proposal is the result of an agreement between Duke and solar industry groups — the North Carolina Sustainable Energy Association; the Southern Environmental Law Center, which represented Vote Solar and the Southern Alliance for Clean Energy; solar panel maker Sunrun Inc.; and the Solar Energy Industries Association.

The deal is similar to one approved by regulators in South Carolina last year, while in Nova Scotia a solar charge was delayed after controversy.

Daniel Brookshire of the North Carolina Sustainable Energy Association said he hopes the agreement will help the solar industry.

"We reached an agreement here that we think will provide certainty over the next decade, at least, for those interested in pursuing solar for their homes, and for our members who are solar installers," Brookshire said.

But other environmental and consumer groups oppose the changes, amid debates over who pays for grid upgrades elsewhere. Jim Warren with NC WARN said the rules would slow the expansion of rooftop solar in North Carolina.

"It would make it even harder for ordinary people to go solar," Warren said. "This would make it more complicated and more expensive, even for wealthier homeowners."

State regulators still must approve the proposal, even as courts weigh aspects of the electricity monopoly in related solar cases. If state regulators approve it, rates for new net metering customers would take effect Jan. 1, 2023.

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Alberta Hydropower Potential highlights renewable energy, dams, reservoirs, grid flexibility, contrasting wind and solar growth with limited investment, regulatory hurdles, river basin resources, and decarbonization pathways across Athabasca, Peace, and Slave River systems.

Key Points

It is the technical capacity for new hydro in Alberta's river basins to support a more reliable, lower carbon grid.

✅ 42,000 GWh per year developable hydro identified in studies.

✅ Major potential in Athabasca, Peace, and Slave River basins.

✅ Barriers include high capital costs, market design, water rights.

When you think about renewable energy sources on the Prairies, your mind may go to the wind farms in southern Alberta, or even the Travers Solar Project, southeast of Calgary.

Most of the conversation around renewable energy in the province is dominated by advancements in solar and wind power, amid Alberta's renewable energy surge that continues to attract attention. 

But what about Canada's main source of electricity — hydro power?

More than half of Canada's electricity is generated from hydro sources, with 632.2 terawatt-hours produced as of 2019. That makes it the fourth largest installed capacity of hydropower in the world. 

But in Alberta, it's a different story. 

Currently, hydro power contributes between three and five per cent of Alberta's energy mix, while fossil fuels make up about 89 per cent.

According to Canada's Energy Future report from the Canada Energy Regulator, by 2050 it will make up two per cent of the province's electricity generation shares.

So why is it that a province so rich in mountains and rivers has so little hydro power?

Hydro's history in Alberta
Hydro power didn't always make up such a small sliver of Alberta's electricity generation. Hydro installations began in the early 20th century as the province's population exploded. 

Grant Berg looks after engineering for hydro for TransAlta, Alberta's largest producer of hydro power with 17 facilities across the province.

"Our first plant was Horseshoe, which started in 1911 that we formed as Calgary Power," he said. 

"It was really in response to the City of Calgary growing and having some power needs."

Berg said in 1913, TransAlta's second installation, the Kananaskis Plant, started as Calgary continued to grow.

A historical photo of a hydro-electric dam in Kananaskis Alta. taken in 1914.
Hydro power plant in Kananaskis as seen in 1914. (Glenbow Archives)
Some bigger installations were built in the 1920s, including Ghost reservoir, but by mid-century population growth increased.

"Quite a large build out really, I think in response to the growth in Alberta following the war. So through the 1950s really quite a large build out of hydro from there."

By the 1950s, around half of the province's installed capacity was hydro power.

"Definitely Calgary power was all hydro until the 1950s," said Berg. 

Hydro potential in the province 
Despite the current low numbers in hydroelectricity, Alberta does have potential. 

According to a 2010 study, there is approximately 42,000 gigawatt-hours per year of remaining developable hydroelectric energy potential at identified sites. 

An average home in Alberta uses around 7,200 kilowatt-hours of electricity per year, meaning that the hydro potential could power 5.8 million homes each year. 

"This volume of energy could be sufficient to serve a significant amount of Alberta's load and therefore play a meaningful role in the decarbonization of the province's electric system," the Alberta Electric System Operator said in its 2022 Pathways to Net-Zero Emissions report.

Much of that potential lies in northern Alberta, in the Athabasca, Peace and Slave River basins.

The AESO report says that despite the large resource potential, Alberta's energy-only market framework has attracted limited investment in hydroelectric generation. 

Hydro power was once a big deal in Alberta, but investment in the industry has been in decline since the 1950s. Climate change reporter Christy Climenhaga explains why.
So why does Alberta leave out such a large resource potential on the path to net zero?

The government of Alberta responded to that question in a statement. 

"Hydro facilities, particularly large scale ones involving dams, are associated with high costs and logistical demands," said the Ministry of Affordability and Utilities. 

"Downstream water rights for other uses, such as irrigation, further complicate the development of hydro projects."

The ministry went on to say that wind and solar projects have increased far more rapidly because they can be developed at relatively lower cost and shorter timelines, and with fewer logistical demands.

"Sources from wind power and solar are increasingly more competitive," said Jean-Denis Charlebois, chief economist with the Canadian Energy Regulator. 

Hydro on the path to net zero
Hydro power is incredibly important to Canada's grid, and will remain so, despite growth in wind and solar power across the province.

Charlebois said that across Canada, the energy make-up will depend on the province. 

"Canadian provinces will generate electricity in very different ways from coast to coast. The major drivers are essentially geography," he said. 

Charlebois says that in British Columbia, Manitoba, Quebec and Newfoundland and Labrador, hydropower generation will continue to make up the majority of the grid.

"In Alberta and Saskatchewan, we see a fair bit of potential for wind and solar expansion in the region, which is not necessarily the case on Canada's coastlines," he said.

And although hydro is renewable, it does bring its adverse effects to the environment — land use changes, changes in flow patterns, fish populations and ecosystems, which will have to be continually monitored. 

"You want to be able to manage downstream effects; make sure that you're doing all the proper things for the environment," said Ryan Braden, director of mining and hydro at TransAlta.

Braden said hydro power still has a part to play in Alberta, even with its smaller contributions to the future grid. 

"It's one of those things that, you know, the wind doesn't blow or the sun doesn't shine, this is here. The way we manage it, we can really support that supply and demand," he said.

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Ukraine's EU Energy Integration aims for ENTSO-E synchronization, electricity market liberalization, EU Green Deal alignment, energy efficiency upgrades, hydrogen development, and streamlined grid connections to accelerate reform, market pricing, and sustainable growth.

Key Points

Ukraine's EU Energy Integration syncs with ENTSO-E, liberalizes power markets, and aligns with the EU Green Deal.

✅ ENTSO-E grid synchronization and cross-border trade readiness

✅ Electricity market liberalization and market-based pricing

✅ EU Green Deal alignment: efficiency, hydrogen, coal regions

Ukraine's goal in the energy sector is to ensure the maximum integration of energy markets with EU markets, and in line with the EU plan to dump Russian energy that is reshaping the region, synchronization of Ukraine's integrated energy system with ENTSO-E while leaning on electricity imports as needed to maintain stability. Prime Minister Denys Shmyhal emphasized in his statement at the Fourth Ukraine Reform Conference underway through July 7-8 in Vilnius, the Republic of Lithuania.

The Head of Government presented a plan of reforms in Ukraine until 2030. In particular, energy sector reform and environmental protection, according to the PM, include the liberalization of the electricity market, with recent amendments to the market law guiding implementation, the simplification of connection to the electrical grid system and the gradual transition to market electricity prices, alongside potential EU emergency price measures under discussion, and the monetization of subsidies for vulnerable groups.

"Ukraine shares and fully supports the EU's climate ambitions and aims to synchronize its policies in line with the EU Green Deal, including awareness of Hungary's energy alignment with Russia to ensure coherent regional planning. The interdepartmental working group has determined priority areas for cooperation with the European Union: energy efficiency, hydrogen, transformation of coal regions, waste management," said the Prime Minister.

According to Denys Shmyhal, Ukraine has supported the EU's climate ambitions to move towards climate-neutral development by 2050 within the framework of the European Green Deal and should become an integral part of it in order not only to combat the effects of climate change in synergy with the EU but, as the country prepares for winter energy challenges and strengthens resilience, within the economic strategy development aimed to enhance security and create new opportunities for Ukrainian business, with continued energy security support from partners bolstering implementation.

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