What exactly is clean coal?

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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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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COVID-19 Solar Job Losses are erasing five years of workforce growth, SEIA reports, with U.S. installations and capacity down, layoffs accelerating, 3 GW expected in Q2, and policy support key for economic recovery.

Key Points

COVID-19 Solar Job Losses describe the pandemic-driven decline in U.S. solar employment, installations, and capacity.

✅ SEIA reports a 38% national drop in solar jobs

✅ Q2 installs projected at 3 GW, below forecasts

✅ Layoffs outpace U.S. economy without swift policy aid

Job losses associated with the COVID-19 crisis have wiped out the past five years of workforce growth in the solar energy field, according to a new industry analysis.

The expected June 2020 solar workforce of 188,000 people across the United States is 114,000 below the pre-pandemic forecast of 302,000 workers, a shortfall tied to the solar construction slowdown according to the Solar Energy Industries Association, which said in a statement Monday that the solar industry is now losing jobs at a faster rate than the U.S. economy.

In Massachusetts, the loss of 4,284 solar jobs represents a 52 percent decline from previous projections, according to the association’s analysis.

The national 38 percent drop in solar jobs coincides with a 37 percent decrease in expected solar installations in the second quarter of 2020, and similar pressures have put wind investments at risk across the sector, the association stated. The U.S. is now on track to install 3 gigawatts of new capacity this quarter, though subsequent forecasts anticipated solar and storage growth as investments returned, and the association said the decrease from the expected capacity is equivalent to the electricity needed to power 288,000 homes.

“Thousands of solar workers are being laid off each week, but with swift action from Congress, we know that solar can be a crucial part of our economic recovery,” with proposals such as the Biden solar plan offering a potential policy path, SEIA President and CEO Abigail Ross Hopper said in a statement, as recent analyses point to US solar and wind growth under supportive policies.

Subsequent data showed record U.S. panel shipments as the market rebounded.

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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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London Gateway All-Electric Berth enables shore power and cold ironing for container ships, cutting emissions, improving efficiency, and supporting green logistics, IMO targets, and UK net-zero goals through grid connection and port electrification.

Key Points

It is a shore power berth supplying electricity to ships, cutting emissions and costs while boosting port efficiency.

✅ Grid connection enables cold ironing for container ships

✅ Supports IMO decarbonization and UK net-zero goals

✅ Stabilizes energy costs versus marine fuels

London Gateway, one of the UK’s premier deep-water ports, has unveiled the world’s first all-electric berth, marking a significant milestone in sustainable port operations. This innovative development aims to enhance the port's capacity while reducing its environmental impact. The all-electric berth, which powers vessels using electricity, similar to emerging offshore vessel charging solutions, instead of traditional fuel sources, is expected to greatly improve operational efficiency and cut emissions from ships docking at the port.

The launch of this electric berth is part of London Gateway’s broader strategy to become a leader in green logistics, with parallels in electric truck deployments at California ports that support port decarbonization, aligning with the UK’s ambitious climate goals. By transitioning to electric power, the port reduces reliance on fossil fuels and significantly lowers carbon emissions, contributing to a cleaner environment and supporting the maritime industry’s transition towards sustainability.

The berth will provide cleaner power to container ships, enabling them to connect to the grid while docked, similar to electric ships on the B.C. coast, rather than running their engines, which traditionally contribute to pollution. This innovation supports the UK's broader push for decarbonizing its transportation and logistics sector, especially as the global shipping industry faces increasing pressure to reduce its carbon footprint.

The new infrastructure is expected to increase London Gateway’s operational capacity, allowing for a higher volume of traffic while simultaneously addressing the environmental challenges posed by growing port activities. By integrating advanced technologies like the all-electric berth, and advances such as battery-electric high-speed ferries, the port can handle more shipments without expanding its reliance on traditional fuel-based power sources. This could lead to increased cargo throughput, as shipping lines are incentivized to use a greener, more efficient port for their operations.

The project aligns with broader global trends, including electric flying ferries in Berlin, as ports and shipping companies seek to meet international standards set by the International Maritime Organization (IMO) and other regulatory bodies. The IMO has set aggressive targets for reducing greenhouse gas emissions from shipping, and the UK has pledged to be net-zero by 2050, with the shipping sector playing a crucial role in that transition.

In addition to its environmental benefits, the electric berth also helps reduce the operational costs for shipping lines, as seen with electric ferries scaling in B.C. programs across the sector. Traditional fuel costs can be volatile, whereas electric power offers a more stable and predictable expense. This cost stability could make London Gateway an even more attractive port for international shipping companies, further boosting its competitive position in the global market.

Furthermore, the project is expected to have broader economic benefits, generating jobs and fostering innovation, such as hydrogen crane projects in Vancouver, within the green technology and maritime sectors. London Gateway has already made significant strides in sustainable practices, including a focus on automated systems and energy-efficient logistics solutions. The introduction of the all-electric berth is the latest in a series of initiatives aimed at strengthening the port’s sustainability credentials.

This groundbreaking development sets a precedent for other global ports to adopt similar sustainable technologies. As more ports embrace electrification and other green solutions, the shipping industry could experience a dramatic reduction in its environmental footprint. This shift could have a cascading effect on the wider logistics and supply chain industries, leading to cleaner and more efficient global trade.

London Gateway’s all-electric berth represents a forward-thinking approach to the challenges of climate change and the need for sustainability in the maritime sector. With its ability to reduce emissions, improve port capacity, and enhance operational efficiency, this pioneering project is poised to reshape the future of global shipping. As more ports around the world follow suit, the potential for widespread environmental impact in the shipping industry is significant, providing hope for a greener future in international trade.

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Clean Power Plan Rollback signals EPA's shift to inside-the-fence efficiency at coal plants, emphasizing heat-rate improvements over sector-wide decarbonization, renewables, natural gas switching, demand-side efficiency, and carbon capture under Clean Air Act constraints.

Key Points

A policy shift by the EPA to replace broad emissions rules with plant-level efficiency standards, limiting CO2 cuts.

✅ Inside-the-fence heat-rate improvements at coal units

✅ Potential CO2 cuts limited to about 6% per plant

✅ Alternatives: fuel switching, renewables, carbon capture

President Barack Obama’s signature plan to reduce carbon dioxide emissions from electrical generation took years to develop and touched every aspect of power production and use, from smokestacks to home insulation.

The Trump administration is moving to scrap that plan and has signaled that any alternative it might adopt would take a much less expansive approach, possibly just telling utilities to operate their plants more efficiently.

That’s a strategy environmentalists say is almost certain to fall short of what’s needed.

The Trump administration is making "a wholesale retreat from EPA’s legal, scientific and moral obligation to address the threats of climate change," said former Environmental Protection Agency head Gina McCarthy, the architect of Obama’s Clean Power Plan.

President Donald Trump promised to rip up the initiative, echoing an end to the 'war on coal' message from his campaign, which mandated that states change their overall power mix, displacing coal-fired electricity with that from wind, solar and natural gas. The EPA is about to make it official, arguing the prior administration violated the Clean Air Act by requiring those broad changes to the electricity sector, according to a draft obtained by Bloomberg.

Possible Replacements

Later, the agency will also ask the public to weigh in on possible replacements. The administration will ask whether the EPA can or should develop a replacement rule -- and, if so, what actions can be mandated at individual power plants, though some policymakers favor a clean electricity standard to drive broader decarbonization.

Follow the Trump Administration’s Every Move

Such changes -- such as adding automation or replacing worn turbine seals -- would yield at most a 6 percent gain in efficiency, along with a corresponding fall in greenhouse gas emissions, according to earlier modeling by the Environmental Protection Agency and other analysts. That compares to the 32 percent drop in emissions by 2030 under Obama’s Clean Power Plan.

"In these existing plants, there’s only so many places to look for savings," said John Larsen, a director of the Rhodium Group, a research firm. "There’s only so many opportunities within a big spinning machine like that."

EPA Administrator Scott Pruitt outlined such an "inside-the-fence-line" approach in 2014, later embodied in the Affordable Clean Energy rule that industry groups backed, when he served as Oklahoma’s attorney general. Under his blueprint, states would set emissions standards after a detailed unit-by-unit analysis, looking at what reductions are possible given "the engineering limits of each facility."

The EPA has not decided whether it will promulgate a new rule at all, though it has also proposed new pollution limits for coal and gas plants in separate actions. In a forthcoming advanced notice of proposed rulemaking, the EPA will ask "what inside-the-fence-line options are legal, feasible and appropriate," according to a document obtained by Bloomberg.

Increased efficiency at a coal plant -- known as heat-rate improvement -- translates into fewer carbon-dioxide emissions per unit of electric power generated.

Under Obama, the EPA envisioned utilities would make some straightforward efficiency improvements at coal-fired power plants as the first step to comply with the Clean Power Plan. But that was expected to coincide with bigger, broader changes -- such as using more cleaner-burning natural gas, adding more renewable power projects and simply encouraging customers to do a better job turning down their thermostats and turning off their lights.

Obama’s EPA didn’t ask utilities to wring every ounce of efficiency they could out of coal-fired power plants because they saw the other options as cheaper. A plant-specific approach "would be grossly insufficient to address the public health and environmental impacts from CO2 emissions," Obama’s EPA said.

That approach might yield modest emissions reductions and, in a perverse twist, might event have the opposite effect. If utilities make coal plants more efficient -- thereby driving down operating costs -- they also make them more competitive with natural gas and renewables, "so they might run more and pollute more," said Conrad Schneider, advocacy director for the Clean Air Task Force.  

In a competitive market, any improvement in emissions produced for each unit of energy could be overwhelmed by an increase in electrical output, and debates over changes to electricity pricing under Trump and Perry added further uncertainty.

"A very minor heat rate improvement program would very likely result in increased emissions," Schneider said. "It might be worse than nothing."

Power companies want to get as much electricity as possible from every pound of coal, so they already have an incentive to keep efficiency high, said Jeff Holmstead, a former assistant EPA administrator now at Bracewell LLP. But an EPA regulation known as “new source review” has discouraged some from making those changes, for fear of triggering other pollution-control requirements, he said.

"If EPA’s replacement rule allows companies to improve efficiency without triggering new source review, it would make a real difference in terms of reducing carbon-dioxide emissions," Holmstead said.

Modest Impact

A plant-specific approach doesn’t have to mean modest impact.

"If you’re thinking about what can be done at the power plants by themselves, you don’t stop at efficiency tune-ups," said David Doniger, director of the Natural Resources Defense Council’s climate and clean air program. "You look at things like switching to natural gas or installing carbon capture and storage."

Requirements that facilities use carbon capture technology or swap in natural gas for coal could actually come close to hitting the same goals as in Obama’s Clean Power Plan -- if not go even further, Schneider said. They just would cost more.

The benefit of the Clean Power Plan "is that it enabled states to create programs and enabled companies to find a reduction strategy that was the most efficient and made the most sense for their own content," said Kathryn Zyla, deputy director of the Georgetown Climate Center. "And that flexibility was really important for the states and companies."

Some utilities, including Houston-based Calpine Corp., PG&E Corp. and Dominion Resources Inc., backed the Obama-era approach. And they are still pushing the Trump administration to be creative now.

"The Clean Power Plan achieved a thoughtful, balanced approach that gave companies and states considerable flexibility on how best to pursue that goal," said Melissa Lavinson, vice president of federal affairs and policy for PG&E’s Pacific Gas and Electric utility. “We look forward to working with the administration to devise an alternative plan for decarbonizing the U.S. economy."

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