Detroit Electric resurrected

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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Atlanta Airport Power Outage disrupts Hartsfield-Jackson as an underground fire cripples switchgear redundancy, canceling flights during holiday travel; Georgia Power restores electricity overnight while utility crews probe causes and monitor system resilience.

Key Points

A major Hartsfield-Jackson blackout from an underground fire; power restored as switchgear redundancy is investigated.

✅ Underground fire near Plane Train tunnel damaged switchgear systems

✅ Over 1,100 flights canceled; holiday travel severely disrupted

✅ Georgia Power restored service; redundancy and root cause under review

Power has been restored at the world’s busiest airport after a massive outage Sunday afternoon left planes and passengers stranded for hours, forced airlines to cancel more than 1,100 flights and created a logistical nightmare during the already-busy holiday travel season.

An underground fire caused a complete power outage Sunday afternoon at Hartsfield-Jackson Atlanta International Airport, resulting in thousands of canceled flights at the world's busiest terminal and affecting travelers worldwide.

The massive outage didn’t just leave passengers stranded overnight Sunday, it also affected travelers with flights Monday morning schedules.

According to Paul Bowers, the president and CEO of Georgia Power,  “From our standpoint, we apologize for the inconvenience,” he said. The utility restored power to the airport shortly before midnight.

Utility Crews are monitoring the fixes that restored power and investigating what caused the fire and why it was able to damage redundant systems. Bowers said the fire occurred in a tunnel that runs along the path of the underground Plane Train tunnel near Concourse E.

Sixteen highly trained utility personnel worked in the passageway to reconnect the network.“Our investigation is going through the process of what do we do to ensure we have the redundancy going back at the airport, because right now we are a single source feed,” Bowers said.

“We will have that complete by the end of the week, and then we will turn to what caused the failure of the switchgear.”

Though the cause isn’t yet known, he said foul play is not suspected.“There are two things that could happen,” he said.

“There are inner workings of the switchgear that could create the heat that caused the fire, or the splicing going into that switchgear -- that the cable had a failure on that going into the switch gear.”

When asked if age of the system could have been a failure, Bowers said his company conducts regular inspections.“We constantly inspect,” he said. “We inspect on an annual basis to ensure the reliability of the network, and that redundancy is protection for the airport.”Bowers said he is not familiar with any similar fire or outage at the airport.

“The issue for us is to ensure the reliability is here and that it doesn’t happen again and to ensure that our network is resilient enough to withstand any kind of fire,” he said. He added that Georgia Power will seek to determine what can be done in the future to avoid a similar event, such as those experienced during regional outages in other communities.

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Canada Power Grid Climate Resilience integrates extreme weather planning, microgrids, battery storage, renewable energy, vegetation management, and undergrounding to reduce outages, harden infrastructure, modernize utilities, and safeguard reliability during storms, ice events, and wildfires.

Key Points

Canada's grid resilience hardens utilities against extreme weather using microgrids, storage, renewables, and upgrades.

✅ Grid hardening: microgrids, storage, renewable integration

✅ Vegetation management reduces storm-related line contact

✅ Selective undergrounding where risk and cost justify

The increasing intensity of storms that lead to massive power outages highlights the need for Canada’s electrical utilities to be more robust and innovative, climate change scientists say.

“We need to plan to be more resilient in the face of the increasing chances of these events occurring,” University of New Brunswick climate change scientist Louise Comeau said in a recent interview.

The East Coast was walloped this week by the third storm in as many days, with high winds toppling trees and even part of a Halifax church steeple, underscoring the value of storm-season electrical safety tips for residents.

Significant weather events have consistently increased over the last five years, according to the Canadian Electricity Association (CEA), which has tracked such events since 2003.

#google#

Nearly a quarter of total outage hours nationally in 2016 – 22 per cent – were caused by two ice storms, a lightning storm, and the Fort McMurray fires, which the CEA said may or may not be classified as a climate event.

“It (climate change) is putting quite a lot of pressure on electricity companies coast to coast to coast to improve their processes and look for ways to strengthen their systems in the face of this evolving threat,” said Devin McCarthy, vice president of public affairs and U.S. policy for the CEA, which represents 40 utilities serving 14 million customers.

The 2016 figures – the most recent available – indicate the average Canadian customer experienced 3.1 outages and 5.66 hours of outage time.

McCarthy said electricity companies can’t just build their systems to withstand the worst storm they’d dealt with over the previous 30 years. They must prepare for worse, and address risks highlighted by Site C dam stability concerns as part of long-term planning.

“There needs to be a more forward looking approach, climate science led, that looks at what do we expect our system to be up against in the next 20, 30 or 50 years,” he said.

Toronto Hydro is either looking at or installing equipment with extreme weather in mind, Elias Lyberogiannis, the utility’s general manager of engineering, said in an email.

That includes stainless steel transformers that are more resistant to corrosion, and breakaway links for overhead service connections, which allow service wires to safely disconnect from poles and prevents damage to service masts.

Comeau said smaller grids, tied to electrical systems operated by larger utilities, often utilize renewable energy sources such as solar and wind as well as battery storage technology to power collections of buildings, homes, schools and hospitals.

“Capacity to do that means we are less vulnerable when the central systems break down,” Comeau said.

Nova Scotia Power recently announced an “intelligent feeder” pilot project, which involves the installation of Tesla Powerwall storage batteries in 10 homes in Elmsdale, N.S., and a large grid-sized battery at the local substation. The batteries are connected to an electrical line powered in part by nearby wind turbines.

The idea is to test the capability of providing customers with back-up power, while collecting data that will be useful for planning future energy needs.

Tony O’Hara, NB Power’s vice-president of engineering, said the utility, which recently sounded an alarm on copper theft, was in the late planning stages of a micro-grid for the western part of the province, and is also studying the use of large battery storage banks.

“Those things are coming, that will be an evolution over time for sure,” said O’Hara.

Some solutions may be simpler. Smaller utilities, like Nova Scotia Power, are focusing on strengthening overhead systems, mainly through vegetation management, while in Ontario, Hydro One and Alectra are making major investments to strengthen infrastructure in the Hamilton area.

“The number one cause of outages during storms, particularly those with high winds and heavy snow, is trees making contact with power lines,” said N.S. Power’s Tiffany Chase.

The company has an annual budget of $20 million for tree trimming and removal.

“But the reality is with overhead infrastructure, trees are going to cause damage no matter how robust the infrastructure is,” said Matt Drover, the utility’s director for regional operations.

“We are looking at things like battery storage and a variety of other reliability programs to help with that.”

NB Power also has an increased emphasis on tree trimming and removal, and now spends $14 million a year on it, up from $6 million prior to 2014.

O’Hara said the vegetation program has helped drive the average duration of power outages down since 2014 from about three hours to two hours and 45 minutes.

Some power cables are buried in both Nova Scotia and New Brunswick, mostly in urban areas. But both utilities maintain it’s too expensive to bury entire systems – estimated at $1 million per kilometre by Nova Scotia Power.

The issue of burying more lines was top of mind in Toronto following a 2013 ice storm, but that’s city’s utility also rejected the idea of a large-scale underground system as too expensive – estimating the cost at around $15 billion, while Ontario customers have seen Hydro One delivery rates rise in recent adjustments.

“Having said that, it is prudent to do so for some installations depending on site specific conditions and the risks that exist,” Lyberogiannis said.

Comeau said lowering risks will both save money and disruption to people’s lives.

“We can’t just do what we used to do,” said Xuebin Zhang, a senior climate change scientist at Environment and Climate Change Canada.

“We have to build in management risk … this has to be a new norm.”

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DOE Office of Fossil Energy safeguards energy security via the Strategic Petroleum Reserve, domestic critical minerals from coal byproducts, and carbon capture to curb CO2, strengthening resiliency amid shocks and supporting U.S. manufacturing and defense.

Key Points

A DOE program advancing energy security through SPR stewardship, critical minerals R&D, and carbon capture.

✅ Manages the Strategic Petroleum Reserve for emergency crude supply

✅ Develops domestic critical minerals from coal and mining byproducts

✅ Deploys carbon capture, utilization, and storage to cut CO2

The global economy has just experienced a period of unique transformation because of COVID-19. The fact that remains constant in this new economic landscape is that our society relies on energy; it’s an integral part of our day-to-day lives, even as U.S. energy use has evolved over time. According to the U.S. Energy Information Administration, approximately 80 percent of energy consumption in the United States comes from fossil fuels, so having access to a secure and reliable supply of those energy resources is more important than ever for national energy security considerations today. Below are three examples that highlight how our work at the U.S. Department of Energy’s Office of Fossil Energy (FE) helps ensure the Nation’s energy security and resiliency.

(1) Open crude oil reserves to respond to crises

FE has overall program responsibility for carrying out the mission of the Strategic Petroleum Reserve (SPR), the world’s largest supply of emergency crude oil. These federally-owned stocks are stored in massive underground salt caverns along the coastline of the Gulf of Mexico. The SPR is a powerful tool U.S. leaders use to respond to a wide range of crises, including energy crisis impacts on electricity and fuels, involving crude oil disruption or demand loss.  When the COVID-19 pandemic hit, the oil markets crashed and crude oil demand dropped drastically across the world. U.S. oil producers turned to the SPR to store their oil while broader energy dominance constraints were becoming evident in practice. This helped alleviate the pressure on producers to shut in oil production and proved to be a critical asset for American energy and national security.

(2) Use the Nation’s abundant coal reserves to produce valuable materials

Critical materials, including rare earth elements, are a group of chemical elements and materials with unique properties that support manufacturing of most modern technologies. They are essential components for critical defense and homeland security applications, green energy technologies, hybrid and electric vehicles, and high-value electronics. While these materials are not rare, they are hard to separate and expensive to extract. The United States relies heavily on imports from China. To reduce U.S. dependence on foreign sources, FE has a research and development program aimed at producing a domestic supply of critical materials from the Nation’s abundant coal resources and associated byproducts from legacy and current mining operations. Many of the technologies being developed can also be used to separate critical minerals from other mining materials and byproducts. Tapping into these resources has the potential to create new industries and revitalize coal communities and the workforce in coal-producing regions.

(3) Decrease carbon emissions for a cleaner energy future

FE is committed to balancing the Nation’s energy use with the need to protect the environment, and has a comprehensive portfolio of technological solutions that help keep carbon dioxide (CO2) emissions out of the atmosphere. For example, amid high natural gas prices that reinforce the case for clean electricity, the Department has been investing in carbon capture, utilization, and storage technologies for over a decade. These technologies capture CO2 emissions from various sources, including coal-fired power plants and manufacturing plants, before they enter the atmosphere. Several of these cutting-edge technologies have been deployed at major demonstration sites, supported by clean energy funding that aims to benefit millions. Three of these projects—Petra Nova, Archer Daniels Midland, and Air Products & Chemicals—have captured and injected over 10.8 million metric tons of CO2. The success of these projects is paving the way toward a cleaner and more sustainable American energy future.

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UK low-carbon electricity 2019 saw stalled growth as renewables rose slightly, wind expanded, nuclear output fell, coal hit record lows, and net-zero targets demand faster deployment to cut CO2 intensity below 100gCO2/kWh.

Key Points

Low-carbon sources supplied 54% of UK power in 2019, up just 1TWh; wind grew, nuclear fell, and coal dropped to 2%.

✅ Wind up 8TWh; nuclear down 9TWh amid outages

✅ Fossil fuels 43% of generation; coal at 2%

✅ Net-zero needs 15TWh per year added to 2030

The amount of electricity generated by low-carbon sources in the UK stalled in 2019, Carbon Brief analysis shows.

Low-carbon electricity output from wind, solar, nuclear, hydro and biomass rose by just 1 terawatt hour (TWh, less than 1%) in 2019. It represents the smallest annual increase in a decade, where annual growth averaged 9TWh. This growth will need to double in the 2020s to meet UK climate targets while replacing old nuclear plants as they retire.

Some 54% of UK electricity generation in 2019 came from low-carbon sources, including 37% from renewables and 20% from wind alone, underscoring wind's leading role in the power mix during key periods. A record-low 43% was from fossil fuels, with 41% from gas and just 2% from coal, also a record low. In 2010, fossil fuels generated 75% of the total.

Carbon Brief’s analysis of UK electricity generation in 2019 is based on figures from BM Reports and the Department for Business, Energy and Industrial Strategy (BEIS). See the methodology at the end for more on how the analysis was conducted.

The numbers differ from those published earlier in January by National Grid, which were for electricity supplied in Great Britain only (England, Wales and Scotland, but excluding Northern Ireland), including via imports from other countries.

Low-carbon low
In 2019, the UK became the first major economy to target net-zero greenhouse gas emissions by 2050, increasing the ambition of its legally binding Climate Change Act.

To date, the country has cut its emissions by around two-fifths since 1990, with almost all of its recent progress coming from the electricity sector.

Emissions from electricity generation have fallen rapidly in the decade since 2010 as coal power has been almost phased out and even gas output has declined. Fossil fuels have been displaced by falling demand and by renewables, such as wind, solar and biomass.

But Carbon Brief’s annual analysis of UK electricity generation shows progress stalled in 2019, with the output from low-carbon sources barely increasing compared to a year earlier.

The chart below shows low-carbon generation in each year since 2010 (grey bars) and the estimated level in 2019 (red). The pale grey bars show the estimated future output of existing low-carbon sources after old nuclear plants retire and the pale red bars show the amount of new generation needed to keep electricity sector emissions to less than 100 grammes of CO2 per kilowatt hour (gCO2/kWh), the UK’s nominal target for the sector.

 Annual electricity generation in the UK by fuel, terawatt hours, 2010-2019. Top panel: fuel by fuel. Bottom panel: cumulative total generation from all sources. Source: BEIS energy trends, BM Reports and Carbon Brief analysis. Chart by Carbon Brief using Highcharts.
As the chart shows, the UK will require significantly more low-carbon electricity over the next decade as part of meeting its legally binding climate goals.

The nominal 100gCO2/kWh target for 2030 was set in the context of the UK’s less ambitious goal of cutting emissions to 80% below 1990 levels by 2050. Now that the country is aiming to cut emissions to net-zero by 2050, that 100gCO2/kWh indicator is likely to be the bare minimum.

Even so, it would require a rapid step up in the pace of low-carbon expansion, compared to the increases seen over the past decade. On average, low-carbon generation has risen by 9TWh each year in the decade since 2010 – including a rise of just 1TWh in 2019.

Given scheduled nuclear retirements and rising demand expected by the Committee on Climate Change (CCC) – with some electrification of transport and heating – low-carbon generation would need to increase by 15TWh each year until 2030, just to meet the benchmark of 100gCO2/kWh.

For context, the 3.2 gigawatt (GW) Hinkley C new nuclear plant being built in Somerset will generate around 25TWh once completed around 2026. The world’s largest offshore windfarm, the 1.2GW Hornsea One scheme off the Yorkshire coast, will generate around 5TWh each year.

The new Conservative government is targeting 40GW of offshore wind by 2030, up from today’s figure of around 8GW. If policies are put in place to meet this goal, then it could keep power sector emissions below 100gCO2/kWh, depending on the actual performance of the windfarms built.

However, new onshore wind and solar, further new nuclear or other low-carbon generation, such as gas with carbon capture and storage (CCS), is likely to be needed if demand is higher than expected, or if the 100gCO2/kWh benchmark is too weak in the context of net-zero by 2050.

The CCC says it is “likely” to “reflect the need for more rapid deployment” of low-carbon towards net-zero emissions in its advice on the sixth UK carbon budget for 2033-2037, due in September.

Trading places
Looking more closely at UK electricity generation in 2019, Carbon Brief’s analysis shows why there was so little growth for low-carbon sources compared to the previous year.

There was another increase for wind power in 2019 (up 8TWh, 14%), with record wind generation as several large new windfarms were completed including the 1.2GW Hornsea One project in October and the 0.6GW Beatrice offshore windfarm in Q2 of 2019. But this was offset by a decline for nuclear (down 9TWh, 14%), due to ongoing outages for reactors at Hunterston in Scotland and Dungeness in Kent.

(Analysis of data held by trade organisation RenewableUK suggests some 0.6GW of onshore wind capacity also started operating in 2019, including the 0.2GW Dorenell scheme in Moray, Scotland.)

As a result of these movements, the UK’s windfarms overtook nuclear for the first time ever in 2019, becoming the country’s second-largest source of electricity generation, and earlier, wind and solar together surpassed nuclear in the UK as momentum built. This is shown in the figure below, with wind (green line, top panel) trading places with nuclear (purple) and gas (dark blue) down around 25% since 2010 but remaining the single-largest source.

 Annual electricity generation in the UK by fuel, terawatt hours, 2010-2019. Top panel: fuel by fuel. Bottom panel: cumulative total generation from all sources. Source: BEIS energy trends, BM Reports and Carbon Brief analysis. Chart by Carbon Brief using Highcharts.
The UK’s currently suspended nuclear plants are due to return to service in January and March, according to operator EDF, the French state-backed utility firm. However, as noted above, most of the UK’s nuclear fleet is set to retire during the 2020s, with only Sizewell B in Suffolk due to still be operating by 2030. Hunterston is scheduled to retire by 2023 and Dungeness by 2028.

Set against these losses, the UK has a pipeline of offshore windfarms, secured via “contracts for difference” with the government, at a series of auctions. The most recent auction, in September 2019, saw prices below £40 per megawatt hour – similar to current wholesale electricity prices.

However, the capacity contracted so far is not sufficient to meet the government’s target of 40GW by 2030, meaning further auctions – or some other policy mechanism – will be required.

Coal zero
As well as the switch between wind and nuclear, 2019 also saw coal fall below solar for the first time across a full year, echoing the 2016 moment when wind outgenerated coal across the UK, after it suffered another 60% reduction in electricity output. Just six coal plants remain in the UK, with Aberthaw B in Wales and Fiddlers Ferry in Cheshire closing in March.

Coal accounted for just 2% of UK generation in 2019, a record-low coal share since centralised electricity supplies started to operate in 1882. The fuel met 40% of UK needs as recently as 2012, but has plummeted thanks to falling demand, rising renewables, cheaper gas and higher CO2 prices.

The reduction in average coal generation hides the fact that the fuel is now often not required at all to meet the UK’s electricity needs. The chart below shows the number of days each year when coal output was zero in 2019 (red line) and the two previous years (blue).

 Cumulative number of days when UK electricity generation from renewable sources has been higher than that from fossil fuels. Source: BEIS energy trends, BM Reports and Carbon Brief analysis. Chart by Carbon Brief using Highcharts.
The 83 days in 2019 with zero coal generation amount to nearly a quarter of the year and include the record-breaking 18-day stretch without the fuel.

Great Britain has been running for a record TWO WEEKS without using coal to generate electricity – the first time this has happened since 1882.

The country’s grid has been coal-free for 45% of hours in 2019 so far.https://www.carbonbrief.org/countdown-to-2025-tracking-the-uk-coal-phase-out …

Coal generation was set for significant reductions around the world in 2019 – including a 20% reduction for the EU as a whole – according to analysis published by Carbon Brief in November.

Notably, overall UK electricity generation fell by another 9TWh in 2019 (3%), bringing the total decline to 58TWh since 2010. This is equivalent to more than twice the output from the Hinkley C scheme being built in Somerset. As Carbon Brief explained last year, falling demand has had a similar impact on electricity-sector CO2 emissions as the increase in output from renewables.

This is illustrated by the fact that the 9TWh reduction in overall generation translated into a 9TWh (6%) cut in fossil-fuel generation during 2019, with coal falling by 10TWh and gas rising marginally.

Increasingly renewable
As fossil-fuel output and overall generation have declined, the UK’s renewable sources of electricity have continued to increase. Their output has risen nearly five-fold in the past decade and their share of the UK total has increased from 7% in 2010 to 37% in 2019.

As a result, the UK’s increasingly renewable grid is seeing more minutes, hours and days during which the likes of wind, solar and biomass collectively outpace all fossil fuels put together, and on some days wind is the main source as well.

The chart below shows the number of days during each year when renewables generated more electricity than fossil fuels in 2019 (red line) and each of the previous four years (blue lines). In total, nearly two-fifths of days in 2019 crossed this threshold.

 Cumulative number of days when the UK has not generated any electricity from coal. Source: BEIS energy trends, BM Reports and Carbon Brief analysis. Chart by Carbon Brief using Highcharts.
There were also four months in 2019 when renewables generated more of the UK’s electricity than fossil fuels: March, August, September and December. The first ever such month came in September 2018 and more are certain to follow.

National Grid, which manages Great Britain’s high-voltage electricity transmission network, is aiming to be able to run the system without fossil fuels by 2025, at least for short periods. At present, it sometimes has to ask windfarm operators to switch off and gas plants to start running in order to keep the electricity grid stable.

Note that biomass accounted for 11% of UK electricity generation in 2019, nearly a third of the total from all renewables. Some two-thirds of the biomass output is from “plant biomass”, primarily wood pellets burnt at Lynemouth in Northumberland and the Drax plant in Yorkshire. The remainder was from an array of smaller sites based on landfill gas, sewage gas or anaerobic digestion.

The CCC says the UK should “move away” from large-scale biomass power plants, once existing subsidy contracts for Drax and Lynemouth expire in 2027.

Using biomass to generate electricity is not zero-carbon and in some circumstances could lead to higher emissions than from fossil fuels. Moreover, there are more valuable uses for the world’s limited supply of biomass feedstock, the CCC says, including carbon sequestration and hard-to-abate sectors with few alternatives.

Methodology
The figures in the article are from Carbon Brief analysis of data from BEIS Energy Trends chapter 5 and chapter 6, as well as from BM Reports. The figures from BM Reports are for electricity supplied to the grid in Great Britain only and are adjusted to include Northern Ireland.

In Carbon Brief’s analysis, the BM Reports numbers are also adjusted to account for electricity used by power plants on site and for generation by plants not connected to the high-voltage national grid. This includes many onshore windfarms, as well as industrial gas combined heat and power plants and those burning landfill gas, waste or sewage gas.

By design, the Carbon Brief analysis is intended to align as closely as possible to the official government figures on electricity generated in the UK, reported in BEIS Energy Trends table 5.1.

Briefly, the raw data for each fuel is in most cases adjusted with a multiplier, derived from the ratio between the reported BEIS numbers and unadjusted figures for previous quarters.

Carbon Brief’s method of analysis has been verified against published BEIS figures using “hindcasting”. This shows the estimates for total electricity generation from fossil fuels or renewables to have been within ±3% of the BEIS number in each quarter since Q4 2017. (Data before then is not sufficient to carry out the Carbon Brief analysis.)

For example, in the second quarter of 2019, a Carbon Brief hindcast estimates gas generation at 33.1TWh, whereas the published BEIS figure was 34.0TWh. Similarly, it produces an estimate of 27.4TWh for renewables, against a BEIS figure of 27.1TWh.

National Grid recently shared its own analysis for electricity in Great Britain during 2019 via its energy dashboard, which differs from Carbon Brief’s figures.

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