Power price spikes in Texas undergo scrutiny

AI Load Forecasting for Utilities leverages machine learning, smart meters, and predictive analytics to balance energy demand during COVID-19 disruptions, optimize grid reliability, support demand response, and stabilize rates for residential and commercial customers.

Key Points

AI predicts utility demand with ML and smart meters to improve reliability and reduce costs.

✅ Adapts to rapid demand shifts with accurate short term forecasts

✅ Optimizes demand response and distributed energy resources

✅ Reduces outages risk while lowering procurement and operating costs

The spread of the novel coronavirus that causes COVID-19 has prompted state and local governments around the U.S. to institute shelter-in-place orders and business closures. As millions suddenly find themselves confined to their homes, the shift has strained not only internet service providers, streaming platforms, and online retailers, but the utilities supplying power to the nation’s electrical grid, which face longer, more frequent outages as well.

U.S. electricity use on March 27, 2020 was 3% lower than it was on March 27, 2019, a loss of about three years of sales growth. Peter Fox-Penner, director of the Boston University Institute for Sustainable Energy, asserted in a recent op-ed that utility revenues will suffer because providers are halting shutoffs and deferring rate increases. Moreover, according to research firm Wood Mackenzie, the rise in household electricity demand won’t offset reduced business electricity demand, mainly because residential demand makes up just 40% of the total demand across North America.

Some utilities are employing AI and machine learning for the energy transition to address the windfalls and fluctuations in energy usage resulting from COVID-19. Precise load forecasting could ensure that operations aren’t interrupted in the coming months, thereby preventing blackouts and brownouts. And they might also bolster the efficiency of utilities’ internal processes, leading to reduced prices and improved service long after the pandemic ends.

Innowatts
Innowatts, a startup developing an automated toolkit for energy monitoring and management, counts several major U.S. utility companies among its customers, including Portland General Electric, Gexa Energy, Avangrid, Arizona Public Service Electric, WGL, and Mega Energy. Its eUtility platform ingests data from over 34 million smart energy meters across 21 million customers in more than 13 regional energy markets, while its machine learning algorithms analyze the data to forecast short- and long-term loads, variances, weather sensitivity, and more.

Beyond these table-stakes predictions, Innowatts helps evaluate the effects of different rate configurations by mapping utilities’ rate structures against disaggregated cost models. It also produces cost curves for each customer that reveal the margin impacts on the wider business, and it validates the yield of products and cost of customer acquisition with models that learn the relationships between marketing efforts and customer behaviors (like real-time load).

Innowwatts told VentureBeat that it observed “dramatic” shifts in energy usage between the first and fourth weeks of March. In the Northeast, “non-essential” retailers like salons, clothing shops, and dry cleaners were using only 35% as much energy toward the end of the month (after shelter-in-place orders were enacted) versus the beginning of the month, while restaurants (excepting pizza chains) were using only 28%. In Texas, conversely, storage facilities were using 142% as much energy in the fourth week compared with the first.

Innowatts says that throughout these usage surges and declines, its clients took advantage of AI-based load forecasting to learn from short-term shocks and make timely adjustments. Within three days of shelter-in-place orders, the company said, its forecasting models were able to learn new consumption patterns and produce accurate forecasts, accounting for real-time changes.

Innowatts CEO Sid Sachdeva believes that if utility companies had not leveraged machine learning models, demand forecasts in mid-March would have seen variances of 10-20%, significantly impacting operations.

“During these turbulent times, AI-based load forecasting gives energy providers the ability to … develop informed, data-driven strategies for future success,” Sachdeva told VentureBeat. “With utilities and energy retailers seeing a once-in-a-lifetime 30%-plus drop in commercial energy consumption, accurate forecasting has never been more important. Without AI tools, utilities would see their forecasts swing wildly, leading to inaccuracies of 20% or more, placing an enormous strain on their operations and ultimately driving up costs for businesses and consumers.”

Autogrid
Autogrid works with over 50 customers in 10 countries — including Energy Australia, Florida Power & Light, and Southern California Edison — to deliver AI-informed power usage insights. Its platform makes 10 million predictions every 10 minutes and optimizes over 50 megawatts of power, which is enough to supply the average suburb.

Flex, the company’s flagship product, predicts and controls tens of thousands of energy resources from millions of customers by ingesting, storing, and managing petabytes of data from trillions of endpoints. Using a combination of data science, machine learning, and network optimization algorithms, Flex models both physics and customer behavior, automatically anticipating and adjusting for supply and demand patterns through virtual power plants that coordinate distributed assets.

Autogrid also offers a fully managed solution for integrating and utilizing end-customer installations of grid batteries and microgrids. Like Flex, it automatically aggregates, forecasts, and optimizes capacity from assets at sub-stations and transformers, reacting to distribution management needs while providing capacity to avoid capital investments in system upgrades.

Autogrid CEO Dr. Amit Narayan told VentureBeat that the COVID-19 crisis has heavily shifted daily power distribution in California, where it’s having a “significant” downward impact on hourly prices in the energy market. He says that Autogrid has also heard from customers about transformer failures in some regions due to overloaded circuits, which he expects will become a problem in heavily residential and saturated load areas during the summer months (as utilities prepare for blackouts across the U.S. when air conditioning usage goes up).

“In California, [as you’ll recall], more than a million residents faced wildfire prevention-related outages in PG&E territory in 2019,” Narayan said, referring to the controversial planned outages orchestrated by Pacific Gas & Electric last summer. “The demand continues to be high in 2020 in spite of the COVID-19 crisis, as residents prepare to keep the lights on and brace for a similar situation this summer. If a 2019 repeat happens again, it will be even more devastating, given the health crisis and difficulty in buying groceries.”

AI making a difference
AI and machine learning isn’t a silver bullet for the power grid — even with predictive tools at their disposal, utilities are beholden to a tumultuous demand curve and to mounting climate risks across the grid. But providers say they see evidence the tools are already helping to prevent the worst of the pandemic’s effects — chiefly by enabling them to better adjust to shifted daily and weekly power load profiles.

“The societal impact [of the pandemic] will continue to be felt — people may continue working remotely instead of going into the office, they may alter their commute times to avoid rush hour crowds, or may look to alternative modes of transportation,” Schneider Electric chief innovation officer Emmanuel Lagarrigue told VentureBeat. “All of this will impact the daily load curve, and that is where AI and automation can help us with maintenance, performance, and diagnostics within our homes, buildings, and in the grid.”

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UK Energy Price Cap Cut 2024 signals relief as wholesale gas prices fall; Ofgem price cap drops per Cornwall Insight, aided by LNG supply, mild winter, despite Red Sea tensions and Ukraine conflict impacts.

Key Points

A forecast cut to Great Britain's Ofgem price cap as wholesale gas falls, easing typical annual household bills in 2024.

✅ Cap falls from £1,928 to £1,620 in April 2024

✅ Forecast £1,497 in July, then about £1,541 from October

✅ Drivers: lower wholesale gas, LNG supply, mild winter

Households in Great Britain are set to experience a significant reduction in energy costs this spring, with bills projected to drop by over £300 annually. This decrease is primarily due to a decline in wholesale gas prices, offering some respite to those grappling with the cost of living crisis.

Cornwall Insight, a well-regarded industry analyst, predicts a 16% reduction in average bills from the previous quarter, potentially reaching the lowest levels since the onset of the Ukraine conflict.

The industry’s price cap, indicative of the average annual bill for a typical household, is expected to decrease from the current £1,928, set earlier this month, to £1,620 in April – a reduction of £308 and £40 less than previously forecasted in December, as ministers consider ending the gas-electricity price link to improve market resilience.

Concerns about escalating tensions in the Red Sea, where Houthi rebels have disrupted global shipping, initially led analysts to fear an increase in wholesale oil prices and subsequent impact on household energy costs.

Contrary to these concerns, oil prices have remained relatively stable, and European gas reserves have been higher than anticipated during a mild winter, with European gas prices returning to pre-Ukraine war levels since November.

Cornwall Insight anticipates that energy prices will continue to be comparatively low through 2024. They predict a further decline to £1,497 for a typical annual bill from July, followed by a slight increase to £1,541 starting in October.

This forecast is a welcome development for Britons who have been dealing with increased expenses across various sectors, from food to utilities, amidst persistently high inflation rates, with energy-driven EU inflation hitting lower-income households hardest across member states.

Energy bills saw a steep rise in 2021, which escalated further due to the Ukraine conflict in 2022, driving up wholesale gas prices. This surge prompted government intervention to subsidize bills, with the UK price cap estimated to cost around £89bn to the public purse, capping costs to a typical household at £2,500.

Cornwall Insight noted that the supply of liquified natural gas to Europe had not been as adversely affected by the Red Sea disruptions as initially feared. Moreover, the UK has been well-supplied with gas from the US, which has become a more significant supplier since the Ukraine war, even as US electricity prices have risen to multi-decade highs. Contributing factors also include lower gas prices in Asia, mild weather, and robust gas availability.

Craig Lowrey, a principal consultant at Cornwall Insight, remarked that concerns about Red Sea events driving up energy prices have not materialized, allowing households to expect a reduction in prices.

On Monday, the next-month wholesale gas price dropped by 4% to 65p a therm.

However, Lowrey cautioned that a complete return to pre-crisis energy bill levels remains unlikely due to ongoing market impacts from shifting away from Russian energy sources and persistent geopolitical tensions, as well as policy changes such as Britain’s Energy Security Bill shaping market reforms.

Richard Neudegg, director of regulation at Uswitch, welcomed the potential further reduction of the price cap in April. However, he pointed out that this offers little solace to households currently struggling with high winter energy costs during the winter. Neudegg urged Ofgem, the energy regulator, to prompt suppliers to reintroduce more competitive and affordable fixed-price deals.

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Europe 2023 Energy Shortfall underscores how weak hydro and nuclear offset record solar and wind, tightening grids as natural gas supplies shrink and demand rebounds, heightening risks of electricity shortages across key economies.

Key Points

A regional gap as weak hydro and nuclear offset record solar and wind, straining supply as gas stays tight.

✅ Hydro and nuclear output fell sharply in early 2023

✅ Record solar and wind could not offset the deficit

✅ Industrial demand rebound pressures limited gas supplies

Shortfalls in Europe's hydro and nuclear output have more than offset record electricity generation from wind and solar power sites over the first quarter of 2023, leaving the region vulnerable to acute energy shortages for the second straight year.

European countries fast-tracked renewable energy capacity development in 2022 in the wake of Russia's invasion of Ukraine last February, which upended natural gas flows to the region and sent power prices soaring.

Europe lifted renewable energy supply capacity by a record 57,290 megawatts in 2022, or by nearly 9%, according to the International Energy Agency (IRENA), amid a scramble to replace imported Russian gas with cleaner, home-grown energy.

However, steep drops in both hydro and nuclear output - two key sources of non-emitting energy - mean Europe's power producers have limited ways to lift overall electricity generation, as the region is losing nuclear power at a critical moment, just as the region's economies start to reboot after last year's energy shock.

POWER PLATEAU
Europe's total electricity generation over the first quarter of 2023 hit 1,213 terawatt hours, or roughly 6.4% less than during the same period in 2022, according to data from think tank Ember.

At the same time, European power hits records during extreme heat as plants struggle to cool, exacerbating supply risks.

As Europe's total electricity demand levels were in post-COVID-19 expansion mode in early 2022 before Russia's so-called special operation sent power costs to record highs amid debates over how electricity is priced in Europe, it makes sense that overall electricity use was comparatively stunted in early 2023.

However, efforts are now underway to revive activity at scores of European factories, industrial plants and production lines that were shuttered or curtailed in 2022, so Europe's collective electricity consumption totals are set to trend steadily higher over the remainder of 2023.

With Russian natural gas unavailable in the previous quantities due to sanctions and supply issues, Europe's power producers will need to deploy alternative energy sources, including renewables poised to eclipse coal globally, to feed that increase in power demand.

And following the large jump in renewable capacity brought online in 2022, utilities can deploy more low-emissions energy than ever before across Europe's electricity grids.

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BMW Hydrogen Fuel Cell Strategy positions iX5 and eDrive for zero-emission mobility, leveraging fuel cells, fast refueling, and hydrogen infrastructure as an alternative to BEVs, diversifying drivetrains across premium segments globally, rapidly.

Key Points

BMW's plan to commercialize hydrogen fuel-cell drivetrains like iX5 eDrive for scalable, zero-emission mobility.

✅ Fuel cells enable fast refueling and long range with water vapor only.

✅ Reduces reliance on lithium and cobalt via recyclable materials.

✅ Targets premium SUV iX5; limited pilots before broader rollout.

BMW is hanging in there with hydrogen, a stance mirrored in power companies' hydrogen outlook today. That’s what Oliver Zipse, the chairperson of BMW, reiterated during an interview last week in Goodwood, England. 

“After the electric car, which has been going on for about 10 years and scaling up rapidly, the next trend will be hydrogen,” he says. “When it’s more scalable, hydrogen will be the hippest thing to drive.”

BMW has dabbled with the idea of using hydrogen for power for years, even though it is obscure and niche compared to the current enthusiasm surrounding vehicles powered by electricity. In 2005, BMW built 100 “Hydrogen 7” vehicles that used the fuel to power their V12 engines. It unveiled the fuel cell iX5 Hydrogen concept car at the International Motor Show Germany in 2021. 

In August, the company started producing fuel-cell systems for a production version of its hydrogen-powered iX5 sport-utility vehicle. Zipse indicated it would be sold in the United States within the next five years, although in a follow-up phone call a spokesperson declined to confirm that point. Bloomberg previously reported that BMW will start delivering fewer than 100 of the iX5 hydrogen vehicles to select partners in Europe, the U.S., and Asia, where Asia leads on hydrogen fuel cells today, from the end of this year.

All told, BMW will eventually offer five different drivetrains to help diversify alternative-fuel options within the group, as hybrids gain renewed momentum in the U.S., Zipse says.

“To say in the U.K. about 2030 or the U.K. and in Europe in 2035, there’s only one drivetrain, that is a dangerous thing,” he says. “For the customers, for the industry, for employment, for the climate, from every angle you look at, that is a dangerous path to go to.” 

Zipse’s hydrogen dreams could even extend to the group’s crown jewel, Rolls-Royce, which BMW has owned since 1998. The “magic carpet ride” driving style that has become Rolls-Royce’s signature selling point is flexible enough to be powered by alternatives to electricity, says Rolls-Royce CEO Torsten Müller-Ötvös. 

“To house, let’s say, fuel cell batteries: Why not? I would not rule that out,” Müller-Ötvös told reporters during a roundtable conversation in Goodwood on the eve of the debut of the company’s first-ever electric vehicle, Spectre. “There is a belief in the group that this is maybe the long-term future.”

Such a vehicle would contain a hydrogen fuel-cell drivetrain combined with BMW’s electric “eDrive” system. It works by converting hydrogen into electricity to reach an electrical output of up to 125 kW/170 horsepower and total system output of nearly 375hp, with water vapor as the only emission, according to the brand.

Hydrogen’s big advantage over electric power, as EVs versus fuel cells debates note, is that it can supply fuel cells stored in carbon-fiber-reinforced plastic tanks. “There will [soon] be markets where you must drive emission-free, but you do not have access to public charging infrastructure,” Zipse says. “You could argue, well you also don’t have access to hydrogen infrastructure, but this is very simple to do: It’s a tank which you put in there like an old [gas] tank, and you recharge it every six months or 12 months.”

Fuel cells at BMW would also help reduce its dependency on raw materials like lithium and cobalt, because the hydrogen-based system uses recyclable components made of aluminum, steel, and platinum. 

Zipse’s continued commitment to prioritizing hydrogen has become an increasingly outlier position in the automotive world. In the last five years, electric-only vehicles have become the dominant alternative fuel — as the age of electric cars dawns ahead of schedule — if not yet on the road, where fewer than 3% of new cars have plugs, at least at car shows and new-car launches.

Rivals Mercedes-Benz and Audi scrapped their own plans to develop fuel cell vehicles and instead have poured tens of billions of dollars into developing pure-electric vehicle, including Daimler's electrification plan initiatives. Porsche went public to finance its own electric aspirations. 

BMW will make half of all new-car sales electric by 2030 across the group, with many expecting most drivers to go electric within a decade, which includes MINI and Rolls-Royce. 
 

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Canadian EV Manufacturing is accelerating with GM, Ford, and Project Arrow, integrating cross-border supply chains, battery production, rare-earths like lithium and cobalt, autonomous tech, and home charging to drive clean mobility and decarbonization.

Key Points

Canadian EV manufacturing spans electric and autonomous vehicles, domestic batteries, and integrated US-Canada trade.

✅ GM and Ford retool plants for EVs and autonomous production

✅ Project Arrow showcases Canadian zero-emission supply capabilities

✅ Lithium, cobalt, and battery hubs target cross-border resilience

The storied North American automotive industry, the ultimate showcase of Canada’s high-tensile trade ties with the United States and emerging Canada-U.S. collaboration on EVs momentum, is about to navigate a dramatic hairpin turn.

But as the Big Three veer into the all-electric, autonomous era, some Canadians want to seize the moment and take the wheel.

“There’s a long shadow between the promise and the execution, but all the pieces are there,” says Flavio Volpe, president of the Automotive Parts Manufacturers’ Association.

“We went from a marriage on the rocks to one that both partners are committed to. It could be the best second chapter ever.”

Volpe is referring specifically to GM, which announced late last month an ambitious plan to convert its entire portfolio of vehicles to an all-electric platform by 2035.

But that decision is just part of a cascading transformation across the industry, marking an EV inflection point with existential ramifications for one of the most tightly integrated cross-border manufacturing and supply-chain relationships in the world.

China is already working hard to become the “source of a new way” to power vehicles, President Joe Biden warned last week.

“We just have to step up.”

Canada has both the resources and expertise to do the same, says Volpe, whose ambitious Project Arrow concept — a homegrown zero-emissions vehicle named for the 1950s-era Avro interceptor jet — is designed to showcase exactly that, as recent EV assembly deals in Canada underscore.

“We’re going to prove to the market, we’re going to prove to the (manufacturers) around the planet, that everything that goes into your zero-emission vehicle can be made or sourced here in Canada,” he says.

“If somebody wants to bring what we did over the line and make 100,000 of them a year, I’ll hand it to them.”

GM earned the ire of Canadian auto workers in 2018 by announcing the closure of its assembly plant in Oshawa, Ont. It later resurrected the facility with a $170-million investment to retool it for autonomous vehicles.

“It was, ‘You closed Oshawa, how dare you?’ And I was one of the ‘How dare you’ people,” Volpe says.

“Well, now that they’ve reopened Oshawa, you sit there and you open your eyes to the commitment that General Motors made.”

Ford, too, has entered the fray, promising $1.8 billion to retool its sprawling landmark facility in Oakville, Ont., to build EVs.

It’s a leap of faith of sorts, considering what market experts say is ongoing consumer doubt about EVs and EV supply shortages that drive wait times.

“Range anxiety” — the persistent fear of a depleted battery at the side of the road — remains a major concern, even though it’s less of a problem than most people think.

Consulting firm Deloitte Canada, which has been tracking automotive consumer trends for more than a decade, found three-quarters of future EV buyers it surveyed planned to charge their vehicles at home overnight.

“The difference between what is a perceived issue in a consumer’s mind and what is an actual issue is actually quite negligible,” Ryan Robinson, Deloitte’s automotive research leader, says in an interview.

“It’s still an issue, full stop, and that’s something that the industry is going to have to contend with.”

So, too, is price, especially with the end of the COVID-19 pandemic still a long way off. Deloitte’s latest survey, released last month, found 45 per cent of future buyers in Canada hope to spend less than $35,000 — a tall order when most base electric-vehicle models hover between $40,000 and $45,000.

“You put all of that together and there’s still, despite the electric-car revolution hype, some major challenges that a lot of stakeholders that touch the automotive industry face,” Robinson says.

“It’s not just government, it’s not just automakers, but there are a variety of stakeholders that have a role to play in making sure that Canadians are ready to make the transition over to electric mobility.”

With protectionism no longer a dirty word in the United States and Biden promising to prioritize American workers and suppliers, the Canadian government’s job remains the same as it ever was: making sure the U.S. understands Canada’s mission-critical role in its own economic priorities.

“We’re both going to be better off on both sides of the border, as we have been in the past, if we orient ourselves toward this global competition as one force,” says Gerald Butts, vice-chairman of the political-risk consultancy Eurasia Group and a former principal secretary to Prime Minister Justin Trudeau.

“It served us extraordinarily well in the past … and I have no reason to believe it won’t serve us well in the future.”

Last month, GM announced a billion-dollar plan to build its new all-electric BrightDrop EV600 van in Ingersoll, Ont., at Canada’s first large-scale EV manufacturing plant for delivery vehicles.

That investment, Volpe says, assumes Canada will take the steps necessary to help build a homegrown battery industry — with projects such as a new Niagara-region battery plant pointing the way — drawing on the country’s rare-earth resources like lithium and cobalt that are waiting to be extracted in northern Ontario, Quebec and elsewhere.

Given that the EV industry is still in his infancy, the free market alone won’t be enough to ensure those resources can be extracted and developed, he says.

“General Motors made a billion-dollar bet on Canada because it’s going to assume that the Canadian government — this one or the next one — is going to commit” to building that business.

Such an investment would pay dividends well beyond the auto sector, considering the federal Liberal government’s commitment to lowering greenhouse gas-emissions, including a 2035 EV mandate, and meeting targets set out in the Paris climate accord.

“If you make investments in renewable energy and utility storage using battery technology, you can build an industry at scale that the auto industry can borrow,” Volpe says.

Major manufacturing, retail and office facilities would be able to use that technology to help “shave the peak” off Canada’s GHG emissions and achieve those targets, all the while paving the way for a self-sufficient electric-vehicle industry.

“You’d be investing in the exact same technology you’d use in a car.”

There’s one problem, says Robinson: the lithium-ion batteries on roads right now might not be where the industry ultimately lands.

“We’re not done with with battery technology,” Robinson says. “What you don’t want to do is invest in a technology that is that is rapidly evolving, and could potentially become obsolete going forward.”

Fuel cells — energy-efficient, hydrogen-powered units that work like batteries, but without the need for constant recharging — continue to be part of the conversation, he adds.

“The amount of investment is huge, and you want to be sure that you’re making the right decision, so you don’t find yourself behind the curve just as all that capacity is coming online.”

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Near-Field Thermophotovoltaics captures radiated energy across a nanoscale gap, using thin-film photovoltaic cells and indium gallium arsenide to boost power density and efficiency, enabling compact Army portable power from emitters via radiative heat transfer.

Key Points

A nanoscale TPV method capturing near-field photons for higher power density at lower emitter temperatures.

✅ Nanoscale gap boosts radiative transfer and usable photon flux

✅ Thin-film InGaAs cells recycle sub-band-gap photons via reflector

✅ Achieved ~5 kW/m2 power density with higher efficiency

With the addition of sensors and enhanced communication tools, providing lightweight, portable power has become even more challenging, with concepts such as power from falling snow illustrating how diverse new energy-harvesting approaches are. Army-funded research demonstrated a new approach to turning thermal energy into electricity that could provide compact and efficient power for Soldiers on future battlefields.

Hot objects radiate light in the form of photons into their surroundings. The emitted photons can be captured by a photovoltaic cell and converted to useful electric energy. This approach to energy conversion is called far-field thermophotovoltaics, or FF-TPVs, and has been under development for many years; however, it suffers from low power density and therefore requires high operating temperatures of the emitter.

The research, conducted at the University of Michigan and published in Nature Communications, demonstrates a new approach, where the separation between the emitter and the photovoltaic cell is reduced to the nanoscale, enabling much greater power output than what is possible with FF-TPVs for the same emitter temperature.

This approach, which enables capture of energy that is otherwise trapped in the near-field of the emitter is called near-field thermophotovoltaics or NF-TPV and uses custom-built photovoltaic cells and emitter designs ideal for near-field operating conditions, alongside emerging smart solar inverters that help manage conversion and delivery.

This technique exhibited a power density almost an order of magnitude higher than that for the best-reported near-field-TPV systems, while also operating at six-times higher efficiency, paving the way for future near-field-TPV applications, including remote microgrid deployments in extreme environments, according to Dr. Edgar Meyhofer, professor of mechanical engineering, University of Michigan.

"The Army uses large amounts of power during deployments and battlefield operations and must be carried by the Soldier or a weight constrained system," said Dr. Mike Waits, U.S. Army Combat Capabilities Development Command's Army Research Laboratory. "If successful, in the future near-field-TPVs could serve as more compact and higher efficiency power sources for Soldiers as these devices can function at lower operating temperatures than conventional TPVs."

The efficiency of a TPV device is characterized by how much of the total energy transfer between the emitter and the photovoltaic cell is used to excite the electron-hole pairs in the photovoltaic cell, where insights from near-light-speed conduction research help contextualize performance limits in semiconductors. While increasing the temperature of the emitter increases the number of photons above the band-gap of the cell, the number of sub band-gap photons that can heat up the photovoltaic cell need to be minimized.

"This was achieved by fabricating thin-film TPV cells with ultra-flat surfaces, and with a metal back reflector," said Dr. Stephen Forrest, professor of electrical and computer engineering, University of Michigan. "The photons above the band-gap of the cell are efficiently absorbed in the micron-thick semiconductor, while those below the band-gap are reflected back to the silicon emitter and recycled."

The team grew thin-film indium gallium arsenide photovoltaic cells on thick semiconductor substrates, and then peeled off the very thin semiconductor active region of the cell and transferred it to a silicon substrate, informing potential interfaces with home battery systems for distributed use.

All these innovations in device design and experimental approach resulted in a novel near-field TPV system that could complement distributed resources in virtual power plants for resilient operations.

"The team has achieved a record ~5 kW/m2 power output, which is an order of magnitude larger than systems previously reported in the literature," said Dr. Pramod Reddy, professor of mechanical engineering, University of Michigan.

Researchers also performed state-of-the-art theoretical calculations to estimate the performance of the photovoltaic cell at each temperature and gap size, informing hybrid designs with backup fuel cell solutions that extend battery life, and showed good agreement between the experiments and computational predictions.

"This current demonstration meets theoretical predictions of radiative heat transfer at the nanoscale, and directly shows the potential for developing future near-field TPV devices for Army applications in power and energy, communication and sensors," said Dr. Pani Varanasi, program manager, DEVCOM ARL that funded this work.

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