Virginia regulators seek suggestions on saving energy

Five Nations Energy Transmission Line connects remote First Nations to the Ontario power grid, delivering clean, reliable electricity to Western James Bay through Indigenous-owned transmission infrastructure, replacing diesel generators and enabling sustainable community growth.

Key Points

An Indigenous-owned grid link providing reliable power to Western James Bay First Nations, replacing polluting diesel.

✅ Built by five First Nations; fully Indigenous-owned utility

✅ 270 km line connecting remote James Bay communities

✅ Ended diesel dependence; enabled sustainable development

For the Indigenous communities along northern Ontario’s James Bay — the ones that have lived on and taken care of the lands as long as anyone can remember — the new millenium marked the start of a diesel-less future, even as Ontario’s electricity outlook raised concerns about getting dirtier in policy debates. 

While the southern part of the province took Ontario’s power grid for granted, despite lessons from Europe’s power crisis about reliability, the vast majority of these communities had never been plugged in. Their only source of power was a handful of very loud diesel-powered generators. Because of that, daily life in the Attawapiskat, Kashechewan and Fort Albany First Nations involved deliberating a series of tradeoffs. Could you listen to the radio while toasting a piece of bread? How many Christmas lights could you connect before nothing else was usable? Was there enough power to open a new school? 

The communities wanted a safe, reliable, clean alternative, with Manitoba’s clean energy illustrating regional potential, too. So did their chiefs, which is why they passed a resolution in 1996 to connect the area to Ontario’s grid, not just for basic necessities but to facilitate growth and development, and improve their communities’ quality of life. 

The idea was unthinkable at the time — scorned and dismissed by those who held the keys to Ontario’s (electrical) power, much like independent power projects can be in other jurisdictions. Even some in the community didn’t fully understand it. When the idea was first proposed at a gathering of Nishnawbe Aski Nation, which represents 49 First Nations, one attendee said the only way he could picture the connection was as “a little extension cord running through the bush from Moosonee.” 

But the leadership of Attawapiskat, Kashechewan and Fort Albany First Nations had been dreaming and planning. In 1997, along with members of Taykwa Tagamou and Moose Cree First Nations, they created the first, and thus far only, fully Indigenous-owned energy company in Canada: Five Nations Energy Inc., as partnerships like an OPG First Nation hydro project would later show in action, too. 

Over the next five years, the organization built Omushkego Ishkotayo, the Cree name for the Western James Bay transmission line: “Omushkego” refers to the Swampy Cree people, and “Ishkotayo” to hydroelectric power, while other regions were commissioning new BC generating stations in parallel. The 270-kilometre-long transmission line is in one of the most isolated regions of Ontario, one that can only be accessed by plane, except for a few months in winter when ice roads are strong enough to drive on. The project went online in 2001, bringing reliable power to over 7,000 people who were previously underserved by the province’s energy providers. It also, somewhat controversially, enabled Ontario’s first diamond mine in Attawapiskat territory.

The future the First Nations created 25 years ago is blissfully quiet, now that the diesel generators are shut off. “When the power went on, you could hear the birds,” Patrick Chilton, the CEO of Five Nations Energy, said with a smile. “Our communities were glowing.”

Power, politics and money: Five Nations Energy needed government, banks and builders on board
Chilton took over in 2013 after the former CEO, his brother Ed, passed away. “This was all his idea,” Chilton told The Narwhal in a conversation over Zoom from his office in Timmins, Ont. The company’s story has never been told before in full, he said, because he felt “vulnerable” to the forces that fought against Omushkego Ishkotayo or didn’t understand it, a dynamic underscored by Canada’s looming power problem reporting in recent years. 

The success of Five Nations Energy is a tale of unwavering determination and imagination, Chilton said, and it started with his older brother. “Ed was the first person who believed a transmission line was possible,” he said.

In a Timmins Daily Press death notice published July 2, 2013, Ed Chilton is described as having “a quiet but profound impact on the establishment of agreements and enterprises benefitting First Nations peoples and their lands.” Chilton doesn’t describe him that way, exactly. 

“If you knew my brother, he was very stubborn,” he said. A certified engineering technologist, Ed was a visionary whose whole life was defined by the transmission line. He was the first to approach the chiefs with the idea, the first to reach out to energy companies and government officials and the one who persuaded thousands of people in remote, underserved communities that it was possible to bring power to their region.

After that 1996 meeting of Nishnawbe Aski Nation, there came a four-year-long effort to convince the rest of Ontario, and the country, the project was possible and financially viable. The chiefs of the five First Nations took their idea to the halls of power: Queen’s Park, Parliament Hill and the provincial power distributor Hydro One (then Ontario Hydro). 

“All of them said no,” Chilton said. “They saw it as near to impossible — the idea that you could build a transmission line in the ‘swamp,’ as they called it.” The Five Nations Energy team kept a document at the time tracking how many times they heard no; it topped out at 37. 

One of the worst times was in 1998, at a meeting on the 19th floor of the Ontario Hydro building in the heart of downtown Toronto. There, despite all their preparation and planning, a senior member of the Ontario Hydro team told Chilton, Martin and other chiefs “you’ll build that line over my dead body,” Chilton recalled. 

At the time, Chilton said, Ontario Hydro was refusing to cooperate: unwilling to let go of its monopoly over transmission lines, but also saying it was unable to connect new houses in the First Nations to diesel generators it said were at maximum capacity. (Ontario Hydro no longer exists; Hydro One declined to comment.)

“There’s always naysayers no matter what you’re doing,” Martin said. “What we were doing had never been done before. So of course people were telling us how we had never managed something of this size or a budget of this size.” 

“[Our people] basically told them to blow it up your ass. We can do it,” Chilton said.

So the chiefs of the five nations did something they’d never done before: they went to all of the big banks and many, many charitable foundations trying to get the money, a big ask for a project of this scale, in this location. Without outside support, their pitch was that they’d build it themselves.

This was the hardest part of the process, said Lawrence Martin, the former Grand Chief of Mushkegowuk Tribal Council and a member of the Five Nations Energy board. “We didn’t know how to finance something like this, to get loans,” he told The Narwhal. “That was the toughest task for all of us to achieve.”

Eventually, they got nearly $50 million in funding from a series of financial organizations including the Bank of Montreal, Pacific and Western Capital, the Northern Ontario Heritage Fund Corporation (an Ontario government agency) and the engineering and construction company SNC Lavalin, which did an assessment of the area and deemed the project viable. 

And in 1999, Ed Chilton, other members of the Chilton family and the chiefs were able to secure an agreement with Ontario Hydro that would allow them to buy electricity from the province and sell it to their communities. 

Related News

• Electricity Forum News

• Power Generation News

Hedonistic Sustainability turns Copenhagen's ARC waste-to-energy plant into a public playground, blending ski slope, climbing wall, and trails with carbon-neutral heating, renewables, circular economy design, and green growth for climate action and liveability.

Key Points

A design approach fusing public recreation with clean-energy infrastructure to drive carbon-neutral, livable urban growth.

✅ Waste-to-energy plant doubles as recreation hub

✅ Supports carbon-neutral heating and renewables

✅ Stakeholder-driven, scalable urban climate model

“We call it hedonistic sustainability,” says Jacob Simonsen of the decision to put an artificial ski slope on the roof of the £485m Amager Resource Centre (Arc), Copenhagen’s cutting-edge new waste-to-energy power plant that feeds the city’s district heating network as well. “It’s not just good for the environment, it’s good for life.”

Skiing is just one of the activities that Simonsen, Arc’s chief executive, and Bjarke Ingels, its lead architect, hope will enhance the latest jewel in Copenhagen’s sustainability crown. The incinerator building also incorporates hiking and running trails, a street fitness gym and the world’s highest outdoor climbing wall, an 85-metre “natural mountain” complete with overhangs that rises the full height of the main structure.

In Copenhagen, green transformation goes hand-in-hand with job creation, a growing economy and a better quality of life

Frank Jensen, lord mayor

It’s all part of Copenhagen’s plan to be net carbon-neutral by 2025. Even now, after a summer that saw wildfires ravagethe Arctic Circle and ice sheets in Greenland suffer near-record levels of melt, the goal seems ambitious. In 2009, when the project was formulated, it was positively revolutionary.

“A green, smart, carbon-neutral city,” declared the cover of the climate action plan, aligning with a broader electric planet vision, before detailing the scale of the challenge: 100 new wind turbines; a 20% reduction in both heat and commercial electricity consumption; 75% of all journeys to be by bike, on foot, or by public transport; the biogas-ification of all organic waste; 60,000 sq metres of new solar panels; and 100% of the city’s heating requirements to be met by renewables.

Radical and far-reaching, the scheme dared to rethink the very infrastructure underpinning the city. There’s still not a climate project anywhere else in the world that comes close, even as leaders elsewhere champion a fully renewable grid by 2030.

And, so far, it’s working. CO2 emissions have been reduced by 42% since 2005, and while challenges around mobility and energy consumption remain (new technologies such as better batteries and carbon capture are being implemented, and global calls for clean electricity investment grow), the city says it is on track to achieve its ultimate goal.

More significant still is that Copenhagen has achieved this while continuing to grow in traditional economic terms. Even as some commentators insist that nothing short of a total rethink of free-market economics and corporate structures is required to stave off global catastrophe, the Danish capital’s carbon transformation has happened alongside a 25% growth in its economy over two decades. Copenhagen’s experience will be a model for other world cities as the global energy transition unfolds.

The sentiment that lies behind Arc’s conception as a multi-use public good – “hedonistic sustainability” – is echoed by Bo Asmus Kjeldgaard, former mayor of Copenhagen for the environment and the man originally tasked, back in 2010, with making the plan a reality.

“We combined life quality with sustainability and called it ‘liveability’,” says Kjeldgaard, now CEO of his own climate adaptation company, Greenovation. “We succeeded in building a good narrative around this, one that everybody could believe in.”

The idea was first floated in the late 1990s, when the newly elected Kjeldgaard had a vision of Copenhagen as the environmental capital of Europe. His enthusiasm ran into political intransigence, however, and despite some success, a lack of budget meant most of his work became “just another branding exercise – it was greenwashing”.

We’re such a rich country – change should be easy for us

Claus Nielsen, furniture maker and designer

But after stints as mayor of family and the labour market, and children and young people, he ended up back at environment in 2010 with renewed determination and, crucially, a broader mandate from the city council. “I said: ‘This time, we have to do it right,’” he recalls, “so we made detailed, concrete plans for every area, set the carbon target, and demanded the money and the manpower to make it a reality.”

He brought on board more than 200 stakeholders, from businesses to academia to citizen representatives, and helped them develop 22 specific business plans and 65 separate projects. So far the plan appears on track: there has been a 15% reduction in heat consumption, 66% of all trips in the city are now by bike, on foot or public transport, and 51% of heat and power comes from renewable electricity sources.

The onus placed on ordinary Copenhageners to walk and cycle more, pay higher taxes (especially on cars) and put up with the inconvenience of infrastructure construction has generally been met with understanding and good grace. And while some people remain critical of the fact that Copenhagen airport is not factored into the CO2 calculations – it lies beyond the city’s boundaries – and grumble about precise definitions and formulae, dissent has been rare.

This relative lack of nimbyism and carping about change can, says Frank Jensen, the city’s lord mayor, be traced to longstanding political traditions.

“Caring for the environment and taking responsibility for society in general has been an integral part of the upbringing of many Danes,” he says. “Moreover, there is a general awareness that climate change now calls for immediate, ambitious and collective action.” A 2018 survey by Concito, a thinktank, found that such action was a top priority for voters.

Jensen is keen to stress the cooperative nature of the plan and says “our visions have to be grounded in the everyday lives of people to be politically feasible”. Indeed, involving so many stakeholders, and allowing them to actively help shape both the ends and the means, has been key to the plan’s success so far and the continued goodwill it enjoys. “It’s so important to note that we [the authorities] cannot do this alone,” says Jørgen Abildgaard, Copenhagen’s executive climate programme director.

Many businesses around the world have typically been reluctant to embrace sustainability when a dip in profits or inconvenience might be the result, but not in Copenhagen. Martin Manthorpe, director of strategy, business development and public affairs at NCC, one of Scandinavia’s largest construction and industrial groups, was brought in early on by Abildgaard to represent industry on the municipality’s climate panel, and to facilitate discussions with the wider business community. He thinks there are several reasons why.

“The Danes have a trading mindset, meaning ‘What will I have to sell tomorrow?’ is just as important as ‘What am I producing today?’” he says. “Also, many big Danish companies are still ultimately family-owned, so the culture leans more towards long-term thinking.”

It is, he says, natural for business to be concerned with issues around sustainability and be willing to endure short-term pain: “To do responsible, long-term business, you need to see yourself as part of the larger puzzle that is called ‘society’.”

Furthermore, in Denmark climate change denial is given extremely short shrift. “We believe in the science,” says Anders Haugaard, a local entrepreneur. “Why wouldn’t you? We’re told sustainability brings only benefits and we’ve got no reason to be suspicious.”

“No one would dare argue against the environment,” says his friend Claus Nielsen, a furniture maker and designer. “We’re such a rich country – change should be easy for us.” Nielsen talks about how enlightened his kids are – “my 11-year-old daughter is now a flexitarian ” – and says that nowadays he mainly buys organic; Haugaard doesn’t see a problem with getting rid of petrol cars (the whole country is aiming to be fossil fuel-free by 2050 as the EU electricity use by 2050 is expected to double).

Above all, there’s a belief that sustainability need not make the city poorer: that innovation and “green growth” can be lucrative in and of themselves. “In Copenhagen, green transformation goes hand-in-hand with job creation, a growing economy and a better quality of life,” says Jensen. “We have also shown that it’s possible to combine this transition with economic growth and market opportunities for businesses, and I think that other countries can learn from our example.”

Besides, as Jensen notes, there is little alternative, and even less time: “National states have failed to take enough responsibility, but cities have the power and will to create concrete solutions. We need to start accelerating their implementation – we need to act now.”

Related News

• Electricity Forum News

• Climate Change News

Ukraine Electricity Imports surge to record levels as EU neighbors bolster grid stability amid Russian strikes, supporting energy security, preventing blackouts, and straining cross-border transmission capacity while Ukraine rebuilds damaged infrastructure and diversifies with renewables.

Key Points

Emergency EU power purchases stabilizing Ukraine’s grid after war damage.

✅ Record 19,000 MWh per day from EU interconnectors

✅ Supports grid stability and blackout prevention

✅ Cost and transmission upgrades challenge sustainability

Russia's ongoing war in Ukraine has extended far beyond the battlefield, with critical infrastructure becoming a target. Ukraine's once-robust energy system has sustained significant damage amid energy ceasefire violations and Russian missile and drone strikes. To cope with these disruptions and maintain power supplies for Ukrainian citizens, the country is turning to record-breaking electricity imports from neighboring European nations.

Prior to the war, Ukraine enjoyed a self-sufficient energy sector, even exporting electricity to neighboring countries. However, targeted attacks on power plants and transmission lines have crippled generation capacity. The situation is particularly dire in eastern and southern Ukraine, where ongoing fighting has caused extensive damage.

Faced with this energy crisis, Ukraine is looking to Europe for a lifeline. The country's energy ministry has announced plans to import a staggering amount of electricity – exceeding 19,000 megawatt-hours (MWh) per day – to prepare for winter and stabilize supplies. This surpasses the previous record set in March 2024 and represents a significant increase in Ukraine's reliance on external power sources.

Several European nations are stepping up to support Ukraine. Countries like Poland, Slovakia, Romania, Hungary, which maintains quiet energy ties with Russia today, and Moldova have agreed to provide emergency electricity supplies. These imports will help stabilize Ukraine's power grid and prevent widespread blackouts, especially during peak consumption hours.

The reliance on imports, however, presents its own set of challenges. Firstly, the sheer volume of electricity needed puts a strain on the capacity of neighboring grids. Upgrading and expanding transmission infrastructure will be crucial to ensure a smooth flow of electricity. Secondly, the cost of imported electricity can be higher than domestically generated power amid price hikes and instability globally, placing additional pressure on Ukraine's already strained finances.

Beyond these immediate concerns, the long-term implications of relying on external energy sources need to be considered. Ukraine's long-term goal is to rebuild its own energy infrastructure and regain energy independence. International assistance, including energy security support measures, will be crucial in this endeavor. Financial aid and technical expertise can help Ukraine repair damaged power plants, diversify its energy mix through further investment in renewables, and develop more resilient grid infrastructure.

The war in Ukraine has underscored the importance of energy security. A nation's dependence on a single source of energy, be it domestic or foreign, leaves it vulnerable to disruption, as others consider national security and fossil fuels in their own policies. For Ukraine, diversification and building a more resilient energy infrastructure are key takeaways from this crisis.

The international community also has a role to play. Supporting Ukraine's energy sector not only helps the nation weather the current crisis but also strengthens European energy security as a whole, where concerns over Europe's energy nightmare remain pronounced. A stable and independent Ukraine, less reliant on Russian energy, contributes to a more secure and prosperous Europe.

As the war in Ukraine continues, the battle for energy security rages on. While the immediate focus is on keeping the lights on through imports, the long-term goal for Ukraine is to rebuild a stronger, more resilient energy sector that can power the nation's future. The international community's support will be crucial in helping Ukraine achieve this goal.

Related News

• Electricity Forum News

• Energy Policy News

U.S. Solar Generation 2017 surpassed biomass, delivering 77 million MWh versus 64 million MWh, trailing only hydro and wind; driven by PV expansion, capacity additions, and utility-scale and small-scale growth, per EIA.

Key Points

It was the year U.S. solar electricity exceeded biomass, hitting 77 million MWh and trailing only hydro and wind.

✅ Solar: 77 million MWh; Biomass: 64 million MWh (2017, EIA)

✅ PV expansion; late-year capacity additions dampen annual generation

✅ Hydro: 300 and wind: 254 million MWh; solar thermal ~3 million MWh

Electricity generation from solar resources in the United States reached 77 million megawatthours (MWh) in 2017, surpassing for the first time annual generation from biomass resources, which generated 64 million MWh in 2017. Among renewable sources, only hydro and wind generated more electricity in 2017, at 300 million MWh and 254 million MWh, respectively. Biomass generating capacity has remained relatively unchanged in recent years, while solar generating capacity has consistently grown.

Annual growth in solar generation often lags annual capacity additions because generating capacity tends to be added late in the year. For example, in 2016, 29% of total utility-scale solar generating capacity additions occurred in December, leaving few days for an installed project to contribute to total annual generation despite being counted in annual generating capacity additions. In 2017, December solar additions accounted for 21% of the annual total. Overall, solar technologies operate at lower annual capacity factors and experience more seasonal variation than biomass technologies.

Biomass electricity generation comes from multiple fuel sources, such as wood solids (68% of total biomass electricity generation in 2017), landfill gas (17%), municipal solid waste (11%), and other biogenic and nonbiogenic materials (4%).These shares of biomass generation have remained relatively constant in recent years, even as renewables' rise in 2020 across the grid.

Solar can be divided into three types: solar thermal, which converts sunlight to steam to produce power; large-scale solar photovoltaic (PV), which uses PV cells to directly produce electricity from sunlight; and small-scale solar, which are PV installations of 1 megawatt or smaller. Generation from solar thermal sources has remained relatively flat in recent years, at about 3 million MWh, even as renewables surpassed coal in 2022 nationwide. The most recent addition of solar thermal capacity was the Crescent Dunes Solar Energy plant installed in Nevada in 2015, and currently no solar thermal generators are under construction in the United States.

Solar photovoltaic systems, however, have consistently grown in recent years, as indicated by 2022 U.S. solar growth metrics across the sector. In 2014, large-scale solar PV systems generated 15 million MWh, and small-scale PV systems generated 11 million MWh. By 2017, annual electricity from those sources had increased to 50 million MWh and 24 million MWh, respectively, with projections that solar could reach 20% by 2050 in the U.S. mix. By the end of 2018, EIA expects an additional 5,067 MW of large-scale PV to come online, according to EIA’s Preliminary Monthly Electric Generator Inventory, with solar and storage momentum expected to accelerate. Information about planned small-scale PV systems (one megawatt and below) is not collected in that survey.

Related News

• Electricity Forum News

• Renewable Energy News

France Nuclear Heatwave Output Restrictions signal reduced reactor capacity along the Rhone River, as EDF curbs output to meet cooling-water rules, balance the grid, integrate solar peaks, and limit impacts on power prices.

Key Points

EDF limits reactor output during heat to protect rivers and keep the grid stable under cooling-water rules.

✅ Cuts likely at midday/weekends when solar peaks

✅ Bugey, Saint Alban maintain minimum grid output

✅ France net exporter; price impact expected small

The high temperature warning has come early this year but will affect fewer nuclear power plants, amid a broader France-Germany nuclear dispute over atomic power policy that shapes regional energy flows.

High temperatures could halve nuclear power production at plants along France's Rhone River this week, as European power hits records during extreme heat. 

Output restrictions are expected at two nuclear plants in eastern France due to high temperature forecasts, nuclear operator EDF said, which may limit energy output during heatwaves. It comes several days ahead of a similar warning that was made last year but will affect fewer plants.

The hot weather is likely to halve the available power supply from the 3.6 GW Bugey plant from 13 July and the 2.6 GW Saint Alban plant from 16 July, the operator said.

However, production will be at least 1.8 GW at Bugey and 1.3 GW at Saint Alban to meet grid requirements, and may change according to grid needs, the operator said.

Kpler analyst Emeric de Vigan said the restrictions were likely to have little effect on output in practice. Cuts are likely only at the weekend or midday when solar output was at its peak so the impact on power prices would be slim.

During recent lockdowns, power demand held firm in Europe, offering context for current price dynamics.

He said the situation would need monitoring in the coming weeks, however, noting it was unusually early in the summer for such restrictions to be imposed.

Water temperatures at the Bugey plant already eclipsed the initial threshold for restrictions on 9 July, underscoring France's outage risks under heat-driven constraints. They are currently forecast to peak next week and then drop again, Refinitiv data showed.

"France is currently net exporting large amounts of power – single nuclear units' supply restrictions will not have the same effect as last year," Refinitiv analyst Nathalie Gerl said.

The Garonne River in southern France has the highest potential for critical levels of warming, but its Golfech plant is currently offline for maintenance until mid-August, the data showed, highlighting how Europe is losing nuclear power during critical periods.

"(The restrictions were) to be expected and it will probably occur more often," Greenpeace campaigner Roger Spautz said.

"The authorities must stick to existing regulations for water discharges. Otherwise, the ecosystems will be even more affected," he added.

Related News

• Electricity Forum News

• Power Generation News

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.

Related News

• Electricity Forum News

• Power Generation News