PNNL project gives consumers a say in saving energy

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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Switch-On Project Electric Trucks accelerate California freight decarbonization, deploying Volvo VNR Electric rigs with high-capacity charging infrastructure, zero-emissions operations, and connected safety features to cut greenhouse gases and improve urban air quality.

Key Points

A California program deploying Volvo VNR Electric trucks and charging to decarbonize freight and improve air quality.

✅ 70 Volvo VNR Electric trucks for regional logistics

✅ Strategic high-capacity charging for heavy-duty fleets

✅ Lower TCO via fuel savings and reduced maintenance

In a significant step toward sustainable transportation, the Switch-On project is bringing 70 Volvo VNR Electric trucks to California. This initiative aims to bolster the state's efforts to reduce emissions and transition to greener logistics solutions. The arrival of these electric vehicles marks an important milestone in California's commitment to combating climate change and improving air quality.

The Switch-On Project: Overview and Goals

The Switch-On project is a collaborative effort designed to enhance electric truck adoption in California. It focuses on developing the necessary infrastructure and technology to support electric vehicles (EVs) in the freight and logistics sectors, building on recent nonprofit investments at California ports. The project not only seeks to increase the availability of electric trucks but also aims to demonstrate their effectiveness in real-world applications.

California has set ambitious goals for reducing greenhouse gas emissions, particularly from the transportation sector, which is one of the largest contributors to air pollution. By introducing electric trucks into freight operations, the state aims to significantly cut emissions, improve public health, and pave the way for a more sustainable future.

The Volvo VNR Electric Trucks

The Volvo VNR Electric trucks are specifically designed for regional distribution and urban transport, aligning with Volvo's broader electric lineup as the company expands offerings, making them ideal for the needs of California’s freight industry. With a range of approximately 250 miles on a single charge, these trucks can efficiently handle most regional routes. Equipped with advanced technology, including regenerative braking and connectivity features, the VNR Electric models enhance operational efficiency and safety.

These trucks not only provide a cleaner alternative to traditional diesel vehicles but also promise lower operational costs over time. With reduced fuel expenses and lower maintenance needs, and emerging vehicle-to-grid pilots that can create new value streams, businesses can benefit from significant savings while contributing to environmental sustainability.

Infrastructure Development

A crucial aspect of the Switch-On project is the development of charging infrastructure to support the new fleet of electric trucks. The project partners are working on installing high-capacity charging stations strategically located throughout California while addressing utility planning challenges that large fleets will pose to the power system. This infrastructure is essential to ensure that electric trucks can be charged efficiently, minimizing downtime and maximizing productivity.

The charging stations are designed to accommodate the specific needs of heavy-duty vehicles, and corridor models like BC's Electric Highway provide useful precedents for network design, allowing for rapid charging that aligns with operational schedules. This development not only supports the new fleet but also encourages other logistics companies to consider electric trucks as a viable option for their operations.

Benefits to California

The introduction of 70 Volvo VNR Electric trucks will have several positive impacts on California. Firstly, it will significantly reduce greenhouse gas emissions from the freight sector, contributing to the state’s ambitious climate goals even as grid expansion will be needed to support widespread electrification across sectors. The transition to electric trucks is expected to improve air quality, particularly in urban areas that struggle with high pollution levels.

Moreover, the project serves as a model for other regions considering similar initiatives. By showcasing the practicality and benefits of electric trucks, California hopes to inspire widespread adoption across the nation. As the market for electric vehicles continues to grow, this project can play a pivotal role in accelerating the transition to sustainable transportation solutions.

Industry and Community Reactions

The arrival of the Volvo VNR Electric trucks has been met with enthusiasm from both industry stakeholders and community members. Logistics companies are excited about the opportunity to reduce their carbon footprints and operational costs. Meanwhile, environmental advocates applaud the project as a crucial step toward cleaner air and healthier communities.

California’s commitment to sustainable transportation has positioned it as a leader in the shift to electric vehicles amid an ongoing biofuels vs. EVs debate over the best path forward, setting an example for other states and countries.

Conclusion

The Switch-On project represents a major advancement in California's efforts to transition to electric transportation. With the deployment of 70 Volvo VNR Electric trucks, the state is not only taking a significant step toward reducing emissions but also demonstrating the feasibility of electric logistics solutions.

As infrastructure develops and more electric trucks hit the roads, California is paving the way for a greener, more sustainable future in transportation. The success of this project could have far-reaching implications, influencing policies and practices in the broader freight industry and beyond.

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Vietnam Offshore Wind Regulations expand coastal zones to six nautical miles, remove water depth limits, streamline permits, and boost investment, grid integration, and renewable energy capacity across deeper offshore wind resource areas.

Key Points

Policies extend sites to six nautical miles, scrap depth limits, and speed permits to scale offshore wind.

✅ Extends offshore zones to six nautical miles from shore

✅ Removes water depth limits to access stronger winds

✅ Streamlines permits, aiding grid integration and finance

Vietnam has recently redefined its regulations for offshore wind power projects, marking a significant development in the country's renewable energy ambitions. This strategic shift aims to streamline regulatory processes, enhance project feasibility, and accelerate the deployment of offshore wind energy in Vietnam's coastal regions, amid a trillion-dollar offshore wind market globally.

Regulatory Changes

The Vietnamese government has adjusted offshore wind power regulations by extending the allowable distance from shore for wind farms to six nautical miles (approximately 11 kilometers), a move that aligns with evolving global practices such as Canada's offshore wind plan announced recently by regulators. This expansion from previous limits aims to unlock new areas for development and maximize the utilization of Vietnam's vast offshore wind potential.

Scrapping Depth Restrictions

In addition to extending offshore boundaries, Vietnam has removed restrictions on water depth for offshore wind projects. This revision allows developers to explore deeper waters, where wind resources may be more abundant, thereby diversifying project opportunities and optimizing energy generation capacity.

Strategic Implications

The redefined regulations are expected to stimulate investment in Vietnam's renewable energy sector, attracting domestic and international stakeholders keen on capitalizing on the country's favorable wind resources, with World Bank support for wind underscoring the growing pipeline in developing markets. The move aligns with Vietnam's broader energy diversification goals and commitment to reducing reliance on fossil fuels.

Economic Opportunities

The expansion of offshore wind development zones creates economic opportunities across the value chain, from project planning and construction to operation and maintenance. The influx of investments is anticipated to spur job creation, technology transfer, and infrastructure development in coastal communities, as industry groups like Marine Renewables Canada shift toward offshore wind specialization.

Environmental and Energy Security Benefits

Harnessing offshore wind power contributes to Vietnam's efforts to mitigate greenhouse gas emissions and combat climate change. By integrating renewable energy sources into its energy mix, Vietnam enhances energy security, as seen in the UK offshore wind expansion, reduces dependency on imported fuels, and promotes sustainable economic growth.

Challenges and Considerations

Despite the promising outlook, offshore wind projects face challenges such as technical complexities, environmental impact assessments, and grid integration, as well as exposure to policy risk exemplified by U.S. opposition to offshore wind debates.

Future Outlook

Looking ahead, Vietnam's redefined offshore wind regulations position the country as a key player in the global renewable energy transition, a trend reinforced by progress in offshore wind in Europe elsewhere. Continued policy support, investment facilitation, and technological innovation will be critical in unlocking the full potential of offshore wind power and achieving Vietnam's renewable energy targets.

Conclusion

Vietnam's revision of offshore wind power regulations reflects a proactive approach to advancing renewable energy development and fostering a conducive investment environment. By expanding development zones and eliminating depth restrictions, Vietnam sets the stage for accelerated growth in offshore wind capacity, contributing to both economic prosperity and environmental stewardship. As stakeholders seize opportunities in this evolving landscape, collaboration and innovation will drive Vietnam towards a sustainable energy future powered by offshore wind.

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US SF6 Emissions Decline as NOAA analysis and EPA mitigation show progress, with atmospheric measurements and Greenhouse Gas Reporting verifying reductions from the electric power grid; sulfur hexafluoride's extreme global warming potential underscores inventory improvements.

Key Points

A documented drop in US sulfur hexafluoride emissions, confirmed by NOAA atmospheric data and EPA reporting reforms.

✅ NOAA towers and aircraft show 2007-2018 decline

✅ EPA reporting and utility mitigation narrowed inventory gaps

✅ Winter leaks and servicing signal further reduction options

A new NOAA analysis shows U.S. emissions of the super-potent greenhouse gas sulfur hexafluoride (SF6) have declined between 2007-2018, likely due to successful mitigation efforts by the Environmental Protection Agency (EPA) and the electric power industry, with attention to SF6 in the power industry across global markets. 

At the same time, significant disparities that existed previously between NOAA’s estimates, which are based on atmospheric measurements, and EPA’s estimates, which are based on a combination of reported emissions and industrial activity, have narrowed following the establishment of the EPA's Greenhouse Gas Reporting Program. The findings, published in the journal Atmospheric Chemistry and Physics, also suggest how additional emissions reductions might be achieved. 

SF6 is most commonly used as an electrical insulator in high-voltage equipment that transmits and distributes electricity, and its emissions have been increasing worldwide as electric power systems expand, even as regions hit milestones like California clean energy surpluses in recent years. Smaller amounts of SF6 are used in semiconductor manufacturing and in magnesium production. 

SF6 traps 25,000 times more heat than carbon dioxide over a 100-year time scale for equal amounts of emissions, and while CO2 emissions flatlined in 2019 globally, that comparison underscores the potency of SF6. That means a relatively small amount of the gas can have a significant impact on climate warming. Because of its extremely large global warming potential and long atmospheric lifetime, SF6 emissions will influence Earth’s climate for thousands of years.

In this study, researchers from NOAA’s Global Monitoring Laboratory, as record greenhouse gas concentrations drive demand for better data, working with colleagues at EPA, CIRES, and the University of Maryland, estimated U.S. SF6 emissions for the first time from atmospheric measurements collected at a network of tall towers and aircraft in NOAA’s Global Greenhouse Gas Reference Network. The researchers provided an estimate of SF6 emissions independent from the EPA’s estimate, which is based on reported SF6 emissions for some industrial facilities and on estimated SF6 emissions for others.

“We observed differences between our atmospheric estimates and the EPA’s activity-based estimates,” said study lead author Lei Hu, a Global Monitoring Laboratory researcher who was a CIRES scientist at the time of the study. “But by closely collaborating with the EPA, we were able to identify processes potentially responsible for a significant portion of this difference, highlighting ways to improve emission inventories and suggesting additional emission mitigation opportunities, such as forthcoming EPA carbon capture rules for power plants, in the future.” 

In the 1990s, the EPA launched voluntary partnerships with the electric power, where power-sector carbon emissions are falling as generation shifts, magnesium, and semiconductor industries to reduce SF6 emissions after the United States recognized that its emissions were significant. In 2011, large SF6 -emitting facilities were required to begin tracking and reporting their emissions under the EPA Greenhouse Gas Reporting Program. 

Hu and her colleagues documented a decline of about 60 percent in U.S. SF6 emissions between 2007-2018, amid global declines in coal-fired power in some years—equivalent to a reduction of between 6 and 20 million metric tons of CO2 emissions during that time period—likely due in part to the voluntary emission reduction partnerships and the EPA reporting requirement. A more modest declining trend has also been reported in the EPA’s national inventories submitted annually under the United Nations Framework Convention on Climate Change. 

Examining the differences between the NOAA and EPA independent estimates, the researchers found that the EPA’s past inventory analyses likely underestimated SF6 emissions from electrical power transmission and distribution facilities, and from a single SF6 production plant in Illinois. According to Hu, the research collaboration has likely improved the accuracy of the EPA inventories. The 2023 draft of the EPA’s U.S. Greenhouse Gas Emissions and Sinks: 1990-2021 used the results of this study to support revisions to its estimates of SF6 emissions from electrical transmission and distribution. 

The collaboration may also lead to improvements in the atmosphere-based estimates, helping NOAA identify how to expand or rework its network to better capture emitting industries or areas with significant emissions, according to Steve Montzka, senior scientist at GML and one of the paper’s authors.

Hu and her colleagues also found a seasonal variation in SF6 emissions from the atmosphere-based analysis, with higher emissions in winter than in summer. Industry representatives identified increased servicing of electrical power equipment in the southern states and leakage from aging brittle sealing materials in the equipment in northern states during winter as likely explanations for the enhanced wintertime emissions—findings that suggest opportunities for further emissions reductions.

“This is a great example of the future of greenhouse gas emission tracking, where inventory compilers and atmospheric scientists work together to better understand emissions and shed light on ways to further reduce them,” said Montzka.

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Vehicle-to-Grid (V2G) enables EV batteries to provide grid balancing, flexibility, and demand response, integrating renewables with bidirectional charging, reducing peaker plant reliance, and unlocking distributed energy storage from millions of connected electric vehicles.

Key Points

Vehicle-to-Grid (V2G) lets EVs export power via bidirectional charging to balance grids and support renewables.

✅ Turns parked EVs into distributed energy storage assets

✅ Delivers balancing services and demand response to the grid

✅ Cuts peaker plant use and supports renewable integration

“There are already many Gigawatt-hours of batteries on wheels”, which could be used to provide balance and flexibility to electrical grids, if the “ultimate potential” of vehicle-to-grid (V2G) technology could be harnessed.

That’s according to a panel of experts and stakeholders convened by our sister site Current±, which covers the business models and technologies inherent to the low carbon transition to decentralised and clean energy. Focusing mainly on the UK grid but opening up the conversation to other territories and the technologies themselves, representatives including distribution network operator (DNO) Northern Powergrid’s policy and markets director and Nissan Europe’s director of energy services debated the challenges, benefits and that aforementioned ultimate potential.

Decarbonisation of energy systems and of transport go hand-in-hand amid grid challenges from rising EV uptake, with vehicle fuel currently responsible for more emissions than electricity used for energy elsewhere, as Ian Cameron, head of innovation at DNO UK Power Networks says in the Q&A article.

“Furthermore, V2G technology will further help decarbonisation by replacing polluting power plants that back up the electrical grid,” Marc Trahand from EV software company Nuvve Corporation added, pointing to California grid stability initiatives as a leading example.

While the panel states that there will still be a place for standalone utility-scale energy storage systems, various speakers highlighted that there are over 20GWh of so-called ‘batteries on wheels’ in the US, capable of powering buildings as needed, and up to 10 million EVs forecast for Britain’s roads by 2030.

“…it therefore doesn’t make sense to keep building expensive standalone battery farms when you have all this capacity on wheels that just needs to be plugged into bidirectional chargers,” Trahand said.

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Cannes Film Festival Power Outage disrupts Alpes-Maritimes as an electrical substation fire and a fallen high-voltage line trigger blackouts; arson probe launched, grid resilience tested, traffic and trains snarled, Palais des Festivals on backup power.

Key Points

A May 24, 2025 blackout in Cannes disrupting events, under arson probe, exposing grid risks across Alpes-Maritimes.

✅ Substation fire and fallen high-voltage line triggered blackouts

✅ Palais des Festivals ran on independent backup power

✅ Authorities probe suspected arson; security measures reviewed

A significant power outage on May 24, 2025, disrupted the final day of the Cannes Film Festival in southeastern France. The blackout, which affected approximately 160,000 households in the Alpes-Maritimes region, including the city of Cannes, occurred just hours before the highly anticipated Palme d'Or ceremony. French authorities are investigating the possibility that the outage was caused by arson.

Details of the Outage

The power disruption began early on Saturday morning with a fire at an electrical substation near Cannes. This incident weakened the local power grid. Shortly thereafter, a high-voltage line fell at another location, further exacerbating the situation. The combined events led to widespread power outages, affecting not only the festival but also local businesses, traffic systems, and public transportation, echoing Heathrow Airport outage warnings raised days before a separate disruption. Traffic lights in parts of Cannes and the nearby city of Antibes stopped working, leading to traffic jams and confusion in city centers. Most shops along the Croisette remained closed, and local food kiosks were only accepting cash. Train service in Cannes was also disrupted. 

Impact on the Festival

Despite the challenges, festival organizers managed to keep the main venue, the Palais des Festivals, operational by switching to an independent power supply. They confirmed that all scheduled events and screenings, including the Closing Ceremony, would proceed as planned, a reminder of how grid operators sometimes avoid rolling blackouts to keep essential services running. The power was restored around 3 p.m. local time, just hours before the ceremony, allowing music to resume and the event to continue without further incident.

Investigations and Suspected Arson

French authorities, including the national gendarmerie, are investigating the possibility that the power outage was the result of arson, aligning with grid attack warnings issued by intelligence services. The prefect for the Alpes-Maritimes region, Laurent Hottiaux, condemned the "serious acts of damage to electrical infrastructures" and stated that all resources are mobilized to identify, track down, arrest, and bring to justice the perpetrators of these acts.

While investigations are ongoing, no official conclusions have been drawn regarding the cause of the outage. Authorities are working to determine whether the incidents were isolated or part of a coordinated effort, a question that also arises when utilities implement PG&E wildfire shutoffs to prevent cascading damage.

Broader Implications

The power outage at the Cannes Film Festival underscores the vulnerability of critical infrastructure to potential acts of sabotage. While the immediate impact on the festival was mitigated, the incident raises concerns about the resilience of energy systems, especially during major public events, and amid severe weather like a B.C. bomb cyclone that leaves tens of thousands without power. It also highlights the importance of having contingency plans in place to ensure the continuity of essential services in the face of unexpected disruptions.

As investigations continue, authorities are urging the public to remain vigilant and report any suspicious activities, while planners also prepare for storm-driven outages that compound emergency response. The outcome of this investigation may have implications for future security measures at large-scale events and the protection of critical infrastructure.

While the Cannes Film Festival was able to proceed with its closing events, the power outage serves as a reminder of the potential threats to public safety, as seen when a Western Washington bomb cyclone left hundreds of thousands without power, and the importance of robust security measures to safeguard against such incidents.

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