IBM hopes new utility coalition can boost grid computing

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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Belarus Nuclear Power Infrastructure Review evaluates IAEA INIR Phase 3 readiness at Ostrovets NPP, VVER-1200 reactors, legal and regulatory framework, commissioning, safety, emergency preparedness, and energy diversification in a low-carbon program.

Key Points

An IAEA INIR Phase 3 assessment of Belarus readiness to commission and operate the Ostrovets NPP with VVER-1200 units.

✅ Reviews legal, regulatory, and institutional arrangements

✅ Confirms Phase 3 readiness for safe commissioning and operation

✅ Highlights good practices in peer reviews and emergency planning

An International Atomic Energy Agency (IAEA) team of experts today concluded a 12-day mission to Belarus to review its infrastructure development for a nuclear power programme. The Integrated Nuclear Infrastructure Review (INIR) was carried out at the invitation of the Government of Belarus.

Belarus, seeking to diversify its energy production with a reliable low-carbon source, and aware of the benefits of energy storage for grid flexibility, is building its first nuclear power plant (NPP) at the Ostrovets site, about 130 km north-west of the capital Minsk. The country has engaged with the Russian Federation to construct and commission two VVER-1200 pressurised water reactors at this site and expects the first unit to be connected to the grid this year.

The INIR mission reviewed the status of nuclear infrastructure development using the Phase 3 conditions of the IAEA’s Milestones Approach. The Ministry of Energy of Belarus hosted the mission.

The INIR team said Belarus is close to completing the required nuclear power infrastructure for starting the operation of its first NPP. The team made recommendations and suggestions aimed at assisting Belarus in making further progress in its readiness to commission and operate it, including planning for integration with variable renewables, as advances in new wind turbines are being deployed elsewhere to strengthen the overall energy mix.

“This mission marks an important step for Belarus in its preparations for the introduction of nuclear power,” said team leader Milko Kovachev, Head of the IAEA’s Nuclear Infrastructure Development Section. “We met well-prepared, motivated and competent professionals ready to openly discuss all infrastructure issues. The team saw a clear drive to meet the objectives of the programme and deliver benefits to the Belarusian people, such as supporting the country’s economic development, including growth in EV battery manufacturing sectors.”

The team comprised one expert from Algeria and two experts from the United Kingdom, as well as seven IAEA staff. It reviewed the status of 19 nuclear infrastructure issues using the IAEA evaluation methodology for Phase 3 of the Milestones Approach, noting that regional integration via an electricity highway can shape planning assumptions as well. It was the second INIR mission to Belarus, who hosted a mission covering Phases 1 and 2 in 2012.

Prior to the latest mission, Belarus prepared a Self-Evaluation Report covering all infrastructure issues and submitted the report and supporting documents to the IAEA.

The team highlighted areas where further actions would benefit Belarus, including the need to improve institutional arrangements and the legal and regulatory framework, drawing on international examples of streamlined licensing for advanced reactors to ensure a stable and predictable environment for the programme; and to finalize the remaining arrangements needed for sustainable operation of the nuclear power plant.

The team also identified good practices that would benefit other countries developing nuclear power in the areas of programme and project coordination, the use of independent peer reviews, cooperation with regulators from other countries, engagement with international stakeholders and emergency preparedness, and awareness of regional initiatives such as new electricity interconnectors that can enhance system resilience.

Mikhail Chudakov, IAEA Deputy Director General and Head of the Department of Nuclear Energy attended the Mission’s closing meeting. “Developing the infrastructure required for a nuclear power programme requires significant financial and human resources, and long lead times for preparation and the approval of major transmission projects that support clean power flows, and the construction activities,” he said. “Belarus has made commendable progress since the decision to launch a nuclear power programme 10 years ago.”

“Hosting the INIR mission, Belarus demonstrated its transparency and genuine interest to receive an objective professional assessment of the readiness of its nuclear power infrastructure for the commissioning of the country’s first nuclear power plant,” said Mikhail Mikhadyuk, Deputy Minister of Energy of the Republic of Belarus. ”The recommendations and suggestions we received will be an important guidance for our continuous efforts aimed at ensuring the highest level of safety and reliability of the Belarusian NPP."
 

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Nuclear Power for Net-Zero Grids anchors reliable baseload, integrating renewables with grid stability as solar, wind, and battery storage scale. Advanced reactors complement hydropower, curb natural gas reliance, and accelerate deep decarbonization of electricity systems.

Key Points

Uses nuclear baseload and advanced reactors to stabilize power grids and integrate higher shares of variable renewables.

✅ Provides firm, zero-carbon baseload for renewable-heavy grids

✅ Reduces natural gas dependence and peaker emissions

✅ Advanced reactors enhance safety, flexibility, and cost

Declining solar, wind, and battery technology costs are helping to grow the share of renewables in the world’s power mix to the point that governments are pledging net-zero emission electricity generation in two to three decades to fight global warming.

Yet, electricity grids will continue to require stable baseload to incorporate growing shares of renewable energy sources and ensure lights are on even when the sun doesn’t shine, or the wind doesn’t blow. Until battery technology evolves enough—and costs fall far enough—to allow massive storage and deployment of net-zero electricity to the grid, the systems will continue to need power from sources other than solar and wind.

And these will be natural gas and nuclear power, regardless of concerns about emissions from the fossil fuel natural gas and potential disasters at nuclear power facilities such as the ones in Chernobyl or Fukushima.

As natural gas is increasingly considered as just another fossil fuel, nuclear power generation provides carbon-free electricity to the countries that have it, even as debates over nuclear power’s outlook continue worldwide, and could be the key to ensuring a stable power grid capable of taking in growing shares of solar and wind power generation.

The United States, where nuclear energy currently provides more than half of the carbon-free electricity, is supporting the development of advanced nuclear reactors as part of the clean energy strategy.

But Europe, which has set a goal to reach carbon neutrality by 2050, could find itself with growing emissions from the power sector in a decade, as many nuclear reactors are slated for decommissioning and questions remain over whether its aging reactors can bridge the gap. The gap left by lost nuclear power is most easily filled by natural gas-powered electricity generation—and this, if it happens, could undermine the net-zero goals of the European Union (EU) and the bloc’s ambition to be a world leader in the fight against climate change.

U.S. Power Grid Will Need Nuclear For Net-Zero Emissions

A 2020 report from the University of California, Berkeley, said that rapidly declining solar, wind, and storage prices make it entirely feasible for the U.S. to meet 90 percent of its power needs from zero-emission energy sources by 2035 with zero increases in customer costs from today’s levels.

Still, natural gas-fired generation will be needed for 10 percent of America’s power needs. According to the report, in 2035 it would be possible that “during normal periods of generation and demand, wind, solar, and batteries provide 70% of annual generation, while hydropower and nuclear provide 20%.” Even with an exponential rise in renewable power generation, the U.S. grid will need nuclear power and hydropower to be stable with such a large share of solar and wind.

The U.S. Backs Advanced Nuclear Reactor Technology

The U.S. Department of Energy is funding programs of private companies under DOE’s new Advanced Reactor Demonstration Program (ARDP) to showcase next-gen nuclear designs for U.S. deployment.

“Taking leadership in advanced technology is so important to the country’s future because nuclear energy plays such a key role in our clean energy strategy,” U.S. Secretary of Energy Dan Brouillette said at the end of December when DOE announced it was financially backing five teams to develop and demonstrate advanced nuclear reactors in the United States.

“All of these projects will put the U.S. on an accelerated timeline to domestically and globally deploy advanced nuclear reactors that will enhance safety and be affordable to construct and operate,” Secretary Brouillette said.

According to Washington DC-based Nuclear Energy Institute (NEI), a policy organization of the nuclear technologies industry, nuclear energy provides nearly 55 percent of America’s carbon-free electricity. That is more than 2.5 times the amount generated by hydropower, nearly 3 times the amount generated by wind, and more than 12 times the amount generated by solar. Nuclear energy can help the United States to get to the deep carbonization needed to hit climate goals.

Europe Could See Rising Emissions Without Nuclear Power

While the United States is doubling down on efforts to develop advanced and cheaper nuclear reactors, including microreactors and such with new types of technology, Europe could be headed to growing emissions from the electricity sector as nuclear power facilities are scheduled to be decommissioned over the next decade and Europe is losing nuclear power just when it really needs energy, according to a Reuters analysis from last month.

In many cases, it will be natural gas that will come to the rescue to power grids to ensure grid stability and enough capacity during peak demand because solar and wind generation is variable and dependent on the weather.

For example, Germany, the biggest economy in Europe, is boosting its renewables targets, but it is also phasing out nuclear by next year, amid a nuclear option debate over climate strategy, while its deadline to phase out coal-fired generation is 2038—more than a decade later compared to phase-out plans in the UK and Italy, for example, where the deadline is the mid-2020s.

The UK, which left the EU last year, included support for nuclear power generation as one of the ten pillars in ‘The Ten Point Plan for a Green Industrial Revolution’ unveiled in November.

The UK’s National Grid has issued several warnings about tight supply since the fall of 2020, due to low renewable output amid high demand.

“National Grid’s announcement underscores the urgency of investing in new nuclear capacity, to secure reliable, always-on, emissions-free power, alongside other zero-carbon sources. Otherwise, we will continue to burn gas and coal as a fallback and fall short of our net zero ambitions,” Tom Greatrex, Chief Executive of the Nuclear Industry Association, said in response to one of those warnings.

But it’s in the UK that one major nuclear power plant project has notoriously seen a delay of nearly a decade—Hinkley Point C, originally planned in 2007 to help UK households to “cook their 2017 Christmas turkeys”, is now set for start-up in the middle of the 2020s.

Nuclear power development and plant construction is expensive, but it could save the plans for low-carbon emission power generation in many developed economies, including in the United States.

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Germany Solar-Plus-Storage Cost Parity signals grid parity as solar power with battery storage undercuts conventional electricity. Falling LCOE, policy incentives, and economies of scale accelerate the energy transition and decarbonization across Germany's power market.

Key Points

The point at which solar power with battery storage is cheaper than conventional grid electricity across Germany.

✅ Lower LCOE from tech advances and economies of scale

✅ EEG incentives and streamlined installs cut total costs

✅ Enhances energy security, reduces fossil fuel dependence

Germany, a global leader in renewable energy adoption, with clean energy supplying about half of its electricity in recent years, has reached a significant milestone: the cost of solar power combined with battery storage has now fallen below that of conventional electricity sources. This development marks a transformative shift in the energy landscape, showcasing the increasing affordability and competitiveness of renewable energy technologies and reinforcing Germany’s position as a pioneer in the transition to sustainable energy.

The decline in costs for solar power paired with battery storage represents a breakthrough in Germany’s energy sector, especially amid the recent solar power boost during the energy crisis, where the transition from traditional fossil fuels to cleaner alternatives has been a central focus. Historically, conventional power sources such as coal, natural gas, and nuclear energy have dominated electricity markets due to their established infrastructure and relatively stable pricing. However, the rapid advancements in solar technology and energy storage solutions are altering this dynamic, making renewable energy not only environmentally preferable but also economically advantageous.

Several factors contribute to the cost reduction of solar power with battery storage:

1. Technological Advancements: The technology behind solar panels and battery storage systems has evolved significantly over recent years. Solar panel efficiency has improved, allowing for greater energy generation from smaller installations. Similarly, cheaper batteries have advanced, with reductions in cost and increases in energy density and lifespan. These improvements mean that solar installations can produce more electricity and store it more effectively, enhancing their economic viability.

2. Economies of Scale: As demand for solar and battery storage systems has grown, manufacturers have scaled up production, leading to economies of scale. This scaling has driven down the cost of both solar panels and batteries, making them more affordable for consumers. As the market for these technologies expands, prices are expected to continue decreasing, further enhancing their competitiveness.

3. Government Incentives and Policies: Germany’s commitment to renewable energy has been supported by robust government policies and incentives. The country’s Renewable Energy Sources Act (EEG) and other supportive measures, alongside efforts to remove barriers to PV in Berlin that could accelerate adoption, have provided financial incentives for the adoption of solar power and battery storage. These policies have encouraged investment in renewable technologies and facilitated their integration into the energy market, contributing to the overall reduction in costs.

4. Falling Installation Costs: The cost of installing solar power systems and battery storage has decreased as the industry has matured. Advances in installation techniques, increased competition among service providers, and streamlined permitting processes have all contributed to lower installation costs. This reduction in upfront expenses has made solar with battery storage more accessible and financially attractive to both residential and commercial consumers.

The economic benefits of solar power with battery storage becoming cheaper than conventional power are substantial. For consumers, this shift translates into lower electricity bills and reduced reliance on fossil fuels. Solar installations with battery storage allow households and businesses to generate their own electricity, store it for use during times of low sunlight, and even sell excess power back to the grid, reflecting how solar is reshaping electricity prices in Northern Europe as markets adapt. This self-sufficiency reduces exposure to fluctuating energy prices and enhances energy security.

For the broader energy market, the decreasing cost of solar power with battery storage challenges the dominance of conventional power sources. As renewable energy becomes more cost-effective, it creates pressure on traditional energy providers to adapt and invest in cleaner technologies, including responses to instances of negative electricity prices during renewable surpluses. This shift can accelerate the transition to a low-carbon energy system and contribute to the reduction of greenhouse gas emissions.

Germany’s achievement also has implications for global energy markets. The country’s success in making solar with battery storage cheaper than conventional power serves as a model for other nations pursuing similar energy transitions. As the cost of renewable technologies continues to decline, other countries can leverage these advancements to enhance their own energy systems, reduce carbon emissions, and achieve energy independence amid over 30% of global electricity now from renewables trends worldwide.

The impact of this development extends beyond economics. It represents a significant step forward in addressing climate change and promoting sustainability. By reducing the cost of renewable energy technologies, Germany is accelerating the shift towards a cleaner and more resilient energy system. This progress aligns with the country’s ambitious climate goals and reinforces its role as a leader in global efforts to combat climate change.

Looking ahead, several challenges remain. The integration of renewable energy into existing energy infrastructure, grid stability, and the management of energy storage are all areas that require continued innovation and investment. However, the decreasing cost of solar power with battery storage provides a strong foundation for addressing these challenges and advancing the transition to a sustainable energy future.

In conclusion, the fact that solar power with battery storage in Germany has become cheaper than conventional power is a groundbreaking development with wide-ranging implications. It underscores the technological advancements, economic benefits, and environmental gains associated with renewable energy technologies. As Germany continues to lead the way in clean energy adoption, this achievement highlights the potential for renewable energy to drive global change and reshape the future of energy.

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SaskPower 10% Electricity Rebate promises one-year bill relief for households, farms, businesses, hospitals, schools, and universities in Saskatchewan, boosting affordability amid COVID-19, offsetting rate hikes, and countering carbon tax impacts under Scott Moe's plan.

Key Points

One-year 10% SaskPower rebate lowering bills for residents, farms, and institutions, funded by general revenue.

✅ Applies automatically to all customers for 12 months from Dec 2020.

✅ Average savings: $215 residential; $845 farm; broad sector coverage.

✅ Cost $261.6M, paid from the general revenue fund; separate from carbon tax.

Saskatchewan Party leader Scott Moe says SaskPower customers can expect a one-year, 10 per cent rebate on electricity if they are elected government.

Moe said the pledge aims to make life more affordable for people, including through lower electricity rates initiatives seen in other provinces. The rate would apply to everyone, including residential customers, farmers, businesses, hospitals, schools and universities.

The plan, which would cost government $261.6 million, expects to save the average residential customer $215 over the course of the year and the average farm customer $845.  

“This is a very equitable way to ensure that we are not only providing that opportunity for those dollars to go back into our economy and foster the economic recovery that we are working towards here, in Saskatchewan, across Canada and around the globe, but it also speaks to the affordability for our Saskatchewan families, reducing the dollars a day off to pay for their for their power bill,” Moe said.

The rebate would be applied automatically to all SaskPower bills for 12 months, starting in December 2020. 

Moe said residential customers who are net metering and generating their own power, such as solar power, would receive a $215 rebate over the 12-month period, which is the equivalent of the average residential rebate.

The $261.6 million in costs would be covered by the government’s general revenue fund.   

The Saskatchewan NDP said the proposed reduction is "a big change in direction from the Sask. Party’s long history of making life more expensive for Saskatchewan families." and recently took aim at a SaskPower rate hike approval as part of that critique.

Trent Wotherspoon, NDP candidate for Regina Rosemont and former finance critic, called the pledge criticized the one year time frame and said Saskatchewan people need long term, reliable affordability, noting that the Ontario-Quebec hydro deal has not reduced hydro bills for consumers. Something, he said, is reflected in the NDP plan.

“We've already brought about announcements that bring about affordability, such as the break on SGI auto insurance that'll happen, year after year after year, affordable childcare which has been already announced and committed to things like a decent minimum wage instead of having the lowest minimum wage in Canada,” Wotherspoon said.

The NDP pointed out SaskPower bills have increased by 57 per cent since 2007 for families with an average household income of $75,000, while Nova Scotia's 14% rate hike was recently approved by its regulator.

It said the average bill for such household was $901 in 2007-08 and is now $1,418 in 2019-20, while in neighbouring provinces Manitoba rate increases of 2.5 per cent annually have also been proposed for three years.

"This is on top of the PST increases that the Sask. Party put on everyday families – costing them more than $700 a year," the NDP said.

Moe took aim at the federal Liberal government’s carbon tax, citing concerns that electricity prices could soar under national policies.

He said if the Saskatchewan government wins its court fight against Ottawa, all SaskPower customers can expect to save an additional $150 million per year, and he questioned the federal 2035 net-zero electricity grid target in that context.

“As it stands right now, the Trudeau government plans to raise the carbon tax from $30 to $40 a tonne on Jan. 1,” Moe said. “Trudeau plans to raise taxes and your SaskPower bill, in the middle of a pandemic.  The Saskatchewan Party will give you a break by cutting your power bill.”

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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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