Wal-Mart Goes Solar

By Fortune


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In one of the biggest solar deals to date, Wal-Mart will buy 22 million kilowatt-hours of greenhouse gas-free electricity produced from solar arrays to be installed as a pilot project at 22 stores in California and Hawaii.

The retail giant estimates the move will reduce planet-warming emissions by 6,500 to 10,000 metric tons a year.

The solar systems will be installed by SunPower's (SPWR) PowerLight subsidiary at seven California stores, by SunEdison at four stores in California and four in Hawaii, and by BP Solar (BP) at seven stores in the Golden State. Wal-Mart (WMT) will buy electricity produced by the arrays at market or below market rates and retain ownership of any Renewable Credits.

RECs potentially could be worth a bundle if they're allowed to be traded on carbon markets under consideration in California and Hawaii. For instance, a company that exceeds its limit on greenhouse gas emissions could buy Wal-Mart RECs, which represent CO2 avoided through the use of solar energy. Hawaii recently became the second state after California to pass a cap on greenhouse gas emissions.

The solar companies will arrange financing and installation of the arrays and retain ownership. In SunEdison's case, the Maryland company will finance, operate and own the solar arrays it installs for Wal-Mart. A SunPower spokesperson told reporters that the San Jose company is working with a third party to finance the deal but hasn't finalized the arrangements.

When the power purchase agreements expires, Wal-Mart will have the option to renew the deals, move the equipment to other stores or buy the solar arrays. SunPower, which previously installed solar arrays at three other Wal-Mart stores, will build systems for seven stores to produce 4.6 megawatts of electricity. Each solar array will provide about a quarter of a store's power, according to SunPower.

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UK low-carbon electricity generation stalls in 2019

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

 

Key Points

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

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

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

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

 

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

 

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China to build 525-MW hydropower station on Yangtze tributary

Baima Hydropower Station advances China renewable energy on the Wujiang River, a Yangtze tributary in Chongqing; a 525 MW cascade project approved by NDRC, delivering 1.76 billion kWh and improving river shipping.

 

Key Points

An NDRC-approved 525 MW project on Chongqing's Wujiang River, producing 1.76 billion kWh and improving navigation.

✅ 10.2 billion yuan investment; final cascade plant on Wujiang in Chongqing

✅ Expected output: 1.76 billion kWh; capacity 525 MW; NDRC approval

✅ Improves river shipping; relocation of 5,000 residents in Wulong

 

China plans to build a 525-MW hydropower station on the Wujiang River, a tributary of the Yangtze River, in Southwest China's Chongqing municipality, aligning with projects like the Lawa hydropower station elsewhere in the Yangtze basin.

The Baima project, the last of a cascade of hydropower stations on the section of the Wujiang River in Chongqing, has gotten the green light from the National Development and Reform Commission, China's state planning agency, even as some independent power projects elsewhere face uncertainty, such as the Siwash Creek project in British Columbia, the Chongqing Municipal Commission of Development and Reform said Monday.

The project, in Baima township of Wulong district, is expected to involve an investment of 10.2 billion yuan ($1.6 billion), as China explores compressed air generation to bolster grid flexibility, it said.

#google#

With a power-generating capacity of 525 MW, it is expected to generate 1.76 billion kwh of electricity a year, supporting efforts to reduce coal power production nationwide, and help improve the shipping service along the Wujiang River.

More than 5,000 local residents will be relocated to make room for the project, which forms part of a broader energy mix alongside advances in nuclear energy in China.

 

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London's Newest Electricity Tunnel Goes Live

London Electricity Tunnel strengthens grid modernization with high-voltage cabling from major substations, increasing redundancy, efficiency, and resilience while enabling renewable integration, optimized power distribution, and a stable, low-loss electricity supply across the capital.

 

Key Points

A high-voltage tunnel upgrading London's grid, with capacity, redundancy, and renewable integration for reliable power.

✅ High-voltage cabling from key substations boosts capacity

✅ Redundancy improves reliability during grid faults

✅ Enables renewable integration and lower transmission losses

 

London’s energy infrastructure has recently taken a significant leap forward with the commissioning of its newest electricity tunnel, and related upgrades like the 2GW substation that bolster transmission capacity, a project that promises to enhance the reliability and efficiency of the city's power distribution. This cutting-edge tunnel is a key component in London’s ongoing efforts to modernize its energy infrastructure, support its growing energy demands, and contribute to its long-term sustainability goals.

The newly activated tunnel is part of a broader initiative to upgrade London's aging power grid, which has faced increasing pressure from the city’s expanding population and its evolving energy needs, paralleling Toronto's electricity planning to accommodate growth. The tunnel is designed to carry high-voltage electricity from major substations to various parts of the city, improving the distribution network's capacity and reliability.

The construction of the tunnel was a major engineering feat, involving the excavation of a vast underground passage that stretches several kilometers beneath the city. The tunnel is equipped with advanced technology and materials to ensure its resilience and efficiency, and is informed by advances such as HVDC technology being explored across Europe for stronger grids. It features state-of-the-art cabling and insulation to handle high-voltage electricity safely and efficiently, minimizing energy losses and improving overall grid performance.

One of the key benefits of the new tunnel is its ability to enhance the reliability of London’s power supply. As the city continues to grow and demand for electricity increases, maintaining a stable and uninterrupted power supply is critical. The tunnel helps address this need by providing additional capacity and creating redundancy in the power distribution network, aligning with national efforts to fast-track grid connections that unlock capacity across the UK.

The tunnel also supports London’s sustainability goals by facilitating the integration of renewable energy sources into the grid. With the increasing use of solar, wind, and other clean energy technologies, including the Scotland-to-England subsea link that will carry renewable power, the power grid needs to be able to accommodate and distribute this energy effectively. The new tunnel is designed to handle the variable nature of renewable energy, allowing for a more flexible and adaptive grid that can better manage fluctuations in supply and demand.

In addition to its technical benefits, the tunnel represents a significant investment in London’s future energy infrastructure, echoing calls to invest in smarter electricity infrastructure across North America and beyond. The project has created jobs and stimulated economic activity during its construction phase, and it will continue to provide long-term benefits by supporting a more efficient and resilient power system. The upgrade is part of a broader strategy to modernize the city’s infrastructure and prepare it for future energy challenges.

The completion of the tunnel also reflects a commitment to addressing the challenges of urban infrastructure development. Building such a major piece of infrastructure in a densely populated city like London requires careful planning and coordination to minimize disruption and ensure safety. The project team worked closely with local communities and businesses to manage the construction process and mitigate any potential impacts.

As London moves forward, the new electricity tunnel will play a crucial role in supporting the city’s energy needs. It will help ensure that power is delivered efficiently and reliably to homes, businesses, and essential services. The tunnel also sets a precedent for future infrastructure projects, demonstrating how advanced engineering and technology can address the demands of modern urban environments.

The successful activation of the tunnel marks a significant milestone in London’s efforts to build a more sustainable and resilient energy system. It represents a forward-thinking approach to managing the city’s energy infrastructure and addressing the challenges posed by population growth, increasing energy demands, and the need for cleaner energy sources.

Looking ahead, London will continue to invest in and upgrade its energy infrastructure to support its ambitious climate goals and ensure a reliable power supply for its residents, a trend mirrored by Toronto's preparations for surging demand as that city continues to grow. The new electricity tunnel is just one example of the city’s commitment to innovation and sustainability in its approach to energy management.

In summary, London’s newest electricity tunnel is a major advancement in the city’s power distribution network. By enhancing reliability, supporting the integration of renewable energy, and investing in long-term infrastructure, the tunnel plays a critical role in addressing the city’s energy needs and sustainability goals. As London continues to evolve, such infrastructure projects will be essential in meeting the demands of a growing metropolis and creating a more resilient and efficient energy system for the future.

 

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Entergy Creates COVID-19 Emergency Relief Fund to Help Customers in Need

Entergy COVID-19 Emergency Relief Fund provides financial assistance to ALICE households, low-income seniors, and disabled customers via United Way grants for rent, mortgage, utilities, food, and bill payment support during COVID-19, alongside a disconnect moratorium.

 

Key Points

A shareholder-funded program offering essential grants and bill support to Entergy customers affected by COVID-19.

✅ Shareholders commit $700,000; grants distributed via United Way partners.

✅ Focus on ALICE families, low-income seniors, and disabled customers.

✅ Disconnects suspended; bill tools and LIHEAP advocacy underway.

 

In an effort to help working families experiencing financial hardships as a result of the coronavirus pandemic, the Entergy Charitable Foundation has established the COVID-19 Emergency Relief Fund, recognizing the need for electricity across communities.

"The health and safety of our customers, employees and communities is Entergy's top priority," said Leo Denault, chairman and CEO of Entergy Corporation. "For more than 100 years, Entergy has never wavered in our commitment to supporting our customers and the communities we serve. This pandemic is no different. During this challenging time, we are helping lessen the impact of this crisis on the most vulnerable in our communities. I strongly encourage our business partners to join us in this effort."

As devastating and disruptive as this crisis is for everyone, we know from past experience that those most heavily impacted are ALICE households (low-wage working families) and low-income elderly and disabled customers, who often face energy insecurity during such events - roughly 40%-50% of Entergy's customer base.

"We know from experience that working families and low-income elderly and disabled customers are hardest hit during times of crisis," said Patty Riddlebarger, vice president of Entergy's corporate social responsibility. "We are working quickly to make funds available to community partners that serve vulnerable households to lessen the economic impact of the COVID-19 crisis and ensure that families have the resources they need to get by during this time of uncertainty."

To support our most vulnerable customers, Entergy shareholders are committing $700,000 to the COVID-19 Emergency Relief Fund to help qualifying customers with basic needs such as food and nutrition, rent and mortgage assistance, and other critical needs, alongside measures like Texas utilities waiving fees that ease household costs, until financial situations become more stable. Grants from the fund will be provided to United Way organizations and other nonprofit partners across Entergy's service area that are providing services to impacted households.

Company shareholders will also match employee contributions to the COVID-19 relief efforts of local United Way organizations up to $100,000 to maximize impact.

In addition to establishing the COVID-19 Emergency Relief Fund, Entergy is taking additional steps to support and protect our customers during this crisis, similar to PG&E's pandemic response measures, including:

With support from our regulators, we are temporarily suspending customer disconnects, as seen in New Jersey and New York policies, as we continue to monitor the situation.

We are working with our network of community advocates, as the industry coordination with federal partners continues, to request a funding increase of the Low Income Home Energy Assistance Program to help alleviate financial hardships caused by COVID-19 on vulnerable households.

We are developing bill payment solutions and tools to help customers pay their accumulated balances once the disconnect moratorium is lifted.

Already in place to support vulnerable customers is Entergy's The Power to Care program, which provides emergency bill payment assistance to seniors and disabled individuals. To mark the 20th anniversary of Entergy's low-income customer initiative, the limit of shareholders' dollar for dollar match of customer donations was increased from $500,000 to $1 million per year. Shareholders continue to match employee donations dollar for dollar with no limit.

 

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Turning thermal energy into electricity

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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Cost of US nuclear generation at ten-year low

US Nuclear Generating Costs 2017 show USD33.50/MWh for nuclear energy, the lowest since 2008, as capital expenditures, fuel costs, and operating costs declined after license renewals and uprates, supporting a reliable, low-carbon grid.

 

Key Points

The 2017 US nuclear average was USD33.50/MWh, lowest since 2008, driven by reduced capital, fuel, and operating costs.

✅ Average cost USD33.50/MWh, lowest since 2008

✅ Capital, fuel, O&M costs fell sharply since 2012 peak

✅ License renewals, uprates, market reforms shape competitiveness

 

Average total generating costs for nuclear energy in 2017 in the USA were at their lowest since 2008, according to a study released by the Nuclear Energy Institute (NEI), amid a continuing nuclear decline debate in other regions.

The report, Nuclear Costs in Context, found that in 2017 the average total generating cost - which includes capital, fuel and operating costs - for nuclear energy was USD33.50 per megawatt-hour (MWh), even as interest in next-generation nuclear designs grows among stakeholders. This is 3.3% lower than in 2016 and more than 19% below 2012's peak. The reduction in costs since 2012 is due to a 40.8% reduction in capital expenditures, a 17.2% reduction in fuel costs and an 8.7% reduction in operating costs, the organisation said.

The year-on-year decline in capital costs over the past five years reflects the completion by most plants of efforts to prepare for operation beyond their initial 40-year licence. A few major items - a series of vessel head replacements; steam generator replacements and other upgrades as companies prepared for continued operation, and power uprates to increase output from existing plants - caused capital investment to increase to a peak in 2012. "As a result of these investments, 86 of the [USA's] 99 operating reactors in 2017 have received 20-year licence renewals and 92 of the operating reactors have been approved for uprates that have added over 7900 megawatts of electricity capacity. Capital spending on uprates and items necessary for operation beyond 40 years has moderated as most plants are completing these efforts," it says.

Since 2013, seven US nuclear reactors have shut down permanently, with the Three Mile Island debate highlighting wider policy questions, and another 12 have announced their permanent shutdown. The early closure for economic reasons of reliable nuclear plants with high capacity factors and relatively low generating costs will have long-term economic consequences, the report warns: replacement generating capacity, when needed, will produce more costly electricity, fewer jobs that will pay less, and, for net-zero emissions objectives, more pollution, it says.

NEI Vice President of Policy Development and Public Affairs John Kotek said the "hardworking men and women of the nuclear industry" had done an "amazing job" reducing costs through the institute's Delivering the Nuclear Promise campaign and other initiatives, in line with IAEA low-carbon lessons from the pandemic. "As we continue to face economic headwinds in markets which do not properly compensate nuclear plants, the industry has been doing its part to reduce costs to remain competitive," he said.

"Some things are in urgent need of change if we are to keep the nation's nuclear plants running and enjoy their contribution to a reliable, resilient and low-carbon grid. Namely, we need to put in place market reforms that fairly compensate nuclear similar to those already in place in New York, Illinois and other states," Kotek added.

Cost information in the study was collected by the Electric Utility Cost Group with prior years converted to 2017 dollars for accurate historical comparison.

 

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Whether you would prefer Live Online or In-Person instruction, our electrical training courses can be tailored to meet your company's specific requirements and delivered to your employees in one location or at various locations.