Will electricity supplant natural gas?

By Toronto Star


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Natural gas is a cleaner fuel when compared to coal, but in the context of climate change, it's far from being our saviour. Once all of Ontario's coal plants are shut down – we're told by 2014 – then the next greenhouse gas emitter on the global warming hit list is, by default, natural gas.

"About 36 per cent of Toronto's carbon dioxide emissions come from natural gas," says Philip Jessup, executive director of the Toronto Atmospheric Fund.

It calls attention to our strategy of doubling natural gas plant capacity as part of the province's 20-year power system plan. It also puts the spotlight on "fuel-switching" – that is, ditching your electric stove in favour of natural gas, or getting rid of that electric resistance heating in favour of a natural gas-fired furnace.

Compared to electric heating, there's no disputing that natural gas is currently cheaper. But is it cleaner than electricity?

Not in Ontario. Not in Toronto. In fact, once all coal plants are shut down, a lion's share of the electricity in the province will come from nuclear, hydroelectric and wind power. That means using electricity to heat your home will result in far less greenhouse gas emissions than using a natural gas appliance.

So the question is, how do we make using electricity cheaper?

Duane Hallowell, 34, a former cryogenic engineer with the U.S. navy, is focused on this mission. He founded a company in Maine three years ago, called Hallowell International, aimed at getting households in northern U.S. and Canadian climates off of fossil fuels.

What he invented was a new kind of heat pump, which as a technology has existed for decades. The difference is that Hallowell's heat pump, called Acadia, was designed to work efficiently in temperatures as low as minus 30 degrees Celsius – that is, in Canadian winters.

"For the same amount of energy to heat a house with resistance heating, you could heat three homes with an Acadia," he says. "And that's a worst-case scenario."

There are typically two kinds of electrical heat pump systems – air-source and ground-source.

The latter is what we commonly know as low-temperature geothermal, which cools a building by extracting heat from inside and dumping it in the ground; or in reverse, heats a building by pulling heat out of the ground and releasing it inside.

Geothermal systems can run $25,000 to $35,000 for a residential retrofit, which is a tough bite to swallow even though the payback is much quicker than, say, solar power or small-wind systems. A big part of that cost is the need to drill holes in the ground and line it with tubing. Glycol or food-grade ethanol in the tubing acts as the energy carrier, exchanging heat between the ground and the building.

A ground-source system is more efficient than an air-source one. The temperature in the ground is more constant than the ambient air, so ground-source heat pumps don't have to work as hard.

But hurdles to their deployment remain. If the drilling or tube laying isn't done properly, or if the system isn't sized accurately for a home's cooling and heating needs, fixing it can be a nightmare.

These risks are falling, which is encouraging, and generous government incentives – $7,000 from Ottawa and the province combined – do help ease financial pain. But nagging "what if" worries of ground-source systems remain.

In urban areas, geothermal also poses problems. When you live in the Annex or Beaches and have little backyard space to spare, then the logistics of drilling holes and laying tubing become tricky. Tricky equals higher cost.

Air-source heat pumps work in much the same way as geothermal systems, but instead of the ground, they use outside air to extract and release heat. Home refrigerators work in a similar way. They extract heat from the food in your fridge and release it from coils behind it.

Air conditioners are a one-way heat pump – in summer it extracts heat from inside air and dumps it outside. Air-source heat pumps are popular in the U.S. south because they work like air conditioners, plus they can provide limited heating if temperatures drop.

"Unfortunately, they're still just being developed primarily as air conditioners with a major deficiency in heating," says Hallowell.

It's why they've never taken off in Canada. Once temperatures drop below freezing, a conventional air-source heat pump is useless.

Hallowell saw the neglect, so he went ahead and engineered a better air-source heat pump – one that operates during the summer like an Energy Star central air conditioner but in the winter handles all of a home's heating needs. "Are we as efficient as geothermal?" asks Hallowell. "Well, we're close."

Natural Resources Canada is now testing the Acadia system. I consulted an energy consultant who is also testing it for the Manitoba energy ministry. He didn't want to be named, but had good things to say.

"They're the real deal. Technically, there's no massive, innovative, wizardry here. Just compressors and booster coils and good control systems. Very well done."

His only concern was that Hallowell is still new to the market so it doesn't yet have a track record for service and maintenance. "So if you're getting one of these early units, see if they'd provide guarantees of servicing and back-up."

Hallowell's Canadian distributor, MITS Air Conditioning Inc. of Mississauga, says it costs $14,000 to $16,000 to purchase and install an Acadia system, compared to about $11,000 for a high-end air conditioner and gas furnace.

Unlike geothermal, there's no ripping up of grass. No drilling. "If it does break it's easy to fix because there's nothing underground," says Jim Chaters at MITS.

Currently, the federal government offers a $400 incentive to purchase an air-source heat pump. The province matches that. Hallowell is trying to get that incentive increased so it's at least half of what geothermal systems get.

Chaters, who sells all kinds of conventional heating and cooling equipment, says four years ago he'd never given much thought to heat-pump technology. Then his eco-minded daughter began pushing him to look for better options.

"Air-source heat pumps are the future, because they're getting more and more efficient."

Jessup at the Toronto Atmospheric Fund adds: "We are going to have to move to these technologies in a big way if we are to meet the ambitious (emissions) targets that Toronto council has set."

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Sub-Saharan Africa has a huge electricity problem - but with challenge comes opportunity

Sub-Saharan Africa Energy Access faces critical deficits; SDG7, clean energy finance, off-grid solar, and microgrids drive electrification for health, education, and economy amid World Bank and IEA efforts to expand reliable, affordable power.

 

Key Points

Reliable, affordable power in sub-Saharan Africa via renewables, off-grid solar, and SDG7-led electrification.

✅ SDG7 targets universal, modern energy access by 2030

✅ Off-grid solar and microgrids boost rural electrification

✅ Health, education, and business depend on reliable power

 

Sub-Saharan Africa has an electricity problem. While the world as a whole has made great strides when it comes to providing access to electricity and moving toward universal electricity access worldwide (the world average is now 90 per cent with access, up from 83 per cent in 2010), southern and western African states still lag far behind.

According to Tracking SDG7: The Energy Progress Report, produced by a consortium of organisations including the World Bank, the International Energy Agency and the World Health Organization, 759 million people were without electricity in 2019 and threequarters of them were based in sub-Saharan Africa. At just seven per cent, South Sudan had the lowest access figures; Chad, Burundi and Malawi were only marginally higher. What’s more, due to a combination of factors, the situation is getting worse. In total, the region’s access deficit increased from 556 million people in 2010 to 570 million people in 2019.

These days, being without electricity has an impact on every sphere of life. The Covid-19 pandemic only served to put this into sharper relief. Intermittent electricity meant vaccination doses that rely on cold storage were impossible to deliver and, as more than 70 per cent of the health facilities in sub-Saharan Africa have no access to reliable electricity, the problem was vast. But even without a global pandemic, having no power stymies opportunity in every field, from education to economics.

French photojournalist Pascal Maitre, who has spent much of his career writing about sub-Saharan Africa, wanted to document the problems faced by people in areas with no electricity. He thought particularly carefully about the location for his project. ‘First, I was thinking I could take images in the Democratic Republic of the Congo,’ he says. ‘But then I thought that if you chose a place that has war, it’s logical that electricity won’t really work. So, instead, I wanted to find a place that is quite stable. I decided to go to Benin, where they have a democracy. It is a good example of a country that’s not in really bad shape but where they still have this problem. Also, I didn’t want to go to a place that is very remote, where it is normal not to have good service. So I decided to go to a place around 50 kilometres from the capital that you can get to by road.’

Maitre visited several villages in the region, as well as making trips to Chad and Senegal, and encountered the full range of limitations engendered by the power shortage. From teachers struggling to conduct lessons in the dark to midwives forced to work with only the weak light from a phone, the situation was clearly unacceptable. ‘People were very, very, very upset,’ he says. ‘I conducted a lot of interviews in different villages and lack of electricity touches education, economy, business, security and also emigration, because people have to move to big cities or maybe to Europe to get jobs.’

Where once the situation might have been accepted as the norm, people today are fully aware of the ways in which they are held back by the lack of power. As Maitre remembers: ‘A guy said to me one day, “Do you think it is normal that last time my wife delivered a baby, the midwife had to hold her phone between her teeth in order to see what she was doing?” You feel very frustrated.’ He adds that the fact that most people now have mobile phones only highlights the hardship. ‘Before, maybe it was not so frustrating. But now, most of these people have cellphones. The cellphone company puts antennae everywhere so the phones work, but people cannot recharge their phones. They have to go to the market, where someone will come with a generator to recharge.’

Governments and global organisations are very aware of the problem across the world as a whole. Sustainable Development Goal 7 (SDG7) – one of the 17 goals set out in 2015 by the United Nations General Assembly – was designed to ensure universal access to affordable, reliable, sustainable and modern energy by 2030, underscoring the push for clean, affordable and sustainable electricity for all by 2030. As part of this goal, international financial flows to developing countries in support of clean energy reached US$17 billion in 2018. As a result, some areas have seen huge improvement. According to the Energy Progress Report, in Latin America and the Caribbean, and in Eastern and South-Eastern Asia, the advance of electrification has been enough to approach universal access. By 2019, in Western Asia and North Africa, and Central and South Asia, 94 and 95 per cent of the population respectively had access to electricity.

But these statistics only serve to emphasise just how bad the situation is in sub-Saharan Africa, where electricity systems are unlikely to go green this decade according to several analyses. As the report states: ‘While renewable energy has demonstrated remarkable resilience during the pandemic, the unfortunate fact is that gains in energy access throughout Africa are being reversed: the number of people lacking access to electricity is set to increase in 2020, making basic electricity services unaffordable for up to 30 million people who had previously enjoyed access.’

The small silver lining is that if the situation is dealt with properly, the region could build a renewable-energy system from the ground up, rather than having to undergo the costly and complex transitions underway in developed countries. In rural areas, small-scale or off-grid renewable systems (mostly solar) are expected to play an important role, as highlighted by a recent IRENA report on decarbonisation, in increasing access. In fact, solar panels are already used in many areas. In 2019, 105 million people had access to off-grid solar solutions, up from 85 million in 2016, and almost half lived in sub-Saharan Africa, with 17 million in Kenya and eight million in Ethiopia.

Rachel Kyte is currently serving as the 14th dean of the Fletcher School at Tufts University in the USA, but her CV is long. She was previously CEO of the UN-affiliated Sustainable Energy for All (SeforALL), as well as the World Bank Group vice president and special envoy for climate change, leading the run-up to the Paris Agreement. According to her, a focus on renewables is absolutely essential, both for wider efforts to tackle climate change, with some advocating a fossil fuel lockdown to drive a climate revolution, but also for the people of sub-Saharan Africa. ‘The fossil fuel industry has said it will just extend the centralised fossil-fuel power systems that we have today to reach these people,’ she says.

 

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US NRC streamlines licensing for advanced reactors

NRC Advanced Reactor Licensing streamlines a risk-informed, performance-based, technology-inclusive pathway for advanced non-light water reactors, aligning with NEIMA to enable predictable regulatory reviews, inherent safety, clean energy deployment, and industrial heat, hydrogen, and desalination applications.

 

Key Points

A risk-informed, performance-based NRC pathway streamlining licensing for advanced non-light water reactors.

✅ Aligned with NEIMA: risk-informed, performance-based, tech-inclusive

✅ Predictable licensing for advanced non-light water reactor designs

✅ Enables clean heat, hydrogen, desalination beyond electricity

 

The US Nuclear Regulatory Commission (NRC) voted 4-0 to approve the implementation of a more streamlined and predictable licensing pathway for advanced non-light water reactors, aligning with nuclear innovation priorities identified by industry advocates, the Nuclear Energy Institute (NEI) announced, and amid regional reliability measures such as New England emergency fuel stock plans that have drawn cost scrutiny.

This approach is consistent with the Nuclear Energy Innovation and Modernisation Act (NEIMA), a nuclear innovation act passed in 2019 by the US Congress calling for the development of a risk-informed, performance-based and technology inclusive licensing process for advanced reactor developers.

NEI Chief Nuclear Officer Doug True said: “A modernised regulatory framework is a key enabler of next-generation nuclear technologies that, amid ACORE’s challenge to DOE subsidy proposals in energy market proceedings, can help us meet our energy needs while protecting the climate. The Commission’s unanimous approval of a risk-informed and performance-based licensing framework paves the way for regulatory reviews to be aligned with the inherent safety characteristics, smaller reactor cores and simplified designs of advanced reactors.”

Over the last several years the industry’s Licensing Modernisation Project, sponsored by US Department of Energy, led by Southern Nuclear, and supported by NEI’s Advanced Reactor Regulatory Task Force, and influenced by a presidential order to bolster uranium and nuclear energy, developed the guidance for this new framework. Amid shifts in the fuel supply chain, including the U.S. ban on Russian uranium, this approach will inform the development of a new rule for licensing advanced reactors, which NEIMA requires.

“A well-defined licensing path will benefit the next generation of nuclear plants, especially as regions consider New England market overhaul efforts, which could meet a wide range of applications beyond generating electricity such as producing heat for industry, desalinating water, and making hydrogen – all without carbon emissions,” True noted.

 

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Ontario takes constitutional challenge of its global adjustment electricity fee to Supreme Court

Ontario Global Adjustment Supreme Court Appeal spotlights a constitutional challenge to Ontario's electricity charge, pitting National Steel Car against the IESO over regulatory charge vs tax, procurement policy, and renewable energy feed-in tariff contracts.

 

Key Points

An SCC leave bid on whether Ontario's global adjustment is a valid regulatory charge or an unconstitutional tax.

✅ Appeals Court revived case for full record review

✅ Dispute centers on regulatory charge vs tax classification

✅ FIT renewables contracts and procurement policies at issue

 

The Ontario government wants the Supreme Court of Canada to weigh in on a constitutional challenge being brought against a large provincial electricity charge, a case the province claims raises issues of national importance.

Ontario’s attorney general and its Independent Electricity System Operator applied for permission to appeal to the Supreme Court in January, according to the court’s website.

The province is trying to appeal a Court of Appeal decision reinstating the challenge from November that said a legal challenge by Hamilton, Ont.-based National Steel Car Ltd. should be sent back to a lower-court for a full hearing.

Court reinstates constitutional challenge to Ontario's hefty ‘global adjustment’ electricity charge
National Steel Car appealing decision in legal challenge of Ontario electricity fee it calls an unconstitutional tax
Doug Ford’s cancellation of green energy deals costs Ontario taxpayers $231 million
National Steel Car launched its legal challenge in 2017, with the maker of steel rail cars claiming the province’s global adjustment electricity charge was a tax intended to fund certain post-financial-crisis policy goals. Since it is allegedly a tax, and one not imposed by the provincial legislature, the company’s argument is the global adjustment is unconstitutional, and also in breach of a provincial law requiring a referendum for new taxes.

The global adjustment mostly bridges the gap between the province’s hourly electricity price and the price guaranteed under contracts and regulated rates with power generators. It also helps cover the cost of building new electricity infrastructure and providing conservation programs, but the fee now makes up most of the commodity portion of a household power bill in the province.

Ontario argued the global adjustment is a valid regulatory charge, and moved to have National Steel Car’s challenge thrown out. An Ontario Superior Court judge agreed, and dismissed the challenge in 2018, saying it was “plain, obvious and beyond doubt” it could not succeed. However, an appeals court judge disagreed, writing in a decision last November that the “merits should not have been determined on a pleadings motion and without the development of a full record.”

In filings made to the Supreme Court, both the IESO and Ontario’s Ministry of the Attorney General argued their proposed appeals raise “issues of national and public importance,” such as whether incorporating environmental and social policy goals in procurement could turn attempts by a public body to recover costs into an unconstitutional tax.

Most applications for leave to appeal to the Supreme Court are dismissed, but the Ontario government claims the court’s guidance is required in this case, as it could lead to questions being raised about other fees or charges, such as money raised from fishing licences.

“A failure to dispose of this claim at the pleadings stage may well result in such uncertainty that public authorities across Canada decline to incorporate the kind of environmental and social policy goals objected to in this case into the decisions they make about how to spend funds raised from regulatory charges,” the filing from the attorney general states. “Alternatively, it may induce governments not to engage in cost recovery in connection with publicly supplied goods and services, which can otherwise be sound public policy.”

The government has so far had to pay National Steel Car $250,000 in legal costs “to avoid responding to the credible claim that the Global Adjustment is an unconstitutional tax,” said David Trafford of Morse Shannon LLP, one of National Steel Car’s lawyers.

“The application for leave to appeal is the next step in this effort to avoid having to respond to the case on the merits,” Trafford added in an email.

The application for leave to appeal is the next step in this effort to avoid having to respond to the case on the merits

David Trafford of Morse Shannon, one of National Steel Car’s lawyers
 
National Steel Car has particularly taken issue with the part of the global adjustment that funded contracts for renewable energy under a “feed-in tariff” program, or FIT, which the company called “the main culprit behind the dramatic price increases for electricity.”

The FIT program has been ended, but contracts awarded under it remain in place and form part of the global adjustment. Ontario’s auditor general estimated in 2015 that electricity consumers would pay $9.2 billion more for renewable energy under the government’s guaranteed-price program, a figure that later featured in a dispute between the auditor and the electricity regulator that drew political attention.

National Steel Car said its global adjustment costs grew from $207,260 in 2008 to almost $3.4 million in 2016, reflecting how high electricity rates have pressured manufacturers, to almost $3.4 million in 2016. For 2018, there was approximately $11.2 billion in global adjustment collected, according to the IESO’s reporting.

A spokesperson for the IESO said it “is not in a position to comment” because the case is still before the courts.

Electricity prices have been an ongoing problem for both Ontario consumers and politicians, which the previous Liberal government tried to address in 2017 by, among other things, refinancing global-adjustment costs through the Fair Hydro Plan and other measures.

Since National Steel Car filed its lawsuits, though, the Liberals lost power in the province and were succeeded in 2018 by Premier Doug Ford and the Progressive Conservatives, who made changes to the previous government’s power policies, including legislation to lower electricity rates introduced early in their mandate.

The province has also pursued interprovincial power arrangements, including building on an electricity deal with Quebec as part of its broader energy strategy.

“The present government of Ontario does not agree with the former government’s electricity procurement program, which ceased awarding new contracts in 2016,” Ontario’s attorney general said in a filing. “However, Ontario submits that (the lower-court judge) was correct in holding that it does not give rise to a claim susceptible to being remedied by the courts.”

 

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Maritime Link almost a reality, as first power cable reaches Nova Scotia

Maritime Link Subsea Cable enables HVDC grid interconnection across the Cabot Strait, linking Nova Scotia with Newfoundland and Labrador to import Muskrat Falls hydroelectric power and expand renewable energy integration and reliability.

 

Key Points

A 170-km HVDC subsea link connecting Nova Scotia and Newfoundland and Labrador for Muskrat Falls power and renewables

✅ 170-km HVDC subsea route across Cabot Strait

✅ Connects Nova Scotia and Newfoundland and Labrador grids

✅ Enables Muskrat Falls hydro and renewable energy trade

 

The longest sub-sea electricity cable in North America now connects Nova Scotia and Newfoundland and Labrador, according to the company behind the $1.7-billion Maritime Link project.  

The first of the project's two high-voltage power transmission cables was anchored at Point Aconi, N.S., on Sunday. 

The 170-kilometre long cable across the Cabot Strait will connect the power grids in the two provinces. The link will allow power to flow between the two provinces, as demonstrated by its first electricity transfer milestone, and bring to Nova Scotia electricity generated by the massive Muskrat Falls hydroelectric project in Labrador. 

Ultimately, the Maritime Link will help Nova Scotia reach the renewable energy goals set out by the federal government, said Rick Janega, the president and CEO of Emera Newfoundland and Labrador, whose subsidiary owns the Maritime Link.

"If not for the Maritime Link then really the province would not have the ability to meet those requirements because we're pretty much tapped out of all the hydro in province and all the wind generation without creating new interconnections like the Maritime Link," said Janega. 

Not everyone wanted the link 

Fishermen in Cape Breton had objected to the Maritime Link. They were concerned about how the undersea cable might affect fish in the area. 

The laying of the cable and other construction closed a three-kilometre long and 600-metre wide swath of ocean bottom to fishermen for the entire 2017 lobster season.  

But the company came to an agreement to compensate a group of 60 Cape Breton lobster and crab fishermen affected by the project this season. The terms of the compensation deal were not released. 

 

Long cable, big job

The transmission cable runs northwest of the Marine Atlantic ferry route between North Sydney, N.S., and Port aux Basques, N.L. 

Installation of the second cable is set to begin in June, a major step comparable to BC Hydro's Site C transmission milestone achieved recently. The entire link should be completed by late 2017 and should go into full service by January 2018.

"We're quite confident as soon as the Maritime Link is in service there will be energy transactions between Nova Scotia Power and Newfoundland Hydro. Both utilities have already identified opportunities to save money and exchange energy between the two provinces," said Janega.

That's two years before power is expected to flow from the Muskrat Falls hydro project. The Labrador-based power generating facility has been hampered by delays.

Those kinds of transmission project delays are expected for such a large project, said Janega, and won't stop the Maritime Link from being used. 

"With the Maritime Link going in service this year providing Nova Scotia the opportunity that it needs to be able to reach carbon reductions and to adapt to climate change and to increase renewable energy content and we're very pleased to be at this state today," said Janega.

 

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Revenue from Energy Storage for Microgrids to Total More Than $22 Billion in the Next Decade

Energy Storage for Microgrids enables renewables integration via ESS, boosting resilience and reliability while supporting solar PV and wind, innovative financing, and business models, with strong growth forecast across Asia-Pacific and North America.

 

Key Points

Systems that store energy in microgrids to integrate renewables, boost resilience, and optimize distributed power.

✅ Integrates solar PV and wind with stable, dispatchable output

✅ Reduces costs via new financing and service business models

✅ Expands reliable power for remote, grid-constrained regions

 

A new report from Navigant Research examines the global market for energy storage for microgrids (ESMG), providing an analysis of trends and market dynamics in the context of the evolving digital grid landscape, with forecasts for capacity and revenue that extend through 2026.

Interest in energy storage-enabled microgrids is growing alongside an increase in solar PV and wind deployments. Although not required for microgrids to operate, energy storage systems (ESSs) have emerged as an increasingly valuable component of distributed energy networks, including virtual power plants that coordinate distributed assets, because of their ability to effectively integrate renewable generation.

“There are several key drivers resulting in the growth of energy storage-enabled microgrids globally, including the desire to improve the resilience of power supply both for individual customers and the entire grid, the need to expand reliable electricity service to new areas, rising electricity prices, and innovations in business models and financing,” says Alex Eller, research analyst with Navigant Research. “Innovations in business models and financing will likely play a key role in the expansion of the ESMG market during the coming years.”

One example of microgrid deployment for resilience is the SDG&E microgrid in Ramona built to help communities prepare for peak wildfire season.

According to the report, the most successful companies in this industry will be those that can unlock the potential of new business models to reduce the risk and upfront costs to customers. This is particularly true in Asia Pacific and North America, which are projected to be the largest regional markets for new ESMG capacity by far, a trend underscored by California's push for grid-scale batteries to stabilize the grid.

The report, “Market Data: Energy Storage for Microgrids,” outlines the key market drivers and barriers within the global ESMG market. The study provides an analysis of specific trends, including evolving grid edge trends, and market dynamics for each major world region to illustrate how different markets are taking shape. Global ESMG forecasts for capacity and revenue, segmented by region, technology, and market segment, extend through 2026. The report also briefly examines the major technology issues related to ESSs for microgrids.

Google made energy storage news recently when its parent company Alphabet announced it is hoping to revolutionize renewable energy storage using vats of salt and antifreeze. Alphabet’s secretive research lab, simply named “X,” is developing a system for storing renewable energy that would otherwise be wasted. The project, named “Malta,” is hoping its energy storage systems “has the potential to last longer than lithium-ion batteries and compete on price with new hydroelectric plants and other existing clean energy storage methods, according to X executives and researchers,” reports Bloomberg.

 

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Brand New Renewable Technology Harnesses Electricity From The Cold, Dark Night

Nighttime Thermoelectric Generator converts radiative cooling into renewable energy, leveraging outer space cold; a Stanford-UCLA prototype complements solar, serving off-grid loads with low-power output during peak evening demand, using simple materials on a rooftop.

 

Key Points

A device converting nighttime radiative cooling into electricity, complementing solar for low-power evening needs.

✅ Uses thermocouples to convert temperature gradients to voltage.

✅ Exploits radiative cooling to outer space for night power.

✅ Complements solar; low-cost parts suit off-grid applications.

 

Two years ago, one freezing December night on a California rooftop, a tiny light shone weakly with a little help from the freezing night air. It wasn't a very bright glow. But it was enough to demonstrate the possibility of generating renewable power after the Sun goes down.

Working with Stanford University engineers Wei Li and Shanhui Fan, University of California Los Angeles materials scientist Aaswath Raman put together a device that produces a voltage by channelling the day's residual warmth into cooling air, effectively generating electricity from thin air with passive heat exchange.

"Our work highlights the many remaining opportunities for energy by taking advantage of the cold of outer space as a renewable energy resource," says Raman.

"We think this forms the basis of a complementary technology to solar. While the power output will always be substantially lower, it can operate at hours when solar cells cannot."

For all the merits of solar energy, it's just not a 24-7 source of power, although research into nighttime solar cells suggests new possibilities for after-dark generation. Sure, we can store it in a giant battery or use it to pump water up into a reservoir for later, but until we have more economical solutions, nighttime is going to be a quiet time for renewable solar power. 

Most of us return home from work as the Sun is setting, and that's when energy demands spike to meet our needs for heating, cooking, entertaining, and lighting.

Unfortunately, we often turn to fossil fuels to make up the shortfall. For those living off the grid, it could require limiting options and going without a few luxuries.

Shanhui Fan understands the need for a night time renewable power source well. He's worked on a number of similar devices, including carbon nanotube generators that scavenge ambient energy, and a recent piece of technology that flipped photovoltaics on its head by squeezing electricity from the glow of heat radiating out of the planet's Sun-warmed surface.

While that clever item relied on the optical qualities of a warm object, this alternative device makes use of the good old thermoelectric effect, similar to thin-film waste-heat harvesting approaches now explored.

Using a material called a thermocouple, engineers can convert a change in temperature into a difference in voltage, effectively turning thermal energy into electricity with a measurable voltage. This demands something relatively toasty on one side and a place for that heat energy to escape to on the other.

The theory is the easy part – the real challenge is in arranging the right thermoelectric materials in such a way that they'll generate a voltage from our cooling surrounds that makes it worthwhile.

To keep costs down, the team used simple, off-the-shelf items that pretty much any of us could easily get our hands on.

They put together a cheap thermoelectric generator and linked it with a black aluminium disk to shed heat in the night air as it faced the sky. The generator was placed inside a polystyrene enclosure sealed with a window transparent to infrared light, and linked to a single tiny LED.


 

For six hours one evening, the box was left to cool on a roof-top in Stanford as the temperature fell just below freezing. As the heat flowed from the ground into the sky, the small generator produced just enough current to make the light flicker to life.

At its best, the device generated around 0.8 milliwatts of power, corresponding to 25 milliwatts of power per square metre.

That might just be enough to keep a hearing aid working. String several together and you might just be able to keep your cat amused with a simple laser pointer. So we're not talking massive amounts of power.

But as far as prototypes go, it's a fantastic starting point. The team suggests that with the right tweaks and the right conditions, 500 milliwatts per square metre isn't out of the question.

"Beyond lighting, we believe this could be a broadly enabling approach to power generation suitable for remote locations, and anywhere where power generation at night is needed," says Raman.

While we search for big, bright ideas to drive the revolution for renewables, it's important to make sure we don't let the smaller, simpler solutions like these slip away quietly into the night.

This research was published in Joule.

 

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