Solar LEDs light up developing nations

By Voice of America


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What do traffic lights, remote control devices and cell phone displays have in common?

The answer is light emitting diodes or LEDs. LEDs produce as much light as incandescent light bulbs but consume only 10 percent of the electricity and last many times longer. This is the story of how one man combined LEDs with solar energy technology to bring high-quality, low-cost electric light to poor people around the world.

In 1996 Canadian professor David Irvine-Halliday was on a work trip in Nepal when his return flight was canceled. It would be weeks before he could catch another flight home, but the delay gave him time to hike the Annapurna Circuit, a 14-day trek through the Himalayas.

One day, wandering past a school he heard children singing. He looked in the window and wondered how, without light, the kids could study. Sadly, he realized, these conditions are common in poor countries. Some 1.6 billion people in the world have no access to electricity.

People who aren't connected to the electric grid often get their light from kerosene, candles or burning wood. But, the products are expensive, produce only dim light and generate polluting fumes that cause health and environmental problems. Responding to the need for safe, clean and affordable lighting, Irvine-Halliday set to work on a solution.

Back in his laboratory at the University of Calgary, Alberta, he experimented with light emitting diodes, technology he was familiar with as a professor of renewable energy. "I knew that they were virtually indestructible. They lasted for decades because they were putting them under the Pacific and Atlantic Oceans, and they were going to be there for years and years and years working for 24 hours a day," he says.

Irvine-Halliday settled on a one watt bright white light, a Japanese product he discovered on the Internet. Startled by the intense beam he generated when he rigged the diode to his bike generator, he recalls saying to his partner, "Good God, a child could read by the light of a single diode."

In 2000, Irvine-Halliday returned to Nepal to put the system in homes. He first used pedal power, then turned to hydro and finally turned to solar power generation. The single watt solar LED package works, Irvine-Halliday told Capitol Hill staffers at a recent meeting in Washington, because it is affordable, clean and easy to set up and maintain. "The one-time cost of our system — which consists of a small solar panel, a little motorcycle-sized battery and a couple of LED lamps, is less than one hundred dollars," he says. He adds that's about the same as the cost of kerosene for a year.

What started as a family project has emerged as the Light Up the World Foundation, which has reached 25,000 people in 51 countries. Initially systems were given away. Today, growing numbers of villagers are purchasing and maintaining the equipment. "Our short term goal for the next couple of years is that 80 percent of all the systems that Light up the World is involved [with] will be via micro-credit," Irvine-Halliday says, "where the villager borrows from local micro-credit organizations and pays them back." The organization has made a difference in people's lives beyond Irvine-Halliday's expectations.

Acquiring this simple and non-polluting form of electric light, he points out, promotes education, public health, economic security and a cleaner environment. In January, he will retire from his day job at the University of Calgary. He's also decided to give up leadership in Light up the World Foundation to start a company in India that will develop a more energy-efficient and cheaper lighting system that he hopes will bring even more light to the world's poor.

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We Need a Total Fossil Fuel Lockdown for a Climate Revolution

Renewables 2020 Global Status Report highlights renewable energy gaps beyond power, urging decarbonization in heating, cooling, and transport, greener COVID-19 recovery, market reforms, and rapid energy transition to cut CO2 emissions and fossil fuel dependence.

 

Key Points

REN21's annual report on renewable energy progress and policy gaps across power, heating, cooling, and transport.

✅ Calls for decarbonizing heating, cooling, and transport.

✅ Warns COVID-19 recovery must avoid fossil fuel lock-in.

✅ Urges market reforms to boost energy efficiency and renewables.

 

Growth in renewable power has been impressive over the past five years, with over 30% of global electricity now coming from renewables worldwide. But too little is happening in heating, cooling and transport. Overall, global hunger for energy keeps increasing and eats up progress, according to REN21's Renewables 2020 Global Status Report (GSR), released today. The journey towards climate disaster continues, unless we make an immediate switch to efficient and renewable energy in all sectors in the wake of the COVID-19 pandemic.

"Year after year, we report success after success in the renewable power sector. Indeed, renewable power has made fantastic progress. It beats all other fuels in growth and competitiveness. Many national and global organisations already cry victory. But our report sends a clear warning: The progress in the power sector is only a small part of the picture. And it is eaten up as the world's energy hunger continues to increase. If we do not change the entire energy system, we are deluding ourselves," says Rana Adib, REN21's Executive Director.

The report shows that in the heating, cooling and transport sectors, the barriers are still nearly the same as 10 years ago. "We must also stop heating our homes and driving our cars with fossil fuels," Adib claims.

There is no real disruption in the COVID-19 pandemic

In the wake of the extraordinary economic decline due to COVID-19, the IEA predicts energy-related CO2 emissions are expected to fall by up to 8% in 2020. But 2019 emissions were the highest ever, and the relief is only temporary. Meeting the Paris targets would require an annual decrease of at least 7.6% to be maintained over the next 10 years, and UN analysis on NDC ambition underscores the need for faster action. Says Adib: "Even if the lock-downs were to continue for a decade, the change would not be sufficient. At the current pace, with the current system and current market rules, it would take the world forever to come anywhere near a no-carbon system."

"Many recovery packages lock us into a dirty fossil fuel economy"

Recovery packages offer a once-in-a-lifetime chance to make the shift to a low-carbon economy, and green energy investments could accelerate COVID-19 recovery. But according to Adib there is a great risk for this enormous chance to be lost. "Many of these packages include ideas that will instead lock us further into a dirty fossil fuel system. Some directly promote natural gas, coal or oil. Others, though claiming a green focus, build the roof and forget the foundation," she says. "Take electric cars and hydrogen, for example. These technologies are only green if powered by renewables."

Choosing an energy system that supports job creation and social justice

The report points out that "green" recovery measures, such as investment in renewables and building efficiency, are more cost-effective than traditional stimulus measures and yield more returns. It also documents that renewables deliver on job creation, energy sovereignty, accelerated energy access in developing countries, and clean, affordable and sustainable electricity for all objectives worldwide, alongside reduced emissions and air pollution.

"Renewables are now more cost-effective than ever, and recent IRENA analysis shows their potential to decarbonise the energy sector, providing an opportunity to prioritize clean economic recovery packages and bring the world closer to meeting the Paris Agreement Goals. Renewables are a key pillar of a healthy, safe and green COVID-19 recovery that leaves no one behind," said Inger Andersen, Executive Director of the UN Environment Programme (UNEP). "By putting energy transition at the core of economic recovery, countries can reap multiple benefits, from improved air quality to employment generation."

This contrasts with the true cost of fossil fuels, estimated to be USD 5.2 trillion if costs of negative impacts such as air pollution, effects of climate change, and traffic congestion are counted.

Renewable energy systems support energy sovereignty and democracy, empowering citizens and communities, instead of big fossil fuel producers and consumers. "When spending stimulus money, we have to decide: Do we want an energy system that serves some or a system that serves many?", says Adib. "But it's not only about money. We must end any kind of support to the fossil economy, particularly when it comes to heating, cooling and transport. Governments need to radically change the market conditions and rules and demonstrate the same leadership as during the COVID-19 pandemic."

The report finds:

Total final energy demand continues to be on the rise (1.4% annually from 2013 to 2018). Despite significant progress in renewable power generation, the share of renewables in total final energy demand barely increased (9.6% in 2013 to 11% in 2018). Compared to the power sector, the heating, cooling and transport sectors lag far behind (renewable energy share in power, 26%, heating and cooling, 10%, transport, 3%).

Today's progress is largely the result of policies and regulations initiated years ago and focus on the power sector. Major barriers seen in heating, cooling and transport are still almost the same a decade on. Policies are needed to create the right market conditions.

The renewable energy sector employed around 11 million people worldwide in 2018

In 2019, the private sector signed power purchase agreements (PPAs) for a record growth of over 43% from 2018 to 2019 in new renewable power capacity.

The global climate strikes have reached unprecedented levels with millions of people across 150 countries. They have pushed governments to step up climate ambitions. As of April 2020, 1490 jurisdictions - spanning 29 countries and covering 822 million citizens - had issued "climate emergency" declarations, many of which include plans and targets for more renewable-based energy systems.

While some countries are phasing out coal, examples such as Europe's green surge show how renewables can soar as emissions fall, yet others continued to invest in new coal-fired power plants. In addition, funding from private banks for fossil fuel projects has increased each year since the signing of the Paris Agreement, totaling USD 2.7 trillion over the last three years.

"It is clear, renewable power has become mainstream and that is great to see. But the progress in this one sector should not lead us to believe that renewables are a guaranteed success. Governments need to take action beyond economic recovery packages. They also need to create the rules and the environment to switch to an efficient and renewables-based energy system, and action toward 100% renewables is urgently needed worldwide. Globally. Now." concludes Arthouros Zervos, President of REN21.

 

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Gas-electric hybrid vehicles get a boost in the US from Ford, others

U.S. Hybrid Vehicle Sales Outlook highlights rising hybrid demand as an EV bridge, driven by emissions rules, range anxiety, charging infrastructure gaps, and automaker strategies from Ford, Toyota, and Stellantis across U.S. markets.

 

Key Points

Forecast of U.S. hybrid sales shaped by EV adoption, emissions rules, charging access, and automaker strategies.

✅ S&P sees hybrids at 24% of U.S. sales by 2028

✅ Bridges ICE to EV amid range and charging concerns

✅ Ford, Toyota, Stellantis expand U.S. hybrid lineups

 

Hybrid gasoline-electric vehicles may not be dying as fast as some predicted in the auto sector’s rush to develop all-electric models.

Ford Motor is the latest of several top automakers, including Toyota and Stellantis, planning to build and sell hundreds of thousands of hybrid vehicles in the U.S. over the next five years, industry forecasters told Reuters.

The companies are pitching hybrids as an alternative for retail and commercial customers who are seeking more sustainable transportation, but may not be ready to make the leap to a full electric vehicle.

"Hybrids really serve a lot of America," said Tim Ghriskey, senior portfolio strategist at New York-based investment manager Ingalls & Snyder. "Hybrid is a great alternative to a pure electric vehicle (and) it's an easier sell to a lot of customers."

Interest in hybrids is rebounding as consumer demand for pure electrics has not accelerated as quickly as expected, with EV market share dipping in Q1 2024 according to some analyses. Surveys cite a variety of reasons for tepid EV demand, from high initial cost and concerns about range to lengthy charging times and a shortage of public charging infrastructure in many regions.

“With the tightening of emissions requirements, hybrids provide a cleaner fleet without requiring buyers to take the leap into pure electrics,” said Sam Fiorani, vice president at AutoForecast Solutions.

S&P Global Mobility estimates hybrids will more than triple over the next five years, accounting for 24% of U.S. new vehicle sales in 2028. Sales of pure electrics will claim about 37%, supported by strong U.S. EV sales into 2024 momentum, leaving combustion vehicles — including so-called “mild” hybrids — with a nearly 40% share.

S&P estimates hybrids will account for just 7% of U.S. sales this year, and pure electrics 9%, underscoring that EV sales still lag gas cars as internal combustion engine (ICE) vehicles take more than 80%.

Historically, hybrids have accounted for less than 10% of total U.S. sales, with Toyota’s long-running Prius among the most popular models. The Japanese automaker has consistently said hybrids will play a key role in the company's long-range electrification plans as it slowly ramps up investment in pure EVs.

Ford is the latest to roll out more aggressive hybrid plans. On its second-quarter earnings call in late July, Chief Executive Jim Farley surprised analysts, saying Ford expects to quadruple its hybrid sales over the next five years after earlier promising an aggressive push into all-electric vehicles.

“This transition to EVs will be dynamic,” Farley told analysts. “We expect the EV market to remain volatile until the winners and losers shake out.”

Among Ford’s competitors, General Motors appears to have little interest in hybrids in the U.S., while Stellantis will follow Toyota and Ford’s hedge by offering U.S. buyers a choice of different powertrains, including hybrids, until sales of pure electric vehicles start to take off after mid-decade, a potential EV inflection point according to forecaster GlobalData.

In a statement, GM said it, echoing leadership's view that EVs won't go mainstream until key issues are addressed, "continues to be committed to its all-electric future ... While we will have hybrid vehicles in our global fleet, our focus remains on transitioning our portfolio to electric by 2030.”

Stellantis said hybrids now account for 36% of Jeep Wrangler sales and 19% of Chrysler Pacifica sales. In addition to new pure electric models coming soon, "we are very bullish on hybrids going forward," a spokesperson said.

This year, manufacturers are marketing more than 60 hybrids in the U.S. Toyota and its premium Lexus brand are selling at least 18 different hybrid models, enabling the Japanese automaker to maintain its stranglehold on the sector.

Hyundai and sister brand Kia offer seven hybrid models, with Ford and Lincoln six. Stellantis offers just three, and GM’s sole entry, due out later this year, is a hybrid version of the Chevrolet Corvette sports car.

But hybrids remain in short supply at many U.S. dealerships.

Andrew DiFeo, dealer principal at Hyundai of St. Augustine, south of Jacksonville, FL, doesn't see EV adoption hitting the levels the Biden administration wants until EV charging networks are as ubiquitous as gas stations.

"Hybrids are a great bridge to whatever the future holds,” said DiFeo, adding, “I've got zero in stock (and) I've got customers that want all of them."

 

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The gloves are off - Alberta suspends electricity purchase talks with B.C.

Alberta-BC Pipeline Dispute centers on Trans Mountain expansion, diluted bitumen shipments, federal approval, spill response capacity, and electricity trade, as Alberta suspends power talks and Ottawa insists the Kinder Morgan project proceeds in national interest.

 

Key Points

Dispute over Trans Mountain expansion, bitumen limits, and jurisdiction between Alberta, B.C., and Canada.

✅ Alberta suspends BC electricity talks as leverage

✅ Ottawa affirms federal approval and spill response

✅ BC plans advisory panel on diluted bitumen risks

 

Alberta Premier Rachel Notley says her government is suspending talks with British Columbia on the purchase of electricity from the western province.

It’s the first step in Alberta’s fight against the B.C. government’s proposal to obstruct the Kinder Morgan oil pipeline expansion project by banning increased shipments of diluted bitumen to the province’s coast.

Up to $500 million annually for B.C.’s coffers from electricity exports hangs in the balance, Notley said.

“We’re prepared to do what it takes to get this pipeline built — whatever it takes,” she told a news conference Thursday after speaking with Prime Minister Justin Trudeau on the phone.

Notley said she told Trudeau, who’s in Edmonton for a town-hall meeting, that the federal government needs to act decisively to end the dispute.

Speaking on Edmonton talk radio station CHED earlier in the day, Trudeau said the pipeline expansion is in the national interest and will go ahead, even as the federal government undertakes a study on electrification across sectors.

“That pipeline is going to get built,” Trudeau said. “We will stand by our decision. We will ensure that the Kinder Morgan pipeline gets built.”

B.C.’s environment minister has said his minority government plans to ban increased shipments until it can determine that shippers are prepared and able to properly clean up a spill, and, separately, has implemented an electricity rate freeze affecting consumers. He said he will establish an independent scientific advisory panel to study the issue.

The move infuriated Notley, who has accused B.C. of trying to change the rules after the federal government gave the project the green light. B.C. has the right to regulate how any spills would be cleaned up, but can’t dictate what flows through pipelines, she said.

Trudeau said Canada needs to get Alberta’s oil safely to markets other than the U.S. energy market today. He said the federal government did the research and has spent billions on spill response.

“The Kinder Morgan pipeline is not a danger to the B.C. coast,” he said.

Notley said she thanked Trudeau for his assurance that the project will go ahead, but the federal government has to do more to ensure the pipeline’s expansion.

“This is not an Alberta-B.C. issue. This is a Canada-B.C. issue,” she said. “This kind of uncertainty is bad for investment and bad for working people

“Enough is enough. We need to get these things built.”

B.C. Premier John Horgan said his government consulted Alberta and Ottawa about his province’s intentions, noting that Columbia River Treaty talks also shape regional electricity policy.

“I don’t see what the problem is,” Horgan said Thursday at a school opening north of Kelowna, B.C. “It’s within our jurisdiction to put in place regulations to protect the public interest.

“That’s what we are doing.”

He downplayed any possibility of court action or sanctions by Alberta.

“There’s nothing to take to court,” Horgan said. “We are consulting with the people of B.C. It’s way too premature to talk about those sorts of issues.

“Sabre-rattling doesn’t get you very far.”

Speaking in Ottawa, Natural Resources Minister Jim Carr wouldn’t say what Canada might do if British Columbia implements its regulation.

“That’s speculative,” said Carr.

He noted at this point, B.C. has just pledged to consult. He said the federal government heard from thousands of people before the pipeline was approved.

“That’s what they have announced — an intention to consult. We have already consulted.”

B.C.’s proposal creates more uncertainty for Kinder Morgan’s already-delayed Trans Mountain expansion project that would nearly triple the capacity of its pipeline system to 890,000 barrels a day.

 

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South Africa's Eskom could buy less power from wind farms during lockdown

Eskom Wind Power Curtailment reflects South Africa's lockdown-driven drop in electricity demand, prompting grid-balancing measures as Eskom signals reduced IPP procurement from renewable energy projects during low-demand hours, despite guarantees and flexible generation constraints.

 

Key Points

A temporary reduction of wind IPP purchases by Eskom to balance surplus grid capacity during the COVID-19 lockdown slump

✅ Demand drop of 7,500 MW reduced need for variable renewables.

✅ Curtailment likely during low-demand early-morning hours.

✅ IPP revenues protected via contract extensions and guarantees.

 

South African state utility Eskom has told independent wind farms that it could buy less of their power in the coming days, as electricity demand has plummeted during a lockdown, reflecting the Covid-19 impact on renewables worldwide, aimed at curbing the spread of the coronavirus.

Eskom, which is mired in a financial crisis and has struggled to keep the lights on in the past year, said on Tuesday that power demand had dropped by more than 7,500 megawatts since the lockdown started on Friday and that it had taken offline some of its own generators.

The utility supplements its generating capacity, which is mainly derived from coal, by buying power from solar and wind farms, as wind becomes a competitive source of electricity globally, under contracts signed as part of the government’s renewable energy programme.

Spokesman Sikonathi Mantshantsha said Eskom had not yet curtailed power procurement from wind farms but that it had told them, echoing industry warnings on wind investment risk seen by the sector, this could happen “for a few hours a day during the next few days, perhaps until the lockdown is lifted”.

“Most of them are able to feed power into the grid in the early hours of the day. That coincides with the lowest demand period and can highlight curtailment challenges when supply exceeds need. And we now have a lot more capacity than needed,” Mantshantsha said.

During the lockdown imposed by President Cyril Ramaphosa, businesses apart from those deemed “essential services” are closed, mirroring Spanish wind factory closures elsewhere. Many power-hungry mines and furnaces have suspended operations.

Eskom has relatively little of its own “flexible generation” capacity, which can be ramped up or down easily, unlike regions riding a renewables boom in South Australia to export power.

The government has committed to buy up to 200 billion rand ($11.1 billion) of electricity from independent power producers and has issued state guarantees for those purchases.

“They will be compensated for their losses, amid U.S. utility-solar slowdowns being reported - each day lost will be added to their contracts,” Mantshantsha said of the wind farms. “In the end they will not be worse off.”

 

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Federal Government announces funding for Manitoba-Saskatchewan power line

Birtle Transmission Line connects Manitoba Hydro to SaskPower, enabling 215 MW of clean hydroelectricity, improving grid reliability, supporting affordable rates, and advancing Green Infrastructure goals under the Investing in Canada Plan across Manitoba and Saskatchewan.

 

Key Points

A 46 km line moving up to 215 MW from Manitoba Hydro to SaskPower, improving reliability and supplying cleaner power.

✅ Enables interprovincial grid tie between Manitoba and Saskatchewan

✅ Delivers up to 215 MW of renewable hydroelectricity

✅ Supports affordable rates and lower GHG emissions

 

The federal government announced funding for the Birtle Transmission Line Monday morning.

The project will help Manitoba Hydro build a transmission line from Birtle South Station in the Municipality of Prairie View to the Manitoba–Saskatchewan border 46 kilometres northwest. Once completed, the new line will allow up to 215 megawatts of hydroelectricity to flow from the Manitoba Hydro power grid to the SaskPower power grid, similar to the Great Northern Transmission Line connecting Manitoba and Minnesota today.

The government said the transmission line would create a more stable energy supply, keep energy rates affordable and help Saskatchewan's efforts to reduce cumulative greenhouse-gas emissions in that province.

"The Government of Canada is proud to be working with Manitoba to support projects that create jobs and improve people's lives across the province. The Birtle Transmission Line will provide the region with reliable and greener energy, as seen with Canadian hydropower to New York projects, that will help protect our environment while laying the groundwork for clean economic growth," said Jim Carr, member of Parliament for Winnipeg South Centre, on behalf of Catherine McKenna, minister of infrastructure and communities.

The Government of Canada is investing more than $18.7 million, and the government of Manitoba is contributing more than $42 million in this project through the Green Infrastructure Stream of the Investing in Canada Plan, which also supports Atlantic grid improvements nationwide.

"The Province of Manitoba has one of the cleanest electricity grids in Canada and the world with over 99 per cent of our electricity generated from clean, renewable sources, rooted in Manitoba's hydro history," said Central Services Minister Reg Helwer. "The Made-in-Manitoba Climate and Green Plan is good not only for Manitoba but for Canada and globally."

Jay Grewal, president, and CEO of Manitoba Hydro said the funding is a great example of co-operation between the provincial and federal governments, including investments in smart grid technology that modernize local networks.

"We are very pleased that Manitoba Hydro's Birtle Transmission Project is among the first projects to receive funding under the Canada Infrastructure Program, and we would like to thank both levels of governments for recognizing the importance of the project as we strengthen ties with our neighbours in Saskatchewan, as U.S.-Canada transmission approvals advance elsewhere," said Grewal.

A spokesperson for Manitoba Hydro said it’s too early to say how many jobs will be created during construction, as final contracts have not yet been awarded.

 

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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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