Romania enhances safety at Cernavoda, IAEA reports

Iceland Bitcoin Mining Energy Shortage highlights surging cryptocurrency and blockchain data center electricity demand, as hydroelectric and geothermal power strain to cool servers, stabilize grid, and meet rapid mining farm growth amid Arctic-friendly conditions.

Key Points

Crypto mining data centers in Iceland are outpacing renewable power, straining the grid and exceeding residential electricity demand.

✅ Hydroelectric and geothermal capacity nearing allocation limits

✅ Cooling-friendly climate draws energy-hungry mining farms

✅ Grid planning and regulation lag rapid data center growth

The value of bitcoin may have stumbled in recent months, but in Iceland it has known only one direction so far: upward. The stunning success of cryptocurrencies around the globe has had a more unexpected repercussion on the island of 340,000 people: It could soon result in an energy shortage in the middle of the Atlantic Ocean.

As Iceland has become one of the world's prime locations for energy-hungry cryptocurrency servers — something analysts describe as a 21st-century gold-rush equivalent — the industry’s electricity demands have skyrocketed, too. For the first time, they now exceed Icelanders’ own private energy consumption, and energy producers fear that they won’t be able to keep up with rising demand if Iceland continues to attract new companies bidding on the success of cryptocurrencies, a concern echoed by policy moves like Russia's proposed mining ban amid electricity deficits.

Companies have flooded Iceland with requests to open new data centers to “mine” cryptocurrencies in recent months, even as concerns mount that the country may have to slow down investments amid an increasingly stretched electricity generation capacity, a dynamic seen in BC Hydro's suspension of new crypto connections in Canada.

“There was a lot of talk about data centers in Iceland about five years ago, but it was a slow start,” Johann Snorri Sigurbergsson, a spokesman for Icelandic energy producer HS Orka, told The Washington Post. “But six months ago, interest suddenly began to spike. And over the last three months, we have received about one call per day from foreign companies interested in setting up projects here.”

“If all these projects are realized, we won’t have enough energy for it,” Sigurbergsson said.

Every cryptocurrency in the world relies on a “blockchain” platform, which is needed to trade with digital currencies. Tracking and verifying a transaction on such a platform is like solving a puzzle because networks are often decentralized, and there is no single authority in charge of monitoring payments. As a result, a transaction involves an immense number of mathematical calculations, which in turn occupy vast computer server capacity. And that requires a lot of electricity, as analyses of bitcoin's energy use indicate worldwide.

The bitcoin rush may have come as a surprise to locals in sleepy Icelandic towns that are suddenly bustling with cryptocurrency technicians, but there’s a simple explanation. “The economics of bitcoin mining mean that most miners need access to reliable and very cheap power on the order of 2 or 3 cents per kilowatt hour. As a result, a lot are located near sources of hydro power, where it’s cheap,” Sam Hartnett, an associate at the nonprofit energy research and consulting group Rocky Mountain Institute, told the Washington Post.

Top financial regulators briefed a Senate panel on Feb. 6 about their work with cryptocurrencies like Bitcoin, and the risks to potential investors. (Reuters)

Located in the middle of the Atlantic Ocean and famous for its hot springs and mighty rivers, Iceland produces about 80 percent of its energy in hydroelectric power stations, compared with about 6 percent in the United States, and innovations such as underwater kites illustrate novel ways to harness marine energy. That and the cold climate make it a perfect location for new data-mining centers filled with servers in danger of overheating.

Those conditions have attracted scores of foreign companies to the remote location, including Germany's Genesis Mining, which moved to Iceland about three years ago. More have followed suit since then or are in the process of moving. 

While some analysts are already sensing a possible new revenue source for the country that is so far mostly known abroad as a tourist haven and low-budget airline hub, others are more concerned by a phenomenon that has so far mostly alarmed analysts because of its possible financial unsustainability, alongside issues such as clean energy's dirty secret that complicate the picture. Some predictions have concluded that cryptocurrency computer operations may account for “all of the world’s energy by 2020” or may already account for the equivalent of Denmark's energy needs. Those predictions are probably too alarmist, though. 

Most analysts agree that the real energy-consumption figure is likely smaller, and several experts recently told the Washington Post that bitcoin — currently the world's biggest cryptocurrency — used no more than 0.14 percent of the world’s generated electricity, as of last December. Even though global consumption may not be as significant as some have claimed, it still presents a worrisome drain for a tiny country such as Iceland, where consumption suddenly began to spike with almost no warning — and continues to grow fast.

Some networks are considering or have already pushed through changes to their protocols, designed to reduce energy use. But implementing such changes for the leading currency, bitcoin, won't be as easy because it is inherently decentralized. The companies that provide the vast amounts of computing power needed for these transactions earn a small share, comparable to a processing fee or a reward.

They are the source of the Icelandic bitcoin miners’ income — a revenue source that many Icelanders are still not quite sure what to make of, especially if the lights start flickering.

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Seattle Capitol Hill Apartment Fire highlights an electrical fire from an overheated power strip, a two-alarm response by 70 firefighters, safe evacuation, displaced resident aid, and prevention tips like smoke detectors and load limits.

Key Points

Two-alarm early-morning blaze in Seattle traced to an overheated power strip, displacing one resident and injuring none.

✅ Origin: overheated power strip ignited nearby combustibles

✅ Response: 70 firefighters, two-alarm, rapid containment

✅ Safety: avoid overloads; inspect cords; use smoke detectors

An early-morning fire in Seattle’s Capitol Hill neighborhood severely damaged a three-story apartment building, displacing one resident. The blaze, which broke out around 4:34 a.m. on a Friday, drew more than 70 firefighters to the scene, as other critical sectors have implemented on-site staffing during outbreaks to maintain operations, and was later traced to an overheated power strip.

The Fire Incident

The Seattle Fire Department responded to the fire, which had started on the second floor of the building in the 1800 block of 12th Avenue. Upon arrival, crews were met with heavy smoke and flames coming from one unit. The fire quickly spread to a unit on the third floor, prompting the Seattle Fire Department to escalate their response to a two-alarm fire due to its size and the potential threat to nearby structures.

Firefighters initially attempted to contain the blaze from the exterior before they moved inside the building to fully extinguish the fire. Thankfully, the fire was contained to the two affected units, preventing the destruction of the remaining seven apartments in the building.

All residents safely evacuated the building on their own. Despite the substantial damage to the two apartments, no injuries were reported. One resident was displaced by the fire and was assisted by the Red Cross in finding temporary accommodation.

Cause of the Fire

Investigators later determined that the fire was accidental, most likely caused by an overheated electrical power strip. The power strip had reportedly ignited nearby combustible materials, sparking the flames that quickly spread throughout the unit. Although the exact details are still under investigation, the fire serves as a stark reminder of the potential risks associated with overloaded or damaged electrical equipment and how electrical safety knowledge gaps can contribute to incidents.

The Risks of Power Strips

Power strips, while essential for providing multiple outlets, can pose a serious fire hazard if used improperly, and specialized arc flash training in Vancouver underscores the importance of understanding electrical hazards across settings.

This fire in Seattle highlights the importance of maintaining electrical devices and following proper usage guidelines. According to experts, it is crucial to regularly inspect power strips for any visible damage, such as frayed cords or scorch marks, and to replace them if necessary. It's also advisable to avoid using power strips with high-power appliances like space heaters, microwaves, or refrigerators.

Impact and Community Response

The fire has raised awareness about the dangers of electrical hazards in residential buildings, especially in older apartment complexes where wiring systems may not be up to modern standards. Local authorities and fire safety experts are urging residents to review safety guidelines and ensure that their living spaces are free from potential fire hazards and to avoid dangerous stunts at dams and towers that can lead to serious injuries.

Seattle's fire department, which responded to this incident, continues to emphasize fire prevention and safety education. This event also highlights the importance of having working smoke detectors and clear escape routes in apartment buildings, and ongoing fire alarm training can improve system reliability. The Seattle Fire Department recommends that all tenants know the locations of fire exits and practice safe evacuation procedures, especially in high-rise or multi-unit buildings.

Additionally, the Red Cross has stepped in to assist the displaced resident. The organization provides temporary shelter, food, and financial aid for those affected by disasters like fires. The fire underscores the importance of having emergency preparedness plans in place and the need for immediate relief for those who lose their homes in such incidents.

The Seattle apartment fire, which displaced one resident and caused significant damage to two units, serves as a reminder of the potential dangers associated with improperly maintained or overloaded electrical devices, especially power strips, and how industry recognition, such as a utility safety award, reinforces best practices. While the cause of this fire was linked to an overheated power strip, it could have easily been prevented with regular inspections and safer practices.

As fire departments continue to respond to similar incidents, it is critical for residents to stay informed about fire safety, particularly regarding electrical equipment and outdoor hazards like safety near downed power lines in storm conditions. Awareness, proper maintenance, and following safety protocols can significantly reduce the risk of electrical fires and help protect residents from harm.

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Alliant Energy Net-Zero Carbon Plan outlines carbon-neutral electricity by 2050, coal retirements by 2040, major solar and wind additions, gas transition, battery storage, hydrogen, and carbon credits to reduce emissions and lower customer costs.

Key Points

Alliant Energy's strategy to reach carbon-neutral power by 2050 via coal phaseout, renewables, storage, and offsets.

✅ Targets net-zero electricity by 2050

✅ Retires all coal by 2040; expands solar and wind

✅ Uses storage, hydrogen, and offsets to bridge gaps

Alliant Energy has joined a small but growing group of utilities aiming for carbon-neutral electricity by 2050.

In a report released Wednesday, the Madison-based company announced a goal of “net-zero carbon dioxide emissions” from its electricity generation along with plans to eliminate all coal-powered generation by 2040, a decade earlier than the company’s previous target.

Alliant, which is pursuing plans that would make it the largest solar energy generator in Wisconsin, said it is on track to cut its 2005 carbon emissions in half by 2030.

Both goals are in line with targets an international group of scientists warn is necessary to avoid the most catastrophic impacts of climate change. But reducing greenhouse gasses was not the primary motivation, said executive vice president and general counsel Jim Gallegos.

“The primary driver is focused on our customers and communities and setting them up … to be competitive,” Gallegos said. “We do think renewables are going to do it better than fossil fuels.”

Alliant has told regulators it can save customers up to $6.5 billion over the next 35 years by adding more than 1,600 megawatts of renewable generation, closing one of its two remaining Wisconsin coal plants and taking other undisclosed actions.

In a statement, Alliant chairman and CEO John Larsen said the goal is part of broader corporate and social responsibility efforts “guided by our strategy and designed to deliver on our purpose — to serve customers and build stronger communities.”

Coal out; gas remains
The goal applies only to Alliant’s electricity generation — the company has no plans to stop distributing natural gas for heating — and is “net-zero,” meaning the company could use some form of carbon capture or purchase carbon credits to offset continuing emissions.

The plan relies heavily on renewable generation — seen in regions embracing clean power across North America — including the addition of up to 1,000 megawatts of new Wisconsin solar plants by the end of 2023 and 1,000 megawatts of Iowa wind generation added over the past four years — as well as natural gas generators to replace its aging coal fleet.

But Jeff Hanson, Alliant’s director of sustainability, said eliminating or offsetting all carbon emissions will require new tools, such as battery storage or possibly carbon-free fuels such as hydrogen, and awareness of the Three Mile Island debate over the role of nuclear power in the mix.

“Getting to the 2040 goals, that’s all based on the technologies of today,” Hanson said. “Can we get to net zero today? The challenge would be a pretty high bar to clear.”

Gallegos said the plan does not call for the construction of more large-scale natural gas generators like the recently completed $700 million West Riverside Energy Center in Beloit, though natural gas will remain a key piece of Alliant’s generation portfolio.

Alliant announced plans in May to close its 400-megawatt Edgewater plant in Sheboygan by the end of 2022, echoing how Alberta is retiring coal by 2023 as markets shift, but has not provided a date for the shutdown of the jointly owned 1,100-megawatt Columbia Energy Center near Portage, which received about $1 billion worth of pollution-control upgrades in the past decade.

Alliant’s Iowa subsidiary plans to convert its 52-year-old, 200-megawatt Burlington plant to natural gas by the end of next year and a pair of small coal-fired generators in Linn County by 2025. That leaves the 250-megawatt plant in Lansing, which is now 43 years old, and the 734-megawatt Ottumwa plant as the remaining coal-fired generators, even as others keep a U.S. coal plant running indefinitely elsewhere.

Earlier this year, the utility asked regulators to approve a roughly $900 million investment in six solar farms across the state with a total capacity of 675 megawatts, similar to plans in Ontario to seek new wind and solar to address supply needs. The company plans to apply next year for permission to add up to 325 additional megawatts.

Alliant said the carbon-neutral plan, which entails closing Edgewater along with other undisclosed actions, would save customers between $2 billion and $6.5 billion through 2055 compared to the status quo.

Tom Content, executive director of the Citizens Utility Board, said the consumer advocacy group wants to ensure that ratepayers aren’t forced to continue paying for coal plants that are no longer needed while also paying for new energy sources and would like to see a bigger role for energy efficiency and more transparency about the utilities’ pathways to decarbonization.

‘They could do better’
Environmental groups said the announcement is a step in the right direction, though they say utilities need to do even more to protect the environment and consumers.

Amid competition from cheaper natural gas and renewable energy and pressure from environmentally conscious investors, U.S. utilities have been closing coal plants at a record pace in recent years, as industry CEOs say a coal comeback is unlikely in the U.S., a trend that is expected to continue through the next decade.

“This is not industry leadership when we’re talking about emission reductions,” said Elizabeth Katt Reinders, regional campaign director for the Sierra Club, which has called on Alliant to retire the Columbia plant by 2026.

Closing Edgewater and Columbia would get Alliant nearly halfway to its emissions goals while saving customers more than $250 million over the next decade, according to a Sierra Club study released earlier this year.

“Retiring Edgewater was a really good decision. Investing in 1,000 megawatts of new solar is game-changing for Wisconsin,” Katt Reinders said. “In the same breath we can say this emissions reduction goal is unambitious. Our analysis has shown they can do far more far sooner.”

Scott Blankman, a former Alliant executive who now works as director of energy and air programs for Clean Wisconsin, said Alliant should not run the Columbia plant for another 20 years.

“If they’re saying they’re looking to get out of coal by 2040 in Wisconsin I’d be very disappointed,” Blankman said. “I do think they could do better.”

Alliant is the 15th U.S. investor-owned utility to set a net-zero target, according to the Natural Resources Defense Council, joining Madison Gas and Electric, which announced a similar goal last year. Minnesota-based Xcel Energy, which serves customers in western Wisconsin, was the first large investor-owned utility to set such a target, as state utilities report declining returns in coal operations.

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Atlin Hydro and Transmission Project delivers First Nation-led clean energy via hydropower to the Yukon grid, replacing diesel, cutting emissions, and creating jobs, with a 69-kV line from Atlin, B.C., supplying about 35 GWh annually.

Key Points

A First Nation-led 8.5 MW hydropower and 69-kV line supplying clean energy to the Yukon, reducing diesel use.

✅ 8.5 MW capacity; ~35 GWh annually to Yukon grid

✅ 69-kV, 92 km line links Atlin to Jakes Corner

✅ Creates 176 construction jobs; cuts diesel and emissions

A First Nation-led clean-power generation project for British Columbia’s Northwest will provide a significant economic boost and good jobs for people in the area, as well as ongoing revenue from clean energy sold to the Yukon.

“This clean-energy project has the potential to be a win-win: creating opportunities for people, revenue for the community and cleaner air for everyone across the Northwest,” said Premier John Horgan. “That’s why our government is proud to be working in partnership with the Taku River Tlingit First Nation and other levels of government to make this promising project a reality. Together, we can build a stronger, cleaner future by producing more clean hydropower to replace fossil fuels – just as they have done here in Atlin.”

The Province is contributing $20 million toward a hydroelectric generation and transmission project being developed by the Taku River Tlingit First Nation (TRTFN) to replace diesel electricity generation in the Yukon, which is also supported by the Government of Yukon and the Government of Canada, and comes as BC Hydro demand fell during COVID-19 across the province.

“Renewable-energy projects are helping remote communities reduce the use of diesel for electricity generation, which reduces air pollution, improves environmental outcomes and creates local jobs,” said Bruce Ralston, Minister of Energy, Mines and Low Carbon Innovation. “This project will advance reconciliation with TRTFN, foster economic development in Atlin and support intergovernmental efforts to reduce greenhouse gas emissions.”

TRTFN is based in Atlin with territory in B.C., the Yukon, and Alaska. TRTFN is an active participant in clean-energy development and, since 2009, has successfully replaced diesel-generated electricity in Atlin with a 2.1-megawatt (MW) hydro facility amid oversight issues such as BC Hydro misled regulator elsewhere in the province today.

TRTFN owns the Tlingit Homeland Energy Limited Partnership (THELP), which promotes economic development through clean energy. THELP plans to expand its hydro portfolio by constructing the Atlin Hydro and Transmission Project and selling electricity to the Yukon via a new transmission line, in a landscape shaped by T&D rates decisions in jurisdictions like Ontario for cost recovery.

The Government of Yukon is requiring its Yukon Energy Corporation (YEC) to generate 97% of its electricity from renewable resources by 2030. This project provides an opportunity for the Yukon government to reduce reliance on diesel generators and to meet future load growth, at a time when Manitoba Hydro's debt pressures highlight utility cost challenges.

The new transmission line between Atlin and the Yukon grid will include a fibre-optic data cable to support facility operations, with surplus capacity that can be used to bring high-speed internet connectivity to Atlin residents for the first time.

“Opportunities like this hydroelectricity project led by the Taku River Tlingit First Nation is a great example of identifying and then supporting First Nations-led clean-energy opportunities that will support resilient communities and provide clean economic opportunities in the region for years to come. We all have a responsibility to invest in projects that benefit our shared climate goals while advancing economic reconciliation.” said George Heyman, Minister of Environment and Climate Change Strategy.

“Thank you to the Government of British Columbia for investing in this important project, which will further strengthen the connection between the Yukon and Atlin. This ambitious initiative will expand renewable energy capacity in the North in partnership with the Taku River Tlingit First Nation while reducing the Yukon’s emissions and ensuring energy remains affordable for Yukoners.“ said Sandy Silver, Premier of Yukon.

“The Atlin Hydro Project represents an important step toward meeting the Yukon’s growing electricity needs and the renewable energy targets in the Our Clean Future strategy. Our government is proud to contribute to the development of this project and we thank the Government of British Columbia and all partners for their contributions and commitment to renewable energy initiatives. This project demonstrates what can be accomplished when communities, First Nations and federal, provincial and territorial governments come together to plan for a greener economy and future.” said John Streicker, Minister Responsible for the Yukon Development Corporation. 

“Atlin has enjoyed clean and renewable energy since 2009 because of our hydroelectric project. Over its lifespan, Atlin’s hydro opportunity will prevent more than one million tonnes of greenhouse gases from being created to power the southern Yukon. We are looking forward to the continuation of this project. Our collective dream is to meet our environmental and economic goals for the region and our local community within the next 10 years. We are so grateful to all our partners involved for their financial support, as we continue onward in creating an energy efficient and sustainable North.” said Charmaine Thom, Taku River Tlingit First Nation spokesperson.

Quick Facts:

• The 8.5-MW project is expected to provide an average of 35 gigawatt hours of energy annually to the Yukon. To accomplish this, TRTFN plans to leverage the existing water storage capability of Surprise Lake, add new infrastructure, and send power 92 km north to Jakes Corner, Yukon, along a new 69-kilovolt transmission line.
• The project is expected to cost $253 - 308.5 million, the higher number reflecting recently estimated impacts of inflation and supply chain cost escalation, alongside sector accounting concerns such as deferred BC Hydro costs noted in recent reports.
• The project is expected to have a positive impact on local and provincial economic development in the form of, even as governance debates like Manitoba Hydro board changes draw attention elsewhere:
• 176 full-time positions during construction;
• six to eight full-time positions in operations and maintenance over 40 years; and
• increased business for B.C. contractors.
• Territorial and federal funders have committed $151.1 million to support the project, most recently the $32.2 million committed in the 2022 federal bdget.

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Iran Renewable Energy Strategy targets productivity first, then wind power expansion, investment, and exports, overcoming US sanctions, banking and forex limits, via private sector partnerships, precise wind maps, and regional grid interconnections.

Key Points

A policy prioritizing efficiency, wind deployment, and investor access while navigating US sanctions and currency limits.

✅ Prioritize efficiency, then scale wind generation capacity

✅ Leverage private sector, rial contracts, attract foreign capital

✅ Map high-wind corridors: Zabol, Khaf, Doroud; target exports

Deputy Energy Minister on Renewable Energies Affairs says the U.S. sanctions have currently affected the economic, banking and forex sectors of the country as the country‘s medicine is under sanctions and it means renewable energies are also under sanctions, and, globally, pandemic disruptions have compounded pressures on supply chains.

Speaking in a press conference yesterday, Mohammad Satkin said leading countries first focus on productivity then they turn to electricity production and the ministry in the first step has focused on productivity then on renewables, noting that renewables are now the cheapest new power in many regions, reiterating that the ministry will use all existing potentials in this regard especially in utilizing wind.

He added that the ministry is doing its best that the country would become the hub in the region for rush of investors and those who want take advantage of Iran’s experience in renewables, as markets like the U.S. scale renewables to a quarter of generation in coming years.

Satkin added that in the eastern part, the country has the biggest windy fields with capacity over 40mw. So the ministry is doing its best with full support of the private sector in equipping and investing in this field to carry out new policies.

He noted that in the past 12 years, wind potentials of the country have been under study, noting that country has three special channels in the east as one of them is north of Zabol which is very valuable in terms of energy and it has capability for construction of 2 to 3mw power station.

Satkin further said Khaf channel is the other one which has one of the most unique winds in the world, while Saudi wind expansion underscores regional momentum, and it can be developed for over 1000mw station. The windy region of Doroud is the third channel where the 50mw project has been kicked off there and it has capability for construction of some thousand-megawatt wind power station.

He added that Iran has prepared one of the most precise maps and it has even identified the border regions like with Afghanistan and perhaps in the future, Iran and Afghanistan may launch a joint project as Iran has enough expertise to offer its neighboring countries and as IRENA's decarbonisation roadmap highlights wider socio-economic benefits.

On signing agreement with foreign companies, Satkin said the ministry pays the sum of all contracts with domestic companies is paid in national currency rial as it is unable to pay in dollar or other currencies but Iranian companies may enjoy having foreign backings, including initiatives like ADFD-IRENA funding that support developing markets, and the ministry tries to attract foreign capital.

He also pointed to exports of renewables, adding that the government has authorized export of renewable energy but it needs proper planning to be assured of electricity production in order to export it to the neighboring states whenever they need, especially as Ireland targets over one-third green power within a few years.

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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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