U.S. renewables standard offers mixed bag

Jay Grewal Manitoba Hydro Appointment marks the first woman CEO at the Crown utility, amid debt, rate increase plans, privatization debate, and Metis legal challenge, following board turmoil and Premier Pallister's strained relations.

Key Points

The selection of Jay Grewal as Manitoba Hydro's first woman CEO amid debt, rate hikes, and legal disputes.

✅ First woman CEO of Manitoba Hydro

✅ Faces debt, rate hikes, and project overruns

✅ Amid privatization debate and Metis legal action

The Manitoba government has appointed a new president and chief executive officer at its Crown-owned energy utility.

Jay Grewal becomes the first woman to head Manitoba Hydro, and takes over the top spot as the utility faces mounting financial challenges, rising electricity demand and turmoil.

Grewal has previously held senior roles at Capstone Mining Corp and B.C. Hydro, and is currently president of the Northwest Territories Power Corporation.

She will replace outgoing president Kelvin Shepherd, who recently announced he is retiring, on Feb. 4.

The utility was hit by the sudden resignations of nine of its 10 board members in March, who said they had been unable to meet with Premier Brian Pallister to discuss pressing issues like servicing energy-intensive customers facing the utility.

Manitoba Hydro is also in the middle of a battle between the Progressive Conservative government and the Manitoba Metis Federation over the cancellation of two agreements that would have given the Metis $87 million.

The federation has launched a legal challenge over one deal and says its likely going to do the same over the second agreement.

Grewal also takes over the utility at a time when it has racked up billions of dollars in debt building new generating stations and transmission lines. Manitoba Hydro has told the provincial regulatory agency it needs rate increases of nearly eight per cent a year for the next few years to help pay for the projects.

The utility also exports electricity, with deals such as SaskPower's purchase agreement expanding sales to Saskatchewan.

"Ms. Grewal is a proven leader, with extensive senior leadership experience in the utility, resource and consulting sectors," Crown Services Minister Colleen Mayer said in a written statement Thursday.

The Opposition New Democrats said Grewal's appointment is a sign the government wants to privatize Manitoba Hydro. Grewal's time at B.C. Hydro coincided with the privatization of some parts of that Crown utility, the NDP said.

The B.C. premier at the time, Gordon Campbell, was recently hired by Manitoba to review two major projects that ran over-budget and have added to the provincial debt.

NDP Leader Wab Kinew asked Pallister in the legislature Thursday to promise not to privatize Manitoba Hydro. Pallister would only point to a law that requires a referendum to be held before a Crown entity can be sold off.

"We stand by that (law)," Pallister said. "We believe Manitobans are the proper decision-makers in respect of any of the future structuring of Manitoba Hydro."

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Atlantic Canada Energy Regulatory Reform accelerates smart grids, renewables, hydrogen, and small modular reactors to meet climate targets, enabling interprovincial transmission, EV charging, and decarbonization toward a net-zero grid by 2035 with agile, collaborative policies.

Key Points

A policy shift enabling smart grids, clean energy, and transmission upgrades to decarbonize Atlantic Canada by 2035.

✅ Agile rules for smart grids, EV load, and peak demand balancing

✅ Interprovincial transmission: Maritime Link, NB-PEI, Atlantic Loop

✅ Supports hydrogen, SMRs, and renewables to cut GHG emissions

Atlantica Centre for Energy Senior Policy Consultant Neil Jacobsen says the future of Atlantic Canada’s electricity grid depends on agile regulations, supported by targeted research such as the $2M Atlantic grid study, that match the pace at which renewable technologies are being developed in the race to meet Canada’s climate goals.

In an interview, Jacobsen stressed the need for a more modernized energy regulatory framework, so the Atlantic Provinces can collaborate to quickly develop and adopt cleaner energy.

To this end, Atlantica released a paper that makes the case for responsive smart grid technology, the adaptation of alternative forms of clean energy, the adaptation of hydrogen as an energy source, petroleum price regulation in Atlantic Canada and small modular reactors.

Jacobsen said regulations need to match Canada’s urgency around reducing greenhouse gas emissions by 40 to 45 percent by 2030, achieving a net-neutral national power grid by 2035 and ultimately a net-zero grid by 2050 in Canada – and the goal that 50 percent of Canadian vehicle sales being electric by 2030.

“It’s an evolution of policy and regulations to adapt to a very aggressive timeline of aggressive climate change and decarbonization targets,” said Jacobsen.

“These are transformational energy and environmental commitments, so the path forward really requires the ability to introduce and adapt and move forward with new clean renewable energy technologies.”

Jacobsen said Atlantica’s recommendations are not a criticism of existing regulations– but an acknowledgment that they need to evolve.

He noted newer, clearer regulations will make way for new energy sources – particularly a region that has the countries highest rates of dependency on fossil fuels and growing climate risks, with Atlantic grids under threat from more intense storms.

“We have a long way to go, but at the same time, we have a lot to celebrate. Atlantic Canada is leading the country in reducing greenhouse gas emissions,” said Jacobsen.

“There are new ways of producing energy that requires us to be able to be much more responsive and this is an opportunity to create a higher level of alignment here, in Atlantic Canada.”

Jacobsen said Atlantica is looking to aid interprovincial cooperation in providing power, echoing calls for a western Canadian grid elsewhere, through projects like the 500-megawatt, 170-kilometre Maritime Link that transports power from the Muskrat Falls hydroelectric dam in Labrador, through Newfoundland and across the Cabot Strait, to Nova Scotia – or NB Power’s export of electricity to P.E.I., via sub-sea cables crossing the Northumberland Strait.

He noted streamlined regulations may allow for more potential wider-scale partnerships, like the proposed Atlantic Loop project, aligning with macrogrid investments that would involve upgrading transmission capacity on the East Coast to allow hydroelectric power from Labrador and Quebec to displace coal use in the region.

Atlantic Canada has led the way with adaption new renewable technologies, noted Jacobsen, referring to nuclear startups Moltex Energy and ARC Nuclear Canada’s efforts to develop small modular nuclear reactor technology in New Brunswick, as well as the potential of adopting hydrogen fuel technology and Nova Scotia’s strides in developing offshore renewable energy.

“I don’t think we have any choice other than to be forceful and aggressive in driving forward a renewable energy agenda.”

Jacobsen said cooperation between the Atlantic provinces is crucial because of how challenging it is to meet energy demand with heavy seasonal and daily variations in energy demand in the region – something smart grid technology could address.

Smart Grid Atlantic is a four-year research and demonstration program testing technologies that provide cleaner local power, support a smarter electricity infrastructure across the region, more renewable power, more information and control over power use and more reliable electricity.

“It can be challenging for utilities to meet those cyclical demands, especially as grids are increasingly exposed to harsh weather across Canada. Smart girds add knowledge of the flow of electrons in a way that can help even out those electricity demands – and quite frankly, those demands will only increase when you look at the electrification of the transportation sector,” he said.

Jacobsen said Atlantica’s paper and call for modernized regulations are only the beginning of a conversation.

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Great Northern Transmission Line delivers 250 MW of carbon-free hydropower from Manitoba Hydro, strengthening Midwest grid reliability, enabling wind storage balancing, and advancing Minnesota Power's EnergyForward strategy for cleaner, renewable energy across the region.

Key Points

A 500 kV cross-border line delivering 250 MW of carbon-free hydropower, strengthening reliability and enabling renewables.

✅ 500 kV, 224-mile line from Manitoba to Minnesota

✅ Delivers 250 MW hydropower via ALLETE-Minnesota Power

✅ Enables wind storage and grid balancing with Manitoba Hydro

Minnesota Power, a utility division of ALLETE Inc. (NYSE:ALE), has energized its Great Northern Transmission Line, bringing online an innovative delivery and storage system for renewable energy that spans two states and one Canadian province, similar to the Maritime Link project in Atlantic Canada.

The 500 kV line is now delivering 250 megawatts of carbon-free hydropower from Manitoba, Canada, to Minnesota Power customers.

Minnesota Power completed the Great Northern Transmission Line (GNTL) in February 2020, ahead of schedule and under budget. The 224-mile line runs from the Canadian border in Roseau County to a substation near Grand Rapids, Minnesota. It consists of 800 tower structures which were fabricated in the United States and used 10,000 tons of North American steel. About 2,200 miles of wire were required to install the line's conductors. The GNTL also is contributing significant property tax revenue to local communities along the route.

"This is such an incredible achievement for Minnesota Power, ALLETE, and our region, and is the culmination of a decade-long vision brought to life by our talented and dedicated employees," said ALLETE President and CEO Bethany Owen. "The GNTL will help Minnesota Power to provide our customers with 50 percent renewable energy less than a year from now. As part of our EnergyForward strategy, it also strengthens the grid across the Midwest and in Canada, enhancing reliability for all of our customers."

With the GNTL energized and connected to Manitoba Hydro's recently completed Manitoba-Minnesota Transmission Project at the border, the companies now have a unique "wind storage" mechanism that quickly balances energy supply and demand in Minnesota and Manitoba, and enables a larger role for renewables in the North American energy grid.

The GNTL and its delivery of carbon-free hydropower are important components of Minnesota Power's EnergyForward strategy to transition away from coal and add renewable power sources while maintaining reliable and affordable service for customers, echoing interties like the Maritime Link that facilitate regional power flows. It also is part of a broader ALLETE strategy to advance and invest in critical regional transmission and distribution infrastructure, such as the TransWest Express transmission project, to ensure grid integrity and enable cleaner energy to reduce carbon emissions.

"The seed for this renewable energy initiative was planted in 2008 when Minnesota Power proposed purchasing 250 megawatts of hydropower from Manitoba Hydro. Beyond the transmission line, it also included a creative asset swap to move wind power from North Dakota to Minnesota, innovative power purchase agreements, and a remarkable advocacy process to find an acceptable route for the GNTL," said ALLETE Executive Chairman Al Hodnik. "It marries wind and water in a unique connection that will help transform the energy landscape of North America and reduce carbon emissions related to the existential threat of climate change."

Minnesota Power and Manitoba Hydro, a provincial Crown Corporation, coordinated on the project from the beginning, navigating National Energy Board reviews along the way. It is based on the companies' shared values of integrity, environmental stewardship and community engagement.

"The completion of Minnesota Power's Great Northern Transmission Line and our Manitoba-Minnesota Transmission Project is a testament to the creativity, perseverance, cooperation and skills of hundreds of people over so many years on both sides of the border," said Jay Grewal, president and CEO of Manitoba Hydro. "Perhaps even more importantly, it is a testament to the wonderful, longstanding relationship between our two companies and two countries. It shows just how much we can accomplish when we all work together toward a common goal."

Minnesota Power engaged federal, state and local agencies; the sovereign Red Lake Nation and other tribes, reflecting First Nations involvement in major transmission planning; and landowners along the proposed routes beginning in 2012. Through 75 voluntary meetings and other outreach forums, a preferred route was selected with strong support from stakeholders that was approved by the Minnesota Public Utilities Commission in April 2016.

A four-year state and federal regulatory process culminated in late 2016 when the federal Department of Energy approved a Presidential Permit for the GNTL, similar to the New England Clean Power Link process, needed because of the international border crossing. Construction of the line began in early 2017.

"A robust stakeholder process is essential to the success of any project, but especially when building a project of this scope," Owen said. "We appreciated the early engagement and support from stakeholders, local communities and tribes, agencies and regulators through the many approval milestones to the completion of the GNTL."

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U.S. Power Grid D+ Rating underscores aging infrastructure, rising outages, cyber threats, EMP and solar flare risks, strained transmission lines, vulnerable transformers, and slow permitting, amplifying reliability concerns and resilience needs across national energy systems.

Key Points

ASCE's D+ grade flags aging infrastructure, rising outages, and cyber, EMP, and weather risks needing investment.

✅ Major outages rising; weather remains top disruption driver.

✅ Aging transformers, transmission lines, limited maintenance.

✅ Cybersecurity gaps via smart grid, EV charging, SCADA.

The U.S. power grid just received its “grade card” from the American Society of Civil Engineers (ASCE) and it barely passed.

The overall rating of our antiquated electrical system was a D+. Major power outages in the United States, including widespread blackouts, have grown from 76 in 2007 to 307 in 2011, according to the latest available statistics. The major outage figures do not take into account all of the smaller outages which routinely occur due to seasonal storms.

The American Society of Civil Engineers power grid grade card rating means the energy infrastructure is in “poor to fair condition and mostly below standard, with many elements approaching the end of their service life.” It further means a “large portion of the system exhibits significant deterioration” with a “strong risk of failure.”

Such a designation is not reassuring and validates those who purchased solar generators over the past several years.

#google#

The vulnerable state of the power grid gets very little play by mainstream media outlets. Concerns about a solar flare or an electromagnetic pulse (EMP) attack instantly sending us back to an 1800s existence are legitimate, but it may not take such an extreme act to render the power grid a useless tangle of wires. The majority of the United States’ infrastructure and public systems evaluated by the ASCE earned a “D” rating. A “C” ranking (public parks, rail and bridges) was the highest grade earned. It would take a total of $3.6 trillion in investments by 2020 to fix everything, the report card stated. To put that number in perspective, the federal government’s budget for all of 2012 was slightly more, $3.7 trillion.

“America relies on an aging electrical grid and pipeline distribution systems, some of which originated in the 1880s,” the report read. “Investment in power transmission has increased since 2005, but ongoing permitting issues, weather events, including summer blackouts that strain local systems, and limited maintenance have contributed to an increasing number of failures and power interruptions. While demand for electricity has remained level, the availability of energy in the form of electricity, natural gas, and oil will become a greater challenge after 2020 as the population increases. Although about 17,000 miles of additional high-voltage transmission lines and significant oil and gas pipelines are planned over the next five years, permitting and siting issues threaten their completion. The electric grid in the United States consists of a system of interconnected power generation, transmission facilities, and distribution facilities.”

Harness the power of the sun when the power goes out…

There are approximately 400,000 miles of electrical transmission lines throughout the United States, and thousands of power generating plants dot the landscape. The ASCE report card also stated that new gas-fired and renewable generation issues increase the need to add new transmission lines. Antiquated power grid equipment has reportedly prompted even more “intermittent” power outages in recent years.

The American Society of Civil Engineers accurately notes that the power grid is more vulnerable to cyber attacks than ever before, including Russian intrusions documented in recent years, and it cites the aging electrical system as the primary culprit. Although the decades-old transformers and other equipment necessary to keep power flowing around America are a major factor in the enhanced vulnerability of the power grid, moving towards a “smart grid” system is not the answer. As previously reported by Off The Grid News, smart grid systems and even electric car charging stations make the power grid more accessible to cyber hackers. During the Hack in the Box Conference in Amsterdam, HP ArcSight Product Manager Ofer Sheaf stated that electric car charging stations are in essence a computer on the street. The roadway fueling stations are linked to the power grid electrical system. If cyber hackers garner access to the power grid via the charging stations, they could stop the flow of power to a specific area or alter energy distribution levels and overload the system.

While a relatively small number of electric car charging stations exist in America now, that soon will change. Ongoing efforts by both federal and state governments to reduce our reliance on fossil fuels have resulted in grants and privately funded vehicle charging station projects. New York Governor Andrew Cuomo in April announced plans to build 360 such electrical stations in his state. A total of 3,000 car charging stations are in the works statewide and are slated for completion over the next five years.

SHIELD ActWeather-related events were the primary cause of power outages from 2007 to 2012, according to the infrastructure report card. Power grid reliability issues are emerging as the greatest threat to the electrical system, with rising attacks on substations compounding the risks. The ASCE grade card also notes that retiring and rotating in “new energy sources” is a “complex” process. Like most items we routinely purchase in our daily lives, many of the components needed to make the power grid functional are not manufactured in the United States.

The SHIELD Act is the first real piece of federal legislation in years drafted to address power grid vulnerabilities. While the single bill will not fix all of the electrical system issues, it is a big step in the right direction – if it ever makes it out of committee. Replacing aging transformers, encasing them in a high-tech version of a Faraday cage, and stockpiling extra units so instant repairs are possible would help preserve one of the nation’s most critical and life-saving pieces of infrastructure after a weather-related incident or man-made disaster.

“Geomagnetic storm environments can develop instantaneously over large geographic footprints,” solar geomagnetic researcher John Kappenman said about the fragile state of the power grid. He was quoted in an Oak Ridge National Laboratory report. “They have the ability to essentially blanket the continent with an intense threat environment and … produce significant collateral damage to critical infrastructures. In contrast to well-conceived design standards that have been successfully applied for more conventional threats, no comprehensive design criteria have ever been considered to check the impact of the geomagnetic storm environments. The design actions that have occurred over many decades have greatly escalated the dangers posed by these storm threats for this critical infrastructure.”

The power grid has morphed in size tenfold during the past 50 years. While solar flares, cyber attacks, and an EMP are perhaps the most extensive and frightening threats to the electrical system, the infrastructure could just as easily fail in large portions due to weather-related events exacerbated by climate change across regions. The power grid is basically a ticking time bomb which will spawn civil unrest, lack of food, clean water, and a multitude of fires if it does go down.

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Canadian electricity transmission enables grid resilience, long-distance power trade, and decarbonization by integrating renewables, hydroelectric storage, and HVDC links, providing backup during extreme weather and lowering costs to reach net-zero, clean energy targets.

Key Points

An interprovincial high-voltage grid that shares clean power to deliver reliable, low-cost decarbonization.

✅ Enables resilience by sharing power across weather zones

✅ Integrates renewables with hydro storage via HVDC links

✅ Lowers decarbonization costs through interprovincial trade

As the recent disaster in Texas showed, climate change requires electricity utilities to prepare for extreme events. This “global weirding” is leaving Canadian electricity grids increasingly exposed to harsh weather that leads to more intense storms, higher wind speeds, heatwaves and droughts that can threaten the performance of electricity systems.

The electricity sector must adapt to this changing climate while also playing a central role in mitigating climate change. Greenhouse gas emissions can be reduced a number of ways, but the electricity sector is expected to play a central role in decarbonization, including powering a net-zero grid by 2050 across Canada. Zero-emissions electricity can be used to electrify transportation, heating and industry and help achieve emissions reduction in these sectors.

Enhancing long-distance transmission is viewed as a cost-effective way to enable a clean and reliable power grid, and to lower the cost of meeting our climate targets. Now is the time to strengthen transmission links in Canada, with concepts like a western Canadian electricity grid gaining traction.

Insurance for climate extremes
An early lesson from the Texas power outages is that extreme conditions can lead to failures across all forms of power supply. The state lost the capacity to generate electricity from natural gas, coal, nuclear and wind simultaneously. But it also lacked cross-border transmission to other electricity systems that could have bolstered supply.

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Long-distance transmission offers the opportunity to escape the correlative clutch of extreme weather, by accessing energy and spare capacity in areas not beset by the same weather patterns. For example, while Texas was in its deep freeze, relatively balmy conditions in California meant there was a surplus of electricity generation capability in that region — but no means to get it to Texas. Building new transmission lines and connections across broader regions, including projects like a hydropower line to New York that expand access, can act as an insurance policy, providing a back-up for regions hit by the crippling effects of climate change.

A transmission tower crumpled under the weight of ice.
The 1998 Quebec ice storm left 3.5 million Quebecers and a million Ontarians, as well as thousands in in New Brunswick, without power. CP Photo/Robert Galbraith
Transmission is also vulnerable to climate disruptions, such as crippling ice storms that leave wires temporarily inoperable. This may mean using stronger poles when building transmission, or burying major high-voltage transmission links, or deploying superconducting cables to reduce losses.

In any event, more transmission links between regions can improve resilience by co-ordinating supply across larger regions. Well-connected grids that are larger than the areas disrupted by weather systems can be more resilient to climate extremes.

Lowering the cost of clean power
Adding more transmission can also play a role in mitigating climate change. Numerous studies have found that building a larger transmission grid allows for greater shares of renewables onto the grid, ultimately lowering the overall cost of electricity.

In a recent study, two of us looked at the role transmission could play in lowering greenhouse gas emissions in Canada’s electricity sector. We found the cost of reducing greenhouse gas emissions is lower when new or enhanced transmission links can be built between provinces.

Average cost increase to electricity in Canada at different levels of decarbonization, with new transmission (black) and without new transmission (red). New transmission lowers the cost of reducing greenhouse gas emissions. (Authors), Author provided
Much of the value of transmission in these scenarios comes from linking high-quality wind and solar resources with flexible zero-emission generation that can produce electricity on demand. In Canada, our system is dominated by hydroelectricity, but most of this hydro capacity is located in five provinces: British Columbia, Manitoba, Ontario, Québec and Newfoundland and Labrador.

In the west, Alberta and Saskatchewan are great locations for building low-cost wind and solar farms. Enhanced interprovincial transmission would allow Alberta and Saskatchewan to build more variable wind and solar, with the assurance that they could receive backup power from B.C. and Manitoba when the wind isn’t blowing and the sun isn’t shining.

When wind and solar are plentiful, the flow of low cost energy can reverse to allow B.C. and Manitoba the opportunity to better manage their hydro reservoir levels. Provinces can only benefit from trading with each other if we have the infrastructure to make that trade possible.

A recent working paper examined the role that new transmission links could play in decarbonizing the B.C. and Alberta electricity systems. We again found that enabling greater electricity trade between B.C. and Alberta can reduce the cost of deep cuts to greenhouse gas emissions by billions of dollars a year. Although we focused on the value of the Site C project, in the context of B.C.'s clean energy shift, the analysis showed that new transmission would offer benefits of much greater value than a single hydroelectric project.

The value of enabling new transmission links between Alberta and B.C. as greenhouse gas emissions reductions are pursued. (Authors), Author provided
Getting transmission built
With the benefits that enhanced electricity transmission links can provide, one might think new projects would be a slam dunk. But there are barriers to getting projects built.

First, electricity grids in Canada are managed at the provincial level, most often by Crown corporations. Decisions by the Crowns are influenced not simply by economics, but also by political considerations. If a transmission project enables greater imports of electricity to Saskatchewan from Manitoba, it raises a flag about lost economic development opportunity within Saskatchewan. Successful transmission agreements need to ensure a two-way flow of benefits.

Second, transmission can be expensive. On this front, the Canadian government could open up the purse strings to fund new transmission links between provinces. It has already shown a willingness to do so.

Lastly, transmission lines are long linear projects, not unlike pipelines. Siting transmission lines can be contentious, even when they are delivering zero-emissions electricity. Using infrastructure corridors, such as existing railway right of ways or the proposed Canadian Northern Corridor, could help better facilitate co-operation between regions and reduce the risks of siting transmission lines.

If Canada can address these barriers to transmission, we should find ourselves in an advantageous position, where we are more resilient to climate extremes and have achieved a lower-cost, zero-emissions electricity grid.

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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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