Cheap oil contagion is clear and present danger to Canada

Freedom Cannabis solar array powers an Acheson cannabis facility with 4,574 rooftop panels, a 1,830-kilowatt system by Enmax, cutting greenhouse gas emissions, lowering energy costs, and advancing renewable energy, sustainability, and operational efficiency in Edmonton.

Key Points

A 1,830-kW rooftop solar system with 4,574 panels, cutting GHG emissions and energy costs at the Acheson facility.

✅ 1,830-kW array offsets 1,000+ tonnes GHG annually

✅ Supplies ~8% of annual power; saves $200k-$300k per year

✅ 4,574 rooftop panels installed by Enmax in Acheson

Electricity consumption is one of the biggest barriers to going green in the cannabis industry, where the energy demands of cannabis cultivation often complicate sustainability, but an Edmonton-area pot producer has come up with a sunny solution.

Freedom Cannabis unveiled the largest rooftop solar system used by a cannabis facility in Canada at its 126,000-square foot Acheson location, 20 kilometres west of Edmonton, as solar power in Alberta continues to surge, on Tuesday.

The "state-of-the-art" 1,830-kilowatt solar array—made up of 4,574 panels—was supplied by Enmax and will offset more than 1,000 tonnes of greenhouse gas emissions each year, reflecting how new Alberta solar facilities are undercutting natural gas on price, the company said.

The state-of-the-art solar array—made up of 4,574 panels—was supplied by Enmax and will offset more than 1,000 tonnes of greenhouse gas emissions at Freedom Cannabis every year. Nov. 12, 2019. (Freedom Cannabis)

That will supply roughly eight per cent of the building's annual power consumption and reduce costs by $200,000 to $300,000 annually.

"This strategy will supplement our operating costs for power by up to eight to 10 per cent, so it is something that in time will save us costs on power requirements," said Troy Dezwart, co-founder of Freedom Cannabis.

Dezwart said sustainability was an important issue to the company from its outset, aligning with an Alberta renewable energy surge that is expected to power thousands of jobs.

"We're fortunate enough to be able to have these types of options and pursue them," said Dezwart.

The entire system cost Freedom Cannabis $2.6 million to build, but nearly a million of that came from a provincial rebate program that has since been cancelled by the UCP government, even as a federal green electricity deal with an Edmonton company signals ongoing support.

The company cited a 2017 report that found cannabis growers in the U.S. used enough electricity to power 1.7-million homes, and said cannabis-related power consumption is expected to increase by 1,250 per cent in Ontario over the next five years, even though Canadian solar demand has been lagging overall.

“It’s more important than ever for businesses to manage their energy footprint, and solar is an important part of that solution,” Enmax director Jason Atkinson, said. “This solar installation will help reduce operating costs and offset a significant portion of GHG emissions for decades to come.”

Freedom says it has other initiatives underway to reduce its footprint, in a region planning the Edmonton airport solar farm among other projects, including water remediation and offering 100 per cent recyclable cannabis packaging tins.

The company's first crops are expected to go to market in December.

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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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Hydrogen Energy Transition advances renewable energy integration via electrolysis, carbon capture and storage, and gas hybrids to decarbonize industry, steel, and transport, enable grid storage, replace ammonia feedstocks, and export clean power across continents.

Key Points

Scaling clean hydrogen with renewables and CCS to cut emissions in power and industry, and enable clean transport.

✅ Electrolysis and CCS provide low-emission hydrogen at scale.

✅ Balances renewables with storage and flexible gas assets.

✅ Decarbonizes steel, ammonia, heavy transport, and exports.

I want you to imagine a highway exclusively devoted to delivering the world’s energy. Each lane is restricted to trucks that carry one of the world’s seven large-scale sources of primary energy: coal, oil, natural gas, nuclear, hydro, solar and wind.

Our current energy security comes at a price, as Europe's power crisis shows, the carbon dioxide emissions from the trucks in the three busiest lanes: the ones for coal, oil and natural gas.

We can’t just put up roadblocks overnight to stop these trucks; they are carrying the overwhelming majority of the world’s energy supply.

But what if we expand clean electricity production carried by the trucks in the solar and wind lanes — three or four times over — into an economically efficient clean energy future?

Think electric cars instead of petrol cars. Think electric factories instead of oil-burning factories. Cleaner and cheaper to run. A technology-driven orderly transition. Problems wrought by technology, solved by technology.

Read more: How to transition from coal: 4 lessons for Australia from around the world

Make no mistake, this will be the biggest engineering challenge ever undertaken. The energy system is huge, and even with an internationally committed and focused effort the transition will take many decades.

It will also require respectful planning and retraining to ensure affected individuals and communities, who have fuelled our energy progress for generations, are supported throughout the transition.

As Tony, a worker from a Gippsland coal-fired power station, noted from the audience on this week’s Q+A program:

The workforce is highly innovative, we are up for the challenge, we will adapt to whatever is put in front of us and we have proven that in the past.

This is a reminder that if governments, industry, communities and individuals share a vision, a positive transition can be achieved.

The stunning technology advances I have witnessed in the past ten years, such as the UK's green industrial revolution shaping the next waves of reactors, make me optimistic.

Renewable energy is booming worldwide, and is now being delivered at a markedly lower cost than ever before.

In Australia, the cost of producing electricity from wind and solar is now around A$50 per megawatt-hour.

Even when the variability is firmed with grid-scale storage solutions, the price of solar and wind electricity is lower than existing gas-fired electricity generation and similar to new-build coal-fired electricity generation.

This has resulted in substantial solar and wind electricity uptake in Australia and, most importantly, projections of a 33% cut in emissions in the electricity sector by 2030, when compared to 2005 levels.

And this pricing trend will only continue, with a recent United Nations report noting that, in the last decade alone, the cost of solar electricity fell by 80%, and is set to drop even further.

So we’re on our way. We can do this. Time and again we have demonstrated that no challenge to humanity is beyond humanity.

Ultimately, we will need to complement solar and wind with a range of technologies such as high levels of storage, including gravity energy storage approaches, long-distance transmission, and much better efficiency in the way we use energy.

But while these technologies are being scaled up, we need an energy companion today that can react rapidly to changes in solar and wind output. An energy companion that is itself relatively low in emissions, and that only operates when needed.

In the short term, as Prime Minister Scott Morrison and energy minister Angus Taylor have previously stated, natural gas will play that critical role.

In fact, natural gas is already making it possible for nations to transition to a reliable, and relatively low-emissions, electricity supply.

Look at Britain, where coal-fired electricity generation has plummeted from 75% in 1990 to just 2% in 2019.

Driving this has been an increase in solar, wind, and hydro electricity, up from 2% to 27%. At the same time, and this is key to the delivery of a reliable electricity supply, electricity from natural gas increased from virtually zero in 1990 to more than 38% in 2019.

I am aware that building new natural gas generators may be seen as problematic, but for now let’s assume that with solar, wind and natural gas, we will achieve a reliable, low-emissions electricity supply.

Is this enough? Not really.

We still need a high-density source of transportable fuel for long-distance, heavy-duty trucks.

We still need an alternative chemical feedstock to make the ammonia used to produce fertilisers.

We still need a means to carry clean energy from one continent to another.

Enter the hero: hydrogen.

Hydrogen could fill the gaps in our energy needs. Julian Smith/AAP Image
Hydrogen is abundant. In fact, it’s the most abundant element in the Universe. The only problem is that there is nowhere on Earth that you can drill a well and find hydrogen gas.

Don’t panic. Fortunately, hydrogen is bound up in other substances. One we all know: water, the H in H₂O.

We have two viable ways to extract hydrogen, with near-zero emissions.

First, we can split water in a process called electrolysis, using renewable electricity or heat and power from nuclear beyond electricity options.

Second, we can use coal and natural gas to split the water, and capture and permanently bury the carbon dioxide emitted along the way.

I know some may be sceptical, because carbon capture and permanent storage has not been commercially viable in the electricity generation industry.

But the process for hydrogen production is significantly more cost-effective, for two crucial reasons.

First, since carbon dioxide is left behind as a residual part of the hydrogen production process, there is no additional step, and little added cost, for its extraction.

And second, because the process operates at much higher pressure, the extraction of the carbon dioxide is more energy-efficient and it is easier to store.

Returning to the electrolysis production route, we must also recognise that if hydrogen is produced exclusively from solar and wind electricity, we will exacerbate the load on the renewable lanes of our energy highway.

Think for a moment of the vast amounts of steel, aluminium and concrete needed to support, build and service solar and wind structures. And the copper and rare earth metals needed for the wires and motors. And the lithium, nickel, cobalt, manganese and other battery materials needed to stabilise the system.

It would be prudent, therefore, to safeguard against any potential resource limitations with another energy source.

Well, by producing hydrogen from natural gas or coal, using carbon capture and permanent storage, we can add back two more lanes to our energy highway, ensuring we have four primary energy sources to meet the needs of the future: solar, wind, hydrogen from natural gas, and hydrogen from coal.

Read more: 145 years after Jules Verne dreamed up a hydrogen future, it has arrived

Furthermore, once extracted, hydrogen provides unique solutions to the remaining challenges we face in our future electric planet.

First, in the transport sector, Australia’s largest end-user of energy.

Because hydrogen fuel carries much more energy than the equivalent weight of batteries, it provides a viable, longer-range alternative for powering long-haul buses, B-double trucks, trains that travel from mines in central Australia to coastal ports, and ships that carry passengers and goods around the world.

Second, in industry, where hydrogen can help solve some of the largest emissions challenges.

Take steel manufacturing. In today’s world, the use of coal in steel manufacturing is responsible for a staggering 7% of carbon dioxide emissions.

Persisting with this form of steel production will result in this percentage growing frustratingly higher as we make progress decarbonising other sectors of the economy.

Fortunately, clean hydrogen can not only provide the energy that is needed to heat the blast furnaces, it can also replace the carbon in coal used to reduce iron oxide to the pure iron from which steel is made. And with hydrogen as the reducing agent the only byproduct is water vapour.

This would have a revolutionary impact on cutting global emissions.

Third, hydrogen can store energy, as with power-to-gas in pipelines solutions not only for a rainy day, but also to ship sunshine from our shores, where it is abundant, to countries where it is needed.

Let me illustrate this point. In December last year, I was privileged to witness the launch of the world’s first liquefied hydrogen carrier ship in Japan.

As the vessel slipped into the water I saw it not only as the launch of the first ship of its type to ever be built, but as the launch of a new era in which clean energy will be routinely transported between the continents. Shipping sunshine.

And, finally, because hydrogen operates in a similar way to natural gas, our natural gas generators can be reconfigured in the future as hydrogen-ready power plants that run on hydrogen — neatly turning a potential legacy into an added bonus.

Hydrogen-powered economy
We truly are at the dawn of a new, thriving industry.

There’s a nearly A$2 trillion global market for hydrogen come 2050, assuming that we can drive the price of producing hydrogen to substantially lower than A$2 per kilogram.

In Australia, we’ve got the available land, the natural resources, the technology smarts, the global networks, and the industry expertise.

And we now have the commitment, with the National Hydrogen Strategy unanimously adopted at a meeting by the Commonwealth, state and territory governments late last year.

Indeed, as I reflect upon my term as Chief Scientist, in this my last year, chairing the development of this strategy has been one of my proudest achievements.

The full results will not be seen overnight, but it has sown the seeds, and if we continue to tend to them, they will grow into a whole new realm of practical applications and unimagined possibilities.

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FERC Transmission Rule accelerates grid modernization and interregional high-voltage lines, enabling renewable energy integration, load balancing, and reliability to advance net-zero goals while strengthening resilience, capacity expansion, and decarbonization across U.S. regional transmission organizations.

Key Points

A federal policy mandating interregional grid planning and cost sharing to expand high-voltage lines for renewables.

✅ Expands interregional high-voltage transmission capacity

✅ Improves reliability, resilience, and load balancing

✅ Aligns cost allocation and long-term planning for renewables

On May 13th, 2024, the US took a monumental step towards its clean energy goals. The Federal Energy Regulatory Commission (FERC) approved a long-awaited rule designed to significantly expand the transmission of renewable energy across the nation's power grid, a US grid overhaul that many advocates say was overdue. This decision aligns with President Biden's ambitious plan to achieve net-zero carbon emissions by 2050, with renewable energy playing a central role.

The new rule tackles a critical bottleneck hindering the widespread adoption of renewables – transmission infrastructure. Unlike traditional power plants like coal or natural gas that run constantly, solar and wind power generation fluctuates with weather conditions. This variability poses a challenge for the existing grid, which is not designed to efficiently handle large-scale integration of these intermittent sources, helping explain why the grid isn't 100% renewable today.

The FERC rule aims to address this by promoting the construction of new, high-voltage transmission lines, particularly those connecting different regions, where grid limitations in the Pacific Northwest have highlighted the need for better interregional transfers. This improved connectivity would allow for a more strategic distribution of renewable energy. Imagine solar energy harnessed in the sun-drenched Southwest being transmitted eastward to meet peak demand during hot summer days on the Atlantic Coast.

The benefits of this expanded transmission network are multifaceted. First, it unlocks the full potential of renewable resources by allowing for their efficient utilization across the country, a trend consistent with wind and solar surpassing coal in U.S. generation. Abundant wind power in the Midwest could be utilized on the West Coast, while surplus solar energy from the South could supplement demand in the Northeast.

Second, a more robust grid with a higher capacity for renewables reduces reliance on fossil fuel-based power plants and complements other ways to meet decarbonization goals across sectors. This translates to cleaner air and a significant reduction in greenhouse gas emissions, contributing to the fight against climate change.

Third, a modernized grid with improved long-distance transmission bolsters the nation's energy security. Extreme weather events, a growing concern due to climate change, can disrupt energy production in specific regions. This interconnected grid would provide a buffer, ensuring a more reliable and resilient power supply and helping put regions on the road to 100% renewables even during adverse weather conditions.

The FERC's decision is a win for environmental groups and the renewable energy industry. They see it as a critical step towards a cleaner energy future and a significant driver of job creation in the construction and maintenance of new transmission lines. However, concerns have been raised by some stakeholders, particularly investor-owned utilities. They worry about the potential cost burden associated with building these expansive new lines, and recent reports of stalled grid spending underscore those concerns and the need for efficient cost allocation mechanisms. Striking a balance between efficiency, affordability, and environmental responsibility will be crucial for the successful implementation of this policy.

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Meaford Pumped Storage Project aims to balance the grid with hydro-electric generation, a hilltop reservoir, and transmission lines near Georgian Bay, pending environmental assessment, permitting, and federal review of impacts on fish and drinking water.

Key Points

TC Energy proposal to pump water uphill off-peak and generate 1,000 MW at peak, pending studies and approvals.

✅ Balances grid by storing off-peak energy and generating at peak.

✅ Requires reservoir, break wall, transmission lines, generating station.

✅ Environmental studies and federal review underway before approvals.

Plans for a $3.3 billion hydro-electric project in Meaford are still in the early study stages, but some residents have concerns about what it might mean for the environment, as past Site C stability issues have illustrated for large hydro projects.

A one-year permit was granted for TC Energy Corporation (TC Energy) to begin studies on the proposed location back in May, and cross-border projects like the New England Clean Power Link require federal permits as well to proceed. Local municipalities were informed of the project in June.

TC Energy is proposing to have a pumped storage project at the 4th Canadian Division Training (4CDTC) Meaford property, which is on federal lands.

A letter sent to local municipalities explains that the plan is to balance supply and demand on the electrical grid by pumping water uphill during off-peak hours. It would then release the water back into Georgian Bay during peak periods, generating up to 1,000 megawatts of electricity.

The project is expected to create 800 jobs over four years of construction, in addition to long-term operational positions.

According to the company's website, the proposed pump station would require a large reservoir on the military base, a generating station, transmission lines infrastructure, and a break wall 850 metres from shore.

Some residents fear the project will threaten the bay and the fish, echoing Site C dam concerns shared with northerners, and the region's drinking water.

Meaford's mayor says the town has no jurisdiction on federal lands, but that a list of concerns has been forwarded to the company, while Ontario First Nations have urged government action on urgent transmission needs elsewhere.

TC Energy will tackle preliminary engineering and environmental studies to determine the feasibility of the proposed location, which could take up to two years.

Once the assessments are done, they need to be presented to the government for further review and approval, as seen when Ottawa's Site C stance left work paused pending a treaty rights challenge.

TC Energy's website states that the company anticipates construction to begin in 2022 if it gets all the go-ahead, with the plant to begin operations four years later.

Input from residents is being collected until April 2020, similar to when the National Energy Board heard oral traditional evidence on the Manitoba-Minnesota transmission line.

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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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