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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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Duke Energy Carolinas Solar RFP draws 3.9 GW of utility-scale bids, oversubscribed in DEP and DEC, below avoided cost rates, minimal battery storage, strict PPA terms, and interconnection challenges across North and South Carolina.

Key Points

Utility-scale solar procurement in DEC and DEP, evaluated against avoided cost, with few storage bids and PPA terms.

✅ 3.9 GW bids for 680 MW; DEP most oversubscribed

✅ Most projects 7-80 MWac; few include battery storage

✅ Bids must price below 20-year avoided cost estimate

Last week the independent administrator for Duke’s 680 MW solar solicitation revealed data about the projects which have bid in response to the offer, showing a massive amount of interest in the opportunity.

Overall, 18 individuals submitted bids for projects in Duke Energy Carolinas (DEC) territory and 10 in Duke Energy Progress (DEP), with a total of more than 3.9 GW of proposals – more nearly 6x the available volume. DEP was relatively more over-subscribed, with 1.2 GWac of projects vying for only 80 MW of available capacity.

This is despite a requirement that such projects come in below the estimate of Duke’s avoided cost for the next 20 years, and amid changes in solar compensation that could affect project economics. Individual projects varied in capacity from 7-80 MWac, with most coming within the upper portion of that range.

These bids will be evaluated in the spring of 2019, and as Duke Energy Renewables continues to expand its portfolio, Duke Energy Communications Manager Randy Wheeless says he expects the plants to come online in a year or two.

Lack of storage

Despite recent trends in affordable batteries, of the 78 bids that came in only four included integrated battery storage. Tyler Norris, Cypress Creek Renewables’ market lead for North Carolina, says that this reflects that the methodology used is not properly valuing storage.

“The lack of storage in these bids is a missed opportunity for the state, and it reflects a poorly designed avoided cost rate structure that improperly values storage resources, commercially unreasonable PPA provisions, and unfavorable interconnection treatment toward independent storage,” Norris told pv magazine.

“We’re hopeful that these issues will be addressed in the second RFP tranche and in the current regulatory proceedings on avoided cost and state interconnection standards and grid upgrades across the region.”

Limited volume for North Carolina?

Another curious feature of the bids is that nearly the same volume of solar has been proposed for South Carolina as North Carolina – despite this solicitation being in response to a North Carolina law and ongoing legal disputes such as a church solar case that challenged the state’s monopoly model.

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Covid-19 Energy Transition and Machine Learning reshape climate change policy, electricity planning, and grid operations, from demand forecasting and decarbonization strategies in Europe to scalable electrification modeling and renewable integration across Africa.

Key Points

How the pandemic reshapes energy policy and how ML improves planning, demand forecasts, and grid reliability in Africa.

✅ Pandemic-driven demand shifts strain grid operations and markets

✅ Policy momentum risks rollback; favor future-oriented decarbonization

✅ ML boosts demand prediction, electrification, and grid reliability in Africa

The impact of Covid-19 on the energy system was discussed in an online climate change workshop that also considered how machine learning can help electricity planning in Africa.

This year’s International Conference on Learning Representations event included a workshop held by the Climate Change AI group of academics and artificial intelligence industry representatives, which considered how machine learning can help tackle climate change and highlighted advances by European electricity prediction specialists working in this field.

Bjarne Steffen, senior researcher at the energy politics group at ETH Zürich, shared his insights at the workshop on how Covid-19 and the accompanying economic crisis are affecting recently introduced ‘green’ policies. “The crisis hit at a time when energy policies were experiencing increasing momentum towards climate action, especially in Europe, and in proposals to invest in smarter electricity infrastructure for long-term resilience,” said Steffen, who added the coronavirus pandemic has cast into doubt the implementation of such progressive policies.

The academic said there was a risk of overreacting to the public health crisis, as far as progress towards climate change goals was concerned.

Lobbying

“Many interest groups from carbon-intensive industries are pushing to remove the emissions trading system and other green policies,” said Steffen. “In cases where those policies are having a serious impact on carbon-emitting industries, governments should offer temporary waivers during this temporary crisis, instead of overhauling the regulatory structure.”

However, the ETH Zürich researcher said any temptation to impose environmental conditions to bail-outs for carbon-intensive industries should be resisted. “While it is tempting to push a green agenda in the relief packages, tying short-term environmental conditions to bail-outs is impractical, given the uncertainty in how long this crisis will last,” he said. “It is better to include provisions that will give more control over future decisions to decarbonize industries, such as the government taking equity shares in companies.”

Steffen shared with pv magazine readers an article published in Joule which can be accessed here, and which articulates his arguments about how Covid-19 could affect the energy transition.

Covid-19 in the U.K.

The electricity system in the U.K. is also being affected by Covid-19, even as the U.S. electric grid grapples with climate risks, according to Jack Kelly, founder of London-based, not-for-profit, greenhouse gas emission reduction research laboratory Open Climate Fix.

“The crisis has reduced overall electricity use in the U.K.,” said Kelly. “Residential use has increased but this has not offset reductions in commercial and industrial loads.”

Steve Wallace, a power system manager at British electricity system operator National Grid ESO recently told U.K. broadcaster the BBC electricity demand has fallen 15-20% across the U.K. The National Grid ESO blog has stated the fall-off makes managing grid functions such as voltage regulation more challenging.

Open Climate Fix’s Kelly noted even events such as a nationally-coordinated round of applause for key workers was followed by a dramatic surge in demand, stating: “On April 16, the National Grid saw a nearly 1 GW spike in electricity demand over 10 minutes after everyone finished clapping for healthcare workers and went about the rest of their evenings.”

Climate Change AI workshop panelists also discussed the impact machine learning could have on improving electricity planning in Africa. The Electricity Growth and Use in Developing Economies (e-Guide) initiative funded by fossil fuel philanthropic organization the Rockefeller Foundation aims to use data to improve the planning and operation of electricity systems in developing countries.

E-Guide members Nathan Williams, an assistant professor at the Rochester Institute of Technology (RIT) in New York state, and Simone Fobi, a PhD student at Columbia University in NYC, spoke about their work at the Climate Change AI workshop, which closed on Thursday. Williams emphasized the importance of demand prediction, saying: “Uncertainty around current and future electricity consumption leads to inefficient planning. The weak link for energy planning tools is the poor quality of demand data.”

Fobi said: “We are trying to use machine learning to make use of lower-quality data and still be able to make strong predictions.”

The market maturity of individual solar home systems and PV mini-grids in Africa mean more complex electrification plan modeling is required, similar to integrating AI data centers into Canada's grids at scale.

Modeling

“When we are doing [electricity] access planning, we are trying to figure out where the demand will be and how much demand will exist so we can propose the right technology,” added Fobi. “This makes demand estimation crucial to efficient planning.”

Unlike many traditional modeling approaches, machine learning is scalable and transferable. Rochester’s Williams has been using data from nations such as Kenya, which are more advanced in their electrification efforts, to train machine learning models to make predictions to guide electrification efforts in countries which are not as far down the track.

Williams also discussed work being undertaken by e-Guide members at the Colorado School of Mines, which uses nighttime satellite imagery and machine learning to assess the reliability of grid infrastructure in India, where new algorithms to prevent ransomware-induced blackouts are also advancing.

Rural power

Another e-Guide project, led by Jay Taneja at the University of Massachusetts, Amherst – and co-funded by the Energy and Economic Growth program on development spending based at Berkeley – uses satellite imagery to identify productive uses of electricity in rural areas by detecting pollution signals from diesel irrigation pumps.

Though good quality data is often not readily available for Africa, Williams added, it does exist.

“We have spent years developing trusting relationships with utilities,” said the RIT academic. “Once our partners realize the value proposition we can offer, they are enthusiastic about sharing their data … We can’t do machine learning without high-quality data and this requires that organizations can effectively collect, organize, store and work with data. Data can transform the electricity sector, as shown by Canadian projects to use AI for energy savings, but capacity building is crucial.”

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Sidi Mansour Wind Farm Tunisia will deliver 30 MW as an IPP, backed by UPC Renewables and CFM, under a STEG PPA, supporting 2030 renewable energy targets, grid connection, job creation, and CO2 emissions reduction.

Key Points

A 30 MW wind IPP by UPC and CFM in Sidi Mansour, supplying STEG and advancing Tunisia's 2030 renewable target.

✅ 30 MW capacity under STEG PPA, first wind IPP in Tunisia

✅ Co-developed by UPC Renewables and Climate Fund Managers

✅ Cuts CO2 by up to 56,645 t and creates about 100 jobs

UPC Renewables (UPC) and the Climate Fund Managers (CFM) have partnered to develop a 30 megawatt wind farm in Sidi Mansour, Tunisia, which, amid regional wind expansion efforts, will help the country meet its 30% renewable energy target by 2030.

Tunisia announced the launch of its solar energy plan in 2016, with projects like the 10 MW Tunisian solar park aiming to increase the role of renewables in its electricity generation mix ten-fold to 30%,

This Sidi Mansour Project will help Tunisia meet its goals, reducing its reliance on imported fossil fuels and, mirroring 90 MW Spanish wind build milestones, demonstrating to the world that it is serious about further development of renewable energy investment.

“Chams Enfidha”, the first solar energy station in Tunisia with a capacity of 1 megawatt and located in the Enfidha region. (Ministry of Energy, Mines and Energy Transition Facebook page)

This project will also be among the country’s first Independent Power Producers (IPP). CFM is acting as sponsor, financial adviser and co-developer on the project, in a landscape shaped by IRENA-ADFD funding in developing countries, while UPC will lead the development with its local team. The team will be in charge of permitting, grid connection, land securitisation, assessment of wind resources, contract procurement and engineering.

UPC was selected under the “Authorisation Scheme” tender for the project in 2016, similar to utility-scale developments like a 450 MW U.S. wind farm, and promptly signed a power purchase agreement with Société Tunisienne Electricité et du Gaz (STEG).

Brian Caffyn, chairman of UPC Group, said: “We can start the construction of the Sidi Mansour wind farm in 2020, helping stimulate the Tunisian economy, create local jobs and a social plan for local communities while respecting international environmental protection guidelines.”

Sebastian Surie, CFM’s regional head of Africa, added: “CFM is thrilled to partner with a leading wind developer in the Sidi Mansour Wind Project to assist Tunisia in meeting its renewable energy goals. As potentially the first Wind IPP in Tunisia, this Project will be a testament to how CI1’s full life-cycle financing solution can unlock investment in renewable energy in new markets, as seen in an Irish offshore wind project globally.”

The project will not only provide electricity, but also reduce CO2 emissions by up to 56,645 tonnes and create some 100 new jobs.

Wind turbine in El Haouaria, Tunisia, highlighting advances such as a huge offshore wind turbine that can power 18,000 homes. (Reuters)

Tunisia’s first power station, “Chams Enfidha,” inaugurated at the beginning of July, has a capacity of one megawatt, with an estimated cost of 3.3 million dinars ($1.18 million). The state invested 2.3 million dinars into the project ($820,000), with the remaining 1 million dinars ($360,000) provided by a private investor.

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Hydro-Québec Carillon Refurbishment delivers a $750M hydropower modernization, replacing six turbines and upgrading civil works, water passageways, and grid equipment to extend run-of-river, renewable energy output for peak demand near Montréal.

Key Points

A $750M project replacing six units and upgrading civil, water and electrical systems to supply power for 50 years.

✅ Replaces six generating units with Andritz turbines.

✅ Upgrades civil works, water passageways, and electrical gear.

✅ Extends run-of-river output for 50 years; boosts peak supply.

Hydro-Québec will invest $750 million to refurbish its Carillon generating station with a major powerhouse upgrade that will mainly replace six generating units. The investment also covers the cost of civil engineering work, including making adjustments to water passageways, upgrading electrical equipment and replacing the station roof. Work will start in 2021, aligning with Hydro-Québec's capacity expansion plans for 2021, and continue until 2027.

Carillon generating station is a run-of-river power plant consisting of 14 generating units with a total installed capacity of 753 MW. Built in the early 1960s, it is a key part of Hydro-Québec's hydroelectric generating fleet, which includes the La Romaine complex as well. The station is close to the greater Montréal area and feeds power into the grid to support industrial demand growth during peak consumption periods.

The selected supplier, turbine manufacturer Andritz, has been asked to maximize the project's economic spinoffs in Québec, as Canada continues investing in new turbines across the country to modernize assets. Once the work is completed, the new generating units will be able to provide clean, renewable energy, supporting Hydro-Québec's strategy to reduce fossil fuel reliance for the next 50 years.

"Carillon generating station is a symbol of our hydroelectric development and plays a strategic role in our production fleet. However, most of the generating units' main components date back to the station's original construction from 1959 to 1962. Hydropower generating stations have long service lives - with this refurbishment, Carillon will be producing clean renewable energy for decades to come." said David Murray, Chief Innovation Officer and President, Hydro-Québec Production.

"In light of today's economic situation, this is an important announcement that clearly reaffirms Hydro-Québec's role in relaunching Québec's economy and strengthening interprovincial electricity partnerships that open new markets. Over 600,000 hours of work will be required for everything from the engineering work to component assembly, creating many new high-quality skilled jobs for Québec industries."

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Alberta Electricity Market Reform reshapes policy under the UCP, weighing a capacity market versus energy-only design, AESO reliability rules, renewables targets, coal phase-out, carbon pricing, consumer rates, and investment certainty before AUC decisions.

Key Points

Alberta Electricity Market Reform is the UCP plan to reassess capacity vs energy-only, renewables, and carbon pricing.

✅ Reviews capacity market timeline and AESO procurement

✅ Alters subsidies for renewables; slows wind and solar growth

✅ Adjusts industrial carbon levy; audits Balancing Pool losses

Hearings kicked off this week into the future of the province’s electricity market design, amid an electricity market reshuffle pledged by the province, but a high-stakes decision about the industry’s fate — affecting billions of dollars in investment and consumer costs — won’t be made inside the meeting room of the Alberta Utilities Commission.

Instead, it will take place in the office of Jason Kenney, as the incoming premier prepares to pivot away from the seismic reforms to Alberta’s electricity sector introduced by the Notley government.

The United Conservative Party has promised to adopt market-based policies, reflecting changes to how Alberta produces and pays for power, that will reset how the sector operates, from its approach to renewable energy and carbon pricing to re-evaluating the planned transition to an electricity “capacity market.”

“Every ball in electricity is up in the air right now,” Vittoria Bellissimo, of the Industrial Power Consumers Association of Alberta, said Tuesday during a break in the commission hearings.

Industry players are uncertain how quickly the UCP will change direction on power policies, but there’s little doubt Kenney’s government will take a strikingly different approach to the sector that keeps the lights on in Alberta.

“There’s some things they are going to change that are going to impact the electricity industry significantly,” said Duane Reid-Carlson, chief executive of consultancy EDC Associates.

“But I don’t think it’s going to be upheaval. I think the new government will proceed with caution because electricity is the foundation of our economy.”

Alberta’s electricity market has been turned on its head in recent years due to the recession, power prices dropping to near two-decade lows and several transformative policies initiated by the NDP.

The Notley government’s climate plan included an accelerated phase-out of all coal-fired generation and set targets for more renewable energy.

The most significant, but least-understood, move has been the planned shift to an electricity capacity market in 2021.

Under the strategy, generators will no longer solely be paid for the power produced and sold into the market; they will also receive payments for having electricity capacity available to the grid on demand.

The change was recommended by the Alberta Electric System Operator (AESO) as a way to reduce price volatility and provide more reliability than the current energy-only market, which some argue needs more competition to deliver better outcomes.

The independent system operator and industry officials have spent more than two years planning the transition since the switch was announced in late 2016. Proposed rules for the new system, outlining market changes, are now being discussed at the Alberta Utilities Commission hearings.

However, there is no ironclad guarantee the system remake will go ahead following the UCP’s election victory last week — amid calls to scrap the overhaul from a Calgary retailer — it plans to study the issue further — while other substantive electricity changes are already in store.

The UCP has promised to end “costly subsidies” to renewable energy developments and abandon the NDP’s pledge to have such energy sources make up 30 per cent of all power generation by 2030.

It will remove the planned phase-out of coal-fired electricity generation, although federal regulations for a 2030 prohibition remain in place.

It will also ask the auditor general to conduct a special audit of the massive losses sustained by the province’s Balancing Pool due to power purchase arrangements being handed back to the agency three years ago.

While Kenney has pledged to cancel the provincewide carbon tax, a levy on large industrial greenhouse gas emitters (such has power plants) will still be charged, although at a reduced rate of $20 a tonne.

The biggest unknown remains the power market’s structure, which underpins how the entire system operates.

The UCP has promised to consult on the shift to the capacity market and report back to Albertans within 90 days.

The complex issue may sound like an eye-glazer, but it will have a profound effect on industry investment, as well as how much consumers pay on their monthly electricity bills.

A number of industry players worry the capacity market will lead AESO to procure more power than is necessary, foisting unnecessary costs onto all Albertans.

“I still have concerns for what the impact on consumers is going to be,” said energy market consultant Sheldon Fulton. “I’d love to see the capacity market go away.”

An analysis by EDC Associates found the transition to a capacity market will procure additional electricity before it’s needed, requiring consumers to pay up to 40 per cent more — an extra $1.4 billion — for power in 2021-22 than under the existing market structure.

“I don’t think there’s any prejudged outcome,” said Blake Shaffer, former head trader at TransAlta Corp. and a fellow-in-residence at the C.D. Howe Institute.

“But it really matters about getting this right.”

Evan Bahry, executive director of the Independent Power Producers Society of Alberta, said the fact the UCP’s review was confined to just 90 days is helpful, as it avoids throwing the entire industry into a prolonged period of uncertainty.

As for the greening of Alberta’s power grid, amid growing attention to clean grids and storage, the demise of the NDP’s Renewable Electricity Program will likely slow down the rapid pace of wind and solar development. But it’s unlikely to stop the growth trend as costs continue to fall for such developments.

“Renewables over the last number of years have evolved to the point that they make sense on a subsidy-free basis,” said Dan Balaban, CEO of Greengate Power Corp., which has developed 480 MW of wind power in Alberta and Ontario.

“There is a path to clean electricity ahead.”

Chris Varcoe is a Calgary Herald columnist.

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