Rio Tinto seeking solutions that transform heat from underground mines into electricity


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Rio Tinto waste heat-to-electricity initiative captures underground mining thermal energy at Resolution Copper, Arizona, converting it to renewable power for cooling systems and microgrids, advancing decarbonization, energy efficiency, and the miner's 2050 carbon-neutral goal.

 

Key Points

A program converting underground thermal energy into on-site electricity to cut emissions and support mine cooling.

✅ Captures low-grade heat from rock and geothermal water.

✅ Generates electricity for ventilation, refrigeration, microgrids.

✅ Scalable, safe, and grid- or storage-ready for peak demand.

 

The world’s second-largest miner, Rio Tinto announced that it is accepting proposals for solutions that transform waste heat into electricity for reuse from its underground operations.

In a press release, the company said this initiative is aimed at drastically reducing greenhouse gas emissions, even as energy-intensive projects like bitcoin mining operations expand, so that it can achieve its goal of becoming carbon neutral by 2050.

Initially, the project would be implemented at the Resolution copper mine in Arizona, which Rio owns together with BHP (ASX, LON: BHP). At this site, massive electrically-driven refrigeration and ventilation systems, aligned with broader electrified mining practices, are in charge of cooling the work environment because of the latent heat from the underground rock and groundwater. 

THE INITIATIVE IS AIMED AT REDUCING GREENHOUSE GAS EMISSIONS SO THAT RIO CAN ACHIEVE ITS GOAL OF BECOMING CARBON NEUTRAL BY 2050

“When operating, the Resolution copper mine will be a deep underground block cave mine some 7,000 feet (~2 kilometres) deep, with ambient air temperatures ranging between 168°F to 180°F (76°C to 82°C), conditions that, during heat waves, when bitcoin mining power demand can strain local grids, further heighten cooling needs, and underground water at approximately 194°F (90°C),” the media brief states.

“Rio Tinto is seeking solutions to capture and reuse the heat from underground, contributing towards powering the equipment needed to cool the operations. The solution to capture and convert this thermal energy into electrical energy, such as emerging thin-film thermoelectrics, should be safe, environmentally friendly and cost-effective.”

The miner also said that, besides capturing heat for reuse, the solution should generate electrical energy from low range temperatures below the virgin rock temperature and/or from the high thermal water coming from the underground rock, similar to using transformer waste heat for heating in the power sector. 

At the same time, the solution should be scalable and easily transported through the many miles of underground tunnels that will be built to ventilate, extract and move copper ore to the surface.

Rio requires proposals to offer the possibility of distributing the electrical energy generated back into the electrical grid from the mining operation or stored and used at a later stage when energy is required during peak use periods, especially as jurisdictions aim to use more electricity for heat in colder seasons. 

 

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Europe's Thirst for Electricity Spurs Nordic Grid Blockade

Nordic Power Grid Dispute highlights cross-border interconnector congestion, curtailed exports and imports, hydropower priorities, winter demand spikes, rising spot prices, and transmission grid security amid decarbonization efforts across Sweden, Norway, Finland, and Denmark.

 

Key Points

A clash over interconnectors and capacity cuts reshaping trade, prices, and reliability in the Nordic power market.

✅ Sweden cuts interconnector capacity to protect grid stability

✅ Norway prioritizes higher-priced exports via new cables

✅ Finland and Denmark seek EU action on capacity curtailments

 

A spat over electricity supplies is heating up in northern Europe. Sweden is blocking Norway from using its grids to transfer power from producers throughout the region. That’s angered Norway, which in turn has cut flows to its Nordic neighbor.

The dispute has built up around the use of cross-border power cables, which are a key part of Europe’s plans to decarbonize since they give adjacent countries access to low-carbon resources such as wind or hydropower. The electricity flows to wherever prices are higher, informed by how electricity is priced across Europe, without interference from grid operators -- but in the event of a supply squeeze, flows can be stopped.

Sweden moved to safeguard the security of its grid after Norway started increasing electricity exports through huge new cables to Germany and the U.K. Those exports at times have drawn energy away from Sweden, resulting in the country’s system operator cutting capacity at its Nordic borders, preventing exports but also hindering imports, which it relies on to handle demand spikes during winter.

“This is not a good situation in the long run,” Christian Holtz, a energy market consultant for Merlin & Metis AB.

Norway hit back last week by cutting flows to Sweden, this will prioritize better paying customers in Europe, amid Irish price spikes that highlight dispatchable shortages, giving them access to its vast hydro resources at the expense of its Nordic neighbors. 

By partially closing its borders Sweden can’t access imports either, which it relies on to handle demand spikes during the coldest days of the winter. 

In Denmark, unusual summer and autumn winds have at times delivered extraordinarily low electricity prices that ripple through regional markets.

The Swedish grid manager Svenska Kraftnat has reduced export capacity at cables across its borders by as much as half this year to keep operations secure. Finland and Denmark rely on imports too and the cuts will come at a cost for millions of homes and industries across the four nations already contending with record electricity rates this year. 

Finland and Denmark want the European Union to end the exemption to regulations that make such reductions possible in the first place, as Europe is losing nuclear power and facing tighter supply.

“Imports from our neighboring countries ensure adequacy at times of peak consumption,” said Reima Paivinen, head of operation at the Finland’s Fingrid. “The recent surge in electricity prices throughout Europe does not directly affect the adequacy of electricity, but prices may rise dramatically for short periods.”

Svenska Kraftnat says it’s not political -- it has no choice but to cut capacity until its old grids are expanded to handle the new direction of flows, a challenge mirrored by grid expansion woes in Germany that slow integration. That could take at least until 2030 to complete, it said earlier this year. At the same time, Norway halving available export capacity to about 1,200 megawatts will increase risk of shortages. 

“If we need more we will have to count on imports from other countries,” said Erik Ek, head of strategic operation at Svenska Kraftnat. “If that is not available, we will have to disconnect users the day it gets cold.”

 

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Was there another reason for electricity shutdowns in California?

PG&E Wind Shutdown and Renewable Reliability examines PSPS strategy, wildfire risk, transmission line exposure, wind turbine cut-out speeds, grid stability, and California's energy mix amid historic high-wind events and supply constraints across service areas.

 

Key Points

An overview of PG&E's PSPS decisions, wildfire mitigation, and how wind cut-out limits influence grid reliability.

✅ Wind turbines reach cut-out near 55 mph, reducing generation.

✅ PSPS mitigates ignition from damaged transmission infrastructure.

✅ Baseload diversity improves resilience during high-wind events.

 

According to the official, widely reported story, Pacific Gas & Electric (PG&E) initiated power shutoffs across substantial portions of its electric transmission system in northern California as a precautionary measure.

Citing high wind speeds they described as “historic,” the utility claims that if it didn’t turn off the grid, wind-caused damage to its infrastructure could start more wildfires.

Perhaps that’s true. Perhaps. This tale presumes that the folks who designed and maintain PG&E’s transmission system are unaware of or ignored the need to design it to withstand severe weather events, and that the Federal Energy Regulatory Commission (FERC) and North American Electric Reliability Corp. (NERC) allowed the utility to do so.

Ignorance and incompetence happens, to be sure, but there’s much about this story that doesn’t smell right—and it’s disappointing that most journalists and elected officials are apparently accepting it without question.

Take, for example, this statement from a Fox News story about the Kincade Fires: “A PG&E meteorologist said it’s ‘likely that many trees will fall, branches will break,’ which could damage utility infrastructure and start a fire.”

Did you ever notice how utilities cut wide swaths of trees away when transmission lines pass through forests? There’s a reason for that: When trees fall and branches break, the grid can still function, and even as the electric rhythms of New York City shifted during COVID-19, operators planned for variability.

So, if badly designed and poorly maintained infrastructure isn’t the reason PG&E cut power to millions of Californians, what might have prompted them to do so? Could it be that PG&E’s heavy reliance on renewable energy means they don’t have the power to send when a “historic” weather event occurs, especially as policymakers weigh the postponed closure of three power plants elsewhere in California?

 

Wind Speed Limits

The two most popular forms of renewable energy come with operating limitations, which is why some energy leaders urge us to keep electricity options open when planning the grid. With solar power, the constraint is obvious: the availability of sunlight. One doesn’t generate solar power at night and energy generation drops off with increasing degrees of cloud cover during the day.

The main operating constraint of wind power is, of course, wind speed, and even in markets undergoing 'transformative change' in wind generation, operators adhere to these technical limits. At the low end of the scale, you need about a 6 or 7 miles-per-hour wind to get a turbine moving. This is called the “cut-in speed.” To generate maximum power, about a 30 mph wind is typically required. But, if the wind speed is too high, the wind turbine will shut down. This is called the “cut-out speed,” and it’s about 55 miles per hour for most modern wind turbines.

It may seem odd that wind turbines have a cut-out speed, but there’s a very good reason for it. Each wind turbine rotor is connected to an electric generator housed in the turbine nacelle. The connection is made through a gearbox that is sized to turn the generator at the precise speed required to produce 60 Hertz AC power.

The blades of the wind turbine are airfoils, just like the wings of an airplane. Adjusting the pitch (angle) of the blades allows the rotor to maintain constant speed, which, in turn, allows the generator to maintain the constant speed it needs to safely deliver power to the grid. However, there’s a limit to blade pitch adjustment. When the wind is blowing so hard that pitch adjustment is no longer possible, the turbine shuts down. That’s the cut-out speed.

Now consider how California’s power generation profile has changed. According to Energy Information Administration data, the state generated 74.3 percent of its electricity from traditional sources—fossil fuels and nuclear, amid debates over whether to classify nuclear as renewable—in 2001. Hydroelectric, geothermal, and biomass-generated power accounted for most of the remaining 25.7 percent, with wind and solar providing only 1.98 percent of the total.

By 2018, the state’s renewable portfolio had jumped to 43.8 percent of total generation, with clean power increasing and wind and solar now accounting for 17.9 percent of total generation. That’s a lot of power to depend on from inherently unreliable sources. Thus, it wouldn’t be at all surprising to learn that PG&E didn’t stop delivering power out of fear of starting fires, but because it knew it wouldn’t have power to deliver once high winds shut down all those wind turbines

 

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This Floating Hotel Will Generate Electricity By Rotating All Day

Floating Rotating Eco Hotel harnesses renewable energy via VAWTAU, recycles rainwater for greywater, and follows zero-waste principles. This mobile, off-grid, Qatar-based resort generates electricity by slow 360-degree rotation while offering luxury amenities.

 

Key Points

A mobile, off-grid hotel that rotates to generate power, uses VAWTAU, recycles greywater, and targets zero-waste.

✅ Rotates 360 deg in 24 hours to produce electricity

✅ VAWTAU system: vertical-axis turbine and sun umbrella

✅ Rain capture and greywater recycling minimize waste

 

A new eco-friendly, floating hotel plans to generate its own electricity by rotating while guests relax on board, echoing developments like the solar Marriott hotel in sustainable hospitality.

Led by Hayri Atak Architectural Design Studio (HAADS), the structure will be completely mobile, meaning it can float from place to place, never sitting in a permanent position. Building began in March 2020 and the architects aim for it to be up and running by 2025.

It will be based in Qatar, but has the potential to be located in different areas due to its mobility, and it sits within a region advancing projects such as solar hydrogen production that signal a broader clean-energy shift.

The design includes minimum energy loss and a zero waste principle at its core, aligning with progress in wave energy research that aims to power a clean future. As it will rotate around all day long, this will generate electrical energy to power the whole hotel.

But guests won’t feel too dizzy, as it takes 24 hours for the hotel to spin 360 degrees.

The floating hotel will stay within areas with continuous currents, to ensure that it is always rotating, drawing on ideas from ocean and river power systems that exploit natural flows. This type of green energy production is called ‘vawtau’ (vertical axis wind turbine and umbrella) which works like a wind turbine on the vertical axis, while alternative approaches like kite-based wind energy target stronger, high-altitude currents as well, and functions as a sun umbrella on the coastal band.

Beyond marine-current concepts such as underwater kites, the structure will also make use of rainwater to create power. A cover on the top of the hotel will collect rain to be used for greywater recycling. This is when wastewater is plumbed straight back into toilets, washing machines or outside taps to maximise efficiency.

The whole surface area is around 35,000 m², comparable in scale to emerging floating solar plants that demonstrate modular, water-based infrastructure, and there are a total of 152 rooms. It will have three different entrances so that there is access to the land at any time of the day, thanks to the 140-degree pier that surrounds it.

There will also be indoor and outdoor swimming pools, a sauna, spa, gym, mini golf course and other activity areas.

 

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Buyer's Remorse: Questions about grid modernization affordability

Grid Modernization drives utilities to integrate DER, AMI, and battery storage while balancing reliability, safety, and affordability; regulators pursue cost-benefit analyses, new rate design, and policy actions to guide investment and protect customer-owned resources.

 

Key Points

Upgrading the grid to manage DER with digital tools, while maintaining reliability, safety, and customer affordability.

✅ Cost-benefit analyses guide prudent grid investments

✅ AMI and storage deployments enable DER visibility and control

✅ Rate design reforms support customer-owned resources

 

Utilities’ pursuit of a modern grid, including the digital grid concept, to maintain the reliability and safety pillars of electricity delivery has raised a lot of questions about the third pillar — affordability.

Utilities are seeing rising penetrations of emerging technologies, highlighted in recent grid edge trends reports, like distributed solar, behind-the-meter battery storage, and electric vehicles. These new distributed energy resources (DER) do not eliminate utilities' need to keep distribution systems safe and reliable.

But the need for modern tools to manage DER imposes costs on utilities, prompting calls to invest in smarter infrastructure even as some regulators, lawmakers and policymakers are concerned those costs could drive up electricity rates.

The result is an increasing number of legislative and regulatory grid modernization actions aimed at identifying what is necessary to serve the coming power sector transformation and address climate change risks across the grid.

 

The rise of grid modernization

Grid modernization, which is supported by both conservatives and distributed energy resources advocates, got a lot of attention last year. According to the 2017 review of grid modernization policy by the North Carolina Clean Energy Technology Center (NCCETC), 288 grid modernization policy actions were proposed, pending or enacted in 39 states.

These numbers from NCCETC's first annual review of policy activity set a benchmark against which future years' activity can be measured.

The most common type of state actions, by far, were those that focused on the deployment of advanced metering infrastructure (AMI) and battery energy storage. Those are two of the 2017 trends identified in NCCETC’s 50 States of Grid Modernization report. But deployment of those technologies, while foundational to an updated grid, only begins to prepare distribution systems for the coming power sector transformation.

Bigger advances, including the newest energy system management tools, are being held back by 2017’s other policy actions requiring more deliberation and fact-finding, even as grid vulnerability report cards underscore the risks that modernization seeks to mitigate.

Utilities’ proposals to more fully prepare their grids to deliver 21st century technologies are being met with questions about completeness and cost.

Utilities are being asked to address these questions in comprehensive, public utility commission-led cost-benefit analyses and studies. This is also one of NCCETC’s top 2017 policy action trends for grid modernization. The outcome to date appears to be an increased, but still incomplete, understanding of what is needed to build a 21st century grid.

Among the top objectives of those driving the policy actions are resolving questions about private sector participation in grid modernizaton buildouts and developing new rate designs to protect and support customer-owned distributed energy resources. Actions on those topics are also on NCCETC’s list of 2017 policy trends.

Altogether, the trend list is dominated by actions that do not lead to completion of grid modernization but to more work on it.

 

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Ontario Ministry of Energy proposes growing hydrogen economy through reduced electricity rates

Ontario Hydrogen Strategy accelerates green hydrogen via electrolysis, reduced electricity rates, and IESO pilots, leveraging ICI, interruptible rates, and surplus power to grow clean tech, low-carbon energy, and export markets across Ontario.

 

Key Points

A provincial plan to scale green hydrogen with electricity costs, IESO pilots, and surplus power to boost tech.

✅ Amends ICI to admit hydrogen producers from 50 kW demand

✅ Enables co-located electrolysers to use surplus curtailed power

✅ Offers interruptible rates via IESO pilot for flexible loads

 

The Ontario Ministry of Energy is seeking input on accelerating Ontario’s hydrogen economy. The province has been promoting growth in the clean tech sector, including low-carbon energy production and the Hydrogen Innovation Fund, as an avenue for post-COVID-19 economic recovery. Hydrogen produced through electrolysis (or “green hydrogen”) has been central to these efforts, complimenting both federal and provincial initiatives to create vibrant domestic and export markets for the energy as a principal alternative to conventional fossil fuels.

On April 14, 2022, the Ministry filed a proposal (the Proposal) on the Environmental Registry of Ontario (ERO) to gather input from stakeholders, aligning with the province’s industrial electricity pricing consultation underway. As part of Ontario’s Hydrogen Strategy, the Ministry is considering several options that would provide reduced electricity rates for green hydrogen producers to make production more economically competitive with other energies. To date, the relatively high production cost of green hydrogen has been a challenge facing its adoption, both domestically and internationally.

The Proposal features three options:

  • Amending the rules for the Industrial Conservation Initiative (ICI) applicable to hydrogen producers;
  • Enabling onsite hydrogen production using electricity that would otherwise be curtailed; and
  • Providing an interruptible electricity rate for hydrogen producers.

Option 1: Amending the ICI rules

Option 1 would amend the ICI rules to allow all hydrogen producers with an average monthly peak demand of 50kW to participate. Hydrogen producers’ facilities could qualify for ICI in the first year of operation with a peak demand factor determined based on a deemed consumption profile, using a method yet to be determined by the Ministry. At the end of the first year, their global adjustment (GA) charges would be reconciled based on their actual consumption pattern. As set out in our prior article, GA was introduced by the province in January 2005 to ensure reliable, sustainable and a diverse supply of power at stable and competitive prices, aligning with plans to rely on battery storage to meet rising energy demand. The Ministry’s current proposal would require hydrogen producers to place a security deposit for their facilities’ first year of operation with the Independent Electricity System Operator (IESO) or their Local Distribution Company (LDC) to ensure other consumer would not be adversely affected.

Option 2: Enable onsite hydrogen production using surplus electricity

Option 2 would allow businesses to co-locate hydrogen electrolysers at electricity generation facilities, drawing on recent electrolyzer investment trends, to make use of what would become curtailed generation. Under this option in the Proposal, the developer for the hydrogen production facility would be required to be a separate legal entity from the one that owns or operates the electricity generation facility. Based on this required level of independence, the hydrogen developer would be required to pay the electricity generator for the electricity supply.

At this stage, it is not clear whether, or how the generator would be required to share the revenue with other consumers. The next steps of the Proposal may require regulatory amendments, and/or amendments to electricity generator’s contracts, consistent with efforts enabling storage in Ontario's electricity system to integrate flexible resources.

Option 3: Interruptible electricity rates for hydrogen producers

In 2021, the Ministry posted a proposal on the ERO including an Interruptible Rate Pilot that was to be developed in conjunction with the IESO in order to address stakeholder feedback received during the 2019 Industrial Consultation specific to the challenges of identifying and responding to peak demand events while participating in the ICI. The pilot was targeted towards large electricity consumers, where participants were charged GA at a reduced rate in exchange for agreeing to reduce consumption during system or local reliability events, as identified by IESO.

Option 3 would allow for the introduction for a dedicated stream for hydrogen producers into the interruptible rate pilot, which is currently under development with the IESO. This would take into account the unique circumstances of hydrogen producers, as well as the importance of the hydrogen sector in Ontario’s Low-Carbon Hydrogen Strategy. Under the pilot, participants would be given advance notice by the IESO to reduce demand over a fixed number of hours, several times each year, and emerging vehicle-to-grid models where EV owners can sell electricity back to the grid highlight additional flexibility options. Ultimately, the pilot would support low-carbon hydrogen production by offering large electricity consumers, such as hydrogen producers, reduced electricity rates in exchange for reduces consumption during system or local reliability events.

Following this initial development work, the Ministry intends to consult with stakeholders later this year to determine design details, as well as the timing for the potential roll out of the proposed pilot.

Key takeaways

The design options are not meant to be mutually exclusive, and might be pursued by the Ministry in combination. Ultimately, Ontario is focusing on ways to reduce electricity rates in an attempt to make the province a leader in the adoption of green hydrogen, as made clear in the Ontario Hydrogen Strategy, even as an electricity supply crunch looms, underscoring the urgency. Stakeholders will want to participate in this process given its long-term implications for both the hydrogen and power sectors.

 

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DP Energy Sells 325MW Solar Park to Medicine Hat

Saamis Solar Park advances Medicine Hat's renewable energy strategy, as DP Energy secures AUC approval for North America's largest urban solar, repurposing contaminated land; capacity phased from 325 MW toward an initial 75 MW.

 

Key Points

A 325 MW solar project in Medicine Hat, Alberta, repurposing contaminated land; phased to 75 MW under city ownership.

✅ City acquisition scales capacity to 75 MW in phased build

✅ AUC approval enables construction and grid integration

✅ Reuses phosphogypsum-impacted land near fertilizer plant

 

DP Energy, an Irish renewable energy developer, has finalized the sale of the Saamis Solar Park—a 325 megawatt (MW) solar project—to the City of Medicine Hat in Alberta, Canada. This transaction marks the development of North America's largest urban solar initiative, while mirroring other Canadian clean-energy deals such as Canadian Solar project sales that signal market depth.

Project Development and Approval

DP Energy secured development rights for the Saamis Solar Park in 2017 and obtained a development permit in 2021. In 2024, the Alberta Utilities Commission (AUC) granted approval for construction and operation, reflecting Alberta's solar growth trends in recent years, paving the way for the project's advancement.

Strategic Acquisition by Medicine Hat

The City of Medicine Hat's acquisition of the Saamis Solar Park aligns with its commitment to enhancing renewable energy infrastructure. Initially, the project was slated for a 325 MW capacity, which would significantly bolster the city's energy supply. However, the city has proposed scaling the project to a 75 MW capacity, focusing on a phased development approach, and doing so amid challenges with solar expansion in Alberta that influence siting and timing. This adjustment aims to align the project's scale with the city's current energy needs and strategic objectives.

Utilization of Contaminated Land

An innovative aspect of the Saamis Solar Park is its location on a 1,600-acre site previously affected by industrial activity. The land, near Medicine Hat's fertilizer plant, was previously compromised by phosphogypsum—a byproduct of fertilizer production. DP Energy's decision to develop the solar park on this site exemplifies a productive reuse of contaminated land, transforming it into a source of clean energy.

Benefits to Medicine Hat

The development of the Saamis Solar Park is poised to deliver multiple benefits to Medicine Hat:

  • Energy Supply Enhancement: The project will augment the city's energy grid, much like municipal solar projects that provide local power, providing a substantial portion of its electricity needs.

  • Economic Advantages: The city anticipates financial savings by reducing carbon tax liabilities, as lower-cost solar contracts have shown competitiveness, through the generation of renewable energy.

  • Environmental Impact: By investing in renewable energy, Medicine Hat aims to reduce its carbon footprint and contribute to global sustainability efforts.

DP Energy's Ongoing Commitment

Despite the sale, DP Energy maintains a strong presence in Canada, where Indigenous-led generation is expanding, with a diverse portfolio of renewable energy projects, including solar, onshore wind, storage, and offshore wind initiatives. The company continues to focus on sustainable development practices, striving to minimize environmental impact while maximizing energy production efficiency.

The transfer of the Saamis Solar Park to the City of Medicine Hat represents a significant milestone in renewable energy development. It showcases effective land reutilization, strategic urban planning, and a shared commitment to sustainable energy solutions, aligning with federal green electricity procurement that reinforces market demand. This project not only enhances the city's energy infrastructure but also sets a precedent for integrating large-scale renewable energy projects within urban environments.

 

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