Oncor files to help build renewable energy superhighway

Duke Energy Net Metering Proposal updates rooftop solar compensation with time-of-use rates, lower grid credits, and a minimum charge, aligning payments with electricity demand in North Carolina pending regulators' approval.

Key Points

A plan to swap flat credits for time-of-use rates and a minimum charge for rooftop solar customers in North Carolina.

✅ Time-of-use credits vary by grid demand

✅ $10 minimum use charge plus $14 basic fee

✅ Aims to align solar payouts with actual electricity value

Duke Energy has proposed new rules for how owners of rooftop solar panels are paid for electricity they send to the electric grid. It could mean more complexity and lower payments, but the utility says rates would be fairer.

State legislators have called for changes in the payment rules — known as "net metering" policies that allow households to sell power back to energy firms.

Right now, solar panel owners who produce more electricity than they need get credits on their bills, equal to whatever they pay for electricity. Under the proposed changes, the credit would be lower and would vary according to electricity demand, said Duke spokesperson Randy Wheeless.

"So in a cold winter morning, like now, you would get more, but maybe in a mild spring day, you would get less," Wheeless said Tuesday. "So, it better reflects what the price of electricity is."

Besides setting rates by time of use, solar owners also would have to pay a minimum of $10 a month for electricity, even if they don't use any from the grid. That's on top of Duke's $14 basic charge. Duke said it needs the extra revenue to pay for grid infrastructure to serve solar customers.

The proposal is the result of an agreement between Duke and solar industry groups — the North Carolina Sustainable Energy Association; the Southern Environmental Law Center, which represented Vote Solar and the Southern Alliance for Clean Energy; solar panel maker Sunrun Inc.; and the Solar Energy Industries Association.

The deal is similar to one approved by regulators in South Carolina last year, while in Nova Scotia a solar charge was delayed after controversy.

Daniel Brookshire of the North Carolina Sustainable Energy Association said he hopes the agreement will help the solar industry.

"We reached an agreement here that we think will provide certainty over the next decade, at least, for those interested in pursuing solar for their homes, and for our members who are solar installers," Brookshire said.

But other environmental and consumer groups oppose the changes, amid debates over who pays for grid upgrades elsewhere. Jim Warren with NC WARN said the rules would slow the expansion of rooftop solar in North Carolina.

"It would make it even harder for ordinary people to go solar," Warren said. "This would make it more complicated and more expensive, even for wealthier homeowners."

State regulators still must approve the proposal, even as courts weigh aspects of the electricity monopoly in related solar cases. If state regulators approve it, rates for new net metering customers would take effect Jan. 1, 2023.

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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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Canadian Softwood Lumber Tariffs challenge British Columbia's forestry sector, strain U.S.-Canada trade, and risk redirecting critical minerals and energy resources, threatening North American supply chains, manufacturing, and energy security across integrated markets.

Key Points

Duties imposed by the U.S. on Canadian lumber, affecting BC forestry, trade flows, and North American energy security.

✅ U.S. duties strain BC forestry and cross-border supply chains

✅ Risks redirecting critical minerals and energy exports

✅ Tariff rollback could bolster North American energy security

British Columbia Premier David Eby has raised concerns that U.S. tariffs on Canadian softwood lumber are prompting the province to redirect its critical minerals and energy resources, while B.C. challenges Alberta's electricity export restrictions domestically, away from the United States. In a recent interview, Eby emphasized the broader implications of these tariffs, suggesting they could undermine North American energy security and put electricity exports at risk across the border.

Since 2017, the U.S. Department of Commerce has imposed tariffs on Canadian softwood lumber imports, alleging that Canadian producers benefit from unfair subsidies. These duties have been a persistent source of tension between the two nations, coinciding with Canadian support for energy and mineral tariffs and significantly impacting British Columbia's forestry sector—a cornerstone of the province's economy.

Premier Eby highlighted that the financial strain imposed by these tariffs not only jeopardizes the Canadian forestry industry but also has unintended repercussions for the United States. He pointed out that the economic challenges faced by Canadian producers might lead them to seek alternative markets for their critical minerals and energy resources, as tariff threats boost support for Canadian energy projects domestically, thereby reducing the supply to the U.S. British Columbia is endowed with an abundance of critical minerals essential for various industries, including technology and defense.

The potential redirection of these resources could have significant consequences for American industries that depend on a stable and affordable supply of critical minerals and energy. Eby suggested that the tariffs might incentivize Canadian producers to explore other international markets, even as experts advise against cutting Quebec's energy exports amid the tariff dispute, diminishing the availability of these vital resources to the U.S.

In light of these concerns, Premier Eby has advocated for a reassessment of the tariffs, urging a more cooperative approach between Canada and the United States. He contends that eliminating the tariffs would be mutually beneficial, aligning with views that Biden is better for Canada's energy sector and cross-border collaboration, ensuring a consistent supply of critical resources and fostering economic growth in both countries.

The issue of U.S. tariffs on Canadian softwood lumber remains complex and contentious, with far-reaching implications for trade relations and resource distribution between the two nations. As discussions continue, stakeholders on both sides of the border are closely monitoring the situation, noting that Ford has threatened to cut U.S. electricity exports amid trade tensions, recognizing the importance of collaboration in addressing shared economic and security challenges.

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Canada 100% Renewable Power by 2035 envisions a decentralized grid built on wind, solar, energy storage, and efficiency, delivering zero-emission, resilient, low-cost electricity while phasing out nuclear and gas to meet net-zero targets.

Key Points

Zero-emission, decentralized grid using wind, solar, and storage, plus efficiency, to retire fossil and nuclear by 2035.

✅ Scale wind and solar 18x with storage for reliability.

✅ Phase out nuclear and gas; no CCS or offsets needed.

✅ Modernize grids and codes; boost efficiency, jobs, and affordability.

A powerful derecho that left nearly a million people without power in Ontario and Quebec on May 21 was a reminder of the critical importance of electricity in our daily lives.

Canada’s electrical infrastructure could be more resilient to such events, while being carbon-emission free and provide low-cost electricity with a decentralized grid powered by 100 per cent renewable energy, according to a new study from the David Suzuki Foundation (DSF), a vision of an electric, connected and clean future if the country chooses.

This could be accomplished by 2035 by building a lot more solar and wind, despite indications that demand for solar electricity has lagged in Canada, adding energy storage, while increasing the energy efficiency in buildings, and modernizing provincial energy grids. As this happens, nuclear energy and gas power would be phased out. There would also be no need for carbon capture and storage nor carbon offsets, the modeling study concluded.

“Solar and wind are the cheapest sources of electricity generation in history,” said study co-author Stephen Thomas, a mechanical engineer and climate solutions policy analyst at the DSF.

“There are no technical barriers to reaching 100 per cent zero-emission electricity by 2035 nationwide,” Thomas told The Weather Network (TWN). However, there are considerable institutional and political barriers to be overcome, he said.

Other countries face similar barriers and many have found ways to reduce their emissions; for example, the U.S. grid's slow path to 100% renewables illustrates these challenges. There are enormous benefits including improved air quality and health, up to 75,000 new jobs annually, and lower electricity costs. Carbon emissions would be reduced by 200 million tons a year by 2050, just over one quarter of the reductions needed for Canada to meet its overall net zero target, the study stated.

Building a net-zero carbon electricity system by 2035 is a key part of Canada’s 2030 Emissions Reduction Plan. Currently over 80 per cent of the nation’s electricity comes from non-carbon sources including a 15 per cent contribution from nuclear, with solar capacity nearing a 5 GW milestone nationally. How the final 20 per cent will be emission-free is currently under discussion.

The Shifting Power study envisions an 18-fold increase in wind and solar energy, with the Prairie provinces expected to lead growth, along with a big increase in Canada’s electrical generation capacity to bridge the 20 per cent gap as well as replacing existing nuclear power.

The report does not see a future role for nuclear power due to the high costs of refurbishing existing plants, including the challenges with disposal of radioactive wastes and decommissioning plants at their end of life. As for the oft-proposed small modular nuclear reactors, their costs will likely “be much more costly than renewables,” according to the report.

There are no technical barriers to building a bigger, cleaner, and smarter electricity system, agrees Caroline Lee, co-author of the Canadian Climate Institute’s study on net-zero electricity, “The Big Switch” released in May. However, as Lee previously told TWN, there are substantial institutional and political barriers.

In many respects, the Shifting Power study is similar to Lee’s study except it phases out nuclear power, forecasts a reduction in hydro power generation, and does not require any carbon capture and storage, she told TWN. Those are replaced with a lot more wind generation and more storage capacity.

“There are strengths and weaknesses to both approaches. We can do either but need a wide debate on what kind of electricity system we want,” Lee said.

That debate has to happen immediately because there is an enormous amount of work to do. When it comes to energy infrastructure, nearly everything “we put in the ground has to be wind, solar, or storage” to meet the 2035 deadline, she said.

There is no path to net zero by 2050 without a zero-emissions electricity system well before that date. Here are some of the necessary steps the report provided:

Create a range of skills training programs for renewable energy construction and installation as well as building retrofits.

Prioritize energy efficiency and conservation across all sectors through regulations such as building codes.

Ensure communities and individuals are fully informed and can decide if they wish to benefit from hosting energy generation infrastructure.

Create a national energy poverty strategy to ensure affordable access.

Strong and clear federal and provincial rules for utilities that mandate zero-emission electricity by 2035.

For Indigenous communities, make sure ownership opportunities are available along with decision-making power.

Canada should move as fast as possible to 100 per cent renewable energy to gain the benefits of lower energy costs, less pollution, and reduced carbon emissions, says Stanford University engineer and energy expert Mark Jacobson.

“Canada has so many clean, renewable energy resources that it is one of the easier countries [that can] transition away from fossil fuels,” Jacobson told TWN.

For the past decade, Jacobson has been producing studies and technical reports on 100 per cent renewable energy, including a new one for Canada, even as Canada is often seen as a solar power laggard today. The Stanford report, A Solution to Global Warming, Air Pollution, and Energy Insecurity for Canada, says a 100 per cent transition by 2035 timeline is ideal. Where it differs from DSF’s Shifting Power report is that it envisions offshore wind and rooftop solar panels which the latter did not.

“Our report is very conservative. Much more is possible,” agrees Thomas.

“We’re lagging behind. Canadians really want to get going on building solutions and getting the benefits of a zero emissions electricity system.”

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Utility Battery Storage Rankings measure grid-connected capacity, not ownership, highlighting MW, MWh, and watts per customer across PJM, MISO, and California IOUs, featuring Duke Energy, IPL, ancillary services, and frequency regulation benefits.

Key Points

Rankings that track energy storage connected to utility grids, comparing MW, MWh, and W/customer rather than ownership.

✅ Ranks by MW, MWh, and watts per customer, not asset ownership

✅ Highlights PJM, MISO cases and California IOUs' deployments

✅ Examples: Duke Energy, IPL, IID; ancillary services, frequency response

The rankings do not tally how much energy storage a utility built or owns, but how much was connected to their system. So while IPL built and owns the storage facility in its territory, Duke does not own the 16 MW of storage that connected to its system in 2016. Similarly, while California’s utilities are permitted to own some energy storage assets, they do not necessarily own all the storage facilities connected to their systems.

Measured by energy (MWh), IPL ranked fourth with 20 MWh, and Duke Energy Ohio ranked eighth with 6.1 MWh.

Ranked by energy storage watts per customer, IPL and Duke actually beat the California utilities, ranking fifth and sixth with 42 W/customer and 23 W/customer, respectively.

Duke ready for next step

Given Duke’s plans, including projects in Florida that are moving ahead, the utility is likely to stay high in the rankings and be more of a driving force in development. “Battery technology has matured, and we are ready to take the next step,” Duke spokesman Randy Wheeless told Utility Dive. “We can go to regulators and say this makes economic sense.”

Duke began exploring energy storage in 2012, and until now most of its energy storage efforts were focused on commercial projects in competitive markets where it was possible to earn revenues. Those included its 36 MW Notrees battery storage project developed in partnership with the Department of Energy in 2012 that provides frequency regulation for the Electric Reliability Council of Texas market and two 2 MW storage projects at its retired W.C. Beckjord plant in New Richmond, Ohio, that sells ancillary services into the PJM Interconnection market.

On the regulated side, most of Duke’s storage projects have had “an R&D slant to them,” Wheeless said, but “we are moving beyond the R&D concept in our regulated territory and are looking at storage more as a regulated asset.”

“We have done the demos, and they have proved out,” Wheeless said. Storage may not be ready for prime time everywhere, he said, but in certain locations, especially where it can it can be used to do more than one thing, it can make sense.

Wheeless said Duke would be making “a number of energy storage announcements in the next few months in our regulated states.” He could not provide details on those projects.

More flexible resources
Location can be a determining factor when building a storage facility. For IPL, serving the wholesale market was a driving factor in the rationale to build its 20 MW, 20 MWh storage facility in Indianapolis.

IPL built the project to address a need for more flexible resources in light of “recent changes in our resource mix,” including decreasing coal-fired generation and increasing renewables and natural gas-fired generation, as other regions plan to rely on battery storage to meet rising demand, Joan Soller, IPL’s director of resource planning, told Utility Dive in an email. The storage facility is used to provide primary frequency response necessary for grid stability.

The Harding Street storage facility in May. It was the first energy storage project in the Midcontinent ISO. But the regulatory path in MISO is not as clear as it is in PJM, whereas initiatives such as Ontario storage framework are clarifying participation. In November, IPL with the Federal Energy Regulatory Commission, asking the regulator to find that MISO’s rules for energy storage are deficient and should be revised.

Soller said IPL has “no imminent plans to install energy storage in the future but will continue to monitor battery costs and capabilities as potential resources in future Integrated Resource Plans.”

California legislative and regulatory push

In California, energy storage did not have to wait for regulations to catch up with technology. With legislative and regulatory mandates, including CEC long-duration storage funding announced recently, as a push, California’s IOUs took high places in SEPA’s rankings.

Southern California Edison and San Diego Gas & Electric were first and fourth (63.2 MW and 17.2 MW), respectively, in terms of capacity. SoCal Ed and SDG&E were first and second (104 MWh and 28.4 MWh), respectively, and Pacific Gas and Electric was fifth (17 MWh) in terms of energy.

But a public power utility, the Imperial Irrigation District (IID), ended up high in the rankings – second in capacity (30 MW) and third  in energy (20 MWh) – even though as a public power entity it is not subject to the state’s energy storage mandates.

But while IID was not under state mandate, it had a compelling regulatory reason to build the storage project. It was part of a settlement reached with FERC over a September 2011 outage, IID spokeswoman Marion Champion said.

IID agreed to a $12 million fine as part of the settlement, of which $9 million was applied to physical improvements of IID’s system.

IID ended up building a 30 MW, 20 MWh lithium-ion battery storage system at its El Centro generating station. The system went into service in October 2016 and in May, IID used the system’s 44 MW combined-cycle natural gas turbine at the generating station.

Passing savings to customers
The cost of the storage system was about $31 million, and based on its experience with the El Centro project, Champion said IID plans to add to the existing batteries. “We are continuing to see real savings and are passing those savings on to our customers,” she said.

Champion said the battery system gives IID the ability to provide ancillary services without having to run its larger generation units, such as El Centro Unit 4, at its minimum output. With gas prices at $3.59 per million British thermal units, it costs about $26,880 a day to run Unit 4, she said.

IID’s territory is in southeastern California, an area with a lot of renewable resources. IID is also not part of the California ISO and acts as its own balancing authority. The battery system gives the utility greater operational flexibility, in addition to the ability to use more of the surrounding renewable resources, Champion said.

In May, IID’s board gave the utility’s staff approval to enter into contract negotiations for a 7 MW, 4 MWh expansion of its El Centro storage facility. The negotiations are ongoing, but approval could come in the next couple months, Champion said.

The heart of the issue, though, is “the ability of the battery system to lower costs for our ratepayers,” Champion said. “Our planning section will continue to utilize the battery, and we are looking forward to its expansion,” she said.” I expect it will play an even more important role as we continue to increase our percentage of renewables.”

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Sustainable Marine tidal energy delivers in-stream power to Nova Scotia's grid from Grand Passage, proving low-impact, renewable generation and advancing a floating tidal array at FORCE and Minas Passage in the Bay of Fundy.

Key Points

The first in-stream tidal project supplying clean power to Nova Scotia's grid, proven at Grand Passage.

✅ First to deliver in-stream tidal power to Canada's grid

✅ Demonstration at Grand Passage informs FORCE deployments

✅ Low-impact design and environmental monitoring validated

Sustainable Marine has officially powered up its tidal energy operation in Canada and is delivering clean electricity to the power system in Nova Scotia, on the country’s Atlantic coast, as the province moves to increase wind and solar projects in the years ahead. The company’s system in Grand Passage is the first to deliver in-stream tidal power to the grid in Canada, following provincial approval to harness Bay of Fundy tides that is spurring further development.

The system start-up is the culmination of more than a decade of research, development and testing, including lessons from Scottish tidal projects in recent years and a powerful tidal turbine feeding onshore grids, managing the technical challenges associated with operating in highly energetic environments and proving the ultra-low environmental impact of the tidal technology.

Sustainable Marine is striving to deliver the world’s first floating tidal array at FORCE (Fundy Ocean Research Centre for Energy). This project will be delivered in phases, drawing upon the knowledge gained and lessons learned in Grand Passage, and insights from offshore wind pilots like France’s first offshore wind turbine in Europe. In the coming months the company will continue to operate the platform at its demonstration site at Grand Passage, gradually building up power production, while New York and New England clean energy demand continues to rise, to further prove the technology and environmental monitoring systems, before commencing deployments in the Minas Passage – renowned as the Everest of tidal energy.

The Bay of Fundy’s huge tidal energy resource contains more than four times the combined flow of every freshwater river in the world, with the potential to generate approximately 2,500 MW of green energy, underscoring why independent electricity planning will be important for integrating marine renewables.

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