California utilities commission announces climate credit

Rooftop solar grids transform urban infrastructure with distributed generation, photovoltaic panels, smart grid integration and energy storage, cutting greenhouse gas emissions, lowering utility costs, enabling net metering and community solar for low-carbon energy systems.

Key Points

Rooftop solar grids are PV systems on buildings that generate power, cut emissions, and enable smart grid integration.

✅ Lowers utility bills via net metering and demand offset

✅ Reduces greenhouse gases and urban air pollution

✅ Enables resiliency with storage, smart inverters, and microgrids

As urban areas expand and the climate crisis intensifies, cities are seeking innovative ways to integrate renewable energy sources into their infrastructure. One such solution gaining traction is the installation of rooftop solar grids. A recent CBC News article highlights the significant impact of these solar systems on urban environments, showcasing their benefits and the challenges they present.

Harnessing Unused Space for Sustainable Energy

Rooftop solar panels are revolutionizing how cities approach energy consumption and environmental sustainability. By utilizing the often-overlooked space on rooftops, these systems provide a practical solution for generating renewable energy in densely populated areas. The CBC article emphasizes that this approach not only makes efficient use of available space but also contributes to reducing a city's reliance on non-renewable energy sources.

The ability to generate clean energy directly from buildings helps decrease greenhouse gas emissions and, as scientists work to improve solar and wind power, promotes a shift towards a more sustainable energy model. Solar panels absorb sunlight and convert it into electricity, reducing the need for fossil fuels and lowering overall carbon footprints. This transition is crucial as cities grapple with rising temperatures and air pollution.

Economic and Environmental Advantages

The economic benefits of rooftop solar grids are considerable. For homeowners and businesses, installing solar panels can lead to substantial savings on electricity bills. The initial investment in solar technology is often balanced by long-term energy savings and financial incentives, such as tax credits or rebates, and evidence that solar is cheaper than grid electricity in Chinese cities further illustrates the trend toward affordability. According to the CBC report, these financial benefits make solar energy a compelling option for many urban residents and enterprises.

Environmentally, the advantages are equally compelling. Solar energy is a renewable and clean resource, and increasing the number of rooftop solar installations can play a pivotal role in meeting local and national renewable energy targets, as illustrated when New York met its solar goals early in a recent milestone. The reduction in greenhouse gas emissions from fossil fuel energy sources directly contributes to mitigating climate change and improving air quality.

Challenges in Widespread Adoption

Despite the clear benefits, the adoption of rooftop solar grids is not without its challenges. One of the primary hurdles is the upfront cost of installation. While prices for solar panels have decreased over time, the initial financial outlay remains a barrier for some property owners, and regions like Alberta have faced solar expansion challenges that highlight these constraints. Additionally, the effectiveness of solar panels can vary based on factors such as geographic location, roof orientation, and local weather patterns.

The CBC article also highlights the importance of supportive infrastructure and policies for the success of rooftop solar grids. Cities need to invest in modernizing their energy grids to accommodate the influx of solar-generated electricity, and, in the U.S., record clean energy purchases by Southeast cities have signaled growing institutional demand. Furthermore, policies and regulations must support solar adoption, including issues related to net metering, which allows solar panel owners to sell excess energy back to the grid.

Innovative Solutions and Future Prospects

The future of rooftop solar grids looks promising, thanks to ongoing technological advancements. Innovations in photovoltaic cells and energy storage solutions are expected to enhance the efficiency and affordability of solar systems. The development of smart grid technology and advanced energy management systems, including peer-to-peer energy sharing, will also play a critical role in integrating solar power into urban infrastructures.

The CBC report also mentions the rise of community solar projects as a significant development. These projects allow multiple households or businesses to share a single solar installation, making solar energy more accessible to those who may not have suitable rooftops for solar panels. This model expands the reach of solar technology and fosters greater community engagement in renewable energy initiatives.

Conclusion

Rooftop solar grids are emerging as a key element in the transition to sustainable urban energy systems. By leveraging unused rooftop space, cities can harness clean, renewable energy, reduce greenhouse gas emissions, and, as developers learn that more energy sources make better projects, achieve long-term economic savings. While there are challenges to overcome, such as initial costs and regulatory hurdles, the benefits of rooftop solar grids make them a crucial component of the future energy landscape. As technology advances and policies evolve, rooftop solar grids will play an increasingly vital role in shaping greener, more resilient urban environments.

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Hourly Electricity Emissions Tracking maps grid balancing areas, embodied emissions, and imports/exports, revealing carbon intensity shifts across PJM, ERCOT, and California ISO, and clarifying renewable energy versus coal impacts on health and climate.

Key Points

An hourly method tracing generation, flows, and embodied emissions to quantify carbon intensity across US balancing areas.

✅ Hourly traces of imports/exports and generation mix

✅ Consumption-based carbon intensity by balancing area

✅ Policy insights for renewables, coal, health costs

In the United States, electricity generation accounts for nearly 30% of our carbon emissions. Some states have responded to that by setting aggressive renewable energy standards; others are hoping to see coal propped up even as its economics get worse. Complicating matters further is the fact that many regional grids are integrated, and as America goes electric the stakes grow, meaning power generated in one location may be exported and used in a different state entirely.

Tracking these electricity exports is critical for understanding how to lower our national carbon emissions. In addition, power from a dirty source like coal has health and environment impacts where it's produced, and the costs of these aren't always paid by the parties using the electricity. Unfortunately, getting reliable figures on how electricity is produced and where it's used is challenging, even for consumers trying to find where their electricity comes from in the first place, leaving some of the best estimates with a time resolution of only a month.

Now, three Stanford researchers—Jacques A. de Chalendar, John Taggart, and Sally M. Benson—have greatly improved on that standard, and they have managed to track power generation and use on an hourly basis. The researchers found that, of the 66 grid balancing areas within the United States, only three have carbon emissions equivalent to our national average, and they have found that imports and exports of electricity have both seasonal and daily changes. de Chalendar et al. discovered that the net results can be substantial, with imported electricity increasing California's emissions/power by 20%.

Hour by hour
To figure out the US energy trading landscape, the researchers obtained 2016 data for grid features called balancing areas. The continental US has 66 of these, providing much better spatial resolution on the data than the larger grid subdivisions. This doesn't cover everything—several balancing areas in Canada and Mexico are tied in to the US grid—and some of these balancing areas are much larger than others. The PJM grid, serving Pennsylvania, New Jersey, and Maryland, for example, is more than twice as large as Texas' ERCOT, in a state that produces and consumes the most electricity in the US.

Despite these limitations, it's possible to get hourly figures on how much electricity was generated, what was used to produce it, and whether it was used locally or exported to another balancing area. Information on the generating sources allowed the researchers to attach an emissions figure to each unit of electricity produced. Coal, for example, produces double the emissions of natural gas, which in turn produces more than an order of magnitude more carbon dioxide than the manufacturing of solar, wind, or hydro facilities. These figures were turned into what the authors call "embodied emissions" that can be traced to where they're eventually used.

Similar figures were also generated for sulfur dioxide and nitrogen oxides. Released by the burning of fossil fuels, these can both influence the global climate and produce local health problems.

Huge variation
The results were striking. "The consumption-based carbon intensity of electricity varies by almost an order of magnitude across the different regions in the US electricity system," the authors conclude. The low is the Bonneville Power grid region, which is largely supplied by hydropower; it has typical emissions below 100kg of carbon dioxide per megawatt-hour. The highest emissions come in the Ohio Valley Electric region, where emissions clear 900kg/MW-hr. Only three regional grids match the overall grid emissions intensity, although that includes the very large PJM (where capacity auction payouts recently fell), ERCOT, and Southern Co balancing areas.

Most of the low-emissions power that's exported comes from the Pacific Northwest's abundant hydropower, while the Rocky Mountains area exports electricity with the highest associated emissions. That leads to some striking asymmetries. Local generation in the hydro-rich Idaho Power Company has embodied emissions of only 71kg/MW-hr, while its imports, coming primarily from Rocky Mountain states, have a carbon content of 625kg/MW-hr.

The reliance on hydropower also makes the asymmetry seasonal. Local generation is highest in the spring as snow melts, but imports become a larger source outside this time of year. As solar and wind can also have pronounced seasonal shifts, similar changes will likely be seen as these become larger contributors to many of these regional grids. Similar things occur daily, as both demand and solar production (and, to a lesser extent, wind) have distinct daily profiles.

The Golden State
California's CISO provides another instructive case. Imports represent less than 30% of its total electric use in 2016, yet California electricity imports provided 40% of its embodied emissions. Some of these, however, come internally from California, provided by the Los Angeles Department of Water and Power. The state itself, however, has only had limited tracking of imported emissions, lumping many of its sources as "other," and has been exporting its energy policies to Western states in ways that shape regional markets.

Overall, the 2016 inventory provides a narrow picture of the US grid, as plenty of trends are rapidly changing our country's emissions profile, including the rise of renewables and the widespread adoption of efficiency measures and other utility trends in 2017 that continue to evolve. The method developed here can, however, allow for annual updates, providing us with a much better picture of trends. That could be quite valuable to track things like how the rapid rise in solar power is altering the daily production of clean power.

More significantly, it provides a basis for more informed policymaking. States that wish to promote low-emissions power can use the information here to either alter the source of their imports or to encourage the sites where they're produced to adopt more renewable power. And those states that are exporting electricity produced primarily through fossil fuels could ensure that the locations where the power is used pay a price that includes the health costs of its production.

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Canada Clean Electricity Regulations allow flexible, technology-neutral pathways to a 2035 net-zero grid, permitting limited natural gas with carbon capture, strict emissions standards, and exemptions for emergencies and peak demand across provinces and territories.

Key Points

Federal draft rules for a 2035 net-zero grid, allowing limited gas with CCS under strict performance and compliance standards.

✅ Performance cap: 30 tCO2 per GWh annually for gas plants

✅ CCS must sequester 95% of emissions to comply

✅ Emergency and peak demand exemptions permitted

After facing pushback from Alberta and Saskatchewan, and amid looming power challenges nationwide, Canada's draft net-zero electricity regulations — released today — will permit some natural gas power generation. 

Environment Minister Steven Guilbeault released Ottawa's proposed Clean Electricity Regulations on Thursday.

Provinces and territories will have a minimum 75-day window to comment on the draft regulations. The final rules are intended to pave the way to a net-zero power grid in Canada, aligning with 2035 clean electricity goals established nationally. 

Calling the regulations "technology neutral," Guilbeault said the federal government believes there's enough flexibility to accommodate the different energy needs of Canada's diverse provinces and territories, including how Ontario is embracing clean power in its planning. 

"What we're talking about is not a fossil fuel-free grid by 2035; it's a net zero grid by 2035," Guilbeault said. 

"We understand there will be some fossil fuels remaining … but we're working to minimize those, and the fossil fuels that will be used in 2035 will have to comply with rigorous environmental and emission standards," he added. 

Some analysts argue that scrapping coal-fired electricity can be costly and ineffective, underscoring the trade-offs in transition planning.

While non-emitting sources of electricity — hydroelectricity, wind and solar and nuclear — should not have any issues complying with the regulations, natural gas plants will have to meet specific criteria.

Those operations, the government said, will need to emit the equivalent of 30 tonnes of carbon dioxide per gigawatt hour or less annually to help balance demand and emissions across the grid.

Federal officials said existing natural gas power plants could comply with that performance standard with the help of carbon capture and storage systems, which would be required to sequester 95 per cent of their emissions.

"In other words, it's achievable, and it is achievable by existing technology," said a government official speaking to reporters Thursday on background and not for attribution.

The regulations will also allow a certain level of natural gas power production without the need to capture emissions. Capturing emissions will be exempted during emergencies and peak periods when renewables cannot keep up with demand. 

Some newer plants might not have to comply with the rules until the 2040s, because the regulations apply to plants 20 years after they are commissioned, which dovetails with net-zero by 2050 commitments from electricity associations. 

The two-decade grace period does not apply to plants that open after the regulations are expected to be finalized in 2025.

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Bitcoin energy consumption is driven by mining electricity demand, with TWh-scale power use, carbon footprint concerns, and Cambridge estimates. Rising prices incentivize more hardware; efficiency gains and renewables adoption shape sustainability outcomes.

Key Points

Bitcoin energy consumption is mining's electricity use, driven by price, device efficiency, and energy mix.

✅ Cambridge tool estimates ~121 TWh annual usage

✅ Rising BTC price incentivizes more mining hardware

✅ Efficiency, renewables, and costs shape footprint

"Mining" for the cryptocurrency is power-hungry, with power curtailments reported during heat waves, involving heavy computer calculations to verify transactions.

Cambridge researchers say it consumes around 121.36 terawatt-hours (TWh) a year - and is unlikely to fall unless the value of the currency slumps, even as Americans use less electricity overall.

Critics say electric-car firm Tesla's decision to invest heavily in Bitcoin undermines its environmental image.

The currency's value hit a record $48,000 (£34,820) this week. following Tesla's announcement that it had bought about $1.5bn bitcoin and planned to accept it as payment in future.

But the rising price offers even more incentive to Bitcoin miners to run more and more machines.

And as the price increases, so does the energy consumption, according to Michel Rauchs, researcher at The Cambridge Centre for Alternative Finance, who co-created the online tool that generates these estimates.

“It is really by design that Bitcoin consumes that much electricity,” Mr Rauchs told BBC’s Tech Tent podcast. “This is not something that will change in the future unless the Bitcoin price is going to significantly go down."

The online tool has ranked Bitcoin’s electricity consumption above Argentina (121 TWh), the Netherlands (108.8 TWh) and the United Arab Emirates (113.20 TWh) - and it is gradually creeping up on Norway (122.20 TWh).

The energy it uses could power all kettles used in the UK, where low-carbon generation stalled in 2019, for 27 years, it said.

However, it also suggests the amount of electricity consumed every year by always-on but inactive home devices in the US alone could power the entire Bitcoin network for a year, and in Canada, B.C. power imports have helped meet demand.

Mining Bitcoin
In order to "mine" Bitcoin, computers - often specialised ones - are connected to the cryptocurrency network.

They have the job of verifying transactions made by people who send or receive Bitcoin.

This process involves solving puzzles, which, while not integral to verifying movements of the currency, provide a hurdle to ensure no-one fraudulently edits the global record of all transactions.

As a reward, miners occasionally receive small amounts of Bitcoin in what is often likened to a lottery.

To increase profits, people often connect large numbers of miners to the network - even entire warehouses full of them, as seen with a Medicine Hat bitcoin operation backed by an electricity deal.

That uses lots of electricity because the computers are more or less constantly working to complete the puzzles, prompting some utilities to consider pauses on new crypto loads in certain regions.

The University of Cambridge tool models the economic lifetime of the world's Bitcoin miners and assumes that all the Bitcoin mining machines worldwide are working with various efficiencies.

Using an average electricity price per kilowatt hour ($0.05) and the energy demands of the Bitcoin network, it is then possible to estimate how much electricity is being consumed at any one time, though in places like China's power sector data can be opaque.
 

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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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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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