Measures would provide North Dakota carbon storage rules

Hurricane Grid Resilience examines how utilities manage outages with renewables, microgrids, and robust transmission and distribution systems, balancing solar, wind, and batteries to restore service, harden infrastructure, and improve storm response and recovery.

Key Points

Hurricane grid resilience is a utility approach to withstand storms, reduce outages, and speed safe power restoration.

✅ Focus on T&D hardening, vegetation management, remote switching

✅ Balance generation mix; integrate solar, wind, batteries, microgrids

✅ Plan 12-hour shifts; automate forecasting and outage restoration

When operators of Duke Energy's control room in Raleigh, North Carolina wait for a hurricane, the mood is often calm in the hours leading up to the storm.

“Things are usually fairly quiet before the activity starts,” said Mark Goettsch, the systems operations manager at Duke. “We’re anxiously awaiting the first operation and the first event. Once that begins, you get into storm mode.”

Then begins a “frenzied pace” that can last for days — like when Hurricane Florence parked over Duke’s service territory in September.

When an event like Florence hits, all eyes are on transmission and distribution. Where it’s available, Duke uses remote switching to reconnect customers quickly. As outages mount, the utility forecasts and balances its generation with electricity demand.

The control center’s four to six operators work 12-hour shifts, while nearby staff members field thousands of calls and alarms on the system. After it’s over, “we still hold our breath a little bit to make sure we’ve operated everything correctly,” said Goettsch. Damage assessment and rebuilding can only begin once a storm passes.

That cycle is becoming increasingly common in utility service areas like Duke's.

A slate of natural disasters that reads like a roll call — Willa, Michael, Harvey, Irma, Maria, Florence and Thomas — has forced a serious conversation about resiliency. And though Goettsch has heard a lot about resiliency as a “hot topic” at industry events and meetings, those conversations are only now entering Duke’s control room.

Resilience discussions come and go in the energy industry. Storms like Hurricane Sandy and Matthew can spur a nationwide focus on resiliency, but change is largely concentrated in local areas that experienced the disaster. After a few news cycles, the topic fades into the background.

However, experts agree that resilience is becoming much more important to year-round utility planning and operations as utilities pursue decarbonization goals across their fleets. It's not a fad.

“If you look at the whole ecosystem of utilities and vendors, there’s a sense that there needs to be a more resilient grid,” said Miki Deric, Accenture’s managing director of utilities, transmission and distribution for North America. “Even if they don’t necessarily agree on everything, they are all working with the same objective.”

Can renewables meet the challenge?

After Hurricane Florence, The Intercept reported on coal ash basins washed out by the storm’s overwhelming waters. In advance of that storm, Duke shut down one nuclear plant to protect it from high winds. The Washington Post also recently reported on a slowly leaking oil spill, which could surpass Deepwater Horizon in size, caused by Hurricane Ivan in 2004.

Clean energy boosters have seized on those vulnerabilities.They say solar and wind, which don’t rely on access to fuel and can often generate power immediately after a storm, provide resilience that other electricity sources do not.

“Clearly, logistics becomes a big issue on fossil plants, much more than renewable,” said Bruce Levy, CEO and president at BMR Energy, which owns and operates clean energy projects in the Caribbean and Latin America. “The ancillaries around it — the fuel delivery, fuel storage, water in, water out — are all as susceptible to damage as a renewable plant.”

Duke, however, dismissed the notion that one generation type could beat out another in a serious storm.

“I don’t think any generation source is immune,” said Duke spokesperson Randy Wheeless. “We’ve always been a big supporter of a balanced energy mix, reflecting why the grid isn't 100% renewable in practice today. That’s going to include nuclear and natural gas and solar and renewables as well. We do that because not every day is a good day for each generation source.”

In regard to performance, Wade Schauer, director of Americas Power & Renewables Research at Wood Mackenzie, said the situation is “complex.” According to him, output of solar and wind during a storm depends heavily on the event and its location.

While comprehensive data on generation performance is sparse, Schauer said coal and gas generators could experience outages at 25 percent while stormy weather might cut 95 percent of output from renewables, underscoring clean energy's dirty secret about variability under stress. Ahead of last year’s “bomb cyclone” in New England, WoodMac data shows that wind dropped to less than 1 percent of the supply mix.

“When it comes to resiliency, ‘average performance’ doesn't cut it,” said Schauer.

In the future, he said high winds could impact all U.S. offshore wind farms, since projects are slated for a small geographic area in the Northeast. He also pointed to anecdotal instances of solar arrays in New England taken out by feet of snow. During Florence, North Carolina’s wind farms escaped the highest winds and continued producing electricity throughout. Cloud cover, on the other hand, pushed solar production below average levels.

After Florence passed, Duke reported that most of its solar came online quickly, although four of its utility-owned facilities remained offline for weeks afterward. Only one was because of damage; the other three remained offline due to substation interconnection issues.

“Solar performed pretty well,” said Wheeless. “But did it come out unscathed? No.”

According to installer reports, solar systems fared relatively well in recent storms, even as the Covid-19 impact on renewables constrained projects worldwide. But the industry has also highlighted potential improvements. Following Hurricanes Maria and Irma, the Federal Emergency Management Agency published guidelines for installing and maintaining storm-resistant solar arrays. The document recommended steps such as annual checks for bolt tightness and using microinverters rather than string inverters.

Rocky Mountain Institute (RMI) also assembled a guide for retrofitting and constructing new installations. It described attributes of solar systems that survived storms, like lateral racking supports, and those that failed, like undersized and under-torqued bolts.

“The hurricanes, as much as no one liked them, [were] a real learning experience for folks in our industry,” said BMR’s Levy. “We saw what worked, and what didn’t.”          

Facing the "800-pound gorilla" on the grid

Advocates believe wind, solar, batteries and microgrids offer the most promise because they often rely less on transmitting electricity long distances and could support peer-to-peer energy models within communities.

Most extreme weather outages arise from transmission and distribution problems, not generation issues. Schauer at WoodMac called storm damage to T&D the “800-pound gorilla.”

“I'd be surprised if a single customer power outage was due to generators being offline, especially since loads where so low due to mild temperatures and people leaving the area ahead of the storm,” he said of Hurricane Florence. “Instead, it was wind [and] tree damage to power lines and blown transformers.”

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DARPA RADICS Power Grid Security targets DoD resilience to cyber attacks, delivering early warning, detection, isolation, and characterization tools, plus a secure emergency network to protect critical infrastructure and speed grid restoration and communications.

Key Points

A DoD/DARPA initiative to detect, contain, and rapidly recover the U.S. grid from sophisticated cyber attacks.

✅ Early warning separates attacks from routine outages

✅ Pinpoints intrusion points and malware used

✅ Builds secure emergency network for rapid restoration

The U.S. Department of Defense is growing increasingly concerned about hackers taking down our power grid and crippling the nation, reflecting a renewed focus on grid protection across agencies, which is why the Pentagon has created a $77-million security plan that it hopes will be up and running by 2020.

The U.S. power grid is threatened every few days. While these physical and cyber attacks have never led to wide-scale outages, attacks are getting more sophisticated. According to a 494-page report released by the Department of Energy in January and a new grid report card, the nation’s grid “faces imminent danger from cyber attacks.” Such a major, sweeping attack could threaten “U.S. lifeline networks, critical defense infrastructure, and much of the economy; it could also endanger the health and safety of millions of citizens.” If it were to happen today, America could be powered-down and vulnerable for weeks.

#google#

The DoD is working on an automated system to speed up recovery time to a week or less — what it calls the Rapid Attack Detection, Isolation, and Characterization (RADICS) program. DARPA, the Pentagon’s research arm, originally solicited proposals in late 2015, asking for technology that did three things. Primarily, it had to detect early warning signs and distinguish between attacks and normal outages, especially after intrusions at U.S. electric utilities underscored the risk, but it also had to pinpoint the access point of the attack and determine what malicious software was used. Finally, it must include an emergency system that can rapidly connect various power-supply centers, without any human coordination. This would allow emergency and military responders to have an ad hoc communication system in place moments after an attack.

“If a well-coordinated cyberattack on the nation’s power grid were to occur today, the time it would take to restore power would pose daunting national security challenges,” said DARPA program manager John Everett, in a statement, at the time. “Beyond the severe domestic impacts, including economic and human costs, prolonged disruption of the grid would hamper military mobilization and logistics, impairing the government’s ability to project force or pursue solutions to international crises.”

DARPA plans to spend $77 million on RADICS, while DOE funding to improve the grid complements these initiatives. Last November, SRI International announced it had received $7.3 million from the program. In December, Raython was granted $9 million. The latest addition is BAE Systems, which received $8.6 million last month to develop technology that detects and contains power-grid threats, and creates a secure emergency provisional system that restores some power and communication in the wake of an attack — what is being called a secure emergency network.

According to the military news site Defense Systems, BAE’s SEN would rely on radio, satellite, or wireless internet — particularly as ransomware attacks continue to rise — whatever is available that allows the grid to continue working. The SEN would serve as a wireless connection between separate power grid stations.

While the ultimate goal of the RADICS program will be the restoration of civilian power and communications, the SEN will prioritize communication networks that would be used for defense or combat, so the U.S. government can still wage war while the rest of us are in the dark.

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U.S. Hybrid Vehicle Sales Outlook highlights rising hybrid demand as an EV bridge, driven by emissions rules, range anxiety, charging infrastructure gaps, and automaker strategies from Ford, Toyota, and Stellantis across U.S. markets.

Key Points

Forecast of U.S. hybrid sales shaped by EV adoption, emissions rules, charging access, and automaker strategies.

✅ S&P sees hybrids at 24% of U.S. sales by 2028

✅ Bridges ICE to EV amid range and charging concerns

✅ Ford, Toyota, Stellantis expand U.S. hybrid lineups

Hybrid gasoline-electric vehicles may not be dying as fast as some predicted in the auto sector’s rush to develop all-electric models.

Ford Motor is the latest of several top automakers, including Toyota and Stellantis, planning to build and sell hundreds of thousands of hybrid vehicles in the U.S. over the next five years, industry forecasters told Reuters.

The companies are pitching hybrids as an alternative for retail and commercial customers who are seeking more sustainable transportation, but may not be ready to make the leap to a full electric vehicle.

"Hybrids really serve a lot of America," said Tim Ghriskey, senior portfolio strategist at New York-based investment manager Ingalls & Snyder. "Hybrid is a great alternative to a pure electric vehicle (and) it's an easier sell to a lot of customers."

Interest in hybrids is rebounding as consumer demand for pure electrics has not accelerated as quickly as expected, with EV market share dipping in Q1 2024 according to some analyses. Surveys cite a variety of reasons for tepid EV demand, from high initial cost and concerns about range to lengthy charging times and a shortage of public charging infrastructure in many regions.

“With the tightening of emissions requirements, hybrids provide a cleaner fleet without requiring buyers to take the leap into pure electrics,” said Sam Fiorani, vice president at AutoForecast Solutions.

S&P Global Mobility estimates hybrids will more than triple over the next five years, accounting for 24% of U.S. new vehicle sales in 2028. Sales of pure electrics will claim about 37%, supported by strong U.S. EV sales into 2024 momentum, leaving combustion vehicles — including so-called “mild” hybrids — with a nearly 40% share.

S&P estimates hybrids will account for just 7% of U.S. sales this year, and pure electrics 9%, underscoring that EV sales still lag gas cars as internal combustion engine (ICE) vehicles take more than 80%.

Historically, hybrids have accounted for less than 10% of total U.S. sales, with Toyota’s long-running Prius among the most popular models. The Japanese automaker has consistently said hybrids will play a key role in the company's long-range electrification plans as it slowly ramps up investment in pure EVs.

Ford is the latest to roll out more aggressive hybrid plans. On its second-quarter earnings call in late July, Chief Executive Jim Farley surprised analysts, saying Ford expects to quadruple its hybrid sales over the next five years after earlier promising an aggressive push into all-electric vehicles.

“This transition to EVs will be dynamic,” Farley told analysts. “We expect the EV market to remain volatile until the winners and losers shake out.”

Among Ford’s competitors, General Motors appears to have little interest in hybrids in the U.S., while Stellantis will follow Toyota and Ford’s hedge by offering U.S. buyers a choice of different powertrains, including hybrids, until sales of pure electric vehicles start to take off after mid-decade, a potential EV inflection point according to forecaster GlobalData.

In a statement, GM said it, echoing leadership's view that EVs won't go mainstream until key issues are addressed, "continues to be committed to its all-electric future ... While we will have hybrid vehicles in our global fleet, our focus remains on transitioning our portfolio to electric by 2030.”

Stellantis said hybrids now account for 36% of Jeep Wrangler sales and 19% of Chrysler Pacifica sales. In addition to new pure electric models coming soon, "we are very bullish on hybrids going forward," a spokesperson said.

This year, manufacturers are marketing more than 60 hybrids in the U.S. Toyota and its premium Lexus brand are selling at least 18 different hybrid models, enabling the Japanese automaker to maintain its stranglehold on the sector.

Hyundai and sister brand Kia offer seven hybrid models, with Ford and Lincoln six. Stellantis offers just three, and GM’s sole entry, due out later this year, is a hybrid version of the Chevrolet Corvette sports car.

But hybrids remain in short supply at many U.S. dealerships.

Andrew DiFeo, dealer principal at Hyundai of St. Augustine, south of Jacksonville, FL, doesn't see EV adoption hitting the levels the Biden administration wants until EV charging networks are as ubiquitous as gas stations.

"Hybrids are a great bridge to whatever the future holds,” said DiFeo, adding, “I've got zero in stock (and) I've got customers that want all of them."

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U.S. Power Grid D+ Rating underscores aging infrastructure, rising outages, cyber threats, EMP and solar flare risks, strained transmission lines, vulnerable transformers, and slow permitting, amplifying reliability concerns and resilience needs across national energy systems.

Key Points

ASCE's D+ grade flags aging infrastructure, rising outages, and cyber, EMP, and weather risks needing investment.

✅ Major outages rising; weather remains top disruption driver.

✅ Aging transformers, transmission lines, limited maintenance.

✅ Cybersecurity gaps via smart grid, EV charging, SCADA.

The U.S. power grid just received its “grade card” from the American Society of Civil Engineers (ASCE) and it barely passed.

The overall rating of our antiquated electrical system was a D+. Major power outages in the United States, including widespread blackouts, have grown from 76 in 2007 to 307 in 2011, according to the latest available statistics. The major outage figures do not take into account all of the smaller outages which routinely occur due to seasonal storms.

The American Society of Civil Engineers power grid grade card rating means the energy infrastructure is in “poor to fair condition and mostly below standard, with many elements approaching the end of their service life.” It further means a “large portion of the system exhibits significant deterioration” with a “strong risk of failure.”

Such a designation is not reassuring and validates those who purchased solar generators over the past several years.

#google#

The vulnerable state of the power grid gets very little play by mainstream media outlets. Concerns about a solar flare or an electromagnetic pulse (EMP) attack instantly sending us back to an 1800s existence are legitimate, but it may not take such an extreme act to render the power grid a useless tangle of wires. The majority of the United States’ infrastructure and public systems evaluated by the ASCE earned a “D” rating. A “C” ranking (public parks, rail and bridges) was the highest grade earned. It would take a total of $3.6 trillion in investments by 2020 to fix everything, the report card stated. To put that number in perspective, the federal government’s budget for all of 2012 was slightly more, $3.7 trillion.

“America relies on an aging electrical grid and pipeline distribution systems, some of which originated in the 1880s,” the report read. “Investment in power transmission has increased since 2005, but ongoing permitting issues, weather events, including summer blackouts that strain local systems, and limited maintenance have contributed to an increasing number of failures and power interruptions. While demand for electricity has remained level, the availability of energy in the form of electricity, natural gas, and oil will become a greater challenge after 2020 as the population increases. Although about 17,000 miles of additional high-voltage transmission lines and significant oil and gas pipelines are planned over the next five years, permitting and siting issues threaten their completion. The electric grid in the United States consists of a system of interconnected power generation, transmission facilities, and distribution facilities.”

Harness the power of the sun when the power goes out…

There are approximately 400,000 miles of electrical transmission lines throughout the United States, and thousands of power generating plants dot the landscape. The ASCE report card also stated that new gas-fired and renewable generation issues increase the need to add new transmission lines. Antiquated power grid equipment has reportedly prompted even more “intermittent” power outages in recent years.

The American Society of Civil Engineers accurately notes that the power grid is more vulnerable to cyber attacks than ever before, including Russian intrusions documented in recent years, and it cites the aging electrical system as the primary culprit. Although the decades-old transformers and other equipment necessary to keep power flowing around America are a major factor in the enhanced vulnerability of the power grid, moving towards a “smart grid” system is not the answer. As previously reported by Off The Grid News, smart grid systems and even electric car charging stations make the power grid more accessible to cyber hackers. During the Hack in the Box Conference in Amsterdam, HP ArcSight Product Manager Ofer Sheaf stated that electric car charging stations are in essence a computer on the street. The roadway fueling stations are linked to the power grid electrical system. If cyber hackers garner access to the power grid via the charging stations, they could stop the flow of power to a specific area or alter energy distribution levels and overload the system.

While a relatively small number of electric car charging stations exist in America now, that soon will change. Ongoing efforts by both federal and state governments to reduce our reliance on fossil fuels have resulted in grants and privately funded vehicle charging station projects. New York Governor Andrew Cuomo in April announced plans to build 360 such electrical stations in his state. A total of 3,000 car charging stations are in the works statewide and are slated for completion over the next five years.

SHIELD ActWeather-related events were the primary cause of power outages from 2007 to 2012, according to the infrastructure report card. Power grid reliability issues are emerging as the greatest threat to the electrical system, with rising attacks on substations compounding the risks. The ASCE grade card also notes that retiring and rotating in “new energy sources” is a “complex” process. Like most items we routinely purchase in our daily lives, many of the components needed to make the power grid functional are not manufactured in the United States.

The SHIELD Act is the first real piece of federal legislation in years drafted to address power grid vulnerabilities. While the single bill will not fix all of the electrical system issues, it is a big step in the right direction – if it ever makes it out of committee. Replacing aging transformers, encasing them in a high-tech version of a Faraday cage, and stockpiling extra units so instant repairs are possible would help preserve one of the nation’s most critical and life-saving pieces of infrastructure after a weather-related incident or man-made disaster.

“Geomagnetic storm environments can develop instantaneously over large geographic footprints,” solar geomagnetic researcher John Kappenman said about the fragile state of the power grid. He was quoted in an Oak Ridge National Laboratory report. “They have the ability to essentially blanket the continent with an intense threat environment and … produce significant collateral damage to critical infrastructures. In contrast to well-conceived design standards that have been successfully applied for more conventional threats, no comprehensive design criteria have ever been considered to check the impact of the geomagnetic storm environments. The design actions that have occurred over many decades have greatly escalated the dangers posed by these storm threats for this critical infrastructure.”

The power grid has morphed in size tenfold during the past 50 years. While solar flares, cyber attacks, and an EMP are perhaps the most extensive and frightening threats to the electrical system, the infrastructure could just as easily fail in large portions due to weather-related events exacerbated by climate change across regions. The power grid is basically a ticking time bomb which will spawn civil unrest, lack of food, clean water, and a multitude of fires if it does go down.

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BC Hydro Clean Energy Champions highlights Vancouver's Bloedel Conservatory electrification with a massive heat pump, clean electricity, LED lighting, deep energy efficiency, and 90% greenhouse gas reductions advancing climate action across buildings and industry.

Key Points

A BC Hydro program honoring clean electricity adoption in homes, transport, and industry to replace fossil fuels.

✅ Vancouver's Bloedel Conservatory cut GHGs by 90% with a heat pump

✅ LEDs and electrification boost efficiency, comfort, and reliability

✅ Nominations open for residents, businesses, and Indigenous groups

The City of Vancouver has been selected as BC Hydro’s first Clean Energy Champion for energy efficient upgrades made at the Bloedel Conservatory that cut greenhouse gas emissions by 90 per cent, a meaningful step given concerns about 2050 greenhouse gas targets in B.C.

BC Hydro’s Clean Energy Champions program is officially being launched today to recognize residents, businesses, municipalities, Indigenous and community groups across B.C. that have made the choice to switch from using fossil fuels to using clean electricity in three primary areas: homes and buildings, transportation, and industry, even as drought challenges power generation in B.C. The City of Vancouver is being recognized as the first champion for demonstrating its commitment to using clean energy, including power from projects like Site C's electricity, to fight climate change at its landmark Bloedel Conservatory.

Earlier this year, the City of Vancouver installed a large air source heat pump at Bloedel Conservatory – more than 50 times the size of a heat pump used in a typical B.C. home – that uses electricity instead of natural gas to heat and cool the dome's interior, which is home to more than 500 exotic plants and flowers, and 100 exotic birds, aligning with citywide debates such as Vancouver’s reversal on gas appliances policy. It is the biggest heat pump the City of Vancouver has ever installed, with 210 tonnes of cooling capacity.

A heat pump that provides cooling in the summer and heating in the winter, helping reduce reliance on wasteful air conditioning that can drive up energy bills, is ideal for the conservatory, as its dome is completely made of glass, which can be challenging for temperature regulation. While the dome experiences a lot of heat loss in the colder months, its need for cooling in warmer weather is even greater to ensure the safety of the wildlife and plants that call it home.

The clean energy upgrades do not end there though. All lighting in the building has been upgraded to energy-efficient LEDs, reflecting conservation themes highlighted by 2018 Earth Hour electricity use discussions, and outside colour-changing LEDs now surround the perimeter and light up the dome at night.

BC Hydro is calling for nominations from B.C. residents, businesses, municipalities or Indigenous and community groups that have taken steps to lower their carbon footprint and adopt new clean energy technologies, and continues to support customers through programs like its winter payment plan during colder months. If you or someone you know is a Clean Energy Champion, nominate them at bchydro.com/cleanenergychampions.

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Frisco 100% Renewable Electricity Goal outlines decarbonization via Xcel Energy, wind, solar, and battery storage, enabling beneficial electrification and a smarter grid for 100% municipal power by 2025 and community-wide clean electricity by 2035.

Key Points

Frisco targets 100% renewable electricity: municipal by 2025, community by 2035, via Xcel decarbonization.

✅ Municipal operations to reach 100% renewable electricity by 2025

✅ Community-wide electricity to be 100% carbon-free by 2035

✅ Partnerships: Xcel Energy, wind, solar, storage, grid markets

Frisco has now set a goal of 100-per-cent renewable energy, joining communities on the road to 100% renewables across the country. But unlike some other resolutions adopted in the last decade, this one isn't purely aspirational. It's swimming with a strong current.

With the resolution adopted last week by the town council, Frisco joins 10 other Colorado towns and cities, plus Pueblo and Summit counties, a trend reflected in tracking progress on clean energy targets reports nationwide, in adopting 100-per-cent goals.

The goal is to get the municipality's electricity to 100-per-cent by 2025 and the community altogether by 2035, a timeline aligned with scenarios showing zero-emissions electricity by 2035 is possible in North America.

Decarbonizing electricity will be far easier than transportation, and transportation far easier than buildings. Many see carbon-free electricity as being crucial to both, a concept called "beneficial electrification," and point to ways to meet decarbonization goals that leverage electrified end uses.

Electricity for Frisco comes from Xcel Energy, an investor-owned utility that is making giant steps toward decarbonizing its power supply.

Xcel first announced plans to close its work-horse power plants early to take advantage of now-cheap wind and solar resources plus what will be the largest battery storage project east of the Rocky Mountains. All this will be accomplished by 2026 and will put Xcel at 55 per cent renewable generation in Colorado.

In December, a week after Frisco launched the process that produced the resolution, Xcel announced further steps, an 80 percent reduction in carbon dioxide emissions by 2030 as compared to 2050 levels. By 2050, the company vows to be 100 per cent "carbon-free" energy by 2050.

Frisco's non-binding goals were triggered by Fran Long, who is retired and living in Frisco. For eight years, though, he worked for Xcel in helping shape its response to the declining prices of renewables. In his retirement, he has also helped put together the aspirational goal adopted by Breckenridge for 100-per-cent renewables.

A task force that Long led identified a three-pronged approach. First, the city government must lead by example. The resolution calls for the town to spend $25,000 to $50,000 annually during the next several years to improve energy efficiency in its municipal facilities. Then, through an Xcel program called Renewable Connect, it can pay an added cost to allow it to say it uses 100-per-cent electricity from renewable sources.

Beyond that, Frisco wants to work with high-end businesses to encourage buying output from solar gardens or other devices that will allow them to proclaim 100-per-cent renewable energy. The task force also recommends a marketing program directed to homes and smaller businesses.

Goals of 100-per-cent renewable electricity are problematic, given why the grid isn't 100% renewable today for technical and economic reasons. Aspen Electric, which provides electricity for about two-thirds of the town, by 2015 had secured enough wind and hydro, mostly from distant locations, to allow it to proclaim 100 per cent renewables.

In fact, some of those electrons in Aspen almost certainly originate in coal or gas plants. That doesn't make Aspen's claim wrong. But the fact remains that nobody has figured out how, at least at affordable cost, to deliver 100-per-cent clean energy on a broad basis.

Xcel Energy, which supplies more than 60 per cent of electricity in Colorado, one of six states in which it operates, has a taller challenge. But it is a very different utility than it was in 2004, when it spent heavily in advertising to oppose a mandate that it would have to achieve 10 per cent of its electricity from renewable sources by 2020.

Once it lost the election, though, Xcel set out to comply. Integrating renewables proved far more easily than was feared. It has more than doubled the original mandate for 2020. Wind delivers 82 per cent of that generation, with another 18 per cent coming from community, rooftop, and utility-scale solar.

The company has become steadily more proficient at juggling different intermittent power supplies while ensuring lights and computers remain on. This is partly the result of practice but also of relatively minor technological wrinkles, such as improved weather forecasting, according to an Energy News Network story published in March.

For example, a Boulder company, Global Weather corporation, projects wind—and hence electrical production—from turbines for 10 days ahead. It updates its forecasts every 15 minutes.

Forecasts have become so good, said John T. Welch, director of power operations for Xcel in Colorado, that the utility uses 95 per cent to 98 per cent of the electricity generated by turbines. This has allowed the company to use its coal and natural gas plants less.M

Moreover, prices of wind and then solar declined slowly at first and then dramatically.

Xcel is now comfortable that existing technology will allow it to push from 55 per cent renewables in 2026 to an 80 per cent carbon reduction goal by 2030.

But when announcing their goal of emissions-free energy by mid-century in December, the company's Minneapolis-based chief executive, Ben Fowke, and Alice Jackson, the chief executive of the company's Colorado subsidiary, freely admitted they had no idea how they will achieve it. "I have a lot of confidence they will be developed," Fowke said of new technologies.

Everything is on the table, they said, including nuclear. But also including fossil fuels, if the carbon dioxide can be sequestered. So far, such technology has proven prohibitively expensive despite billions of dollars in federal support for research and deployment. They suggested it might involve new technology.

Xcel's Welch told Energy News Network that he believes solar must play a larger role, and he believes solar forecasting must improve.

Storage technology must also improve as batteries are transforming solar economics across markets. Batteries, such as produced by Tesla at its Gigafactory near Reno, can store electricity for hours, maybe even a few days. But batteries that can store large amounts of electricity for months will be needed in Colorado. Wind is plentiful in spring but not so much in summer, when air conditioners crank up.

Increased sharing of cheap renewable generation among utilities will also allow deeper penetration of carbon-free energy, a dynamic consistent with studies finding wind and solar could meet 80% of demand with improved transmission. Western US states and Canadian provinces are all on one grid, but the different parts are Balkanized. In other words, California is largely its own energy balancing authority, ensuring electricity supplies match electricity demands. Ditto for Colorado. The Pacific Northwest has its own balancing authority.

If they were all orchestrated as one in an expanded energy market across the West, however, electricity supplies and demands could more easily be matched. California's surplus of solar on summer afternoons, for example, might be moved to Colorado.

Colorado legislators in early May adopted a bill that requires the state's Public Utilities Commission to begin study by late this year of an energy imbalance market or regional transmission organization.

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