Utilities warming to ice-storage AC systems

By Toronto Star


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Mountain Equipment Co-Op's newest store, which opened last November in Burlington, is without question the greenest of them all.

A white roof keeps it cooler in the summer. Rooftop windows let in natural sunlight and sensors turn on what lights there are only when needed. Special parking is reserved for customers who drive hybrid-electric and other super-efficient vehicles. Rain is collected from its rooftop and used as grey water for toilets and outside watering.

Atop the roof sit two massive solar arrays consisting of dozens of parabolic mirrors that concentrate the sunlight to generate both electricity and heat for hot-water production. Each array is attached to a motorized tracker, which follows the sun throughout the day to maximize the amount of energy collected.

All said, the building's design makes it 68-per-cent more energy efficient than comparable retail properties, an achievement that has earned it Leadership in Energy and Environmental Design (LEED) certification, with a gold rating.

But there's more. To achieve such high energy-efficiency, the building also cools itself using massive blocks of ice instead of energy-hungry air conditioners. At the back of the building sit four Ice Bear systems, looking like oversized refrigerators knocked on their sides, developed by Santa Clara, Calif.-based Ice Energy Inc.

The concept behind the Ice Bear is quite simple: at night, when electricity is plentiful, a condensing unit pumps refrigerant through copper coils equally distributed through the body of the water-filled unit, which is heavily insulated. The coils freeze the 1,800 litres of water in the unit and then automatically shut off.

During the day, when power demands peak and electricity is more expensive, the system is reversed and the ice is used to cool air that is circulated through a building's ventilation system. The biggest energy draw that's really used at this point is 300 watts to run a ventilation fan. That's the equivalent of having three incandescent light bulbs on.

Each Ice Bear system, when water is completely frozen, can supply the same amount of cooling as a conventional five-tonne rooftop air conditioning system for about six hours – that is, until all the ice melts. It then takes a good 10 or 11 hours to refreeze the water in preparation for the next day.

Now, like most emerging clean technologies, the clear environmental benefits don't necessarily translate into economic benefits. James Alden, the chief operating officer of Toronto-based Summerhill Group, an environmental consultancy that's helping the Ice Bear concept gain traction in Canada, will be the first to tell you that the system is at least double the cost of traditional rooftop air conditioners.

"You're not going to sell this to a customer strictly on a payback perspective, with the exception of companies aiming for LEED certification," like Mountain Equipment Co-Op, he said.

On the other hand, Alden said the system makes sense for utilities looking to eliminate daytime spikes in electricity demand by shifting consumption to periods of low demand – that is, overnight. This can make economic sense on a system-wide scale because it delays the need to build so-called "peaker" power plants and can ease congestion on the grid, possibly deferring costly transmission and distribution upgrades.

He envisions a major utility or group of utilities strategically deploying enough Ice Bear systems to retailers and other commercial buildings throughout the province to shift 30 megawatts of peak-time demand to low-peak periods. The units would be owned by the utilities and could be remotely controlled through a smart grid.

Hydro One, Powerstream, Toronto Hydro, and a number of other utilities have already visited Mountain Equipment Co-Op to learn about the system. "All the large utilities are interested," Alden said, pointing out that under the new Green Energy Act local electric utilities can now do these kinds of projects more freely.

Now, they just have to get creative.

You may remember an Ontario-born company called Tamarack Lake Electric Boat Co., which has developed a solar-hybrid pontoon boat. The company is in the process of moving to New York State and has rebranded itself Buffalo Solar Boats. Seems incentives south of the border were better than those offered – or not offered – here.

But don't fret, as another local has come out with an all-electric solar boat, this one called the Humber Foton. Made by Toronto-based Humber Boat Ltd. (www.humberboats.ca), the Foton is more like a slow-moving fishing boat. A six horsepower electric motor with custom solar panels on the front costs $8,895. The two horsepower model is $7,895.

Don't expect a speedboat. The top model only goes up to 10 km/h for about 1.5 hours before needing a recharge. But if you're on a quiet lake and aren't in a hurry, it may fit the bill.

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From smart meters to big batteries, co-ops emerge as clean grid laboratories

Minnesota Electric Cooperatives are driving grid innovation with smart meters, time-of-use pricing, demand response, and energy storage, including iron-air batteries, to manage peak loads, integrate wind and solar, and cut costs for rural members.

 

Key Points

Member-owned utilities piloting load management, meters, and storage to integrate wind and solar, cutting peak demand.

✅ Time-of-use pricing pilots lower bills and shift peak load.

✅ Iron-air battery tests add multi-day, low-cost energy storage.

✅ Smart meters enable demand response across rural co-ops.

 

Minnesota electric cooperatives have quietly emerged as laboratories for clean grid innovation, outpacing investor-owned utilities on smart meter installations, time-based pricing pilots, and experimental battery storage solutions.

“Co-ops have innovation in their DNA,” said David Ranallo, a spokesperson for Great River Energy, a generation and distribution cooperative that supplies power to 28 member utilities — making it one of the state’s largest co-op players.

Minnesota farmers helped pioneer the electric co-op model more than a century ago, similar to modern community-generated green electricity initiatives, pooling resources to build power lines, transformers and other equipment to deliver power to rural parts of the state. Today, 44 member-owned electric co-ops serve about 1.7 million rural and suburban customers and supply almost a quarter of the state’s electricity.

Co-op utilities have by many measures lagged on clean energy. Many still rely on electricity from coal-fired power plants. They’ve used political clout with rural lawmakers to oppose new pollution regulations and climate legislation, and some have tried to levy steep fees on customers who install solar panels.

Where they are emerging as innovators is with new models and technology for managing electric grid loads — from load-shifting water heaters to a giant experimental battery made of iron. The programs are saving customers money by delaying the need for expensive new infrastructure, and also showing ways to unlock more value from cheap but variable wind and solar power.

Unlike investor-owned utilities, “we have no incentive to invest in new generation,” said Darrick Moe, executive director of the Minnesota Rural Electric Association. Curbing peak energy demand has a direct financial benefit for members.

Minnesota electric cooperatives have launched dozens of programs, such as the South Metro solar project, in recent years aimed at reducing energy use and peak loads, in particular. They include:

Cost calculations are the primary driver for electric cooperatives’ recent experimentation, and a lighter regulatory structure and evolving electricity market reforms have allowed them to act more quickly than for-profit utilities.

“Co-ops and [municipal utilities] can act a lot more nimbly compared to investor-owned utilities … which have to go through years of proceedings and discussions about cost-recovery,” said Gabe Chan, a University of Minnesota associate professor who has researched electric co-ops extensively. Often, approval from a local board is all that’s required to launch a venture.

Great River Energy’s programs, which are rebranded and sold through member co-ops, yielded more than 101 million kilowatt-hours of savings last year — enough to power 9,500 homes for a year.

Beyond lowering costs for participants and customers at large, the energy-saving and behavior-changing programs sometimes end up being cited as case studies by larger utilities considering similar offerings. Advocates supporting a proposal by the city of Minneapolis and CenterPoint Energy to allow residents to pay for energy efficiency improvements on their utility bills through distributed energy rebates used several examples from cooperatives.

Despite the pace of innovation on load management, electric cooperatives have been relatively slow to transition from coal-fired power. More than half of Great River Energy’s electricity came from coal last year, and Dairyland Power, another major power wholesaler for Minnesota co-ops, generated 70% of its energy from coal. Meanwhile, Xcel Energy, the state’s largest investor-owned utility, has already reduced coal to about 20% of its energy mix.

The transition to cleaner power for some co-ops has been slowed by long-term contracts with power suppliers that have locked them into dirty power. Others have also been stalled by management or boards that have been resistant to change. John Farrell, director of the Institute for Local Self-Reliance’s Energy Democracy program, said generalizing co-ops is difficult. 

“We’ve seen some co-ops that have got 75-year contracts for coal, that are invested in coal mines and using their newsletter to deny climate change,” he said. “Then you see a lot of them doing really amazing things like creating energy storage systems … and load balancing [programs], because they are unique and locally managed and can have that freedom to experiment without having to go through a regulatory process.”

Great River Energy, for its part, says it intends to reach 54% renewable generation by 2025, while some communities, like Frisco, Colorado, are targeting 100% clean electricity by specific dates. Its members recently voted to sell North Dakota’s largest coal plant, but the arrangement involves members continuing to buy power from the new owners for another decade.

The cooperative’s path to clean power could become clearer if its experimental iron-air battery project is successful. The project, the first of its kind in the country, is expected to be completed by 2023.

 

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BC residents split on going nuclear for electricity generation: survey

BC Energy Debate: Nuclear Power and LNG divides British Columbia, as a new survey weighs zero-emission clean energy, hydroelectric capacity, the Site C dam, EV mandates, energy security, rising costs, and blackout risks.

 

Key Points

A BC-wide debate on power choices balancing nuclear, LNG, hydro, costs, climate goals, EVs, and grid reliability.

✅ Survey: 43% support nuclear, 40% oppose in BC

✅ 55% back LNG expansion, led by Southern BC

✅ Hydro at 90%; Site C adds 1,100 MW by 2025

 

There is a long-term need to produce more electricity to meet population and economic growth needs and, in particular, create new clean energy sources, with two new BC generating stations recently commissioned contributing to capacity.

Increasingly, in the worldwide discourse on climate change, nuclear power plants are being touted as a zero-emission clean energy source, with Ontario exploring large-scale nuclear to expand capacity, and a key solution towards meeting reduced emissions goals. New technological advancements could make nuclear power far safer than existing plant designs.

When queried on whether British Columbia should support nuclear power for electricity generation, respondents in a new province-wide survey by Research Co. were split, with 43% in favour and 40% against.

Levels of support reached 46% in Metro Vancouver, 41% in the Fraser Valley, 44% in Southern BC, 39% in Northern BC, and 36% on Vancouver Island.

The closest nuclear power plant to BC is the Columbia Generating Station, located in southern Washington State.

The safe use of nuclear power came to the forefront following the 2011 Fukushima nuclear disaster when the most powerful earthquake ever recorded in Japan triggered a large tsunami that damaged the plant’s emergency generators. Japan subsequently shut off many of its nuclear power plants and increased its reliance on fossil fuel imports, but in recent years there has been a policy reversal to restart shuttered nuclear plants to provide the nation with improved energy security.

Over the past decade, Germany has also been undergoing a transition away from nuclear power. But in an effort to replace Russian natural gas, Germany is now using more coal for power generation than ever before in decades, while Ontario’s electricity outlook suggests a shift to a dirtier mix, and it is looking to expand its use of liquefied natural gas (LNG).

Last summer, German chancellor Olaf Scholz told the CBC he wants Canada to increase its shipments of LNG gas to Europe. LNG, which is greener compared to coal and oil, is generally seen as a transitionary fuel source for parts of the world that currently depend on heavy polluting fuels for power generation.

When the Research Co. survey asked BC residents whether they support the further development of the province’s LNG industry, including LNG electricity demand that BC Hydro says justifies Site C, 55% of respondents were supportive, while 29% were opposed and 17% undecided.

Support for the expansion of the LNG is highest in Southern BC (67%), followed by the Fraser Valley (56%), Metro Vancouver (also 56%), Northern BC (55%), and Vancouver Island (41%).

A larger proportion of BC residents are against any idea of the provincial government moving to ban the use of natural gas for stoves and heating in new buildings, with 45% opposed and 39% in support.

Significant majorities of BC residents are concerned that energy costs could become too expensive, and a report on coal phase-outs underscores potential cost and effectiveness concerns, with 84% expressing concern for residents and 66% for businesses. As well, 70% are concerned that energy shortages could lead to measures such as rationing and rolling blackouts.

Currently, about 90% of BC’s electricity is produced by hydroelectric dams, but this fluctuates throughout the year — at times, BC imports coal- and gas-generated power from the United States when hydro output is low.

According to BC Hydro’s five-year electrification plan released in September 2021, it is estimated BC has a sufficient supply of clean electricity only by 2030, including the capacity of the Site C dam, which is slated to open in 2025. The $16 billion dam will have an output capacity of 1,100 megawatts or enough power for the equivalent of 450,000 homes.

The provincial government’s strategy for pushing vehicles towards becoming dependent on the electrical grid also necessitates a reliable supply of power, prompting BC Hydro’s first call for power in 15 years to prepare for electrification. Most BC residents support the provincial government’s requirement for all new car and passenger truck sales to be zero-emission by 2035, with 75% supporting the goal and 21% opposed.
 

 

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Latvia eyes electricity from Belarus nuclear plant

Latvia Astravets electricity imports weigh AST purchases from the Belarusian nuclear plant, impacting the Baltic grid, Lithuania market, energy security, and cross-border trading as Latvia seeks to mitigate supply risks and stabilize power flows.

 

Key Points

Proposed AST purchases of power from Belarus's Astravets plant to bolster Baltic grid supply via Lithuania.

✅ AST evaluates imports to mitigate supply risk

✅ Energy could enter Lithuania via existing trading route

✅ Debate centers on nuclear safety and Baltic grid impacts

 

Latvia’s electricity transmission system operator, AST, is looking at the possibility of purchasing electricity from the soon-to-be completed Belarusian nuclear power plant in Astravets, at a time when Ukraine's electricity exports have resumed in the region, long criticised by the Lithuanian government, Belsat TV has reported.

According to the Latvian media, the Latvian government is seeking to mitigate the risk of a possible drop in electricity supplies amid price spikes in Ireland highlighting dispatchable power concerns, given that energy trading between the Baltic states and third parties is currently carried out only through the Belarusian-Lithuanian border, including Latvian imports from Lithuania.

If AST starts importing electricity from the Belarusian plant to Latvia, in a pattern similar to Georgia's electricity imports during peak demand, the energy is expected to enter the Lithuanian market as well.

Such cross-border flows also mirror responses to Central Asia's electricity shortages seen recently.

The Lithuanian government has repeatedly criticised the nuclear power over national security and environmental safety concerns, as well as a number of emergencies that took place during construction, particularly as Europe is losing nuclear power and confronting energy security challenges.

Debates over infrastructure and safety have also intensified by projects like power lines to reactivate Zaporizhzhia in Ukraine.

The first Astravets reactor, which is being built close to the Lithuanian border in the Hrodno region, is expected to be operational by the end of 2019, a year that saw Belgium's nuclear exports rise across Europe.

 

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America’s Electricity is Safe From the Coronavirus—for Now

US Grid Pandemic Response coordinates control rooms, grid operators, and critical infrastructure, leveraging hydroelectric plants, backup control centers, mutual assistance networks, and deep cleaning protocols to maintain reliability amid reduced demand and COVID-19 risks.

 

Key Points

US Grid Pandemic Response encompasses measures by utilities and operators to safeguard power reliability during COVID-19

✅ Control rooms staffed on-site; operators split across backup centers

✅ Health screenings, deep cleaning, and isolation protocols mitigate contagion

✅ Reduced demand and mutual assistance improve grid resilience

 

Control rooms are the brains of NYPA’s power plants, which are mostly hydroelectric and supply about a quarter of all the electricity in New York state. They’re also a bit like human petri dishes. The control rooms are small, covered with frequently touched switches and surfaces, and occupied for hours on end by a half-dozen employees. Since social distancing and telecommuting isn’t an option in this context, NYPA has instituted regular health screenings and deep cleanings to keep the coronavirus out.

The problem is that each power plant relies on only a handful of control room operators. Since they have a specialized skill set, they can’t be easily replaced if they get sick. “They are very, very critical,” says Gil Quiniones, NYPA president and CEO. If the pandemic worsens, Quiniones says that NYPA may require control room operators to live on-site at power plants to reduce the chance of the virus making it in from the outside world. It sounds drastic, but Quiniones says NYPA has done it before during emergencies—once during the massive 2003 blackout, and again during Hurricane Sandy.

Meanwhile, PJM is one of North America’s nine regional grid operators and manages the transmission lines that move electricity from power plants to millions of customers in 13 states on the Eastern seaboard, including Washington, DC. PJM has had a pandemic response plan on the books for 15 years, but Mike Bryson, senior vice president of operations, says that this is the first time it’s gone into full effect. As of last week, about 80 percent of PJM’s 750 full-time employees have been working from home. But PJM also requires a skeleton crew of essential workers to be on-site at all times in its control centers. As part of its emergency planning, PJM built a backup control center years ago, and now it is splitting control center operators between the two to limit contact.

Past experience with large-scale disasters has helped the energy sector keep the lights on and ventilators running during the pandemic. Energy is one of 16 sectors that the US government has designated as “critical infrastructure,” which also includes the communications industry, transportation sector, and food and water systems. Each is seen as vital to the country and therefore has a duty to maintain operations during national emergencies.

“We need to be treated as first responders,” says Scott Aaronson, the vice president of security and preparedness at the Edison Electric Institute, a trade group representing private utilities. “Everybody's goal right now is to keep the public healthy, and to keep society functioning as best we can. A lack of electricity will certainly create a challenge for those goals.”

America’s electricity grid is a patchwork of regional grid operators connecting private and state-owned utilities. This means simply figuring out who’s in charge and coordinating among the various organizations is one of the biggest challenges to keeping the electricity flowing during a national emergency, according to Aaronson.

Generally, a lot of this responsibility falls on formal energy organizations like the nonprofit North American Electric Reliability Corporation and the Federal Energy Regulatory Commission. But during the coronavirus outbreak, an obscure organization run by the CEOs of electric utilities called the Electricity Subsector Coordinating Council has also served as a primary liaison between the federal government and the thousands of utility companies around the US. Aaronson says the organization has been meeting twice a week for the past three weeks to ensure that utilities are implementing best practices in their response to the coronavirus, as well as to inform the government of material needs to keep the energy sector running smoothly.

This tight-knit coordination will be especially important if the pandemic gets worse, as many forecasts suggest it will. Most utilities belong to at least one mutual assistance group, an informal network of electricity suppliers that help each other out during a catastrophe. These mutual assistance networks are usually called upon following major storms that threaten prolonged outages. But they could, in principle, be used to help during the coronavirus pandemic too. For example, if a utility finds itself without enough operators to manage a power plant, it could conceivably borrow trained operators from another company to make sure the power plant stays online.

So far, utilities and grid operators have managed to make it work on their own. There have been a handful of coronavirus cases reported at power plants, but they haven’t yet affected these plants’ ability to deliver energy. The challenges of running a power plant with a skeleton crew is partially offset by the reduced power demand as businesses shut down and more people work from home, says Robert Hebner, the director of the Center for Electromechanics at the University of Texas. “The reduced demand for power gives utilities a little breathing room,” says Hebner.

A recent study by the University of Chicago’s Energy Policy Institute found that electricity demand in Italy has plunged by 18 percent following the severe increase in coronavirus cases in the country. Energy demand in China also plummeted as a result of the pandemic. Bryson, at PJM, says the grid operator has seen about a 6 percent decrease in electricity demand in recent weeks, but expects an even greater drop if the pandemic gets worse.

Generally speaking, problems delivering electricity in the US occur when the grid is overloaded or physically damaged, such as during California wildfires or a hurricane.

An open question among coronavirus researchers is whether there will be a second wave of the pandemic later this year. During the Spanish flu pandemic in the early 20th century, the second wave turned out to be deadlier than the first. If the coronavirus remerges later this year, it could be a serious threat to reliable electricity in the US, says John MacWilliams, a former associate deputy secretary of the Department of Energy and a senior fellow at Columbia University’s Center on Global Energy Policy.

“If this crisis extends into the fall, we're going to hit hurricane season along the coasts,” MacWilliams says. “Utilities are doing a very good job right now, but if we get unlucky and have an active hurricane season, they're going to get very stressed because the number of workers that are available to repair damage and restore power will become more limited.”

This was a sentiment echoed by Bryson at PJM. “Any one disaster is manageable, but when you start layering them on top of each other, it gets much more challenging,” he adds. The US electricity grid struggles to handle major storms as it is, and these challenges will be heightened if too many workers are home sick. In this sense, the energy sector’s ability to deliver the electricity needed to keep manufacturing medical supplies or keep ventilators running depends to a large extent on our ability to flatten the curve today. The coronavirus is bad enough without having to worry about the lights going out.

 

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State-owned electricity generation firm could save Britons nearly 21bn a year?

Great British Energy could cut UK electricity costs via public ownership, investing in clean energy like wind, solar, tidal, and nuclear, curbing windfall profits, stabilizing bills, and reinvesting returns through a state-backed generator.

 

Key Points

A proposed state-backed UK generator investing in clean power to cut costs and return gains to taxpayers.

✅ Publicly owned investment in wind, solar, tidal, and nuclear

✅ Cuts electricity bills by reducing generators' windfall profits

✅ Funded via bonds or asset buyouts; non-profit operations

 

A publicly owned electricity generation firm could save Britons nearly £21bn a year, according to new analysis that bolsters Labour’s case to launch a national energy company if the party gains power.

Thinktank Common Wealth has calculated that the cost of generating electricity to power homes and businesses could be reduced by £20.8bn or £252 per household a year under state ownership, according to a report seen by the Guardian.

The Labour leader, Keir Starmer, has committed to creating “a publicly owned national champion in clean energy” named Great British Energy.

Starmer is yet to lay out the exact structure of the mooted company, although he has said it would not involve nationalising existing assets, or become involved in the transmission grid or retail supply of energy.

Starmer instead hopes to create a state-backed entity that would invest in clean energy – wind, solar, tidal, nuclear, large-scale storage and other emerging technologies – creating jobs and ensuring windfalls from the growth in low carbon power feed back to the government.

The Common Wealth report, which analysed scenarios for reforming the electricity market, said that a huge saving on electricity costs could be made by buying out assets such as wind, solar and biomass generators on older contracts and running them on a non-profit basis. Funding the measure could require a government bond issuance, or some form of compulsory purchase process.

Last year the government attempted to get companies operating low carbon generators, including nuclear power plants, on older contracts to switch to contracts for difference (CfD), allowing any outsized profits to flow back to taxpayers. However, the government later decided to tax eligible firms through the electricity generator levy instead.

The Common Wealth study concluded that a publicly owned low carbon energy generator would best deliver on Britain’s climate and economic goals, would eliminate windfall profits made by generators and would cut household bills significantly.

MPs and campaigners have argued that Britain’s energy companies should be nationalised since the energy crisis, even as coal-free records have multiplied and renewables still need more support, which has resulted in North Sea oil and gas producers and electricity generators making windfall profits, and a string of retail suppliers collapsing, costing taxpayers billions. Detractors of nationalisation in energy argue it can stifle innovation and expose taxpayers to huge financial risks.

Common Wealth pointed out that more than 40% of the UK’s offshore wind generation capacity was publicly owned by overseas national entities, meaning the benefits of high electricity prices linked to the war in Ukraine had flowed back to other governments.

The study found the publicly owned generator model would create more savings than other options, including a drive for voluntary CfDs; splitting the generation market between low carbon and fossil fuel sources at a time when wind and solar have outproduced nuclear, and a “single buyer model” with nationalised retail suppliers.

 

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Which of the cleaner states imports dirty electricity?

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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