Planners downplay new power line for Toronto

By Toronto Star


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Picture a city with one big electric wire coming in from the east, and another from the west. That's Toronto.

For years, planners said it wasn't enough to supply the city core. If one wire went down, the other would have trouble supplying enough power to keep the central city's lights on.

Worse, the city itself was split into an eastern and western zone with almost no connection between them. If one wire failed, power from the other couldn't move across the city to back it up.

A third wire was essential, the planners said – and they mapped out a route for a new line running down the Don Valley, along Pape Ave. and into the Portlands.

The July blackout further underlined the city's power vulnerability. But electricity planners now insist that no third line is needed.

"We're not really contemplating it any more," says Ben Chin, vice president of the OPA. "It's not in the works."

Chin points to two major projects that have lessened the need for a third line. The gas-fired Portlands Energy Centre gives Toronto a significant local source of power, Chin notes. Although Portlands by itself, at 550 megawatts, can supply only a fraction of Toronto's peak demand of up to 5,000 megawatts.

Bolstering the new supply, Hydro One has installed a high capacity power line, burrowing under Front St., that connects the eastern and western halves of the city. If lines go down in one neighbourhood, power can now flow more freely across the city to back it up.

Conservation programs now getting under way should also reduce the need for a third line, Chin says.

The Independent Electricity System Operator, a provincial agency that runs the wholesale electricity market, cautiously agrees.

"We're not seeing the same sort of pressure we saw a couple of years ago," says vice president Terry Young.

But the IESO's latest assessment of reliability hedges its bets on Toronto, carefully outlining some specific conditions that must be met to ensure a reliable supply for Toronto, should the third line not be built.

And the Toronto Board of Trade is apprehensive about the decision to walk away from the third line. Chief executive Carol Wilding said the city is likely to see more outages in the future.

"With aging infrastructure and rising demand, Toronto stands to experience more incidents like the blackout of July 5," Wilding said in an e-mail.

"More frequent and lengthy power outages would damage the Toronto region's reputation as a place to invest, and drive businesses to consider locating in other jurisdictions. The development of a third transmission line ensuring reliable electricity supply to Toronto is a necessary component of the city's future economic growth."

Blair Peberdy, vice president of Toronto Hydro, shares some of Wilding's concerns. "There needs to be a more secure supply in Toronto," says Peberdy.

But city councillors asked Toronto Hydro to come up with other plans after seeing strong local opposition to the proposed high-voltage line along Pape Ave.

The utility responded to the request from its sole shareholder by proposing its "500-500" plan. It wants to slice the city's demand for power by 500 megawatts – about 10 per cent – while building 500 megawatts of generating capacity within the city.

The Ontario Clean Air Alliance has said 300 megawatts could come from small scale "combined heat and power" plants: small natural gas plants, with the heat exhausted by the turbines being captured and used to heat nearby buildings, or supply industries with steam.

Hospitals, schools, shopping malls and condominiums could host the plants, it suggests.

Toronto Hydro had hoped to build a wind farm off the Scarborough Bluffs, but that has run into turbulence: The province has proposed banning near-shore wind developments across the province.

While conservation and generation are Toronto Hydro's first priority, the utility won't categorically reject the need for a third line.

"Should that not be sufficient, then other options would have to be explored," Peberdy said.

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Climate Solution: Use Carbon Dioxide to Generate Electricity

Methane Hydrate CO2 Sequestration uses carbon capture and nitrogen injection to swap gases in seafloor hydrates along the Gulf of Mexico, releasing methane for electricity while storing CO2, according to new simulation research.

 

Key Points

A method injecting CO2 and nitrogen into hydrates to store CO2 while releasing methane for power.

✅ Nitrogen aids CO2-methane swap in hydrate cages, speeding sequestration

✅ Gulf Coast proximity to emitters lowers transport and power costs

✅ Revenue from methane electricity could offset carbon capture

 

The world is quickly realizing it may need to actively pull carbon dioxide out of the atmosphere to stave off the ill effects of climate change. Scientists and engineers have proposed various carbon capture techniques, but most would be extremely expensive—without generating any revenue. No one wants to foot the bill.

One method explored in the past decade might now be a step closer to becoming practical, as a result of a new computer simulation study. The process would involve pumping airborne CO2 down into methane hydrates—large deposits of icy water and methane right under the seafloor, beneath water 500 to 1,000 feet deep—where the gas would be permanently stored, or sequestered. The incoming CO2 would push out the methane, which would be piped to the surface and burned to generate electricity, whether sold locally or via exporters like Hydro-Que9bec to help defray costs, to power the sequestration operation or to bring in revenue to pay for it.

Many methane hydrate deposits exist along the Gulf of Mexico shore and other coastlines. Large power plants and industrial facilities that emit CO2 also line the Gulf Coast, where EPA power plant rules could shape deployment, so one option would be to capture the gas directly from nearby smokestacks, keeping it out of the atmosphere to begin with. And the plants and industries themselves could provide a ready market for the electricity generated.

A methane hydrate is a deposit of frozen, latticelike water molecules. The loose network has many empty, molecular-size pores, or “cages,” that can trap methane molecules rising through cracks in the rock below. The computer simulation shows that pushing out the methane with CO2 is greatly enhanced if a high concentration of nitrogen is also injected, and that the gas swap is a two-step process. (Nitrogen is readily available anywhere, because it makes up 78 percent of the earth’s atmosphere.) In one step the nitrogen enters the cages; this destabilizes the trapped methane, which escapes the cages. In a separate step, the nitrogen helps CO2 crystallize in the emptied cages. The disturbed system “tries to reach a new equilibrium; the balance goes to more CO2 and less methane,” says Kris Darnell, who led the study, published June 27 in the journal Water Resources Research. Darnell recently joined the petroleum engineering software company Novi Labs as a data scientist, after receiving his Ph.D. in geoscience from the University of Texas, where the study was done.

A group of labs, universities and companies had tested the technique in a limited feasibility trial in 2012 on Alaska’s North Slope, where methane hydrates form in sandstone under deep permafrost. They sent CO2 and nitrogen down a pipe into the hydrate. Some CO2 ended up being stored, and some methane was released up the same pipe. That is as far as the experiment was intended to go. “It’s good that Kris [Darnell] could make headway” from that experience, says Ray Boswell at the U.S. Department of Energy’s National Energy Technology Laboratory, who was one of the Alaska experiment leaders but was not involved in the new study. The new simulation also showed that the swap of CO2 for methane is likely to be much more extensive—and to happen quicker—if CO2 enters at one end of a hydrate deposit and methane is collected at a distant end.

The technique is somewhat similar in concept to one investigated in the early 2010s by Steven Bryant and others at the University of Texas. In addition to numerous methane hydrate deposits, the Gulf Coast has large pools of hot, salty brine in sedimentary rock under the coastline. In this system, pumps would send CO2 down into one end of a deposit, which would force brine into a pipe that is placed at the other end and leads back to the surface. There the hot brine would flow through a heat exchanger, where heat could be extracted and used for industrial processes or to generate electricity, supporting projects such as electrified LNG in some markets. The upwelling brine also contains some methane that could be siphoned off and burned. The CO2 dissolves into the underground brine, becomes dense and sinks further belowground, where it theoretically remains.

Either system faces big practical challenges, and building shared CO2 storage hubs to aggregate captured gas is still evolving. One is creating a concentrated flow of CO2; the gas makes up only .04 percent of air, and roughly 10 percent of the smokestack emission from a typical power plant or industrial facility. If an efficient methane hydrate or brine system requires an input that is 90 percent CO2, for example, concentrating the gas will require an enormous amount of energy—making the process very expensive. “But if you only need a 50 percent concentration, that could be more attractive,” says Bryant, who is now a professor of chemical and petroleum engineering at the University of Calgary. “You have to reduce the [CO2] capture cost.”

Another major challenge for the methane hydrate approach is how to collect the freed methane, which could simply seep out of the deposit through numerous cracks and in all directions. “What kind of well [and pipe] structure would you use to grab it?” Bryant asks.

Given these realities, there is little economic incentive today to use methane hydrates for sequestering CO2. But as concentrations rise in the atmosphere and the planet warms further, and as calls for an electric planet intensify, systems that could capture the gas and also provide energy or revenue to run the process might become more viable than techniques that simply pull CO2 from the air and lock it away, offering nothing in return.

 

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Enel Starts Operations of 450 MW Wind Farm in U.S

High Lonesome Wind Farm powers Texas with 500 MW of renewable energy, backed by a 12-year PPA with Danone North America and a Proxy Revenue Swap, cutting CO2 emissions as Enel's largest project to date.

 

Key Points

A 500 MW Enel wind project in Texas, supplying renewable power via PPAs and hedged by a Proxy Revenue Swap.

✅ 450 MW online; expanding to 500 MW in early 2020

✅ 12-year PPA with Danone North America for 20.6 MW

✅ PRS hedge with Allianz and Nephila stabilizes revenues

 

Enel, through its US renewable subsidiary Enel Green Power North America, Inc. (“EGPNA”), has started operations of its 450 MW High Lonesome wind farm in Upton and Crockett Counties, in Texas, the largest operational wind project in the Group’s global renewable portfolio, alongside a recent 90 MW Spanish wind build in its European pipeline. Enel also signed a 12-year, renewable energy power purchase agreement (PPA) with food and beverage company Danone North America, a Public Benefit Corporation, for physical delivery of the renewable electricity associated with 20.6 MW, leading to an additional 50 MW expansion of High Lonesome that will increase the plant’s total capacity to 500 MW. The construction of the 50 MW expansion is currently underway and operations are due to start in the first quarter of 2020.

“The start of operations of Enel’s largest wind farm in the world marks a significant achievement for our company and reinforces our global commitment to accelerated renewable energy growth,” said Antonio Cammisecra, CEO of Enel Green Power, referencing the largest wind project constructed in North America as evidence of market momentum. “This milestone is matched with a new partnership with Danone North America to support their renewable goals, a reinforcement of our continued commitment to provide customers with tailored solutions to meet their sustainability goals.”

The agreement between Enel and Danone North America will provide enough electricity to produce the equivalent of almost 800 million cups of yogurt1 and over 80 million gallons2 of milk each year and support the food and beverage company’s commitment to securing 100% of its purchased electricity from renewable sources by 2030, in a market where North Carolina’s first wind farm is now fully operational and expanding access to clean power.

Mariano Lozano, president and CEO of Danone North America, added:“This is an exciting and significant step as we continue to advance our 2030 renewable electricity goals. As a public benefit corporation committed to balancing the needs of our business with those of society and the planet, we truly believe that this agreement makes sense from both a business and sustainability point of view. We’re delighted to be working with Enel Green Power to expand their High Lonesome wind farm and grow the renewable electricity infrastructure, such as New York’s biggest offshore wind projects, here in the US.”

In addition, as more US wind projects come online, such as TransAlta’s 119 MW project, the energy produced by a 295 MW portion of the project will be hedged under a Proxy Revenue Swap (PRS) with insurer Allianz Global Corporate & Specialty, Inc.'s Alternative Risk Transfer unit (Allianz), and Nephila Climate, a provider of weather and climate risk management products. The PRS is a financial derivative agreement designed to produce stable revenues for the project regardless of power price fluctuations and weather-driven intermittency, hedging the project from this kind of risk in addition to that associated with price and volume.

Under the PRS agreement, and as other projects begin operations, like Building Energy’s latest plant, High Lonesome will receive fixed payments based on the expected value of future energy production, with adjustments paid depending on how the realized proxy revenue of the project differs from the fixed payment. The PRS for High Lonesome, which is the largest by capacity for a single plant globally and the first agreement of its kind for Enel, was executed in collaboration with REsurety, Inc.

The investment in the construction of the 500 MW plant amounts to around 720 million US dollars. The wind farm is due to generate around 1.9 TWh annually, comparable to a 280 MW Alberta wind farm’s output, while avoiding the emission of more than 1.2 million tons of CO2 per year.

 

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US power coalition demands action to deal with Coronavirus

Renewable Energy Tax Incentive Extensions urged by US trade groups to offset COVID-19 supply chain delays, tax equity shortages, and financing risks, enabling direct pay, PTC and ITC qualification, and standalone energy storage credits.

 

Key Points

Policy measures that extend and monetize clean energy credits to counter COVID-19 disruptions and financing shortfalls.

✅ Extend start construction and safe harbor deadlines

✅ Enable direct pay to offset reduced tax equity

✅ Add a standalone energy storage credit

 

Renewable energy and other trade bodies in the US are calling on Capitol Hill to extend provision of tax incentives to help the sector “surmount the impacts” of the COVID-19 crisis facing clean energy.

In a signed joint letter, the American Council on Renewable Energy (ACORE), American Wind Energy Association (AWEA), Energy Storage Association (ESA), National Hydropower Association (NHA), Renewable Energy Buyers Alliance (REBA), and the Solar Energy Industries Association (SEIA) stated: “With over $50bn in annual investment over each of the past five years, the clean energy sector is one of the nation’s most important economic drivers. But that growth is placed at risk by a range of COVID-19 related impacts”.

These include “supply chain disruptions that have the potential to delay utility solar construction timetables and undermine the ability of wind, solar and hydropower developers to qualify for time-sensitive tax credits, and a sudden reduction in the availability of tax equity, which is crucial to monetising tax credits and financing clean energy projects of all types.”
The letter goes onto state: “Like all sectors of our economy the renewable and clean grid industry – including developers, manufacturers, construction workers, electric utilities, investors and major corporate consumers of renewable power – needs stability.

“The current uncertainty about the ability to qualify for and monetise tax incentives will have real and substantial negative impacts to the entire economy.

On behalf of the thousands of companies that participate in America’s renewable and clean energy economy, the coalition of organisations is requesting the US Government, echoing Senate calls to support clean energy, take three “critical” steps to address pandemic-related disruptions.

The first is an extension of start construction and safe harbour deadlines to ensure that renewable projects can qualify for renewable tax credits amid the Solar ITC extension debate and despite delays associated with supply chain disruptions.

The second is the implementation of provisions that will allow renewable tax credits to be available for direct pay to facilitate their monetisation, supporting U.S. solar and wind growth in the face of reduced availability of tax equity.

Thirdly, the signatories have requested the enactment of a direct pay tax credit for standalone energy storage to foster renewable growth as the industry sets sights on market majority and help secure a more resilient grid.

 

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Berlin urged to remove barriers to PV

Germany Solar Cap Removal would accelerate photovoltaics, storage, and renewables, replacing coal and nuclear during phaseout with 10GW per year toward 162GW by 2030, boosting grid resilience, O&M jobs, and domestic clean energy growth.

 

Key Points

A policy change to scrap the 52GW limit, enabling 10GW/year PV and storage to replace coal and nuclear capacity.

✅ Scrap 52GW cap to prevent post-2020 market slump

✅ Add 10GW PV annually; scale residential, commercial, grid storage

✅ Create jobs in planning, installation, and O&M through 2030

 

The German Solar Association (BSW) has called on the government to remove barriers to the development of new solar power capacity in Germany and storage capacity needed to replace coal and nuclear generation that is being phased out.

A 52GW cap should be scrapped, otherwise there is a risk that a market slump will occur in the solar industry after 2020, BSW said, especially as U.S. solar expansion plans signal accelerating global demand.

BSW managing director Carsten Körnig said: “Time is running out, and further delays are irresponsible. The 52GW mark will already be reached within a few months.”
A new report from BSW, in cooperation with Bonn-based marketing and social research company EuPD Research and The smarter E Europe initiative, said 10GW a year is needed as well as an increase in battery storage capacity.

This would lead to cumulative photovoltaic capacity of 162GW and 15GW residential, commercial and grid storage systems by 2030, in line with global renewable records being set, leading to new job opportunities.

The number of jobs in the domestic photovoltaic and storage industries could increase to 78,000 by the end of the next decade from today’s level of 26,400, aligning with forecasts of wind and solar reaching 50% by mid-century, said 'The Energy Transition in the Context of the Nuclear and Coal Phaseout – Perspectives in the Electricity Market to 2040' study.

Job growth would take place for the most part in the fields of planning, installation and operations and maintenance of PV systems, as solar uptake in Poland increases, the report said.

In maintenance alone, employment would increase from 9,200 to 26,000, with additional opened up by tapping into the market potential of medium- to long-term storage systems, alongside changing electricity prices in Northern Europe that favor flexibility, it said.

The report added that industry revenue could grow from €5bn to €12.5bn in the coming decade.

The report was supported by BayWa Re E3/DC, Fronius, Goldbeck Solar, IBC Solar, Panasonic, Sharp, Siemens, Sonnen, Suntech, Tesvolt and Varta.

 

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Why Canada should invest in "macrogrids" for greener, more reliable electricity

Canadian electricity transmission enables grid resilience, long-distance power trade, and decarbonization by integrating renewables, hydroelectric storage, and HVDC links, providing backup during extreme weather and lowering costs to reach net-zero, clean energy targets.

 

Key Points

An interprovincial high-voltage grid that shares clean power to deliver reliable, low-cost decarbonization.

✅ Enables resilience by sharing power across weather zones

✅ Integrates renewables with hydro storage via HVDC links

✅ Lowers decarbonization costs through interprovincial trade

 

As the recent disaster in Texas showed, climate change requires electricity utilities to prepare for extreme events. This “global weirding” is leaving Canadian electricity grids increasingly exposed to harsh weather that leads to more intense storms, higher wind speeds, heatwaves and droughts that can threaten the performance of electricity systems.

The electricity sector must adapt to this changing climate while also playing a central role in mitigating climate change. Greenhouse gas emissions can be reduced a number of ways, but the electricity sector is expected to play a central role in decarbonization, including powering a net-zero grid by 2050 across Canada. Zero-emissions electricity can be used to electrify transportation, heating and industry and help achieve emissions reduction in these sectors.

Enhancing long-distance transmission is viewed as a cost-effective way to enable a clean and reliable power grid, and to lower the cost of meeting our climate targets. Now is the time to strengthen transmission links in Canada, with concepts like a western Canadian electricity grid gaining traction.


Insurance for climate extremes
An early lesson from the Texas power outages is that extreme conditions can lead to failures across all forms of power supply. The state lost the capacity to generate electricity from natural gas, coal, nuclear and wind simultaneously. But it also lacked cross-border transmission to other electricity systems that could have bolstered supply.

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Long-distance transmission offers the opportunity to escape the correlative clutch of extreme weather, by accessing energy and spare capacity in areas not beset by the same weather patterns. For example, while Texas was in its deep freeze, relatively balmy conditions in California meant there was a surplus of electricity generation capability in that region — but no means to get it to Texas. Building new transmission lines and connections across broader regions, including projects like a hydropower line to New York that expand access, can act as an insurance policy, providing a back-up for regions hit by the crippling effects of climate change.

A transmission tower crumpled under the weight of ice.
The 1998 Quebec ice storm left 3.5 million Quebecers and a million Ontarians, as well as thousands in in New Brunswick, without power. CP Photo/Robert Galbraith
Transmission is also vulnerable to climate disruptions, such as crippling ice storms that leave wires temporarily inoperable. This may mean using stronger poles when building transmission, or burying major high-voltage transmission links, or deploying superconducting cables to reduce losses.

In any event, more transmission links between regions can improve resilience by co-ordinating supply across larger regions. Well-connected grids that are larger than the areas disrupted by weather systems can be more resilient to climate extremes.


Lowering the cost of clean power
Adding more transmission can also play a role in mitigating climate change. Numerous studies have found that building a larger transmission grid allows for greater shares of renewables onto the grid, ultimately lowering the overall cost of electricity.

In a recent study, two of us looked at the role transmission could play in lowering greenhouse gas emissions in Canada’s electricity sector. We found the cost of reducing greenhouse gas emissions is lower when new or enhanced transmission links can be built between provinces.

Average cost increase to electricity in Canada at different levels of decarbonization, with new transmission (black) and without new transmission (red). New transmission lowers the cost of reducing greenhouse gas emissions. (Authors), Author provided
Much of the value of transmission in these scenarios comes from linking high-quality wind and solar resources with flexible zero-emission generation that can produce electricity on demand. In Canada, our system is dominated by hydroelectricity, but most of this hydro capacity is located in five provinces: British Columbia, Manitoba, Ontario, Québec and Newfoundland and Labrador.

In the west, Alberta and Saskatchewan are great locations for building low-cost wind and solar farms. Enhanced interprovincial transmission would allow Alberta and Saskatchewan to build more variable wind and solar, with the assurance that they could receive backup power from B.C. and Manitoba when the wind isn’t blowing and the sun isn’t shining.

When wind and solar are plentiful, the flow of low cost energy can reverse to allow B.C. and Manitoba the opportunity to better manage their hydro reservoir levels. Provinces can only benefit from trading with each other if we have the infrastructure to make that trade possible.

A recent working paper examined the role that new transmission links could play in decarbonizing the B.C. and Alberta electricity systems. We again found that enabling greater electricity trade between B.C. and Alberta can reduce the cost of deep cuts to greenhouse gas emissions by billions of dollars a year. Although we focused on the value of the Site C project, in the context of B.C.'s clean energy shift, the analysis showed that new transmission would offer benefits of much greater value than a single hydroelectric project.

The value of enabling new transmission links between Alberta and B.C. as greenhouse gas emissions reductions are pursued. (Authors), Author provided
Getting transmission built
With the benefits that enhanced electricity transmission links can provide, one might think new projects would be a slam dunk. But there are barriers to getting projects built.

First, electricity grids in Canada are managed at the provincial level, most often by Crown corporations. Decisions by the Crowns are influenced not simply by economics, but also by political considerations. If a transmission project enables greater imports of electricity to Saskatchewan from Manitoba, it raises a flag about lost economic development opportunity within Saskatchewan. Successful transmission agreements need to ensure a two-way flow of benefits.

Second, transmission can be expensive. On this front, the Canadian government could open up the purse strings to fund new transmission links between provinces. It has already shown a willingness to do so.

Lastly, transmission lines are long linear projects, not unlike pipelines. Siting transmission lines can be contentious, even when they are delivering zero-emissions electricity. Using infrastructure corridors, such as existing railway right of ways or the proposed Canadian Northern Corridor, could help better facilitate co-operation between regions and reduce the risks of siting transmission lines.

If Canada can address these barriers to transmission, we should find ourselves in an advantageous position, where we are more resilient to climate extremes and have achieved a lower-cost, zero-emissions electricity grid.

 

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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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