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Fuel supply chains in the Western Interconnect: Evaluating availability during extreme weather events
The Electricity Journal 33 (2020) 106694
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Fuel supply chains in the Western Interconnect: Evaluating availability during extreme weather events
T
John C. Bell*, Nephi Kharadia, Dakota Roberson University of Idaho, Idaho, USA
A R T I C LE I N FO
A B S T R A C T
Keyword: Fuel supply
During the winter of 2017, the eastern continental United States experienced an extreme weather event resulting in below average temperatures and consistently overcast skies. This event, referred to as a bombogenesis or “Bomb Cyclone” (BC), is one of a handful of extreme weather events experienced in the U.S. in recent years in which signif- icant strain is placed on U.S. electric interconnections. A U.S. Department of Energy study summarizing the impact of the BC indicated that coal and fuel oil/dual-firing plants provided sufficient reserves to prevent severe electricity shortages which would have otherwise resulted in significant widespread outages in the Eastern Interconnect (EI). A large regional transmission organization issued several responses to address the report’s concern regarding fuel supply security, highlighting the importance of timely fuel supply policy, and initiating a cross-institutional conversation to this end. The resultant policy conversations are not unique to the EI and generalizations are therefore of great interest to stakeholders in the western United States; a similar analysis is used to investigate the impact of a BC-like event placing strain of similar magnitude on the Western Interconnect, while introducing a resilience metric associated with the storability of fuel.
1. Introduction From December 27th, 2017 to January 8th, 2018, the Eastern Interconnect (EI) of the continental United States experienced an extreme weather pattern resulting in exceptionally low temperatures, overcast skies, and mild wind energy production - an event referred to as the Bomb Cyclone (BC). The BC, or “bombogenesis”, is created when a midlatitude cyclone experiences a rapid drop in pressure, thus increasing the intensity of the cyclone (National Oceanic and Atmospheric Administration, 2019). The Department of Energy’s National Energy Technology Laboratory (NETL) published a comprehensive study examining power plant performance during the relatively unique demand requirements throughout the duration of the BC. The report entitled “Reliability, Resilience and the Oncoming Wave of Retiring Baseload Units” indicates that without coal and fuel oil/dualfiring plants, the EI may have suffered severe electricity shortages resulting in widespread blackouts (Balash et al., 2018). PJM, a regional transmission organization (RTO) responsible for coordinating transmission in 13 Eastern states, promptly issued several responses. The first indicates that there was in fact no concern regarding generation capability; rather, a market-induced price spike primarily associated with the availability of natural gas lead to the majority dispatch of otherwise more expensive coal generation (PJM, ⁎
Corresponding author. E-mail address: [email protected] (J.C. Bell).
https://doi.org/10.1016/j.tej.2019.106694
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2018a). PJM retains that natural gas and nuclear units were not unreliable nor otherwise unavailable to serve the elevated demand requirements based on their system performance report published several weeks prior (PJM, 2018b). The NETL report concluded “In PJM, the largest of the ISOs, coal provided the most resilient form of generation, due to available reserve capacity and on-site fuel availability, far exceeding all other sources (providing three times the incremental generation from natural gas and twelve times that from nuclear units), without available capacity from partially utilized coal units, PJM would have experienced shortfalls leading to interconnect-wide blackouts” (Balash et al., 2018), a conclusion with which PJM strongly disagreed (PJM, 2018a). The second response issued by PJM highlights the importance of fuel supply and the corresponding policies necessary to ensure fuel security. PJM demonstrated, by stress-testing of a model system with roughly 300 different scenarios ranging from normal to extreme operating conditions, that their system is reliable and will remain so into the foreseeable future (PJM, 2018c). While several conflicting points of view and competing interests are expressed in these various analyses, the fact remains that weather-related power outages of varying degrees of severity have occurred historically and their impacts are becoming increasingly more prevalent throughout parts of the EI. Recent summer heat waves have resulted in
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several high-profile outages, such as the so-called “Broadway Blackout”, due to forecasting and operational errors in New York city, for example (Barron and Zaveri, 2019; Waterfield, 2019). Hurricanes and other anomalous superstorms have brought significant loads offline in the Gulf Coast (Amadeo, 2019), as well as in New York and New Jersey (CNN, 2018). The resultant policy conversations from these and other recent events are not unique to the EI and are therefore of great interest to stakeholders in the Western Interconnect (WI); thus, a similar analysis incorporating data from the original NETL report and policy dialog derived through the resulting national discussion is presented here, reinforced by aggregated regional data pertinent to the West. This data is used to assess the potential impact to the WI of an event which would cause similar system loading and stress as that experienced due to the BC. Trends unique to the WI are also identified, including the significant geographical disparity between generation and load areas, a more complex fuel supply chain, and exclusivity with regard to a general lack of regional transmission operator(s). Wildfires in the WI have resulted not only in direct outages but more recently in pre-planned load shedding to avoid the potential for initiating additional wildfires, and are briefly discussed (Walton, 2019). The effects of wildfires in the WI may be of comparable magnitude to to severe weather events on the EI, as grid infrastructure is damaged, loads shed, and generators potentially taken offline temporarily. Considering these additional factors, the analysis identifies and discusses relevant policies and their corresponding sensitivities pertaining to the WI, similar to those found in the NETL and PJM analyses. This work will also introduce the concept of fuel storability as a metric of grid resilience.
NERC’s primary responsibility is to develop standards to ensure the reliability and adequacy of bulk power trans- mission, as well as monitoring and ensuring standards compliance. In conjunction with FERC, the Federal Energy Regulatory Commission charged with standards enforcement, NERC provides educational and training resources as part of it’s program to ensure that power system operators remain up to date and proficient in their duties. NERC also investigates and analyzes the causes of significant power system disturbances a posteriori in order to help prevent the occurrence of similar events in the future. The four major electrical interconnections are the Western Interconnection, Eastern Interconnection, Que´bec, and ERCOT Interconnection. The states within the Continental U.S. which belong to each of these interconnections are found in Table 1. 2. Data sources and aggregation Sources used to collect and aggregate the data for this study are introduced, while the proceeding section expands on synthesizing trends. Data analyzed in this study was obtained primarily from the U.S. Energy Information Administration (EIA) beginning in the year 2001, as this is the year in which the EIA began collecting comprehensive monthly generation data (Anon, 2019b). Generation data for both the WI and EI are normalized by the total generation for the interconnection in megawatts to yield generation by source as a percentage of the total power generation for a given interconnect. No additional processing or modification of the data was introduced, unless otherwise specifically noted. 2.1. Sources of electricity generation
1.1. Regional interconnections A collection of relevant sources for electricity generation is presented. Generation data is arranged by fuel source, as in Fig. 2, where coal generation is provided for both the WI and EI. Figs. 3 and 4 depict the same information related to natural gas and petroleum generation, respectively. Fig. 5 shows wind and solar production, and Fig. 6 for nuclear and hydropower generation.
A preliminary discussion of the continent’s regional interconnections is warranted. The North American Electric Reliability Corporation (NERC) oversees eight regional reliability entities (as illustrated in Fig. 1) and encompasses the majority of the interconnected power systems of North America.
Fig. 1. A map of the United States, Canada, and parts of Mexico, broken down by regional entities as overseen by NERC and adapted from (Anon, 2019a). 2
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Table 1 Electrically synchronized states in continental U.S. (excludes connections to Canadian and Mexican transmission). Note: back-to-back DC converters isolate the asynchronous systems and are not considered here. Interconnect
State
Western Eastern
AZ AL MA NY TX
ERCOT
CA AR MD OH
CO CT ME OK
ID DE MI PA
MT FL MN RI
NM GA MO SC
NV IA MS SD
OR IL NC TN
UT IN ND VA
WA KS NE VT
WY KY NH WI
LA NJ WV
(i.e., no headroom).
Fig. 7 shows the percentage of generation from fuel sources considered “storable”; these sources include hydro- power, coal, nuclear, biomass, wood, and petroleum. Storable fuels are fuels which may be physically stored on-site before consumption and thus relate a measure of deterministic fuel supply availability. These fuels are in contrast to those which must be consumed immediately upon delivery and thus rely on a real-time supply chain mechanism, including natural gas and wind, as well as thermal and photovoltaic solar generation. Note that this does not refer to the availability of energy storage post-fuel consumption (e.g., grid-scale batteries, flywheels, etc.). Table 2 collates the annual average storability data from 2001 to 2018, recognizing that hydropower is only deemed storable as a function of imposed reservoir limitations.
3. Trends As generation data for the WI and the EI is examined, certain trends become apparent. Examining such trends can assist in illustrating a fleet’s generation makeup projected in to the future, allowing the effects of retirement and system stress scenarios to be analyzed. In this section, trends in key areas of generation will be shown from both the WI and the EI (Fig. 8).
3.1. Trends common to both interconnections 2.2. Capacity factors
Several trends are consistent across the data, mostly independent of geography and interconnection. Cyclical effects of thermal units, for example, are found in all data. Cycles associated with planned maintenance and outages typically occur on an annual basis. Seasonal refueling (nuclear units) and maintenance outages (all thermal units) typically require several weeks to complete. These outages are commonly scheduled for spring and fall seasons (referred to as “shoulder” months) when loading is modest (Tyra et al., 2019). General trends shown in the data indicate an overall increase in utilization of natural gas, solar, and wind sources in both interconnections, although at differing rates. Similarly, coal and petroleum resources have experienced a reduction in generation, also at differing rates, depending upon interconnection. Hydropower and nuclear have maintained relatively similar levels of market penetration. Nationwide retirements of coal, natural gas, petroleum, and nuclear plants in the United States are illustrated in Fig. 9. Wind generation experienced a significant increase in both the EI and the WI between 2001 and 2018. As seen in Fig. 5, the EI went from nearly no wind capacity to 5.0 % beginning in 2005. The WI had nearly zero, as well, in 2001, increasing to 9 % in 2018. Capacity factors across fleets in either interconnection are similar, as expected, since fuel type largely dictates capacity factor and assets are operated in deregulated or quasi-deregulated markets in both interconnections (with relatively minor exception) (Tyra et al., 2019).
The ability of a generation asset to respond to a desired increase in capacity is loosely coupled to its capacity factor, depending upon the fuel source. The capacity factor is the ratio of the actual generation produced to the maximum potential generation (Tyra et al., 2019). Generators traditionally used for baseload generation retain high capacity factors due typically to their competitive pricing and readilyavailable fuel. Load-following and peaking generators such as natural gas turbines have low capacity factors as they are used to ramp output according to load demand. Renewable generators typically have low capacity factors, as well, due instead to the inability to store or control the fuel source. Table 3 and Table 4 illustrate the wide variability in a fleet’s capacity factor (Tyra et al., 2019). The tables are broken up by non- fossil and fossil fuel sources. Direct comparison of capacity factors between storable sources and nonstorable sources may provide a source of confusion with respect to availability of a resource to increase generation as there are several additional factors which influence this capability. Therefore, similar associated terms include the concept of ‘headroom’, i.e., the quantity of available power a generator can increase above its current operating condition on demand. Table 3 suggests that nuclear plants operate with little headroom, while natural gas fired combustion turbines operate with significant headroom, as expected. Headroom is difficult to define for renewable sources which aren’t actively curtailed, as they typically operate at their instantaneous maximum power output, as available
Fig. 2. Coal generation for the Eastern and Western Interconnects. 3
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Fig. 3. Natural gas generation for the Eastern and Western Interconnects.
hydropower generation is located. Petroleum generation in the WI remained at less than 1 % from 2001 to 2018, as seen in Fig. 4. In the EI, petroleum generation went from 5 % down to about 0.5 % from 2001 to 2012, and remained at 0.5 % from 2012 to 2018 with three exceptions. In each of these three exceptions, petroleum generation went from 0.5 % to 2 %, and immediately returned to 0.5 %. These spikes occurred in the EI in January 2014, February 2015, and January 2018. In each of these months, there were notable cold weather events that resulted in abnormally cold temperatures across the EI, resulting in consumption patterns similar to those discussed in NETL’s BC report (Balash et al., 2018). Nuclear power generation is also consistent in both the EI and WI from 2001 to 2018, as seen in Fig. 6. A drastic decline in nuclear generation in the WI from 2012 to 2013 is due in large part to the retirement of the San Onofre Nuclear Generating Station in Southern California. This retirement noticeably reduced the WI’s nuclear generation to around 8 %, as compared to 24 % in the EI. This retirement is identified in the 2013 data in Fig. 9, as well. Solar generation for both the EI and WI had minimal grid-wide penetration, just under 1 % from 2001 to 2012, as seen in Fig. 5. In 2012, solar generation in the WI began to increase rapidly, approaching 6 % in 2018. In the EI, solar generation remained closer to 0 % until 2016, when significant solar generation was added. In 2018, solar remains at less than 1 %. The greater amount of solar generation in the WI is attributed to an abundance of low population areas with a large amount of sun exposure, such as the deserts of Arizona, Nevada, and California. A notable trend shown in Fig. 7 is the decline in generation from storable fuel sources. A storable fuel source is defined as a fuel that can be stored locally before consumption, removing supply chain or weather dependence. For example, coal is considered a storable fuel because it can be stockpiled in storage facilities before being consumed, while natural gas cannot be stored as it must be consumed immediately. For the purposes of this study, storable fuels include hydropower, coal, nuclear, biomass, wood, and petroleum. In the EI, storable fuel
3.2. Trends unique to the western interconnection As noted previously, Fig. 2 indicates that from 2001 to 2018, coal generation has been in steady decline in both interconnections. However, a more significant reduction in the proportion of coal is notable in the EI, dropping from 60 % to 30 %. Meanwhile, the use of coal has fallen 15 % in the West, from 35 % to 20 %. Steady decline of this fuel source is due to significant coal plant retirements in the mid 2010’s, as coal is replaced with other fuels. Actual and planned coal retirement capacities are depicted in Figs. 10 and 11, respectively. Predicted retirements amount to a roughly two gigawatt reduction in coal capacity nationwide per year in the coming six years. Natural gas usage in the EI has experienced steady growth since 2001, increasing from 5 % to in excess of 35 %. The WI experienced less drastic growth in natural gas generation during that same period, increasing on average by roughly 0.3 % year-over-year for a total of around 6 % since 2001. These trends are illustrated in Fig. 3. Most natural gas produced in the WI is exported to other areas of North America. 2008 flow patterns show that a large amount of WI-produced natural gas is transported to and consumed by areas in the EI (ICF International, 2009). Around 2009, natural gas export from Western Canada to the EI declined due to increasing US natural gas production, increased Canadian consumption of natural gas in the extraction and processing of crude bitumen, and increased competition from new natural gas pipelines in the US (National Energy Board, 2011). Because of the low demand and lower prices for Canadian natural gas, producers are exploring other potential markets, such as Asia (Horter, 2009); the U.S. began to export liquid natural gas in 2016. Hydropower generation remains consistent from 2001 to 2018 in both the EI and the WI, as seen in Fig. 6. However, the WI produces a much higher proportion of hydropower generation then the EI, roughly 25 % vs. 4 %, respectively. The significant annual cycles are due to higher reservoir capacity in the spring due to the spring snowpack melt and resultant runoff. This is a particularly significant phenomenon in the Pacific Northwest, an area in which the majority of the WI’s
Fig. 4. Petroleum generation for the Eastern and Western Interconnects. 4
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Fig. 5. Wind & Solar generation for the Eastern and Western Interconnects.
Fig. 6. Nuclear & Hydro generation for the Eastern and Western Interconnects.
Fig. 7. Percentage of storable fuels for Eastern and Western Interconnects. Storable fuels include Hydro, Coal, Nuclear, Biomass, Wood, and Petroleum.
Table 2 Annual percentage of fuel storability in the WI and EI. Year
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
WI EI
70.0 89.8
74.2 87.5
73.2 88.8
69.9 87.8
70.4 86.8
68.8 85.4
64.9 84.0
63.2 84.0
62.9 80.8
64.3 78.8
69.3 75.9
61.9 69.6
59.7 72.5
58.8 72.4
55.8 66.2
56.2 62.9
58.8 63.3
54.5 59.9
projected that both interconnections will have roughly the same amount of storable fuel on hand, as illustrated in Fig. 7
generation declined from roughly 90 % to 60 % from 2001 to 2018. Storable generation in the WI declined from 75 % to 50 % in the same time period. The disparity between interconnects shrank from 20 % to 5 % in this time period, illustrating possibly the most important trend in fuel supply security noted herein. Within the next five years, it is
5
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Table 3 Average annual capacity factors (%) by non-fossil fuel sources. Period
Nuclear
Hydro
Wind
Solar (PV)
Solar (Thermal)
Other Gasses
Biomass
Geothermal
2014 2015 2016 2017 2018 Mean
91.7 92.3 92.3 92.2 92.6 92.2
37.3 35.8 38.2 43.1 42.8 39.4
34.0 32.2 34.5 34.6 37.4 34.5
25.9 25.8 25.1 25.7 26.1 25.7
19.8 22.1 22.2 21.8 23.6 21.9
68.9 68.7 69.7 68.0 73.3 69.7
58.9 55.3 55.6 57.8 49.3 55.4
74.0 74.3 73.9 74.0 77.3 74.7
Table 4 Average annual capacity factors (%) by fossil fuel sources, where I.C.E. is ‘internal combustion engine’. Coal Period 2014 2015 2016 2017 2018 Mean
61.1 54.7 53.3 53.7 54.0 55.4
Natural Gas
Petroleum
Combined Cycle
Combustion Turbine
Steam Turbine
I.C.E.
Steam Turbine
Combustion Turbine
I.C.E.
48.3 55.9 55.5 51.3 57.6 53.7
5.2 6.9 8.3 6.7 11.8 7.8
10.4 11.5 12.4 10.5 13.7 11.7
8.5 8.9 9.6 9.9 NA 7.4
12.5 13.3 11.5 13.5 13.9 12.9
1.1 1.1 1.1 0.9 2.5 1.3
1.4 2.2 2.6 2.3 NA 1.7
Fig. 8. Total generation (GW) displayed by source and stacked bars by state.
Fig. 9. Retirements from 2008 to 2020 in the United States, as adapted from (Jell and Bowman, 2018).
4. Analysis
natural or man made events, such as wildfires, present a similar threat to infrastructure and may lead to less-than-ideal transmission and generation operating conditions. Heatwaves which commonly occur during the summer months in the Southwest load the WI heavily, as
While the WI has not historically been subjected to the frequent large weather events to which the EI has become accustomed, other
6
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Fig. 10. Past and future predicted coal retirements in the United States from 2010 to 2025, adapted from (Johnson and Chau, 2019).
Fig. 11. Predicted coal retirements in the United States from 2019 to 2025, adapted from (Johnson and Chau, 2019).
which resulted in bottlenecks may prevent future price spikes due to outages through redundancy. Infrastructure projects such as those required to alleviate this strain are time and capital intensive, as many competing interests (e.g., regulation, property access, tribal rights, etc.) are at stake. Recall that the concept of storability herein is posed as one of physical fuel storage. Grid-scale energy storage devices, including large batteries and flywheels, for example, present the potential for a modern and future energy storage surrogate, to a modest degree. Electrochemical energy storage may be useful in reducing the impact of a loss of fuel storability, as it will be available on demand, should the situation arise for it to be deployed. However, current technology provides electrochemical storage solutions on the order of megawatts, sufficient for attending to the needs of local services, for example, but insufficient for grid-scale weather-related shortcomings of traditional generation. As technology in these areas continue to improve, their contribution in this will become more significant in the next several decades. A final consideration is that of pumped storage hydropower (PSH), whereby a doubly-fed induction motor/generator, for example, may be used to both generate electricity via a hydrotubine, while also available to pump water from a lower reservoir to one of higher potential for later usage when needed. Coupled with local renewable resources, this storage technique provides a promising methodology for alleviating the concerns discussed here with regard to grid-scale energy storage. While the number of PSH plants in the United States of significant size are still quite low, additional investment in this storage technology may provide the services required to meet load during extreme weather events, filling the void when generation elsewhere is unable to do so.
well. These issues coupled with the potential for inaccurate weather forecasts and maintenance outages provide the ingredients for an anomalous event in the WI such as that induced by the BC. Motivations to reshape the nation’s resource portfolios are numerous, including: economics, public policy, techno-logical advances, and environmental concerns. Improved fossil fuel recovery techniques have sustained a competitive advantage for natural gas over other fuels which are not able to reap the advantages of improved fuel recovery. The Environmental Protection Agency through the Clean Air Act of 1990 (Environmental Protection Agency, 2017) and Mercury and Air Toxics Standards (MATS) (Environmental Protection Agency, 2018) require power plants to limit the amount of toxic byproducts emitted in the combustion of fossil fuels, resulting in economically less competitive coal plants, as well. These fundamental economic drivers coupled with state mandated renewable portfolio standards (RPSs) and regulatory concern regarding the siting and commissioning of new coal and nuclear plants are of primary importance to the trends identified above. The combined impact is a reduced quantity of storable fuel by over 30 % in the EI and 20 % in the WI. Note that the trend is less significant in the WI, primarily due to the presence of significant hydropower and an overall slower adoption of natural gas in lieu of coal, relative to the EI. As retirements of coal plants continue in to the foreseeable future, nuclear and hydro power will be relied upon as primary sources of storable fuel in both interconnections. The WI will likely maintain a notable advantage vıs-á-vıs the EI, in this regard, reducing its susceptibility to temporarily reduced availability to natural gas. As noted previously, headroom on nuclear plants (more predominant in the EI) is not as flexible as hydro and coal plants, suggesting that the WI is more well equipped to respond to weather events which increase consumption while decreasing the ability of natural gas plants to respond in kind. The development of additional natural gas pipelines should also be considered as a method of alleviating energy system strain. As the U.S. continues to increase gas production and export, parallel paths to those
5. Conclusions Recent national trends have induced the migration of historically storable fuel supplies toward less-storable alternatives in the two largest electric interconnections in North America. Exogenous factors 7
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contributing to this shift include raw fuel expenditures, state and national policy, plant life-cycle considerations, and improved accessibility to modern inverter-based distributed resources. Though helping to achieve policy goals and increase diversity of generation assets, the recent trend toward reliance on just-in-time fuel supplies may make vulnerable those large inter- connections which rely significantly on these fuel sources at the expense of decommissioning those with guaranteed fuel source availability. The vulnerabilities, while in dispute, range from to price spikes, at best, and load imbalance or instability, at worst. Storability of fuel is considered here as a simplistic resilience criterion used to illustrate the aforementioned trend. Both Eastern and Western Interconnections in North America have demonstrated a precipitous decline in traditionally storable fuels, making them both potentially more vulnerability to extreme weather events which may limit availability to natural gas (for various reasons including increased direct residential and commercial consumption, transmission bottlenecks, etc.). The WI has undergone less of a shift in storability than the EI, with a high percentage of its storable fuel derived from hydropower which possesses non-egligible headroom under most operating conditions. This is in contrast to the higher penetration of nuclear power found in the EI, which offers little headroom as it is a traditionally baseloading fuel source operated near or above its capacity factor.
2013/07/13/world/americas/hurricane-sandy-fast-facts/index.html. Walton, R., 2019. CalFire: Pg&e Power Lines Sparked Tuesday Blaze. Utility Drive Jun. Anon, 2019a. North American Electric Reliability Corporation. https://www.nerc.com/ Pages/default.aspx. Anon, 2019b. Energy Information Administration. https://www.eia.gov. Tyra, B., Cassar, C., Liu, J., Wong, P., Yildiz, O., 2019. Electric Power Monthly With Data for June 2019. U.S. Energy Information Administration June. Jell, S., Bowman, M., 2018. Almost All Power Plants That Retired in the Past Decade Were Powered by Fossil Fuels. Dec URL. U.S. Energy Information Administration. https:// www.eia.gov/todayinenergy/detail.php?id=37814#. Johnson, S., Chau, K., 2019. More u.s. Coal-fired Power Plants are Decommissioning as Retirements Continue - Today in Energy. July URL. U.S. Energy Information Administration - EIA - Independent Statistics and Analysis. https://www.eia.gov/ todayinenergy/detail.php?id=40212&src=email#.XTsZorQzJZc.twitter. ICF International, 2009. Natural Gas Pipeline and Storage Infrastructure Projections through 2030. Oct URL. The INGAA Foundation. https://www.ingaa.org/File.aspx? id=10509. National Energy Board, 2011. Fact Sheet: Challenges for Future Natural Gas Deliverability in Canada. National Energy Board May. Horter, W., 2009. Citizens Guide to Liquefied Natural Gas in British Columbia. May URL. Dogwood Initiative. https://dogwoodbc.ca/wp-content/uploads/2016/08/ DogwoodInitiative_LNG_CitizenGuide_May2009_Web.pdf. Environmental Protection Agency, 2017. 1990 Clean Air Act Amendment Summary. Jan URL. Environmental Protection Agency. https://www.epa.gov/clean-air-actoverview/1990-clean-air-act-amendment-summary. Environmental Protection Agency, 2018. Regulatory Actions - Final Mercury and Air Toxics Standards (mats) for Power Plants. Dec URL. Environmental Protection Agency. https://www.epa.gov/mats/regulatory-actions-final-mercury-and-airtoxics-standards-mats-power-plants. John Bell is a Graduate Research Student of Electrical Engineering at the University of Idaho. He currently focuses his studies in electrical grid stability and security. John is currently part of a research team working on the cyber security of HVDC control systems. Before joining the University of Idaho, he was a student at Brigham Young University – Idaho where he graduated with a bachelor’s degree in Mechanical Engineering. During his time at BYU-Idaho he was a part of the ASME aerospace and human-powered vehicle challenge teams. In his free time, he enjoys racing motorcycles or snowboarding during the winter months.
References National Oceanic and Atmospheric Administration, 2019. What Is Bombogenesis? National Ocean Service Website. https://oceanservice.noaa.gov/facts/ bombogenesis.html. Balash, P., Kern, K., Brewer, J., Adder, J., Nichols, C., Pickenpaugh, G., Shuster, E., 2018. Reliability, resilience and the oncoming wave of retiring baseload units. Natl. Energy Technol. Lab.(March). PJM, 2018a. Perspective and Response of Pjm Interconnection to National Energy Technology Laboratories. https://www.pjm.com/∼/media/library/reports-notices/ weather-related/20180413-pjm-response-to-netl-report.ashx Mar. . PJM, 2018b. Pjm Cold Snap Performance. Feb. https://www.pjm.com/-/media/library/ reports-notices/weather-related/20180226-january-2018-cold-weather-event-report. ashx. PJM, 2018c. Fuel Security Analyzing Fuel Supply Resilience in the Pjm Region. https:// www.pjm.com/-/media/committees-groups/ committees/mrc/20181101-fuel-security/20181101- pjm-fuel-security-summary.ashx?la=en Nov. . Barron, J., Zaveri, M., 2019. Power Restored to Manhattans West Side After Major Blackout. July URL. The New York Times. https://www.nytimes.com/2019/07/13/ nyregion/nyc-power-outage.html. Waterfield, S., 2019. Brooklyn, Queens Power Outage Latest: Thousands of Con Edison Customers Affected by Blackout Caused by Extreme Heat Wave. July URL. Newsweek. https://www.newsweek.com/brooklyn-queens-power-outage-conedison-blackout-heat-wave-1450420. Amadeo, K., 2019. Hurricane Harvey Facts, Damage and Costs. June URL. The Balance. https://www.thebalance.com/hurricane-harvey-facts-damage-costs-4150087. CNN, 2018. Hurricane Sandy Fast Facts. October URL. CNN. https://www.cnn.com/
Nephi Kharadia is a second year graduate student and research assistant at the University of Idaho, Idaho Falls campus. He is pursuing an M.S. in Electrical Engineering, and was awarded a Nuclear Regulatory Commission Fellowship. Currently, Nephi is working on implementations of classical high performance control theory, including nuclear power and hydropower applications. He holds a B.S. in Mechanical Engineering from Brigham Young University – Idaho, where he focused on the design and testing of various rocket systems. In his free time, Nephi can be found exploring the outdoors, honing his photography skills, and tinkering with electronics. Dakota Roberson is an Assistant Professor of Electrical and Computer Engineering at the University of Idaho where he leads an interdisciplinary research team studying electrical grid stability and security. Before joining the University of Idaho, he was with Sandia National Laboratories. Dakota was awarded the Ph.D. in Electrical Engineering with a Graduate Minor in Statistics at the University of Wyoming, where he won the Fisher Innovation Challenge for contributions to energy storage control. He holds a B.S. in Electrical Engineering, Minor Mathematics, from the same institution. In his free time, he is an outdoorsman and motorcyclist and can be found playing guitar or painting during the winter months.
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The Electricity Journal journal homepage: www.elsevier.com/locate/tej
Fuel supply chains in the Western Interconnect: Evaluating availability during extreme weather events
T
John C. Bell*, Nephi Kharadia, Dakota Roberson University of Idaho, Idaho, USA
A R T I C LE I N FO
A B S T R A C T
Keyword: Fuel supply
During the winter of 2017, the eastern continental United States experienced an extreme weather event resulting in below average temperatures and consistently overcast skies. This event, referred to as a bombogenesis or “Bomb Cyclone” (BC), is one of a handful of extreme weather events experienced in the U.S. in recent years in which signif- icant strain is placed on U.S. electric interconnections. A U.S. Department of Energy study summarizing the impact of the BC indicated that coal and fuel oil/dual-firing plants provided sufficient reserves to prevent severe electricity shortages which would have otherwise resulted in significant widespread outages in the Eastern Interconnect (EI). A large regional transmission organization issued several responses to address the report’s concern regarding fuel supply security, highlighting the importance of timely fuel supply policy, and initiating a cross-institutional conversation to this end. The resultant policy conversations are not unique to the EI and generalizations are therefore of great interest to stakeholders in the western United States; a similar analysis is used to investigate the impact of a BC-like event placing strain of similar magnitude on the Western Interconnect, while introducing a resilience metric associated with the storability of fuel.
1. Introduction From December 27th, 2017 to January 8th, 2018, the Eastern Interconnect (EI) of the continental United States experienced an extreme weather pattern resulting in exceptionally low temperatures, overcast skies, and mild wind energy production - an event referred to as the Bomb Cyclone (BC). The BC, or “bombogenesis”, is created when a midlatitude cyclone experiences a rapid drop in pressure, thus increasing the intensity of the cyclone (National Oceanic and Atmospheric Administration, 2019). The Department of Energy’s National Energy Technology Laboratory (NETL) published a comprehensive study examining power plant performance during the relatively unique demand requirements throughout the duration of the BC. The report entitled “Reliability, Resilience and the Oncoming Wave of Retiring Baseload Units” indicates that without coal and fuel oil/dualfiring plants, the EI may have suffered severe electricity shortages resulting in widespread blackouts (Balash et al., 2018). PJM, a regional transmission organization (RTO) responsible for coordinating transmission in 13 Eastern states, promptly issued several responses. The first indicates that there was in fact no concern regarding generation capability; rather, a market-induced price spike primarily associated with the availability of natural gas lead to the majority dispatch of otherwise more expensive coal generation (PJM, ⁎
Corresponding author. E-mail address: [email protected] (J.C. Bell).
https://doi.org/10.1016/j.tej.2019.106694
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2018a). PJM retains that natural gas and nuclear units were not unreliable nor otherwise unavailable to serve the elevated demand requirements based on their system performance report published several weeks prior (PJM, 2018b). The NETL report concluded “In PJM, the largest of the ISOs, coal provided the most resilient form of generation, due to available reserve capacity and on-site fuel availability, far exceeding all other sources (providing three times the incremental generation from natural gas and twelve times that from nuclear units), without available capacity from partially utilized coal units, PJM would have experienced shortfalls leading to interconnect-wide blackouts” (Balash et al., 2018), a conclusion with which PJM strongly disagreed (PJM, 2018a). The second response issued by PJM highlights the importance of fuel supply and the corresponding policies necessary to ensure fuel security. PJM demonstrated, by stress-testing of a model system with roughly 300 different scenarios ranging from normal to extreme operating conditions, that their system is reliable and will remain so into the foreseeable future (PJM, 2018c). While several conflicting points of view and competing interests are expressed in these various analyses, the fact remains that weather-related power outages of varying degrees of severity have occurred historically and their impacts are becoming increasingly more prevalent throughout parts of the EI. Recent summer heat waves have resulted in
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several high-profile outages, such as the so-called “Broadway Blackout”, due to forecasting and operational errors in New York city, for example (Barron and Zaveri, 2019; Waterfield, 2019). Hurricanes and other anomalous superstorms have brought significant loads offline in the Gulf Coast (Amadeo, 2019), as well as in New York and New Jersey (CNN, 2018). The resultant policy conversations from these and other recent events are not unique to the EI and are therefore of great interest to stakeholders in the Western Interconnect (WI); thus, a similar analysis incorporating data from the original NETL report and policy dialog derived through the resulting national discussion is presented here, reinforced by aggregated regional data pertinent to the West. This data is used to assess the potential impact to the WI of an event which would cause similar system loading and stress as that experienced due to the BC. Trends unique to the WI are also identified, including the significant geographical disparity between generation and load areas, a more complex fuel supply chain, and exclusivity with regard to a general lack of regional transmission operator(s). Wildfires in the WI have resulted not only in direct outages but more recently in pre-planned load shedding to avoid the potential for initiating additional wildfires, and are briefly discussed (Walton, 2019). The effects of wildfires in the WI may be of comparable magnitude to to severe weather events on the EI, as grid infrastructure is damaged, loads shed, and generators potentially taken offline temporarily. Considering these additional factors, the analysis identifies and discusses relevant policies and their corresponding sensitivities pertaining to the WI, similar to those found in the NETL and PJM analyses. This work will also introduce the concept of fuel storability as a metric of grid resilience.
NERC’s primary responsibility is to develop standards to ensure the reliability and adequacy of bulk power trans- mission, as well as monitoring and ensuring standards compliance. In conjunction with FERC, the Federal Energy Regulatory Commission charged with standards enforcement, NERC provides educational and training resources as part of it’s program to ensure that power system operators remain up to date and proficient in their duties. NERC also investigates and analyzes the causes of significant power system disturbances a posteriori in order to help prevent the occurrence of similar events in the future. The four major electrical interconnections are the Western Interconnection, Eastern Interconnection, Que´bec, and ERCOT Interconnection. The states within the Continental U.S. which belong to each of these interconnections are found in Table 1. 2. Data sources and aggregation Sources used to collect and aggregate the data for this study are introduced, while the proceeding section expands on synthesizing trends. Data analyzed in this study was obtained primarily from the U.S. Energy Information Administration (EIA) beginning in the year 2001, as this is the year in which the EIA began collecting comprehensive monthly generation data (Anon, 2019b). Generation data for both the WI and EI are normalized by the total generation for the interconnection in megawatts to yield generation by source as a percentage of the total power generation for a given interconnect. No additional processing or modification of the data was introduced, unless otherwise specifically noted. 2.1. Sources of electricity generation
1.1. Regional interconnections A collection of relevant sources for electricity generation is presented. Generation data is arranged by fuel source, as in Fig. 2, where coal generation is provided for both the WI and EI. Figs. 3 and 4 depict the same information related to natural gas and petroleum generation, respectively. Fig. 5 shows wind and solar production, and Fig. 6 for nuclear and hydropower generation.
A preliminary discussion of the continent’s regional interconnections is warranted. The North American Electric Reliability Corporation (NERC) oversees eight regional reliability entities (as illustrated in Fig. 1) and encompasses the majority of the interconnected power systems of North America.
Fig. 1. A map of the United States, Canada, and parts of Mexico, broken down by regional entities as overseen by NERC and adapted from (Anon, 2019a). 2
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Table 1 Electrically synchronized states in continental U.S. (excludes connections to Canadian and Mexican transmission). Note: back-to-back DC converters isolate the asynchronous systems and are not considered here. Interconnect
State
Western Eastern
AZ AL MA NY TX
ERCOT
CA AR MD OH
CO CT ME OK
ID DE MI PA
MT FL MN RI
NM GA MO SC
NV IA MS SD
OR IL NC TN
UT IN ND VA
WA KS NE VT
WY KY NH WI
LA NJ WV
(i.e., no headroom).
Fig. 7 shows the percentage of generation from fuel sources considered “storable”; these sources include hydro- power, coal, nuclear, biomass, wood, and petroleum. Storable fuels are fuels which may be physically stored on-site before consumption and thus relate a measure of deterministic fuel supply availability. These fuels are in contrast to those which must be consumed immediately upon delivery and thus rely on a real-time supply chain mechanism, including natural gas and wind, as well as thermal and photovoltaic solar generation. Note that this does not refer to the availability of energy storage post-fuel consumption (e.g., grid-scale batteries, flywheels, etc.). Table 2 collates the annual average storability data from 2001 to 2018, recognizing that hydropower is only deemed storable as a function of imposed reservoir limitations.
3. Trends As generation data for the WI and the EI is examined, certain trends become apparent. Examining such trends can assist in illustrating a fleet’s generation makeup projected in to the future, allowing the effects of retirement and system stress scenarios to be analyzed. In this section, trends in key areas of generation will be shown from both the WI and the EI (Fig. 8).
3.1. Trends common to both interconnections 2.2. Capacity factors
Several trends are consistent across the data, mostly independent of geography and interconnection. Cyclical effects of thermal units, for example, are found in all data. Cycles associated with planned maintenance and outages typically occur on an annual basis. Seasonal refueling (nuclear units) and maintenance outages (all thermal units) typically require several weeks to complete. These outages are commonly scheduled for spring and fall seasons (referred to as “shoulder” months) when loading is modest (Tyra et al., 2019). General trends shown in the data indicate an overall increase in utilization of natural gas, solar, and wind sources in both interconnections, although at differing rates. Similarly, coal and petroleum resources have experienced a reduction in generation, also at differing rates, depending upon interconnection. Hydropower and nuclear have maintained relatively similar levels of market penetration. Nationwide retirements of coal, natural gas, petroleum, and nuclear plants in the United States are illustrated in Fig. 9. Wind generation experienced a significant increase in both the EI and the WI between 2001 and 2018. As seen in Fig. 5, the EI went from nearly no wind capacity to 5.0 % beginning in 2005. The WI had nearly zero, as well, in 2001, increasing to 9 % in 2018. Capacity factors across fleets in either interconnection are similar, as expected, since fuel type largely dictates capacity factor and assets are operated in deregulated or quasi-deregulated markets in both interconnections (with relatively minor exception) (Tyra et al., 2019).
The ability of a generation asset to respond to a desired increase in capacity is loosely coupled to its capacity factor, depending upon the fuel source. The capacity factor is the ratio of the actual generation produced to the maximum potential generation (Tyra et al., 2019). Generators traditionally used for baseload generation retain high capacity factors due typically to their competitive pricing and readilyavailable fuel. Load-following and peaking generators such as natural gas turbines have low capacity factors as they are used to ramp output according to load demand. Renewable generators typically have low capacity factors, as well, due instead to the inability to store or control the fuel source. Table 3 and Table 4 illustrate the wide variability in a fleet’s capacity factor (Tyra et al., 2019). The tables are broken up by non- fossil and fossil fuel sources. Direct comparison of capacity factors between storable sources and nonstorable sources may provide a source of confusion with respect to availability of a resource to increase generation as there are several additional factors which influence this capability. Therefore, similar associated terms include the concept of ‘headroom’, i.e., the quantity of available power a generator can increase above its current operating condition on demand. Table 3 suggests that nuclear plants operate with little headroom, while natural gas fired combustion turbines operate with significant headroom, as expected. Headroom is difficult to define for renewable sources which aren’t actively curtailed, as they typically operate at their instantaneous maximum power output, as available
Fig. 2. Coal generation for the Eastern and Western Interconnects. 3
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Fig. 3. Natural gas generation for the Eastern and Western Interconnects.
hydropower generation is located. Petroleum generation in the WI remained at less than 1 % from 2001 to 2018, as seen in Fig. 4. In the EI, petroleum generation went from 5 % down to about 0.5 % from 2001 to 2012, and remained at 0.5 % from 2012 to 2018 with three exceptions. In each of these three exceptions, petroleum generation went from 0.5 % to 2 %, and immediately returned to 0.5 %. These spikes occurred in the EI in January 2014, February 2015, and January 2018. In each of these months, there were notable cold weather events that resulted in abnormally cold temperatures across the EI, resulting in consumption patterns similar to those discussed in NETL’s BC report (Balash et al., 2018). Nuclear power generation is also consistent in both the EI and WI from 2001 to 2018, as seen in Fig. 6. A drastic decline in nuclear generation in the WI from 2012 to 2013 is due in large part to the retirement of the San Onofre Nuclear Generating Station in Southern California. This retirement noticeably reduced the WI’s nuclear generation to around 8 %, as compared to 24 % in the EI. This retirement is identified in the 2013 data in Fig. 9, as well. Solar generation for both the EI and WI had minimal grid-wide penetration, just under 1 % from 2001 to 2012, as seen in Fig. 5. In 2012, solar generation in the WI began to increase rapidly, approaching 6 % in 2018. In the EI, solar generation remained closer to 0 % until 2016, when significant solar generation was added. In 2018, solar remains at less than 1 %. The greater amount of solar generation in the WI is attributed to an abundance of low population areas with a large amount of sun exposure, such as the deserts of Arizona, Nevada, and California. A notable trend shown in Fig. 7 is the decline in generation from storable fuel sources. A storable fuel source is defined as a fuel that can be stored locally before consumption, removing supply chain or weather dependence. For example, coal is considered a storable fuel because it can be stockpiled in storage facilities before being consumed, while natural gas cannot be stored as it must be consumed immediately. For the purposes of this study, storable fuels include hydropower, coal, nuclear, biomass, wood, and petroleum. In the EI, storable fuel
3.2. Trends unique to the western interconnection As noted previously, Fig. 2 indicates that from 2001 to 2018, coal generation has been in steady decline in both interconnections. However, a more significant reduction in the proportion of coal is notable in the EI, dropping from 60 % to 30 %. Meanwhile, the use of coal has fallen 15 % in the West, from 35 % to 20 %. Steady decline of this fuel source is due to significant coal plant retirements in the mid 2010’s, as coal is replaced with other fuels. Actual and planned coal retirement capacities are depicted in Figs. 10 and 11, respectively. Predicted retirements amount to a roughly two gigawatt reduction in coal capacity nationwide per year in the coming six years. Natural gas usage in the EI has experienced steady growth since 2001, increasing from 5 % to in excess of 35 %. The WI experienced less drastic growth in natural gas generation during that same period, increasing on average by roughly 0.3 % year-over-year for a total of around 6 % since 2001. These trends are illustrated in Fig. 3. Most natural gas produced in the WI is exported to other areas of North America. 2008 flow patterns show that a large amount of WI-produced natural gas is transported to and consumed by areas in the EI (ICF International, 2009). Around 2009, natural gas export from Western Canada to the EI declined due to increasing US natural gas production, increased Canadian consumption of natural gas in the extraction and processing of crude bitumen, and increased competition from new natural gas pipelines in the US (National Energy Board, 2011). Because of the low demand and lower prices for Canadian natural gas, producers are exploring other potential markets, such as Asia (Horter, 2009); the U.S. began to export liquid natural gas in 2016. Hydropower generation remains consistent from 2001 to 2018 in both the EI and the WI, as seen in Fig. 6. However, the WI produces a much higher proportion of hydropower generation then the EI, roughly 25 % vs. 4 %, respectively. The significant annual cycles are due to higher reservoir capacity in the spring due to the spring snowpack melt and resultant runoff. This is a particularly significant phenomenon in the Pacific Northwest, an area in which the majority of the WI’s
Fig. 4. Petroleum generation for the Eastern and Western Interconnects. 4
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Fig. 5. Wind & Solar generation for the Eastern and Western Interconnects.
Fig. 6. Nuclear & Hydro generation for the Eastern and Western Interconnects.
Fig. 7. Percentage of storable fuels for Eastern and Western Interconnects. Storable fuels include Hydro, Coal, Nuclear, Biomass, Wood, and Petroleum.
Table 2 Annual percentage of fuel storability in the WI and EI. Year
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
WI EI
70.0 89.8
74.2 87.5
73.2 88.8
69.9 87.8
70.4 86.8
68.8 85.4
64.9 84.0
63.2 84.0
62.9 80.8
64.3 78.8
69.3 75.9
61.9 69.6
59.7 72.5
58.8 72.4
55.8 66.2
56.2 62.9
58.8 63.3
54.5 59.9
projected that both interconnections will have roughly the same amount of storable fuel on hand, as illustrated in Fig. 7
generation declined from roughly 90 % to 60 % from 2001 to 2018. Storable generation in the WI declined from 75 % to 50 % in the same time period. The disparity between interconnects shrank from 20 % to 5 % in this time period, illustrating possibly the most important trend in fuel supply security noted herein. Within the next five years, it is
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Table 3 Average annual capacity factors (%) by non-fossil fuel sources. Period
Nuclear
Hydro
Wind
Solar (PV)
Solar (Thermal)
Other Gasses
Biomass
Geothermal
2014 2015 2016 2017 2018 Mean
91.7 92.3 92.3 92.2 92.6 92.2
37.3 35.8 38.2 43.1 42.8 39.4
34.0 32.2 34.5 34.6 37.4 34.5
25.9 25.8 25.1 25.7 26.1 25.7
19.8 22.1 22.2 21.8 23.6 21.9
68.9 68.7 69.7 68.0 73.3 69.7
58.9 55.3 55.6 57.8 49.3 55.4
74.0 74.3 73.9 74.0 77.3 74.7
Table 4 Average annual capacity factors (%) by fossil fuel sources, where I.C.E. is ‘internal combustion engine’. Coal Period 2014 2015 2016 2017 2018 Mean
61.1 54.7 53.3 53.7 54.0 55.4
Natural Gas
Petroleum
Combined Cycle
Combustion Turbine
Steam Turbine
I.C.E.
Steam Turbine
Combustion Turbine
I.C.E.
48.3 55.9 55.5 51.3 57.6 53.7
5.2 6.9 8.3 6.7 11.8 7.8
10.4 11.5 12.4 10.5 13.7 11.7
8.5 8.9 9.6 9.9 NA 7.4
12.5 13.3 11.5 13.5 13.9 12.9
1.1 1.1 1.1 0.9 2.5 1.3
1.4 2.2 2.6 2.3 NA 1.7
Fig. 8. Total generation (GW) displayed by source and stacked bars by state.
Fig. 9. Retirements from 2008 to 2020 in the United States, as adapted from (Jell and Bowman, 2018).
4. Analysis
natural or man made events, such as wildfires, present a similar threat to infrastructure and may lead to less-than-ideal transmission and generation operating conditions. Heatwaves which commonly occur during the summer months in the Southwest load the WI heavily, as
While the WI has not historically been subjected to the frequent large weather events to which the EI has become accustomed, other
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Fig. 10. Past and future predicted coal retirements in the United States from 2010 to 2025, adapted from (Johnson and Chau, 2019).
Fig. 11. Predicted coal retirements in the United States from 2019 to 2025, adapted from (Johnson and Chau, 2019).
which resulted in bottlenecks may prevent future price spikes due to outages through redundancy. Infrastructure projects such as those required to alleviate this strain are time and capital intensive, as many competing interests (e.g., regulation, property access, tribal rights, etc.) are at stake. Recall that the concept of storability herein is posed as one of physical fuel storage. Grid-scale energy storage devices, including large batteries and flywheels, for example, present the potential for a modern and future energy storage surrogate, to a modest degree. Electrochemical energy storage may be useful in reducing the impact of a loss of fuel storability, as it will be available on demand, should the situation arise for it to be deployed. However, current technology provides electrochemical storage solutions on the order of megawatts, sufficient for attending to the needs of local services, for example, but insufficient for grid-scale weather-related shortcomings of traditional generation. As technology in these areas continue to improve, their contribution in this will become more significant in the next several decades. A final consideration is that of pumped storage hydropower (PSH), whereby a doubly-fed induction motor/generator, for example, may be used to both generate electricity via a hydrotubine, while also available to pump water from a lower reservoir to one of higher potential for later usage when needed. Coupled with local renewable resources, this storage technique provides a promising methodology for alleviating the concerns discussed here with regard to grid-scale energy storage. While the number of PSH plants in the United States of significant size are still quite low, additional investment in this storage technology may provide the services required to meet load during extreme weather events, filling the void when generation elsewhere is unable to do so.
well. These issues coupled with the potential for inaccurate weather forecasts and maintenance outages provide the ingredients for an anomalous event in the WI such as that induced by the BC. Motivations to reshape the nation’s resource portfolios are numerous, including: economics, public policy, techno-logical advances, and environmental concerns. Improved fossil fuel recovery techniques have sustained a competitive advantage for natural gas over other fuels which are not able to reap the advantages of improved fuel recovery. The Environmental Protection Agency through the Clean Air Act of 1990 (Environmental Protection Agency, 2017) and Mercury and Air Toxics Standards (MATS) (Environmental Protection Agency, 2018) require power plants to limit the amount of toxic byproducts emitted in the combustion of fossil fuels, resulting in economically less competitive coal plants, as well. These fundamental economic drivers coupled with state mandated renewable portfolio standards (RPSs) and regulatory concern regarding the siting and commissioning of new coal and nuclear plants are of primary importance to the trends identified above. The combined impact is a reduced quantity of storable fuel by over 30 % in the EI and 20 % in the WI. Note that the trend is less significant in the WI, primarily due to the presence of significant hydropower and an overall slower adoption of natural gas in lieu of coal, relative to the EI. As retirements of coal plants continue in to the foreseeable future, nuclear and hydro power will be relied upon as primary sources of storable fuel in both interconnections. The WI will likely maintain a notable advantage vıs-á-vıs the EI, in this regard, reducing its susceptibility to temporarily reduced availability to natural gas. As noted previously, headroom on nuclear plants (more predominant in the EI) is not as flexible as hydro and coal plants, suggesting that the WI is more well equipped to respond to weather events which increase consumption while decreasing the ability of natural gas plants to respond in kind. The development of additional natural gas pipelines should also be considered as a method of alleviating energy system strain. As the U.S. continues to increase gas production and export, parallel paths to those
5. Conclusions Recent national trends have induced the migration of historically storable fuel supplies toward less-storable alternatives in the two largest electric interconnections in North America. Exogenous factors 7
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contributing to this shift include raw fuel expenditures, state and national policy, plant life-cycle considerations, and improved accessibility to modern inverter-based distributed resources. Though helping to achieve policy goals and increase diversity of generation assets, the recent trend toward reliance on just-in-time fuel supplies may make vulnerable those large inter- connections which rely significantly on these fuel sources at the expense of decommissioning those with guaranteed fuel source availability. The vulnerabilities, while in dispute, range from to price spikes, at best, and load imbalance or instability, at worst. Storability of fuel is considered here as a simplistic resilience criterion used to illustrate the aforementioned trend. Both Eastern and Western Interconnections in North America have demonstrated a precipitous decline in traditionally storable fuels, making them both potentially more vulnerability to extreme weather events which may limit availability to natural gas (for various reasons including increased direct residential and commercial consumption, transmission bottlenecks, etc.). The WI has undergone less of a shift in storability than the EI, with a high percentage of its storable fuel derived from hydropower which possesses non-egligible headroom under most operating conditions. This is in contrast to the higher penetration of nuclear power found in the EI, which offers little headroom as it is a traditionally baseloading fuel source operated near or above its capacity factor.
2013/07/13/world/americas/hurricane-sandy-fast-facts/index.html. Walton, R., 2019. CalFire: Pg&e Power Lines Sparked Tuesday Blaze. Utility Drive Jun. Anon, 2019a. North American Electric Reliability Corporation. https://www.nerc.com/ Pages/default.aspx. Anon, 2019b. Energy Information Administration. https://www.eia.gov. Tyra, B., Cassar, C., Liu, J., Wong, P., Yildiz, O., 2019. Electric Power Monthly With Data for June 2019. U.S. Energy Information Administration June. Jell, S., Bowman, M., 2018. Almost All Power Plants That Retired in the Past Decade Were Powered by Fossil Fuels. Dec URL. U.S. Energy Information Administration. https:// www.eia.gov/todayinenergy/detail.php?id=37814#. Johnson, S., Chau, K., 2019. More u.s. Coal-fired Power Plants are Decommissioning as Retirements Continue - Today in Energy. July URL. U.S. Energy Information Administration - EIA - Independent Statistics and Analysis. https://www.eia.gov/ todayinenergy/detail.php?id=40212&src=email#.XTsZorQzJZc.twitter. ICF International, 2009. Natural Gas Pipeline and Storage Infrastructure Projections through 2030. Oct URL. The INGAA Foundation. https://www.ingaa.org/File.aspx? id=10509. National Energy Board, 2011. Fact Sheet: Challenges for Future Natural Gas Deliverability in Canada. National Energy Board May. Horter, W., 2009. Citizens Guide to Liquefied Natural Gas in British Columbia. May URL. Dogwood Initiative. https://dogwoodbc.ca/wp-content/uploads/2016/08/ DogwoodInitiative_LNG_CitizenGuide_May2009_Web.pdf. Environmental Protection Agency, 2017. 1990 Clean Air Act Amendment Summary. Jan URL. Environmental Protection Agency. https://www.epa.gov/clean-air-actoverview/1990-clean-air-act-amendment-summary. Environmental Protection Agency, 2018. Regulatory Actions - Final Mercury and Air Toxics Standards (mats) for Power Plants. Dec URL. Environmental Protection Agency. https://www.epa.gov/mats/regulatory-actions-final-mercury-and-airtoxics-standards-mats-power-plants. John Bell is a Graduate Research Student of Electrical Engineering at the University of Idaho. He currently focuses his studies in electrical grid stability and security. John is currently part of a research team working on the cyber security of HVDC control systems. Before joining the University of Idaho, he was a student at Brigham Young University – Idaho where he graduated with a bachelor’s degree in Mechanical Engineering. During his time at BYU-Idaho he was a part of the ASME aerospace and human-powered vehicle challenge teams. In his free time, he enjoys racing motorcycles or snowboarding during the winter months.
References National Oceanic and Atmospheric Administration, 2019. What Is Bombogenesis? National Ocean Service Website. https://oceanservice.noaa.gov/facts/ bombogenesis.html. Balash, P., Kern, K., Brewer, J., Adder, J., Nichols, C., Pickenpaugh, G., Shuster, E., 2018. Reliability, resilience and the oncoming wave of retiring baseload units. Natl. Energy Technol. Lab.(March). PJM, 2018a. Perspective and Response of Pjm Interconnection to National Energy Technology Laboratories. https://www.pjm.com/∼/media/library/reports-notices/ weather-related/20180413-pjm-response-to-netl-report.ashx Mar. . PJM, 2018b. Pjm Cold Snap Performance. Feb. https://www.pjm.com/-/media/library/ reports-notices/weather-related/20180226-january-2018-cold-weather-event-report. ashx. PJM, 2018c. Fuel Security Analyzing Fuel Supply Resilience in the Pjm Region. https:// www.pjm.com/-/media/committees-groups/ committees/mrc/20181101-fuel-security/20181101- pjm-fuel-security-summary.ashx?la=en Nov. . Barron, J., Zaveri, M., 2019. Power Restored to Manhattans West Side After Major Blackout. July URL. The New York Times. https://www.nytimes.com/2019/07/13/ nyregion/nyc-power-outage.html. Waterfield, S., 2019. Brooklyn, Queens Power Outage Latest: Thousands of Con Edison Customers Affected by Blackout Caused by Extreme Heat Wave. July URL. Newsweek. https://www.newsweek.com/brooklyn-queens-power-outage-conedison-blackout-heat-wave-1450420. Amadeo, K., 2019. Hurricane Harvey Facts, Damage and Costs. June URL. The Balance. https://www.thebalance.com/hurricane-harvey-facts-damage-costs-4150087. CNN, 2018. Hurricane Sandy Fast Facts. October URL. CNN. https://www.cnn.com/
Nephi Kharadia is a second year graduate student and research assistant at the University of Idaho, Idaho Falls campus. He is pursuing an M.S. in Electrical Engineering, and was awarded a Nuclear Regulatory Commission Fellowship. Currently, Nephi is working on implementations of classical high performance control theory, including nuclear power and hydropower applications. He holds a B.S. in Mechanical Engineering from Brigham Young University – Idaho, where he focused on the design and testing of various rocket systems. In his free time, Nephi can be found exploring the outdoors, honing his photography skills, and tinkering with electronics. Dakota Roberson is an Assistant Professor of Electrical and Computer Engineering at the University of Idaho where he leads an interdisciplinary research team studying electrical grid stability and security. Before joining the University of Idaho, he was with Sandia National Laboratories. Dakota was awarded the Ph.D. in Electrical Engineering with a Graduate Minor in Statistics at the University of Wyoming, where he won the Fisher Innovation Challenge for contributions to energy storage control. He holds a B.S. in Electrical Engineering, Minor Mathematics, from the same institution. In his free time, he is an outdoorsman and motorcyclist and can be found playing guitar or painting during the winter months.
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