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3 Cost Per Mile: New Construction Distribution

3 Cost Per Mile: New Construction Distribution

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The most significant obstacle to undergrounding utility infrastructure is the high costs of making these conversions. Currently, new underground distribution construction and overhead to underground conversions cost five to ten times more than comparable overhead construction. But utilities continue to support undergrounding. Nearly all new residen...

Contexts in source publication

Context 1
... simple visual example of the complexity of the underground cable compared to the overhead wire is the conductor used to transmit electricity. Figure 6.2, Utility Cables, shows an example of an overhead conductor and an underground cable. ...
Context 2
... Conductor Underground Cable Figure 6.3 Cost Per Mile: New Construction Distribution -This chart presents a range of costs for new construction of distribution. ...
Context 3
... in the opinion of the author, there is not enough data to provide a full range of potential conversion costs for transmission in this report. Figure 6.5 State Reports Conversion Cost Comparison -This chart provides a comparison of the conversion cost data collected by the EEI survey and data collected by various state studies. The states conducting each study and the year the study was published are listed in the table; more information about each study can be found in Chapter 8. ...

Citations

... For example, the Dixie Fire in 2021the largest non-complex wildfire in California's history that burned over 960,000 acres-was caused by distribution lines contacting a tree 30,31 . Burying power lines is an effective but costly approach to mitigate such a coupled risk of wildfires and power grids 32 . Although some utilities may maintain the information of line-burying status of their own distribution grids, such data is privately owned by various stakeholders as data silos and not publicly available. ...
Article
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Detailed and location-aware distribution grid information is a prerequisite for various power system applications such as renewable energy integration, wildfire risk assessment, and infrastructure planning. However, a generalizable and scalable approach to obtain such information is still lacking. In this work, we develop a machine-learning-based framework to map both overhead and underground distribution grids using widely-available multi-modal data including street view images, road networks, and building maps. Benchmarked against the utility-owned distribution grid map in California, our framework achieves > 80% precision and recall on average in the geospatial mapping of grids. The framework developed with the California data can be transferred to Sub-Saharan Africa and maintain the same level of precision without fine-tuning, demonstrating its generalizability. Furthermore, our framework achieves a R² of 0.63 in measuring the fraction of underground power lines at the aggregate level for estimating grid exposure to wildfires. We offer the framework as an open tool for mapping and analyzing distribution grids solely based on publicly-accessible data to support the construction and maintenance of reliable and clean energy systems around the world.
... Figure 2 shows the correlations between median annual household income and various distribution grid characteristics conditioning on wildfire threat-characterized by average annual wildfire probability over 2026-2050-for California's two major utilities, that is, PG&E and Southern California Edison (SCE), and both territories. Supplementary Fig. 5 shows the same correlations conditioning on housing unit density-a potential confounding factor due to the confined space and higher cost efficiency of undergrounding in densely populated areas 25 . We also run multivariate ordinary least squares regressions with various grid characteristics as dependent variables and potentially related demographic characteristics as independent variables to validate the correlations. ...
... However, such fractions are substantially lower in SCE territory (Fig. 2e), potentially due to the sparser tree cover and lower tree heights in SCE territory to tree growth 24 . By contrast, system hardening-such as utility pole replacement and power line undergrounding-can protect grid components themselves from ignition, which requires non-recurring yet high upfront costs 6,25,26 . Pre-emptive de-energization is the last-resort option for wildfire mitigation by pro-actively turning off power during severe weather with obvious benefits for risk mitigation but substantial negative consequences for electricity supply 2,27 and for overall decarbonization trajectories 28 . ...
... Among system hardening approaches, power line undergrounding is the most permanent, effective, yet costly approach for minimizing the grid-wildfire interplay 25,[29][30][31][32] . Undergrounding can not only protect grids when a wildfire does occur, but also prevent wildfires from happening by largely eliminating faults and ignitions 6,25 . ...
Article
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Climate-induced extreme weather conditions make electricity infrastructure more vulnerable. They increase the risk of power-line-ignited wildfires which can, in turn, jeopardize electric power delivery. Here, leveraging machine learning, we show that lower-income communities in California not only have lower fractions of power distribution lines undergrounded, but overhead lines and poles in their neighbourhoods are also more vulnerable to wildfires. Should they bear the cost of undergrounding fire-prone lines themselves, they would have to pay a disproportionately higher cost per household. We propose a cost allocation scheme with an income threshold below which the cost is borne by utility-wide ratepayers and above which the cost is borne locally. This scheme can not only minimize the average of undergrounding costs per household as a share of income, but also homogenize such cost–income ratios across communities. Our research demonstrates the opportunity to appropriately integrate existing policies to make electricity infrastructure affordable, equitable and reliable amidst climate change.
... Electricity is distributed worldwide mainly via overhead lines and increasingly using underground power cables [3][4][5][6]. Since the transmission of electricity is associated with the release of heat in the power line, an important issue affecting the permissible current carrying capacity (ampacity) of the cable used is a way of removing heat from the power cable, especially in the underground line [7][8][9]. ...
Article
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The article presents the hardware and software configuration of the developed multi-channel temperature measurement system as well as calibration procedures and measurement results verifying the properties of measurement channels. The system has been developed and dedicated primarily for measuring the temperature distribution in a laboratory model simulating underground power lines. With the adopted configuration of the analog part of each measurement channel, the main functions in the system developed as a virtual instrument are performed in its software. The instrument input circuits contain NTC (negative temperature coefficient) thermistors used as temperature sensors. The resistance of each of the thermistors connected in the voltage divider circuits is converted into a voltage. The obtained voltages in the measurement channels, after analog-to-digital conversion (ADC), are processed in subsequent operations in the instrument’s software. In addition to the basic function of the device, which is the multi-channel temperature measurement, the operations of identifying the characteristics of the thermistors used and calibrating each of the individual measurement channels are performed. The article contains sample results of the calibration of measurement channels and temperature verification measurements used to evaluate the properties of the developed system. The obtained inaccuracy of the temperature measurement in each of the channels is less than 0.4 °C.
... Undergrounding demands a high initial outlay, particularly for transmission lines (Parsons Brinckerhoff 2012, Teegala andSingal 2015), albeit lower for distribution lines (Hall 2013). In the longer term, however, undergrounding can reduce the operational and maintenance costs for distribution lines and improve reliability owing to fewer outages (Fenrick andGetachew 2012, Glass andGlass 2019). ...
... In the longer term, however, undergrounding can reduce the operational and maintenance costs for distribution lines and improve reliability owing to fewer outages (Fenrick andGetachew 2012, Glass andGlass 2019). Over the lifetime of a distribution cable, undergrounding appears cost-effective and is becoming standard practice in several European countries (Haas et al. 2005, Raab et al. 2012; it is also increasingly used in parts of the United States to reduce the risk of wildfires (Hall 2013). Although technically and financially more challenging, the burial of high-voltage (i.e. over 110 kV) transmission lines has been undertaken where they bisect areas of high natural value (Prinsen et al. 2012) and should not be discarded in critical areas for bustards. ...
Article
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Bustards comprise a highly threatened family of birds and, being relatively fast, heavy fliers with very limited frontal visual fields, are particularly susceptible to mortality at powerlines. These infrastructures can also displace them from immediately adjacent habitat and act as barriers, fragmenting their ranges. With geographically ever wider energy transmission and distribution grids, the powerline threat to bustards is constantly growing. Reviewing the published and unpublished literature up to January 2021, we found 2,774 records of bustard collision with powerlines, involving 14 species. Some studies associate powerline collisions with population declines. To avoid mortalities, the most effective solution is to bury the lines; otherwise they should be either routed away from bustard-frequented areas, or made redundant by local energy generation. When possible, new lines should run parallel to existing structures and wires should preferably be as low and thick as possible, with minimal conductor obstruction of vertical airspace, although it should be noted that these measures require additional testing. A review of studies finds limited evidence that 'bird flight diverters' (BFDs; devices fitted to wires to induce evasive action) achieve significant reductions in mortality for some bustard species. Nevertheless , dynamic BFDs are preferable to static ones as they are thought to perform more effectively. Rigorous evaluation of powerline mortalities, and effectiveness of mitigation measures, need systematic carcass surveys and bias corrections. Whenever feasible, assessments of displacement and barrier effects should be undertaken. Following best practice guidelines proposed with this review paper to monitor impacts and mitigation could help build a reliable body of evidence on best ways to prevent bustard mortality at powerlines. Research should focus on validating mitigation measures and quantifying, particularly for threatened bustards, the population effects of powerline grids at the national scale, to account for cumulative impacts on bustards and establish an equitable basis for compensation measures.
... For example, power line collisions can be completely prevented by burying wires (Raab et al. 2012, APLIC 2012. However, burying transmission lines is infrequently used specifically to address avian collisions because construction costs can be millions of dollars per kilometer more than for overhead transmission systems (Hall 2009) and because other environmental impacts must be considered (Brockbank 2015, D'Amico et al. 2018. Removing overhead shield wires can reduce collisions (Bevanger and Brøseth 2001) but is rarely practical because shield wires are installed to protect electrical systems from lightning strikes (APLIC 2012). ...
Article
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Collisions with anthropogenic structures by long-distance migrants and threatened and endangered species are a growing global conservation concern. Increasing the visibility of these structures may reduce collisions but may only be accepted by local residents if it does not create a visual disturbance. Recent research has shown the potential for ultraviolet (UV) light, which is nearly imperceptible to humans, to mitigate avian collisions with anthropogenic structures. We tested the effectiveness of two UV (390–400 nm) Avian Collision Avoidance Systems (ACASs) at reducing collisions at two 260-m spans of marked power lines at the Iain Nicolson Audubon Center at Rowe Sanctuary, an important migratory bird stopover location in Nebraska. We used a randomized design and a tiered model selection approach employing generalized linear models and the Akaike Information Criterion to assess the effectiveness of ACASs considering environmental (e.g., precipitation) and detection probability (e.g., migration chronology) variables. We found focal (assessed power line) and distal (neighboring power line) ACAS status and environmental variables were important predictors of avian collisions. Our top model suggests that the focal ACAS illumination reduced collisions by 88%, collisions were more likely at moderate (10–16 km/h) compared to lower or higher wind speeds, and collision frequency decreased with precipitation occurrence. Our top model also indicates that the distal ACAS illumination reduced collisions by 39.4% at the focal power line when that ACAS was off, suggesting a positive “neighbor effect” of power line illumination. Although future applications of ACASs would benefit from additional study to check for potential negative effects (for example, collisions involving nocturnal foragers such as bats or caprimulgiform birds drawn to insects), we suggest that illuminating power lines, guy wires, towers, wind turbines, and other anthropogenic structures with UV illumination will likely lower collision risks for birds while increasing human acceptance of mitigation measures in urban areas.
... However, they are more exposed to external influences that may cause short circuits [1][2][3]. The cost of building an overhead line is up to 4-10 times lower than that of an underground line [4][5][6], however, the operation of overhead lines must take into account the enormous costs of removing the effects of natural disasters [7,8]. The presence of overhead lines disturbs the harmony of the environment and causes numerous limitations in terms of town planning, development and the use of the land through which they run. ...
... The outer space of the pipe in the trench is filled with a material that can improve the thermal properties of the underground power system. Usually it is a cement-sand mixture that has a low thermal resistivity and prevents the soil from drying out in the vicinity of cable ducts [7,18]. The thermal stability of the backfill material is an important property to ensure the same conditions for the buried cable throughout its life time. ...
Article
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The paper deals with the important challenges in terms of electricity transmission by means of underground cable lines. The power cable’s performance is characterized by an ampacity that represents its maximum electric current-carrying capacity. The ampacity of power cables depends on their ability to diffuse the heat generated by the current flow into the environment. In the performed research, the analysis of the efficiency of heat dissipation from the cable is based on the measurement of temperatures at selected points in individual sections of the cable. As a consequence, the proposed test stand and applied research methodology are vital for the experimental evaluation of the analyzed thermal phenomena in the investigated underground cable lines. The research program covers an in-depth analysis based on the results related to the vital parameters of the investigated cable. The experimental methodology was used to analyze the influence of the properties of the medium surrounding the cable on its temperature, and thus on the ampacity of the cable. A novelty of this paper concerns the carrying out of the experimental laboratory research with actual measurements of the temperature distribution in specific points of the casing pipe based on the original test stand. The paper presents the novel concept of the developed stand for testing heat dissipation from the cable in a casing pipe with pipe sections filled with various media, equipped with a power supply system ensuring easy control of the power dissipated in the cable. The preliminary results of the comparative tests, in which the temperature distribution in the sections of the casing pipes was recorded, indicate that the findings are satisfactorily consistent with the assumptions related to the purpose of the research. The use of appropriate materials surrounding the cable contributes to more effective heat dissipation, and as it has been shown for the examined case in originally planned and conducted tests, it can lower the cable temperature by more than 20 °C, contributing to a significant increase in the ampacity of the cable. For example, it was recorded that for different media filling the pipes, the cable reached 30 °C with different currents flowing through cable of 60 A and 120 A, respectively.
... However, burying power lines is not economically feasible in all countries and terrains, especially where the electric network is growing rapidly or is already extensive, and funding for ground cabling will not be available in the near future (Antal, 2010). When technically feasible, the costs of installing underground cables can be 4-10 times higher than the construction of traditional overhead lines (Hall, 2013;Parsons Brinckerhoff, 2012). Transmission lines are particularly problematic because their burying entails greater technical and legal challenges (particularly to ensure low levels of electromagnetic fields at the surface) and consequently much higher costs (e.g. ...
... Raab et al., 2012). Higher costs are a major concern for electric utilities since not all consumers, despite the increasing public awareness of the problem, are willing to pay more for undergrounding (APLIC, 2012;Hall, 2013). Thus, worldwide it is likely that overhead power lines will remain in use for power transmission at least, unless significant impacts justify the additional costs (APLIC, 2012;Haas et al., 2005;SNH, 2016). ...
... Note that the cost per mile to underground existing transmission lines widely varies. The Edison Electric Institute reports that converting overhead transmission lines to underground ranges between $1.3 and $14.7 million per mile in 2022 dollars [70]. We have chosen to use a cost of $3 million/mile taking into account that [67] reports the cost of undergrounding is approximately seven times the cost of installing covered conductors per mile along with the cost values reported in other sources [71]. ...
Preprint
Wildfires pose a growing risk to public safety in regions like the western United States, and, historically, electric power systems have ignited some of the most destructive wildfires. To reduce wildfire ignition risks, power system operators preemptively de-energize high-risk power lines during extreme wildfire conditions as part of "Public Safety Power Shutoff" (PSPS) events. While capable of substantially reducing acute wildfire risks, PSPS events can also result in significant amounts of load shedding as the partially de-energized system may not be able to supply all customer demands. We investigate the extent to which infrastructure investments can support system operations during PSPS events by enabling reduced load shedding and wildfire ignition risk. We consider the installation of grid-scale batteries, solar PV, and line hardening or maintenance measures (e.g., undergrounding or increased vegetation management). Optimally selecting the locations, types, and sizes of these infrastructure investments requires considering the line de-energizations associated with PSPS events. Accordingly, this paper proposes a multi-period optimization formulation that locates and sizes infrastructure investments while simultaneously choosing line de-energizations to minimize wildfire ignition risk and load shedding. The proposed formulation is evaluated using two geolocated test cases along with realistic infrastructure investment parameters and actual wildfire risk data from the US Geological Survey. We evaluate the performance of investment choices by simulating de-energization decisions for the entire 2021 wildfire season with optimized infrastructure placements. With investment decisions varying significantly for different test cases, budgets, and operator priorities, the numerical results demonstrate the proposed formulation's value in tailoring investment choices to different settings.
... The best practice to prevent bird collisions with power lines in close proximity to landfill sites would be to bury existing power lines and use underground cabling for new structures (Marques et al., 2020), as power line marking is not efficient enough in preventing collisions (Bernardino et al., 2019). This encompasses much higher costs (Bernardino et al., 2018;Hall, 2013) than traditional overhead power lines, thus we recommend its implementation only within 1 km of landfill sites. Alternatively, existing power lines could be potentially re-routed away from these areas, whenever possible, at a lower cost. ...
Article
Anthropogenic structures are increasingly encroaching wildlife habitats, creating conflicts between humans and animals. Scaling up renewable energy requires new infrastructures such as power lines, that cause high mortality among birds since they act as obstacles to flight and are used for perching and nesting, which can result in collisions or electrocutions. These interactions often endanger wildlife populations and may also result in high financial costs for companies. Flight behaviour plays a crucial role in collision risk, and the study of flight altitudes enables us to understand what drives birds to fly at collision risk altitudes. This allows the identification of high-risk areas, conditions and bird behaviours, and the implementation of mitigation measures by power line companies. In this study, we use boosted random tree modelling to identify drivers of white stork (Ciconia ciconia) flight altitudes and to investigate the factors that lead them to fly at collision risk altitudes. We found that the main drivers of flight altitude for this soaring bird species were time of day, distance to the nearest landfill site and cloud cover density. Bird age, habitat type and season were comparatively less important. Collision risk increases during crepuscular hours near landfill sites, also in days with high cloud cover density and during the breeding season. In recent years, hundreds to thousands of storks congregate daily at landfill sites to take advantage of the predictability and superabundance of anthropogenic food waste. Some of these sites have high density of power lines, becoming collision risk hotspots for storks and other landfill users. Despite being susceptible to collision, our results suggest that white storks can avoid power lines to a certain extent, by changing their flight altitude at ca. 80 m from these structures. This study shows that the implementation of mitigation measures for existing power lines should be prioritized in areas in the vicinity of landfill sites within white stork distribution ranges, and the projection of new lines should avoid those areas. These measures would benefit species vulnerable to mortality due to power line collision, and it would also reduce associated power outages and economic costs.
... There are numerous studies on the impact of extreme weather on above-ground electrical infrastructure [5,6,7,8,9,10] or on energy systems in general [11,12,13,14] and the aftermath of power outages caused by extreme weather events [15,16,17,18]. However, these studies mainly focus on outages caused by natural hazards or effects of climate change. ...
Preprint
Full-text available
Prolonged power outages debilitate the economy and threaten public health. Existing research is generally limited in its scope to a single event, an outage cause, or a region. Here, we provide one of the most comprehensive analyses of U.S. power outages for 2002--2017. We categorized all outage data collected under U.S. federal mandates into four outage causes and computed industry-standard reliability metrics. Our spatiotemporal analysis reveals six of the most resilient U.S. states since 2010, improvement of power resilience against natural hazards in the south and northeast regions, and a disproportionately large number of human attacks for its population in the Western Electricity Coordinating Council region. Our regression analysis identifies several statistically significant predictors and hypotheses for power resilience. Furthermore, we propose a novel framework for analyzing outage data using differential weighting and influential points to better understand power resilience. We share curated data and code as Supplementary Materials.