Abstract:A near-term strategy to reduce emissions from rail vehicles, as a path to full electrification for maximal decarbonisation, is to partially electrify a route, with the remainder of the route requiring an additional self-powered traction option. These rail vehicles are usually powered by a diesel engine when not operating on electrified track and are referred to as bi-mode vehicles. This paper analyses the benefits of discontinuous electrification compared to continuous electrification using the CO2 estimates f… Show more
“…Note that in addition to energy savings, there are significant benefits of intermittent electrification over continuous electrification in terms of CO 2 . 21 A comparison of the CO 2 emitted at 35% of electrification between diesel-OLE and battery-OLE trains is given in Figure 7.Figure 7.Comparison of CO 2 from diesel only, OLE without regeneration, and diesel-OLE and battery-OLE with regeneration on forward journey.…”
Section: Resultsmentioning
confidence: 99%
“…Note that in addition to energy savings, there are significant benefits of intermittent electrification over continuous electrification in terms of CO 2 . 21 A comparison of the CO 2 emitted at 35% of electrification between diesel-OLE and battery-OLE trains is given in Figure 7.…”
Section: Co 2 Savingsmentioning
confidence: 99%
“…In, 7 a bi-mode and an electric train was able to complete the 7-km-long Severn Tunnel. The authors’ previous work in 21 used a high-fidelity model to demonstrate the advantages of optimal intermittent electrification in saving CO 2 compared with diesel-only running. This work is novel in that it added a battery model to the high-definition model developed in, 21 and used this high-definition model to investigate optimal intermittent electrification of a route with off-wire battery running.…”
Section: Introductionmentioning
confidence: 99%
“…To develop an optimal electrification strategy, the route is divided into discrete sections to identify which sections of the route should be electrified first based on the maximum energy consumption, similar to the authors' previous approach in. 21 In contrast to, 21 this work considers the energy consumption running both directions on the route, which represents a more holistic approach to route electrification. For given percentages of optimal electrification, minimal battery sizes that allow the train to complete the journey are determined.…”
The fastest way to decarbonise traction energy of a railway network is full electrification of the network. However, full electrification can be costly and is often delayed due to complicated planning procedures. Often, it is not financially viable to electrify certain sections of the network due to geographical challenges such as hillsides and requirements to raise or lower the tracks. Intermittent electrification can provide a way to reduce emissions on a route without fully electrifying it. This paper presents an optimal intermittent electrification strategy and compares its effects on required battery size to a ‘common-sense’ approach. The “common-sense” approach is a heuristic electrification method where high-power sections of the route are electrified first. Energy savings are demonstrated using a validated high-fidelity bi-mode train model on the Newbury-Plymouth route of Great Western Railway in the UK. Unlike prior research, the optimal electrification strategy considers energy consumptions for both directions of a journey on the route and is therefore optimal regardless of travel direction. The 278-km Newbury-Plymouth route was divided into 50 equal discrete sections for the optimization process, which then identified sections that should be prioritised for electrification as they consume the maximum energy. A high charge/discharge lithium titanite-oxide battery was modelled and installed on the virtual vehicle to determine the required battery sizing for given optimal percentages of intermittent electrification. The battery sizing strategy includes battery wear effects from charge/discharge cycle life and shows the battery life to be 1.42 years if kept at 55°C and 6 years if kept at 25°C. At 36% electrification, using the ‘common-sense’ approach, the battery weighs 10,500 kg and the battery-OLE train reduces the CO2 emissions and energy usage on the route by 83% when compared to the diesel-only train.
“…Note that in addition to energy savings, there are significant benefits of intermittent electrification over continuous electrification in terms of CO 2 . 21 A comparison of the CO 2 emitted at 35% of electrification between diesel-OLE and battery-OLE trains is given in Figure 7.Figure 7.Comparison of CO 2 from diesel only, OLE without regeneration, and diesel-OLE and battery-OLE with regeneration on forward journey.…”
Section: Resultsmentioning
confidence: 99%
“…Note that in addition to energy savings, there are significant benefits of intermittent electrification over continuous electrification in terms of CO 2 . 21 A comparison of the CO 2 emitted at 35% of electrification between diesel-OLE and battery-OLE trains is given in Figure 7.…”
Section: Co 2 Savingsmentioning
confidence: 99%
“…In, 7 a bi-mode and an electric train was able to complete the 7-km-long Severn Tunnel. The authors’ previous work in 21 used a high-fidelity model to demonstrate the advantages of optimal intermittent electrification in saving CO 2 compared with diesel-only running. This work is novel in that it added a battery model to the high-definition model developed in, 21 and used this high-definition model to investigate optimal intermittent electrification of a route with off-wire battery running.…”
Section: Introductionmentioning
confidence: 99%
“…To develop an optimal electrification strategy, the route is divided into discrete sections to identify which sections of the route should be electrified first based on the maximum energy consumption, similar to the authors' previous approach in. 21 In contrast to, 21 this work considers the energy consumption running both directions on the route, which represents a more holistic approach to route electrification. For given percentages of optimal electrification, minimal battery sizes that allow the train to complete the journey are determined.…”
The fastest way to decarbonise traction energy of a railway network is full electrification of the network. However, full electrification can be costly and is often delayed due to complicated planning procedures. Often, it is not financially viable to electrify certain sections of the network due to geographical challenges such as hillsides and requirements to raise or lower the tracks. Intermittent electrification can provide a way to reduce emissions on a route without fully electrifying it. This paper presents an optimal intermittent electrification strategy and compares its effects on required battery size to a ‘common-sense’ approach. The “common-sense” approach is a heuristic electrification method where high-power sections of the route are electrified first. Energy savings are demonstrated using a validated high-fidelity bi-mode train model on the Newbury-Plymouth route of Great Western Railway in the UK. Unlike prior research, the optimal electrification strategy considers energy consumptions for both directions of a journey on the route and is therefore optimal regardless of travel direction. The 278-km Newbury-Plymouth route was divided into 50 equal discrete sections for the optimization process, which then identified sections that should be prioritised for electrification as they consume the maximum energy. A high charge/discharge lithium titanite-oxide battery was modelled and installed on the virtual vehicle to determine the required battery sizing for given optimal percentages of intermittent electrification. The battery sizing strategy includes battery wear effects from charge/discharge cycle life and shows the battery life to be 1.42 years if kept at 55°C and 6 years if kept at 25°C. At 36% electrification, using the ‘common-sense’ approach, the battery weighs 10,500 kg and the battery-OLE train reduces the CO2 emissions and energy usage on the route by 83% when compared to the diesel-only train.
“…Assumptions: [1] Electric mileage is always rounded down, and diesel mileage rounded up, to provide a worst-case scenario estimate; [2] Assumes a service pattern that may or may not currently exist, of a skip-stop express in the inner suburban portion of the route; [3] Reasonable assumptions about station stops made in portions of the line currently has no direct service; [11] Assuming service operated via the NEC with appropriate arrangements at Readville; [12] Includes two-way switching movement to and from coach yard.…”
Section: Methodology B: Energy Assessment For Service Feasibility And...mentioning
As societal attitudes toward fossil fuels shifts, commuter railroads may be coming under increased scrutiny for their contribution to greenhouse gas (GHG) emissions. This analysis explores new possibilities created by battery-electric locomotives (BELs) in conjunction with partial electrification for en-route recharging in electrified territory. We propose a systemwide network approach that starts with one or more substations in geographically strategic locations, then electrifying just enough for sufficient electrical charge, with BELs running off the wire in non-electrified areas. As 25,000-V alternating-current substations generally have an 18–26-mi reach, considerable possibilities exist for new-start electrifications. This is significantly more cost effective than a traditional approach that electrifies one corridor at a time. Although BELs are in technical development, and certain implementation challenges remains on commuter railroads, we believe BELs required to enable this type of electrification are within reach of current battery technology. Drawing on examples in Boston, Philadelphia, Chicago, and Minneapolis, six strategies are outlined: (1) minimizing electrification costs by electrifying radial commuter networks from a centrally located substation, (2) for systems with longer routes, using BELs to extend the central substation’s reach, (3) extending new electric service beyond existing electrifications with BELs, (4) using BELs to create new trans-regional services, (5) co-locating railroad-owned feeder lines with utility infrastructure such as electric transmission rights-of-way to maximize the geographic reach of supply substations, and (6) providing charging pads in certain limited situations. Preliminary ridership, energy sufficiency, and lifecycle cost analyses were performed to show the feasibility of BEL technology in conjunction with a substation-based, supply-side approach to designing electrification projects.
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