To accurately compare emissions of a BE truck with that of a diesel truck, it is important to consider the upstream emissions associated with the fuel cycle in addition to the tailpipe emissions, to capture the emissions associated with generation of the electricity used to charge the BE vehicles. The on-road emissions rates calculated via MOVES and shown in Table 5 were combined with upstream “well-to-pump” fuel cycle emissions from GREET Model. Fuel cycle emissions rates for diesel and electricity production are shown in Table 8. Figure 12 and Figure 13 show the total emissions for both the diesel and BEV options. As expected, the BEV option yields fewer emissions over the vehicle’s lifetime than the ICE option.The economic, business case for BEVs versus diesel trucks in this use-case example is very similar, with the BEV being about half a cent cheaper per mile. However, the break even point is not until the very end of the vehicle’s useful lifetime. If the fleet plans to operate the vehicles for their entire 20-year lifetime on this use-case, then in the long run the BEVs are the better choice. However, there are lots of external factors to consider. Finding locations suitable for installation of private EV chargers will add additional costs for this example, and current operations will need to evolve to accommodate the technology switch. Minor changes of other parameters, such as fuel prices and fuel economy, VMT, interest and discount rate and other financial terms, incentives, pollution taxes, and maintenance costs may be enough to swing the economic comparison in favor of one technology over another. Being able to analyze a wide variety of parameter adjustments, vertical grow racks tailored to a specific scenario, quickly and easily is of high value to fleet managers.
TCOST, the tool discussed in the following section, was designed to enable fleet managers to model their scenario as well as alternative scenarios with adjusted parameters more quickly and easily by removing knowledge barriers while simultaneously leveraging the power of preexisting models utilized in this use-case example.This section will familiarize the reader with the concepts, functions, and data used in TCOST before presenting a sensitivity analysis exploring the effects of parameter adjustments in the context of the use-case example from the previous section to demonstrate how the tool can be used by fleet owners to explore the effectiveness of ICE and BE technology for their business and generate insightful comparative data to make informative decisions about the future purchases of their fleet. TCOST is a parametric spreadsheet-based tool intended to assist fleet managers seeking to quantitatively evaluate the increased costs or savings of opting to acquire BE MHDV units compared to diesel MHDVs projected into the future for the duration of the vehicle’s useful life, assumed to be 20 years. The model uses a series of 21 input variables defined by the user to produce total cost of ownership for a diesel truck versus a BE truck in the same use case. The input page of the spreadsheet model is shown in Figure 14. TCOST is intended to serve a simplified model distilling the functions of several preexisting models into an easy-to-use tool that can help perform electrification analysis and allow users to vary input values to evaluate how each parameter can affect electrification potential in each scenario.
The main outputs of TCOST are comparative total cost of ownership figures broken down by cost category , both as a gross number and on a per-mile basis, as well as a series of visualizations comparing cost breakdowns, break even points, and the expected tailpipe and fuel cycle emissions for both technologies.Maintenance costs for diesel and BE vehicles were taken from AFLEET and California HVIP. Maintenance costs are set to grow by 1% compounded annually by default to reflect the aging and deterioration of vehicle components. Default fuel economy figures for each technology type and vehicle regulatory class are taken from CARB. TCOST uses EIA national average fuel price projections for diesel fuel and commercial electricity. If desired, users can enter their local fuel prices and the tool will project the EIA national trends onto the input starting prices provided by the user and use those in the calculations instead. Table 9 shows the default vehicle parameters in the tool. The model includes parameters for modeling the economic implications of the acquisition of levels 1, 2, and 3 chargers. The purchase prices for each level of charger were based on chargers for sale and listed in CALSTART’s EVSE catalogue . As a caveat, charger installation often comes with additional expenses for utility service upgrades and other necessary investments upstream on the electrical power system. That is, not all fleets can immediately install chargers if the grid conditions are not ready for such installations. These expenses can vary depending on current infrastructure status at the specific location and must be considered independently as part of the decision-making procedure.TCOST calculates WTP and PTW emissions of both technology types to compare the environmental impacts of each option. WTP emissions for diesel fuel were sourced from the “conventional diesel from crude oil for U.S. refineries” fuel pathway within the GREET model.
This fuel pathway includes emissions from the extraction, transportation, refinement, and delivery of the finished diesel fuel product. For electricity, WTP emissions were taken from the “distributed – U.S. mix” pathway in GREET. This includes the generation and transmission of electrical power, including transmission losses, for a national average generation resource portfolio. Future versions of the model will include state-specific or FERC region-specific WTP electricity emissions. PTW energy use and emissions were calculated using per-mile emissions rates by regulatory class calculated using MOVES for diesel vehicles. PTW emissions for BEVs were assumed to be null. The on-road estimates of energy use were multiplied by GREET energy use and emissions rates to estimate upstream emissions and energy use associated with fuel and electricity production. Emissions are reported by TCOST for CO2, VOCs, CO, NOx, CH4, PM10, and PM2.5. Emissions rates are depicted in a table in Appendix A of this report. Upstream vehicle cycle emissions associated with vehicle manufacturing and retirement were excluded in this version of TCOST due to insufficient data coverage for every regulatory class in GREET. In future versions, these will be calculated through a simulated reconstruction of vehicle components in a vehicle-cycle simulation model like Autonomie® to expand the available inventory of vehicle cycle data. Inputs are set by the user and TCOST calculates the corresponding economic comparison of both technology types, reporting lifetime savings and generating four comparative visualizations: cost schedules for the diesel and BE truck , a cost of ownership comparison line graph , and a clustered column chart showing the emissions difference between each technology. Critically, TCOST allows users to override all default parameters with custom values which makes the tool useful for modeling a huge variety of operational and economic scenarios. Users of the tool need only type directly into the input cells to tailor the tool to their fleet conditions and drastically improve model precision for their scenario. Using their conditions as a baseline, they can evaluate the effects of minor parameter changes on cost comparisons between the two technologies.TCOST inputs were set to reflect the conditions described by the use-case example. The example inputs are shown in Appendix B of the report. Where input values were not known, default values were assumed to be reasonable estimates of conditions and were left unchanged. The fuel economy values were taken directly from the results of the MOVES-Matrix simulation and are reflective of the on-road conditions for the use-case. The total cost of ownership reported by TCOST was $630,715.29 for the diesel option and $626,982.88 for the BE option, 4×4 plastic tray resulting in a lifetime savings of $3,732.41 for the BE option with a break even point in the 20th and final year of operational life.
While the BE option costs over twice as much for the initial acquisition of the vehicle, the operation and maintenance costs combined are less than half that of the diesel option over the vehicle lifespan. These cost savings come with the caveat of charger citing and utility upgrade costs, as well as any potential alterations to the drayage operation that might incur additional costs or lost revenue . The visualizations produced by TCOST are shown in Figure 15 through Figure 18. These visuals show the large influence of purchase capital cost and taxes during the first six years of vehicle ownership, and the large difference in on-road operating costs and maintenance costs that show up in the cumulative cost curves across the diesel and BEV alternatives. By comparing these charts, fleet owners and operators can quickly gain insight into the economics and environmental impacts of each potential fleet procurement decision.The use case example presented above for Appalachian Regional Port Drayage results in very small savings that take almost the entire life of the vehicle to realize, compared to some use case examples in the literature that appear to take less than five years to reach payback. Fortunately, TCOST can be customized to specific use cases, allowing fleet owners to easily adjust parameters to identify sub-fleets that make more sense to electrify and to perform sensitivity analysis, helping to assess specific deployment scenario risk and make informed investment decisions. A selection of parameters was adjusted, one at a time, to isolate their effects on the TCO difference between the two technologies. The results of the sensitivity analysis are shown in Figure 19 and are discussed in more detail below. The parameters with the highest sensitivities are BEV purchase price and ICE fuel economy , followed by miles per day, diesel price, and ICE maintenance cost . The sensitivity analysis indicates that a high amount of risk involved in the investment decision, as altering these parameters even slightly can affect total cost savings by over 100%. However, this percentage difference in savings is some when misleading, because the savings were so small to begin with. That is, the high percentage changes observed here do not equate to high absolute values. But, the model sensitivity analysis does indicate that assumed future conditions does have a large impact on the simulation.Because diesel fuel economy won’t change very much over time, due to the consistent on-road conditions of the vocation, the most critical parameter in play is the purchase prices of the BEVs. If there are any incentives available to the fleet for investing in BE trucks, a simple reduction of purchase price by only 1% would almost double expected savings under these conditions. Much recent regulatory focus has been on monetary incentives for BE technology because purchase price represents the largest expense occurred by an electrifying fleet. Fuel prices are notoriously hard to project. If diesel becomes more expensive in the long-term, it would improve the savings of BE investments. Even if diesel fuel prices in the operational area are notably higher than the national average used in TCOST, it would have a large impact on savings. If the fleet is expected to travel more daily miles in the future, additional miles travelled would also have significant impact on the fleet’s savings . Finally, under a diesel option, if future retrofits are required to keep the vehicle and fleet compliant with evolving emissions standards, diesel maintenance costs might increase, positively impacting fleet savings under the BE option. TCOST enables fleet managers to quickly and accurately adjust parameters to model a variety of possible scenarios to produce sensitivity analyses like this. TCOST customizability and parametric design allow the tool to quickly model case-specific conditions or a variety of alternative futures. Its spreadsheet-based nature is accessible, reducing modeling knowledge and information barriers, and allowing fleets of all shapes and sizes to gather data to make informed decisions about the futures of their fleets.Fruit trees should be planted where they will receive full sun for 6 or more hours per day during the growing season. For maximum production, fruit trees need soil that is deep and well drained. Such soils do not occur everywhere in California, especially in residential areas where the topsoil may have been partially removed by land grading and the remaining soil has been compacted by the weight of construction machinery.