California faces significant challenges in years to come as it grapples with increasing demands to move goods within and through the state while meeting increasingly stringent air pollution standards, requirements, and goals.
This report is designed to help the California Cleaner Freight Coalition (the “Coalition”) evaluate local, regional, and statewide proposals to introduce new zero- and low-emission strategies and technologies that aim to address the state’s growing freight transport demands while concurrently meeting increasingly stringent air pollution and other environmental requirements.
Comparing and contrasting different freight strategies and technologies is a complex and difficult task. It requires the ability to gauge the multiple environmental impacts of different fuels and technologies, different transportation modes, and in different applications. Plus, what works in one location may be wholly unsuited for use in another location. These are always apples-to-oranges comparisons, and as such, exact quantitative comparisons are difficult and sometimes impossible.
In this report, we have tried to resolve this difficulty by developing the concept of “freight pathways” as a way to compare the emissions of different freight movement strategies on a ton-mile or per container basis. Conceptually, the “freight pathway” is the series of freight movement strategies and technologies that is used to transport goods between two end points. For example, the movement of a shipping container between a port terminal and an inland intermodal facility typically involves a combination of cargo handling events, which could include transport by on-road truck and/or rail. In some locations, short-sea shipping could add a third option. To make matters even more complicated, the truck or locomotive could be powered by diesel, natural gas, or a variety of hybrid and electric technologies.
The specific combination of these events defines the “freight pathway.” By estimating the emissions of nitrogen oxides (NOx), particulate matter < 2.5 µm (PM), and greenhouse gases (GHG) associated with each step along the pathway, the total emissions associated with the freight pathway may be constructed. Further, new pathways can be constructed by combining alternative steps. For example, a pathway that uses near-dock rail facilities for transport may be compared to a pathway that uses on-dock rail for transport by replacing near-dock truck drayage activities with on-dock rail activities while leaving the rail line-haul activities unmodified.
To produce quantitative results from each freight pathway, the emissions associated with each step in the pathway have been calculated. In this study, GNA has relied on our analyses of the existing research literature, publicly available emissions inventories, and project and program proposals from a variety of California public agencies to construct our own emissions model. We then used this emissions model to quantify the emission reductions of 32 different freight pathways.
Because of the sensitivity of emissions to the specific equipment used and geographic region of operation, the figures provided in this study should be considered as illustrative only. Moreover, some unavoidable regional biases exist in the presented data. However, the freight pathway model provides a framework for the Coalition to make judgments about freight proposals that exist or that will be made, and will give the Coalition the tools to conduct further site-specific and project-specific investigations that can be tailored to a particular location, region, and equipment inventory.
Both emissions from the tailpipe and those created upstream are included in the analysis. Upstream emissions are those associated with producing various fuels and transporting them. While this analysis quantifies the amount of both types of emissions, it does not assess the geographical differences in where they occur. For example, upstream emissions associated with power plants often occur far from freight-impacted communities and outside regions that suffer from extreme air pollution, although some power is generated in urbanized and polluted areas as well. When evaluating the health risks and benefits of various strategies, the location of the emissions and the amount of emissions must be considered, as well as the impact of various pollution regulations impacting stationary sources such as power plants or hydrogen production facilities. Upstream emissions associated with electricity and hydrogen production are based on CARB’s VISION model for heavy-duty trucks. Specifically, this analysis uses the VISION model emissions estimates for 2020. The 2020 California average grid mix is assumed to include 10 percent coal, 30 percent natural gas, and the remainder derived from renewables and large hydro (47 percent) and nuclear power plants (13 percent). By 2050, the grid mix is assumed to be 20 percent natural gas with the remainder being renewables and large hydro (72.5 percent) and nuclear power plants (7.5 percent). These changes in the grid mix reduce the well-to-tank emissions between 2020 and 2050. Hydrogen production estimates assume a combination of steam reforming of natural gas (80 percent) and renewably produce hydrogen (20 percent). Other electricity and hydrogen production scenarios were not evaluated.
The assumptions for the carbon intensity of liquid fuels also reflect the year 2020. In particular, diesel fuel is assumed to meet the requirements of the low carbon fuel standards (LCFS) which calls for a 10 percent reduction in carbon intensity. While the LCFS allows replacement fuels such as electricity and biogas to contribute to LCFS compliance, for this analysis, diesel fuel itself is assumed to achieve a 10 percent reduction. No reduction in the carbon intensity of natural gas is assumed. This report does not reflect recent updates to Argonne National Laboratory’s GREET model released in October 2013. The most significant changes to the GREET model that relate to this report include significant reductions in the upstream GHG emissions associated with natural gas. Under the updated GREET model, it is expected that natural gas-fueled trucks would show additional GHG reductions versus diesel trucks.
It is worth noting that, for some of the freight pathways, there are no specific proposals at specific locations in California—or where there are proposals, the public documents do not enable an effective comparison between the proposed project and other strategies that we have studied in this report. Thus, while we have been able to build an emissions model to estimate the comparative emissions of our freight pathways, there is no way to build a cost model to eliminate the inherent apples-to-oranges comparisons that we are faced with. Thus, costs are presented where they exist, but further cost information is not available at this time.
This analysis includes a select set of freight pathways and is not inclusive of all freight pathways or technologies. Further analysis is warranted, especially in the areas of air cargo movement, cross-border freight movement, cargo handling equipment, marine strategies such as cold ironing, urban delivery trucks, and others.
In each section that follows, we present our material in the following manner:
- The technology in a nutshell: a brief summary of the technology or strategy.
- Who is developing the technology and where: a summary of the key government or industry stakeholders involved in the technology or strategy, plus a summary of where the technology or strategy may be in use, under development, or proposed in California. In some cases, non-California projects are also discussed.
- Where appropriate, a series of tables and charts that demonstrate the relative emissions performance of each of the technologies or strategies that comprise the freight pathways discussed in the section.
- A summary of the strengths, weaknesses, opportunities and challenges to the further progress of the technology or strategy.
The strategy and technology summaries and emissions modeling presented in this report should provide a valuable tool to the Coalition as it considers the wide range of potential projects that will be proposed for California’s Freight transport system in years to come.
Key takeaways from this report include the following points:
- Due to major improvements made in emission controls in on-road heavy-duty engines over the past decade, trucks meeting the EPA 2010 emission standard can produce comparable or fewer NOx and PM emissions than some current “baseline” versions of more efficient technologies (on a ton-mile basis), such as marine vessels and locomotives. However, diesel trucks generally produce greater greenhouse gas emissions than other technologies.
- In the 2020 timeframe, many of the baseline off-road equipment groups considered in this report will be replaced by equipment meeting more stringent emissions standards (e.g. Tier 2 engines will be replaced by Tier 4 engines). As existing marine and locomotive engines are replaced with new engines meeting these Tier 4 emissions standards, the marine and rail pathways tend to become significantly cleaner than pathways based on on-road trucks meeting EPA 2010 emissions standards.
- The combination of improved efficiency from electrified drivetrains and the relatively low-emission California grid mix make electrified pathways the cleanest options, where electrification is applicable.