Reflecting on the various workshop participants’ comments that transportation is likely to be treated differently from other energy-consuming sectors, Bob Marlay noted that transportation still seems to be stovepiped, perhaps more than other sectors, and while there has been much important work done in looking at the various components (roads, vehicles, batteries), there might be more value in viewing the sector as a system, particularly given that the sector is one of the main leverage points in achieving an emissions-free economy. Brian Murray wondered if modelers could improve how they capture the transportation sector in their models. In general, he pointed out that models tend to focus on fuel economy standards but do not generally reflect responses to a carbon price.
Bryan Hubbell explained that there are potential interactions and efficiencies to be had in integrating air quality and climate modeling. Due to the magnitude and immediacy of air-pollution-related health effects, it is also important not to forget that there are existing air quality goals that we will continue pursuing as we begin to address climate change issues. Timing and spatial location will be important considerations, because when considering GHG emission reductions, there are potential co-benefits to reducing criteria air pollutants, depending on location.
EPA’s Office of Air Quality Planning and Standards (OAQPS) normally deals with sector-level models but is investigating ways to link these to macro models by developing models that communicate with one another, sending carbon prices down or sending technology/production constraints up (Figure 7). Its industrial sectors integrated solutions model (ISIS) will be linked directly to ADAGE, but also linked through MARKAL, which will act as a bridge between ADAGE and the sector-specific outputs for technology and emissions, along with the air quality impacts fed back from ADAGE’s outputs. EPA has also been developing a control strategy tool (CoST), which is a database of control strategies for criteria pollutants and toxics, along with cost curves and associated emission reductions. OAQPS is working on adding GHG control technologies and is also cooperating with the Office of Atmospheric Programs to develop closer linkages between benefits assessments and large-scale CGE modeling.