Estimating environmental co-benefits of U.S. GHG reduction pathways using the GCAM-USA Integrated Assessment Model (A&WMA Presentation)
Citation:
Ou, Y., W. Shi, S. Smith, J. West, Chris Nolte, AND Dan Loughlin. Estimating environmental co-benefits of U.S. GHG reduction pathways using the GCAM-USA Integrated Assessment Model (A&WMA Presentation). A&WMA: Finding Common Ground on Climate Change Mitigation and Adaptation, Arlington, VA, October 10 - 11, 2017.
Impact/Purpose:
Presented at the Air & Waste Management Association (A&WMA) international conference on climate change mitigation and adaptation to address emerging policies and technologies for greenhouse gas (GHG) emissions reductions and mitigation along with estimating climate change impacts and adaptation strategies.
Description:
A variety of technological pathways lead to reduced greenhouse gas (GHG) emissions. However, different pathways can have substantially different impacts on other environmental endpoints, such as air quality and energy-related water demand. In this study we use the Global Change Assessment Model-USA to compare two stylized low-carbon pathways, one emphasizing nuclear energy and carbon capture (NUC/CCS) and one emphasizing renewable energy (RE). These pathways are compared with a baseline scenario (BASE) in which both technologies are available. Environmental metrics such as air pollutant emissions, mortality costs attributable to fine particulate matter (PM2.5), and energy-related water demands are evaluated for 50% and 80% GHG mitigation targets at 2050. The targets are met primarily through deployment of low-carbon power generation technologies, with some additional reductions achieved through electrification of the industrial and transportation sectors. On the national scale, the pathway focused primarily on renewables, RE, requires lower water consumption than one focused on nuclear and CCS technologies due to the large cooling demands associated with nuclear power. Both alternative pathways result in PM health benefits under GHG reduction targets compared with BASE. RE produces greater health benefits under a 50% reduction target compared with NUC/CCS, as coal is more rapidly phased out in RE, leading to significantly reduced emissions of primary PM2.5 in the electric sector. By contrast, PM health benefits are very similar under an 80% reduction scenario, since both pathways are dominated by clean technologies with very low CO2 and air pollutant emissions from all sectors. The environmental co-benefits differ from state to state as a result of their respective energy system composition, technology shares in end-use sectors, and resource availability. This study suggests that examining multiple environmental impacts within an integrated assessment modeling framework allows simultaneous consideration of interactions and tradeoffs among air pollution, GHG mitigation, energy system and environmental goals.