New report outlines steps needed to reduce petroleum use and greenhouse gas emissions

By Bill Holloway

A new report outlines what would be required to substantially reduce both petroleum usage and greenhouse gas emissions by 2050. It concludes that the goals are ambitious but achievable; however, government incentives, mandates, and research funding will be needed. The goals are unlikely to be achieved by market forces alone.

The Committee on Transitions to Alternative Vehicles and Fuels, part of the National Research Council’s Division on Engineering and Physical Sciences, evaluates potential vehicle- and fuel-based strategies for the United States to reach goals of reducing petroleum consumption by 50 percent in 2030 and 80 percent in 2050, and reducing GHG emissions by 80 percent by 2050 from 2005 baseline levels. The report’s analysis focuses on light-duty vehicles (LDV) – passenger vehicles and light trucks, which consume almost half of all petroleum used in the U.S. and generate 17 percent of U.S. GHG emissions.

Concerns over energy security from petroleum imports and the effect of GHG emissions on global climate are driving interest in alternatives. In response to a 2010 congressional mandate the NRC undertook research to assess the potential for vehicle and fuel technology options to achieve substantial reductions in petroleum use and GHG emissions by 2050 relative to 2005.

The report finds that the petroleum reduction goals are likely reachable by 2050 but may be overly ambitious for 2030. While total LDV petroleum use is expected to decline in response to national GHG requirements, the Corporate Average Fuel Economy standards, and possible advances in biofuels, the authors believe a 50 percent reduction in LDV petroleum use by 2030 is highly unlikely. This is primarily because so many of the vehicles on the road in 2030 will have been built in 2015 and earlier, prior to expected advances in fuel efficiency. They believe the goal of reducing LDV petroleum use by 80 percent in 2050 is more achievable, assuming continued gains in fuel efficiency beyond that mandated by the 2025 CAFE standards and either a dramatic expansion of the use of biofuels or a large-scale shift from internal combustion vehicles towards natural gas or electricity via batteries or fuel cells.

While the authors believe the goal of reducing LDV GHG emissions by 80 percent by 2050 may be technically achievable, it involves significant uncertainty and will require at least two of the following four options: much higher efficiency conventional vehicles and/or the use of electric, hydrogen, or biofuel vehicles. If vehicles powered by electricity using batteries or fuel cells are to be a majority of the fleet in 2050, they would have to be a significant fraction of new car sales by 2035.

The primary initial barriers to greater public acceptance of alternative vehicles identified in the report are limited fueling infrastructure, limited vehicle variety, and higher purchase costs. However, per mile operational costs are expected to be lower than for conventional vehicles and, as these alternative technologies become more widespread, many of the major barriers are expected to fade.

Although the report provides useful insight into how to green the LDV fleet, it assumes a steadily increasing level of total vehicle travel and neglects solutions based on shifting land use patterns to reduce travel distances and demand-based solutions, such as increased walking, biking, and transit. If, as SSTI has reported in the past, per capita VMT continues to decline, and cities and states continue their shift towards greater connectivity and providing multimodal transportation options, the goals of achieving dramatic reductions in LDV petroleum use and GHG emissions over the next four decades may be well within reach.  

Bill Holloway is a Transportation Policy Analyst at SSTI.