Imagine the future of transportation: after leaving your home in the morning, you hop on a driverless car that stops in front of your home. It will drive you directly to wherever you tell it to go. Traffic jam? No worries: cars are controlled by a smart traffic management system. Running out of fuel? Never: they have an advanced battery sufficient to absorb and store energy from sunlight. This may come true someday, but according to experts from the government, national labs, and think tanks, the transportation sector will largely look the same as it does today in the next 10 years — yet growing emissions from the sector demand action and new solutions today.

In 2016, carbon dioxide (CO2) emissions from the U.S. transportation sector exceeded emissions from the power sector for the first time since 1979. Looking to the future, vehicle efficiency is of great importance. Over the next 30 years, electric vehicles (EVs) will grow and fuel economy will increase, but conventional gasoline vehicles will continue to dominate the U.S. vehicle fleet. That was the conclusion witnesses came to at a recent Congressional hearing about the future of transportation fuels and vehicles, which underscored the complicated task of decarbonizing the diffuse and diverse transportation sector.

Figure 1: Light-duty Vehicle Sales by Fuel Type (millions of vehicles)

Source: U.S. Energy Information Administration

According to the Energy Information Administration’s (EIA) Annual Energy Outlook of 2018 (AEO 2018), sales of new electric, plug-in hybrid electric, and hybrid vehicles are expected to jump to 19 percent of vehicle sales in 2050 compared to just four percent in 2017. As shown in Figure 1, the total share of conventional gasoline vehicles is estimated to drop from 95 percent in 2017 to 78 percent in 2050 because of the growth of electric vehicles. Despite the strong growth in EVs, conventional gasoline vehicles will likely still dominate the vehicle market with 71 percent of new sales in 2050, according to EIA projections.

The witnesses all agreed that electrification will be the driver of the transportation sector going forward, but uncertainties remain in both the pace of technology breakthroughs and policy support for various pathways. The analysts agreed that petroleum and biofuels will likely continue to remain the largest part of the fuel mix in the transportation sector for the next several decades.

At the hearing, Dr. Jeremy Martin from the Union of Concerned Scientists testified, “Smart deployment of biofuels can support the progress of vehicle efficiency.” He added that the recent growth in biofuel volumes had mainly come from biodiesel, which is made from vegetable oil, animal fat, or recycled cooking oil. Biomethane, a waste-based transportation fuel, and cellulosic ethanol, made from corn-kernel fiber and corn stalks, are also growing.

John Eichberger, Executive Director of the Fuels Institute, was confident that EVs would definitely play a major role in the market, but this process would take time. “If every vehicle sold today were equipped with a new technology, it would take about seven years before the new feature is present in more than 50 percent of the vehicles on the road—and that is assuming 100 percent immediate and persistent market adoption” (see Figure 2 below).

Figure 2: Vehicle Market Penetration of New Technology (Percent)

Source: Fuels Institute

To provide research support for future transportation technologies, the Co-Optimization of Fuels & Engines (Co-Optima) initiative, an R&D collaboration between the U.S. Department of Energy (DOE), national labs, and industry, is working to improve the efficiency, performance, and affordability of transportation options. According to Dr. John Farrell, Co-Optima's Project Technical Lead and the Laboratory Program Manager for Vehicle Technologies at the National Renewable Energy Laboratory (NREL), much of the initiative's research has been focused on fuel blendstocks containing renewable fuel blends. Such renewable gasoline fuel blends can be used in small, highly efficient engines. Biofuel blends can be produced from various resources. Currently, most biofuels are made from corn ethanol, but forestry and agricultural residues and algae could also become major sources of biofuels.

The government is also funding research on electric vehicles. Today, EVs face three primary challenges to greater deployment: charging infrastructure, battery technology, and affordability. NREL and DOE are working to tackle these challenges by researching the potential to establish a national extreme fast charging (XFC) network for EVs. Research on wireless and road charging stations is also underway to save drivers time and solve logistical concerns. Furthermore, NREL’s Battery Internal Short-Circuit Device and Isothermal Battery Calorimeters could improve the safety performance of EV batteries and lower their cost and size, making EVs more affordable for consumers.

The hearing witnesses agreed that advancements in technology and research are leading us to a future of cleaner transportation, but regulations and policies pose uncertainties. On April 2, EPA announced it would revise the national Corporate Average Fuel Economy (CAFE) standards that regulate vehicle emissions. EPA Administrator Scott Pruitt has argued that the current standards are too strict and that there should be a unified national standard. However, at the hearing, all witnesses agreed that stricter CAFE standards are necessary to improve fuel efficiency, increase U.S. automakers’ competitiveness, and drive consumer behavioral changes. According to the Annual Energy Outlook of 2018 report, with CAFE and advanced technologies, the average new light-duty vehicle fuel economy is expected to increase from 33.4 miles per gallon (mpg) in 2017 to 48.6 mpg by 2050. Using additional technologies, like renewable fuels, could also provide an immediate boost in vehicle efficiency.


Author: Jieyi Lu