The National Renewable Energy Laboratory (NREL) has released a comprehensive vision for deeply decarbonizing transportation. It is a strategy rooted in cross-cutting research and engineering to enable industry stakeholders, communities, government agencies, and early adopters to meet their climate goals.

According to the Intergovernmental Panel on Climate Change, greenhouse gas emissions must be reduced by 50%–85% by 2050 to limit global warming to two degrees Celsius (four degrees Fahrenheit). The transportation sector is the largest source of greenhouse gas emissions in the United States, accounting for about 28% of total carbon emissions.

At the basic level, our strategy is simple: pair the best technology with the right application—whether that’s an electrified ride to school, a hydrogen-fueled big rig, or a commercial flight powered by low-carbon biofuel. We envision a mobility system fueled with clean, renewable energy, delivered directly by vehicle electrification, or indirectly by low-carbon, energy-dense fuels and renewable hydrogen for those sectors, like marine and aviation, that are harder to electrify.

—Chris Gearhart, director of NREL’s Center for Integrated Mobility Sciences

NREL’s science-driven approach for decarbonizing transportation leverages decades of the laboratory’s clean energy research and arrives as major shifts are occurring in the 21^st century mobility landscape. Fewer commuters are on the roads as telecommuting becomes more prevalent, yet the rise in e-commerce has placed greater demands on legacy freight mobility systems. The US population continues to grow and age. New technologies, fuels, and business models are on the horizon, forcing a reevaluation of “normal.”

In NREL’s vision, adapting to such shifts and meeting the call to reduce emissions demands a research mindset that looks beyond individual technologies. Rather, it is a multi-pronged strategy that provides the scientific building blocks for advancing important research and engineering priorities, such as:

• Accelerating innovations in vehicle technologies, such as increased vehicle electrification (batteries and fuel cells), connectivity, and automation;

• Increasing transportation efficiency by reducing emissions and decarbonizing transport across the light-, medium-, and heavy-duty vehicle; rail, aviation, and marine sectors;

• Maximizing future use of renewable electrons through time- and sector-shifting, a process encompassing storing renewable electrons as hydrogen, liquid fuels, and chemicals (to be used in long-term storage); and

• Optimally integrating transportation with buildings, the grid, and renewables to realize system-wide benefits.

Long a leader in transportation decarbonization research, NREL’s leading scientists and cutting-edge facilities have prepared the laboratory to innovate emerging technologies and trends from a variety of angles.

The collective knowledge and expertise at NREL is astounding. In NREL’s bioenergy program, for example, we have chemists studying the fundamental chemistry of converting biomass and waste materials into fuel. Down the line, analysts look at that process in terms of economics and strategies for accelerating deployment. Others study how to optimize that fuel for use in advanced low-emission engines for ground transportation, as well as achieving higher performance (than conventional fossil fuel) in jet engines for commercial aviation.

—Zia Abdullah, NREL’s bioenergy laboratory program manager

Like bioenergy, hydrogen sits at the center of NREL’s strategy for a transportation system decoupled from carbon emissions. While today’s market for hydrogen as a transportation fuel is limited to California and parts of Hawaii and the East Coast, experts at NREL think it will play an increasingly key role across the country to store energy and provide the emissions-free muscle needed for heavy-duty trucking, rail, and marine freight.

Hydrogen is an abundant and highly effective energy carrier, and with support from DOE’s Hydrogen and Fuel Cell Technologies Office we have shown how to harness its potential in sectors that are more difficult to decarbonize. We anticipate rapid advances in hydrogen fueling infrastructure, next-generation electrolysis technologies, larger-scale deployment of green hydrogen production, and durable, low-cost fuel cell systems, which we think will make it competitive in multiple markets across the nation.

—Keith Wipke, laboratory program manager for NREL’s Fuel Cell and Hydrogen Technologies Program