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Slideshow: Sustainable Transportation

NREL research, development, and deployment accelerate efforts to put energy-efficient, low-emission cars and trucks on the road.

The federal government has rolled out ambitious new fuel economy goals. By 2025, average fuel economy is supposed to be 54.5 miles per gallon (mpg)—almost double what it was just five years ago.

NREL researchers realize that reaching this target will require multiple approaches, touching many different areas of vehicle and fuel technology. View the different areas and approaches that NREL is focusing on to reach these targets in the slideshow below.

A blue, yellow, green, and red road-like graph showing the different areas of vehicle and fuel technology, including: electric vehicles, hybrid-electric vehicles, fuel cell vehicles, and internal combustion engines.

Routes to 54.5 MPG

This diagram illustrates the numerous routes explored in the quest to achieve the 54.5 mpg goal, from early electric vehicles to today's wide range of vehicle and fuel options.

Illustration by Dean Armstrong and Ahmad Pesaran, NREL

A photo of a silver Toyota Prius driving down a road past a sign that reads, "NREL"

Hybrid Electric Vehicles

Hybrid cars currently command the lion's share of the electric vehicle market. Almost 269,000 hybrid vehicles such as this Toyota Prius were sold in 2011. NREL research is helping develop battery, power electronic, electric motor, and thermal management technology for the next generation of hybrid vehicles.

Photo by Dennis Schroeder, NREL

A photo of a small, white Mitsubishi i-MiEV plugged into an electric charging station in a white laboratory

Plug-In Electric Vehicles

There are already 13 car models, including this Mitsubishi i-MiEV, that plug into electrical outlets to get all or part of their fuel. Automakers plan to roll out more models in the coming year. NREL research and development helps manufacturers optimize vehicle efficiency and performance, as well as the interface with charging units and the electricity grid.

Photo by Dennis Schroeder, NREL

A photo of a grey Toyota Highlander SUV parked in front of a single hydrogen fueling station. The Colorado Rockies can be seen in the background

Fuel Cell Electric Vehicles

Fuel cell electric vehicles, such as the one picture here, can currently deliver a 300-to-400-mile driving range and 2,000-hour fuel cell durability. With the Wind-to-Hydrogen project, NREL is able to create fuel completely from renewable energy to power hydrogen fuel cell vehicles. The lab also provides industry partners with technical and deployment support to help bring these vehicles to market.

Photo by Chris Ainscough, NREL

A photo of a white electric-drive delivery truck with the red and white Staples logo on the side parked in a parking lot

Fuel-Efficient Medium- and Heavy-Duty Vehicles

Heavy-duty vehicles account for 26% of U.S. transportation sector petroleum consumption, using approximately 800 million barrels of oil each year. Electric-drive models require much less energy, but even traditional diesel-fuel trucks can be made considerably more efficient. NREL helps fleet manufacturers and operators adopt energy-saving technologies and practices best suited to operational realities.

Photo by Trish Cozart, NREL

A photo of the side of a brown UPS truck; a refueling hose from a compressed natural gas pump is connected to the side of the truck

Natural Gas

Natural gas powers more than 100,000 vehicles in the United States, and as much as 90% of the gas needed to fuel these vehicles is domestically produced. Currently, most natural gas vehicles have been converted from conventional gasoline engines, rather than factory produced. NREL is exploring ways to fill gaps in the marketplace for natural gas-powered medium- and heavy-duty commercial vehicles, such as this delivery van.

Photo by Pat Corkery, NREL

A photo of a biodiesel gas pump, with three refueling hoses; a green hose for Premium Biodiesel, a yellow hose for Ethanol, and a blue hose for Unleaded.


Biodiesel use in the United States surpassed 1 billion gallons in 2011. The E-85 pictured here, an 85% ethanol and 15% gasoline blend, is sold at 2,535 stations nationwide. Biofuels can be produced from vegetable oil, algal oil, animal fats, and waste grease. NREL's biodiesel research examines fuel chemistry, quality, stability, operability, emissions, and equipment and infrastructure compatibility.

Photo by Charles Bensinger, DOE

A photo of two silver vehicles parked under a large solar canopy

Vehicle-to-Grid Integration

NREL examines the interaction of plug-in electric vehicles with building energy systems, utility grids, and renewable energy sources. Vehicle-to-grid (V2G) technology makes it possible to store energy in and source energy from vehicle batteries to balance intermittent renewable resources, enhance microgrid stability, or reduce demand for costly grid-fed electricity at peak hours. NREL uses an 18-kilowatt solar array with V2G components to test possible configurations.

Photo by Dennis Schroeder, NREL

A close-up photo of a black and white plug-in for an electric vehicle charging station

Fast Charging

Plug-in electric vehicle owners normally charge at home, but sometimes vehicles need a little extra juice to serve the driving needs of that day. Fast charge technology like the one pictured at NREL's Vehicle Testing and Integration Facility offers an extra 40-60 miles of range in 15-25 minutes of charging. The lab works toward integrating fast chargers with renewables and grid operations, in addition to developing technology to enable even faster refill rates.

Photo by Dennis Schroeder, NREL

An illustration of a small plug-in hybrid vehicle, showing the in-road inductive apparatus, located at the bottom of the vehicle.

Inductive Charging

Plug-in hybrid electric vehicle users fail to connect to available outlets up to 25% of the time. Most electric-drive vehicles can only travel 60-100 miles on one charge, and systems take hours instead of minutes to refuel. Wireless inductive or conductive charging that automatically replenishes battery power can eliminate missed charging opportunities, shorten refueling time, and extend vehicle range. NREL researchers are assessing the fuel savings potential and viability of wireless stationary charging and in-motion power delivery.

Illustration by Dean Armstrong

A colorful illustration of a city with cars driving on the roadways. Some of the cars have yellow circles under them indicating autonomous charging while driving or parked on a city street.

Intelligent Transportation

Connected car penetration is projected to increase by 60% globally by 2017, which can help realize $20B in fuel and productivity savings. Intelligent transportation encompasses autonomous driving, parking, retrieval, and charging capabilities, as well as vehicle-to-vehicle communications to avert traffic congestion and collisions. Features such as self-parking have already become common in some commercial models. NREL is exploring the possible energy-saving benefits related to this future line of research.

Illustration by Dean Armstrong, NREL

A photo of a person holding a Blackberry over the hood of a black sedan. The hood of the car has a blue, white, and green decal with wind turbines on it and reads, "PHEV"

Communications Technology

The number one non-cost barrier to consumers' adoption of fully electric vehicles is range anxiety—the fear that low-capacity batteries will strand them between changing stations. The NREL-developed Alternative Fueling Station Locator makes it possible for drivers to access charging station locations, maps, and directions using their smartphones. This is just one way rapidly advancing communications technology can support widespread deployment of electric-drive vehicles.

Photo by Pat Corkery, NREL

Sustainable Transportation

Fall 2013 / Issue 5

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