Author: Alex Schroeder, Transportation Technology Deployment Manager, National Renewable Energy Laboratory (NREL)

Forty years after the Arab Oil Embargo, gasoline prices of nearly $4 per gallon have become the new normal, and more and more Americans are starting to understand the value of reducing the country’s petroleum consumption, greenhouse gas emissions, and dependence on foreign oil. Colorado businesses and government agencies, along with regionally-based research facilities such as the Energy Department’s National Renewable Energy Laboratory (NREL), are advancing innovations and the business climate needed to bring sustainable transportation solutions into the mainstream. Not that drivers will stop using oil altogether, but in addition to the recent surge in domestic oil production, the nation is rapidly developing clean, renewable, and affordable options for getting from point A to point B.

A Lifetime of Progress in Five Years

Steady progress is being made in diversifying the mix of vehicle technologies, laying the groundwork for low- and zero-carbon transportation. In 2008, there were 50 hybrid and flex-fuel passenger vehicle models. Five years later, consumers have 155 models to choose from, including fully-electric vehicles. Drivers in Colorado and across the nation are plugging in cars at electric charging stations, powering delivery trucks with compressed and liquefied natural gas, running utility vehicles on locally produced biofuels, and filling the tanks of shuttle buses with propane. Passenger cars are getting an average of 16% more miles to the gallon than they did just five years ago.

A “Silver Buckshot” Solution

While many people once envisioned a “silver bullet” solution to transportation energy challenges, the answer more closely resembles silver buckshot. A sustainable transportation future will require widespread adoption of many options, including alternative fuel and electrified vehicles, rideshare and mass transit, and fuel-efficient gasoline-powered vehicles. In addition, any dramatic decrease in petroleum consumption will require changes in medium- and heavy-duty vehicle technology and operations, as well as fundamental shifts in how light-duty vehicles are designed and used.

Hybrid electric vehicles, which have become increasingly affordable, can now be found on roads across the country. Although plug-in electric vehicles (PEVs) currently command less than 1% of the automotive market, they continue to grow in popularity and are seen as crucial to reducing the country’s oil dependency. Plug-in hybrids and fully-electric vehicles sip energy and produce little or no emissions. High sticker prices, however, combined with short driving ranges and relatively long refueling times in plug-in and fully-electric models, have presented barriers to more widespread adoption.

“Electric vehicles are an important part of the mix, but they need to deliver the best possible driving experience at an affordable cost,” says Chris Gearhart, director of NREL’s Transportation and Hydrogen Systems Center. “We’re getting there. Our work on batteries, power electronics, and climate control systems is focused on delivering an experience that can truly compete with that of conventional vehicles.”

Like fully electric vehicles, hydrogen-powered fuel cell electric vehicles (FCEVs) promise zero emissions, but also offer a significantly greater driving range and rapid refueling time.

“Toyota believes that the outstanding driving range, fast refueling and fuel economy afforded by fuel-cell EVs make it an ideal transportation solution. But to truly be environmentally sustainable, we believe hydrogen will need to be produced renewably,” says Jaycie Chitwood, future fuels and environmental strategy manager for Toyota Motor Sales, U.S.A. “This is why we’re an enthusiastic partner with NREL, using Toyota Highlander FCEVs for real-world testing of fueling with wind-generated hydrogen.”

Advanced biofuels present another solution. There is renewed interest in examining new biomass feedstocks, biofuel blends that are compatible and able to ‘drop in’ to existing fueling infrastructure, and mid-level ethanol blends that could unlock more efficient and higher performing engines.

“About 10% of all gasoline sold today consists of biofuels. With a projected annual supply of more than 1.3 billion tons of biomass feedstock, we know this resource has even more potential,” says NREL Fuels Performance Group Manager Matthew Thornton. “Right now, we’re looking at deployment opportunities for cellulosic ethanol and beginning R&D on drop-in biofuels that will work with legacy vehicles and fueling infrastructures.”

The Energy Information Administration has also projected a 44% increase in U.S. natural gas production between 2011 and 2040, due in large part to more economical shale gas extraction methods. This increased supply positions compressed and liquefied natural gas as an affordable and abundant alternative to gasoline and diesel, offering savings of up to $2 per gallon in some states. Fleets have taken notice of this, and sales of medium and heavy-duty compressed natural gas vehicles have increased dramatically over the past few years. Earlier this year, Ford revealed that sales of vehicles with engines prepped to run on natural gas and propane had soared 350% since 2009.

At the same time, traditional vehicles powered by petroleum-burning internal combustion engines are becoming increasingly more fuel-efficient. NREL’s work with industry has led to improved engine design, aerodynamics, power electronics, and thermal management. A large number of passenger vehicles now get 30-40 mpg and produce fewer emissions. With more than 230 million gasoline-powered cars on American roads, continued refinement of these vehicles is at least equal in importance to developing new technology.

The Right Fit for Each Transportation Need

Some technologies lend themselves better to specific applications.  Industry experts and fleet operators are working with NREL and other research institutions to better understand vehicle drive cycles and match them up to the appropriate technology in order to maximize fuel savings. For example, PEVs can provide an ideal solution for commuters who travel relatively short distances and have access to electric charging at home or the workplace.

Hybrid vehicles might be the right choice for frequent stop-and-start, in-city taxi and bus services. On the other hand, compressed natural gas can provide a perfect fit for fuel intensive, return-to-base, fleet operations such as refuse and work trucks.

“We have to look at how people are using these vehicles,” says NREL’s Kevin Walkowicz, manager of NREL’s vehicle Testing and Analysis Group, “That’s the only way to make sure that the technology really will deliver the greatest energy savings for a reasonable cost while meeting operational demands.”

Clearing Infrastructure Hurdles

Key to the deployment of all of these technologies is infrastructure to make refueling or recharging convenient and cost effective. Grid, station, and equipment limitations pose real and perceived barriers to widespread adoption of alternative fuel vehicles. U.S. Energy Secretary Ernest Moniz recently singled out infrastructure  as a major hurdle that requires more concerted attention.

Most cars are parked about 95% of the time, usually at home or at work.  Ensuring access to charging at both of these locations can go a long way towards easing range anxiety and encouraging consumers to consider purchasing electric vehicles.

”While most people have the means to charge electric cars at home overnight, sometimes it can be difficult to power up at work or on the road,“ says Wendy Dafoe, NREL’s DOE Clean Cities project leader. “Between DOE’s new Workplace Charging Challenge spurring employers to offer on-site vehicle charging stations and the internet-based Alternative Fueling Station Locator, drivers soon will have more places to charge and an easy way to find them.”  DOE and NREL are making this station locator even more accessible via an iPhone app that is being released in October 2013.

The market for alternative fuel vehicles has been heavily impacted by a chicken-or-the-egg conundrum. Until public fueling stations are readily available, individuals will be less likely to buy these vehicles. But unless more people purchase alternative fuel vehicles, station operators will not find it economically feasible to expand their networks.

Connecting Vehicles, Buildings, and the Grid

Integrating energy grid, real estate, and transportation planning through a more comprehensive systems approach presents enormous potential for energy savings.  NREL’s new Energy Systems Integration Facility, is being used in tandem with the lab’s Vehicle Testing and Integration Facility to explore interaction between vehicles, the electric grid, buildings, and transportation infrastructure in a way that will facilitate a more efficient transfer of both energy and information.

Vehicle-to-grid technology makes it possible for vehicles to become valuable grid resources while conserving energy. Vehicle batteries are capable of both providing and storing energy to balance intermittent renewable resources, enhance micro-grid stability, or reduce demand for grid-fed electricity at peak hours.

Shifting Demographics and Transportation Habits

Americans have driven fewer miles every year since 2005, something that has not been seen since records were first tracked in 1960. Generational gaps are emerging, with the number of 16-to-24-year-olds with a driver’s license hitting a 40-year low in 2011.  These shifts present opportunities for disruptive business models and technologies to provide both incremental and dramatic transformation.  Changes in priorities have helped car-share, mass transit, and bike-share programs flourish in communities previously dominated by the single-occupancy-vehicle lifestyle.

Continuing Innovation, Unprecedented Advances

Ambitious federal fuel economy goals call for an average fuel economy of 54.5 mpg by 2025. DOE’s cross-agency EV Everywhere Grand Challenge initiative is pushing for R&D breakthroughs that will more than double fully electric vehicles’ driving range and cut system costs by 75%. And who knows where new ventures into wireless inductive charging for electric vehicles, autonomous computer-controlled vehicles, or transportation-oriented urban planning might lead? Whatever the direction, Colorado’s cleantech community, in partnership with research institutions such as NREL and strong industry partners, is certain to remain at the forefront.