Last summer, Castlen Kennedy went on a 10-day, 2,500 mile roadtrip from Austin, Texas to Boston, Massachusetts. Driving with her friend, Cheryl Dalton, Castlen drove through 13 states in this 10-day period, all in the comfort of a Chevy Tahoe that had been converted to run on natural gas, in addition to gasoline. Over the 2,500 miles, Castlen and Cheryl managed to drive exclusively on natural gas, saving about 22% in total fuel costs and 25% in carbon dioxide (CO2) emissions compared to a gasoline vehicle. And, they showed how this alternative fuel can work even in the face of limited infrastructure.

The “chicken and the egg” problem is often cited as being a killer of alternative transportation fuel proposals, including natural gas. For shorter trips, owners can fill their tanks with natural gas or charge their batteries with electricity in their own garage. But, alternative fuel vehicle owners can face difficulties when going on a roadtrip that requires them to travel longer distances.

Today, the transportation sector is optimized for petroleum-based fuels. There are nearly 130,000 fueling stations around the country where on can fill their vehicle with gasoline and (often) diesel. But, in most cases, the infrastructure doesn’t currently exist for alternative fuels on a large scale, a notable exception being the E10 that can be found at almost every filling station thanks to federal regulations. For example, there are only about 1,000 natural gas filling stations throughout the United States, which can pose a problem to natural gas vehicle owners.

During their roadtrip, Castlen and Cheryl showed how one can successfully navigate through the limited infrastructure problem (with a few sacrifices in spontaneity). While their Tahoe had the ability to run on gasoline, they were able to use natural gas exclusively for their 2,500 trek from Austin to Boston. And, since they were followed on their journey by a gasoline-only Chevy Avalanche (running with the same engine and chassis as the Tahoe), Castlen and Cheryl were able to provide a real-world comparison of natural gas versus gasoline for long distance travel.

I recently spoke to Castlen about her trip, to get her perspective on the lessons learned from this experience.

MCL: Could you tell us a bit about how the idea for this trip came about?

CK: As a graduate student studying policy and geosciences, natural gas - in particular shale gas - was being discussed regularly in the classroom. I was also working part time for an oil and gas producer where the impact of the shales and the increase in domestic supply had sparked conversation of new and increased ways to utilize natural gas – transportation was one of those options. I decided to explore natural gas as a transportation fuel for my thesis research and decided an actual on-road experiment would add a personal narrative to my research.

MCL: Why did you decide to use compressed natural gas (CNG) as your fuel for this trip?

CK: CNG is an alternative fuel and while I had read plenty about the advantages and disadvantages I wanted to experience them first hand. I knew the fuel burned cleaner and was cheaper than gasoline, but the lack of refueling stations presented a serious challenge for natural gas vehicles.

MCL: What were you hoping to learn from this experience?

CK: Discussions in the classroom and at work, coupled with the national attention that Natural Gas Vehicles (NGVs) were getting through ideas such as the “Pickens Plan”, focused on the NGV application for heavy duty and fleet vehicles – or those that tend to have lower payback periods. I was curious as to whether or not NGVs may be a viable option in the passenger vehicle market, and wanted to determine for myself whether or not the benefits outweighed the drawbacks. I also wanted to document the story and allow others to follow along as I tried to make the journey. I used a website where I maintained a blog and used social media to share my experiences along the way.

MCL: If you plot the driving route from Austin to Boston using Google Maps, it shows a total distance travelled of 1,958 miles. Why did you choose the 2,500 mile route?

CK: There are approximately 1,000 compressed natural gas (CNG) stations in the country, compared to nearly 130,000 gasoline stations. In order to go from CNG station to CNG station and refuel, I had to travel out of the way in some instances.

MCL: Did you have any trouble during the drive – for example, when trying to fill up the Tahoe?

CK: The station equipment varied a little from station to station. For example, some of the new stations were easier to use - at some stops it took a little longer to figure out how to operate the equipment. Another problem we ran into was access at some of the stations. Not all CNG stations are open 24 hours or to the public for that matter, so its important that drivers know the details of each station before they arrive. I called each station several times before the trip to confirm and reconfirm their hours, public access and what forms of payment they accepted.

MCL: What were the main things that y’all learned about using CNG as a transportation fuel?

CK: We had a similar vehicle (same engine and chassis) follow us but run on gasoline so we would have some comparative data. The CNG vehicle saved about 24% on fuel costs, averaging 11 cents per mile in total cost, while the gasoline vehicle averaged 14 cents per mile. I also had an emissions test performed on the vehicle and learned that there was a 25% reduction in CO2 emissions [compared to the gasoline vehicle].

Total trip data:

MCL: If the United States were to move toward a higher number of natural gas vehicles, what big-picture changes would need to be made?

CK: Infrastructure is the biggest challenge. Vehicles need places to refuel. There is an effort underway that focuses on [access to CNG for] heavy-duty (HD) trucks and plans to build out infrastructure to support them. As these stations pop up to support the HD market, the full market will benefit from increased refueling stations.

Texas, for example, recently passed legislation to encourage the heaviest trucks on the state’s major interstate’s to convert to natural gas, and even set up a grant program to help cover the cost of station development. In addition, the NAT GAS Act, currently pending in the US Congress, would offer incentives for both HD and light duty vehicles and help speed up the conversion of vehicles to natural gas.

MCL: Any big barriers currently sitting in front of higher use levels of natural gas for the U.S. transportation fleet?

CK: Infrastructure as mentioned above, but the other major challenge is the incremental cost of NGVs over traditional gasoline or diesel-powered vehicles. The vehicles cost more up front, even though operation costs are lower because of the reduced fuel costs. This is why HD trucks are such an ideal fit – they travel more miles than the average passenger vehicle, and can get a faster payback. As more are ordered we hope to see the incremental cost to come down. The same can be said for the passenger vehicle market.

MCL: Thanks, Castlen.

You can view Castlen’s video from the conclusion of her trip below. In it, she briefly discusses the challenges you face when trying to drive an alternative fuel vehicle across the country.

Photo credit:

  1. “Tracking the Trip” graphic from the Green American Roadtrip blog and used with permission.