For an undergraduate, Josh Tibbitts faced an unusual problem last winter: where to find a source of high-pressure natural gas for a new research lab. We’re not talking about double or triple the pressure that produces the blue flame in your furnace or a kitchen stove — typically less than one-quarter of a pound per square inch (PSI). Tibbitts needed to find a supply at 2,000 PSI.
The senior in the Energy Systems Engineering program at OSU-Cascades in Bend talked with utilities and gas suppliers, but despite some efforts to help, he came up empty-handed. “We got a lot of blank stares,” he says. “Or like they’re thinking, ‘Are you out of your mind? What do you need this for?’ They just thought we were crazy.”
It wasn’t the first time Tibbitts had pushed into new terrain. A native of Utah, he moved to Ashland in 2000 where he worked as a building contractor and cabinetmaker. After the recession hit, orders dried up, so he folded his business and enrolled at OSU-Cascades. His timing, it turned out, was perfect. With a $700,000 grant from the U.S. Department of Energy (DOE), Chris Hagen, assistant professor in Energy Systems Engineering, had just begun building a lab to develop a way for people to pump natural gas into cars and trucks at home. He needed students with skills to move the project along.
Now Tibbitts works as a project manager for Hagen. “I couldn’t have been in a better place at a better time,” Tibbitts says.
The CNG Promise
Hagen’s lab could be at the forefront of a change in our driving habits. The United States has a plentiful supply of natural gas, partly based on the controversial practice known as fracking. Running our vehicles on methane, its primary component, could reduce our dependence on foreign energy sources. A methane fill-up can also help address the threat of global warming. On an energy-equivalent basis, natural gas produces five percent to nine percent fewer greenhouse gas emissions than does gasoline. DOE’s research program known as MOVE, Methane Opportunities for Vehicular Energy, aims to increase the use of natural gas in transportation.
So, Hagen has subcontracted with researchers at Colorado State University and worked with Czero, an engineering company in Fort Collins, Colorado, to develop a method for compressing and storing natural gas in a vehicle. But there’s a problem: This fuel takes up a lot of space. In fact, it takes 127 cubic feet of natural gas, about the size of a coat closet, to equal the energy content of one gallon of gasoline. Imagine filling up your car with the methane equivalent of 10 gallons of gasoline. You’d need a tank the size of a small bedroom.
To give natural gas vehicles a range comparable to those that run on gasoline, the OSU-Cascades researchers are developing a system that will pump a lot of methane into a reinforced gas tank. Their goal is to compress natural gas to nearly 3,600 PSI. Moreover, they plan to run the vehicle’s engine as a compressor, so drivers can refuel quickly at home.
And that takes us back to Tibbitts’ search for a source of high-pressure natural gas. The researchers need a steady, high-volume supply to do experiments. Just breaking in a custom-built test engine will take about 40 hours of continuous operation. “You run (the engine) at low rpm consistently,” says Tibbitts, “so the seals really seal before you start working it hard. That’s an industry standard. To run the engine for 40 hours straight, we need quite a bit of gas.”
After breaking in the engine, they will test it in what they call “fill mode.” One of the engine’s cylinders has been modified to act as a compressor — pumping natural gas into a storage tank — while the remaining cylinders would power the process. Researchers aim for their system to complete a fill-up in under two hours.
After exhausting sources of natural gas in Central Oregon, Tibbitts was able to strike a deal with Airgas, a national supplier of industrial gases. The company will make regular deliveries of five-foot high cylinders of compressed methane.
A Framework for Experiments
That wasn’t the only job on Tibbitts’ plate. He also coordinated teams of electricians, plumbers, welders and other technicians to construct the heart of the lab’s testing facility: a massive steel frame that holds test engines and a 1,400-pound electric motor. Other components include computers to collect and store data and, for the safety of people working in the lab, a half-inch-thick bulletproof Lexan shield to separate the pressurized engines from the workspace.
Regular visits from DOE officials kept the pressure on the research team as well. “It was a lot needing to come together at once,” Tibbitts says. “There have been times when it got stressful.”
Hagen praises Tibbitt’s contribution to the project. “Josh really takes to the task and gets the job done,” says Hagen. “He takes charge and comes to me only if he has questions.”
For Tibbitts, compressed natural gas is part of a holistic approach to energy. “A lot of people want to subscribe to all renewables,” he says, “but the truth is that there is no one way. It will take a variety of approaches. Natural gas has benefits for energy independence and provides an economic boost at home. It’s something that has to be explored.”
Tibbitts plans to graduate in March after completing a capstone project on thermal energy storage for Hydro Flask, a Bend startup company that makes stainless steel, vacuum-insulated water bottles.
