Do you remember in the “Back to the Future” movies how Doc Brown rigged the DeLorean to use garbage as a vehicle fuel? Engineers in Missouri think we could be doing that soon — with some extra steps added so the garbage doesn’t go directly into the vehicle.

Researchers at the Missouri University of Science and Technology say biowaste like food scraps and manure could be converted into renewable natural gas to fuel vehicles. The proposed process also could use renewable hydrogen from surplus electricity generated by solar or wind sources.

The challenges

The lead researcher says there is abundant biogas production from organic waste in both urban and rural areas across the country. However, few facilities convert that biogas into vehicle-grade fuel because of the costs of in-house production technologies and creating an RNG pipeline. They estimate a pipeline buildout costs about $1 million per mile.

“It costs too much for smaller operators to clean biogas to pipeline standards, including separation of CO2,” Fateme Rezaei, associate professor of chemical and biochemical engineering at Missouri S&T, said in a news release. “They offer lower-grade RNG for heating and electricity production, but conventional natural gas vehicles run on pipeline-grade natural gas or compressed natural gas. Compressing RNG to fueling station pressure is too expensive for small biogas operators.”

The solutions

The team is developing on-vehicle technology to overcome these challenges. It would provide low-pressure fuel storage and gas separation in the same tank. 

• The fuel conversion and storage would take place in a tank on the vehicle itself. That eliminates the need to process fuel at a stationary facility and to create a pipeline to transport the fuel.
• A material in the tank would separate methane from carbon dioxide and isolate the CO2 so it can be returned to a fueling station as a commodity. 
• The driver would be able to choose between running the vehicle on renewable natural gas or a blend of RNG and the hydrogen stored in the tank.

The technology could benefit cities by providing a valuable way to manage their tons of food waste. It could also help farmers and others in rural areas, Rezaei said. “Biowaste is plentiful in those areas, and this technology would reduce the barriers to fueling vehicles with natural gas.”