Natural gas-powered vehicles, or NGVs, may soon be getting increased fuel storage thanks to help from scientists at the University of California, Berkeley.
Chemists at the U.S. Department of Energy’s Lawrence Berkeley National Laboratory have developed metal-organic frameworks (MOFs) that resemble colored table salt but actually contain “sponge-like 3D crystals with an extraordinary large internal surface area that feature flexible gas-absorbing pores,” according to a recent Berkeley Lab press release.
MOFs have such a high capacity for natural gas storage that an NGV equipped with the high-tech material would provide the same driving range of a conventional auto, according to Berkeley Lab.
“Our flexible MOFs can be used to boost the usable capacity of natural gas in a tank, reduce the heating effects associated with filling an ANG (absorbed natural gas) tank, and reduce the cooling effects upon discharging the gas from the ANG tank,” says Jeffrey Long, a chemist with Berkeley Lab’s Materials Sciences Division and U.C. Berkeley who is leading this research. “This ability to maximize the deliverable capacity of natural gas while also providing internal heat management during adsorption and desorption demonstrates a new concept in the storage of natural gas that provides a possible path forward for ANG applications where none was envisioned before.”
Long told the Wall Street Journal this week that since MOFs reduce the high pressure normally required for natural gas storage, it’s feasible that cars may be fueled up at home using a household compressor attached to a natural gas line.
MOFs are currently extracted from cobalt or iron and combined with other substances. The storage capacity of MOFs is so great, that one gram of the powder provides a surface area that is the equivalent of a football field, Long told the Wall Street Journal.
Berkeley Lab reports that Long and his colleagues are working on making the storage capacity of MOFs even greater, which would help address storage problems associated with hydrogen.
Though the supply of natural gas in the U.S. continues to grow beyond its current reserve
of 360 trillion cubic feet, Berkeley Lab contends that natural gas has not proven to be a popular alternative fuel because of the “cumbersome and expensive on-board gas storage tanks and the cost of dispensing compressed natural gas to vehicles.”
Natural Gas Vehicles for America, a trade organization, states on its website that the greater purchase price currently associated with natural gas vehicles (NGVs) is owed to the increased expense of their high-pressure fuel tanks.
“However, the cost to fill the tank with natural gas is about $2 less per gasoline gallon equivalent,” states NGVA. “The substantial savings on fuel costs, which depend on the fuel efficiency of the vehicle and the number of miles driven, can repay the initial investment in a fraction of the vehicle’s life.”