Compressed natural gas, or CNG, has been marketed by some within the fossil fuel industry as a greener alternative to gasoline, but studies show that it’s really just the lesser of two evils. A new study has found that the best use of CNG is to provide a stationary electricity supply for electric vehicles.
Green Car Congress reports that the well-to-wheels study, published in the science journal Energy, came to the conclusion because CNG requires requires a lot of processing for use in automobiles. Another factor is energy efficiency; stationary powerplants use massive turbines to generate electricity with up to a 50% thermal efficiency, about twice the efficiency of small car combustion engines. The Honda Civic CNG gets about 30 MPGe on the equivalent among of natural gas to gasoline, but the Nissan LEAF is rated at 99 MPGe, more than three times as efficient.
Of course there are a number of determining factors that can shift favor with CNG, including the potential application of CNG in conjunction with a hybrid or plug-in drivetrain. As a whole though, EVs powered by CNG end up with a 22% to 35% well-to-pump energy efficiency. In comparison, CNG-powered cars return as little as 11% and up to 22%, meaning at its best, CNG is only as efficient as the worst EVs.
Yet CNG can’t be dismissed entirely as a transition fuel, especially for larger trucks that need to be able travel hundreds of miles while hauling literal tons of cargo. CNG is a cleaner alternative to traditional diesel fuel, especially in the trucking industry, which until recently was allowed to operate while adhering to the thinnest thread of emissions requirements. The government and truck makers have finally gotten real about cleaning up the industry though, and lots of private companies including Anheuser-Busch and Bimbo Bakeries
But your average daily commuter? Electric vehicles are better almost any way you look at it.