NGV Industry Calling for Adoption of Diesel Gallon Equivalent

By Kasia McBride, Marketing Manager, NGVi 


ore and more heavy-duty vehicle fleets are making the transition from diesel to natural gas. Because of this, it is imperative that natural gas is sold in a way that allows retailers and heavy-duty vehicle operators to easily compare it to diesel.

In January 2014, NGVAmerica distributed a “Call to Action” to natural gas companies, fuel retailers, state advocates, fleets and the trucking industry, asking them to support adoption of a national diesel gallon equivalent (DGE) unit as a standard for compressed natural gas (CNG) and liquefied natural gas (LNG).

The new standard would serve as a measuring method for presenting the relative cost of natural gas compared to diesel. This would provide retailers with a convenient way to highlight the economic benefits of natural gas, and allow users to clearly understand the savings associated with the fuel. Creation of a DGE standard would complement ongoing efforts to base the fuel taxes on CNG and LNG energy equivalents, which are themselves derived from diesel energy content. Allowing easy comparison with diesel fuel would not only improve accounting for trucking fleets and fueling station owners, but also help facilitate increased natural gas use for the trucking industry.

The current standard for measurement of both CNG and LNG, adopted in 1994 at the National Conference of Weights and Measures (NCWM), is a gasoline gallon equivalent (GGE).

The NCWM Natural Gas Vehicle Steering Committee is currently reviewing the DGE standard adoption issue. The committee is developing a proposal which will be available for voting later this summer at their annual meeting.

Under this proposal, the DGE standard would change the way CNG and LNG are priced and dispensed at the pump. Since LNG is exclusively used by heavy-duty vehicles, it would only be sold in DGE units. However, CNG would be sold in both GGE and DGE units, depending on whether it is sold at public retail stations, truck stops or other outlets serving heavy-duty vehicles.

According to NGVAmerica, there is a lack of consensus among NCWM members on moving this issue forward. As a matter of fact, several state officials do not support adoption of a DGE unit or the continued use of the GGE unit as the primary methods of selling natural gas. Despite strong industry opposition, these officials propose to require that natural gas be sold in kilograms. It would be the only transportation fuel in America sold in metric units. The proposers advocate that the metric system would apply eventually to all fuels, but currently the only fuel under consideration is natural gas.

Converting the sale of natural gas to kilograms has many drawbacks. “The proposal is not only discriminatory but will put natural gas at a significant disadvantage to other fuels by creating confusion for consumers who are not used to purchasing motor fuel in mass units let alone kilograms. This standard will increase the cost of new pumps and it will impose costly retrofit of existing pumps,” adds NGVAmerica.  

For more information, or to voice your opinion, contact your state’s weights and measures official(s) by going to, or reach out directly to the weights and measures NGV Steering Committee at

To read the full version of NGVAmerica’s “Call to Action” letter regarding NCWM DGE Standard, click here.

← Back to Blog