In the arena of alternative fuels for transportation, natural gas (NG) has proven to be one of the most popular alternatives to traditional liquid fuels in many global markets. NG is an attractive alternative to diesel for medium and heavy-duty vehicles in meeting regulatory standards and an appealing option for reducing operating costs and carbon emissions in many automotive applications.
NG for use as a transportation fuel is available in two forms, compressed gaseous and cryogenically liquefied, with the former being by far the more common.
Despite its lower energy density compared to liquid NG (LNG), compressed NG (CNG) is generally considered the superior option for NGVs that are operating within a limited range where extended driving range is not required. LNG also requires extra processing procedures, driving up overall fuel price.
However, in order for any alternative to gasoline or diesel to be viable as a transportation fuel, a refueling infrastructure must be widely available. The majority of natural gas (NG) refueling options are currently tied to government incentive programs.
Without a critical mass of vehicles in need of fuel, station operators are unwilling to invest in equipment — and without ready access to stations, retail customers do not buy NGVs. Yet, because NG is well-suited to larger vehicles such as refuse trucks and buses, fleet operators frequently take advantage of the low fuel cost by installing private stations.
According to Navigant, the total number of global NGV refueling stations is expected to grow from 23,001 in 2015 to 38,890 in 2025. More than 80 percent of these stations are expected to be CNG stations to support light-duty NGVs.