Total sales of natural gas vehicles (NGVs) are expected to reach more than 35 million from 2015 to 2025, according to a report from Navigant Research. 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. 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.