Natural gas truck sales were up 29% year over year in September, but October and November sales were down 9% from the same months in 2021.

The mixed bag results were published by ACT Research in its Alternative Fuels Quarterly report.

“In the near term, results were even more volatile, with September gaining 12% month over month, October dropping 39% compared to the previous month, and November surging 45% sequentially,” said Steve Tam, vice-president at ACT Research. “Quantifying activity, natural gas sales totaled 3,719 units in 2021 (+10% from 2020). Through the first 11 months of 2022, OEMs have sold 3,497 natural gas-powered Class 8 units.”

The number of natural gas filling stations in the U.S. continues to decline.

“There were 751 public compressed natural gas (CNG) stations open in the U.S. in mid-December 2022, the vast majority of which can accommodate a heavy-duty vehicle,” said Tam. “The liquid natural gas (LNG) station count at the same period was 51, with all able to serve Class 8 vehicles. This translates to 71 fewer public CNG station and three fewer public LNG station since mid-September 2022.”

He added: “Given the existing station count’s downward trajectory, it isn’t a surprise that planned CNG stations are also contracting. That said, number of stations is one measure. What we don’t know is the increase or decrease in the amount of fuel being pumped at each station.”