Shares of Clean Energy Fuels Corp. (Nasdaq; CLNE) plummeted in afterhours trading after the Newport Beach company reported a steep sales drop and loss for the third quarter, and a big charge-off related to underperforming and unprofitable stations.

The nation’s largest builder and operator of natural gas stations posted revenue of $81.8 million, down 15.7% from a year ago and missing analyst estimates of $84.2 million. It posted a loss of $74.1 million. Wall Street expected a loss of $19.6 million.

The company reported a loss of $10.9 million in the same quarter a year ago.

Investors seized on the poor quarterly performance and related disclosures, sending shares down 12% to about $2.10 in extended trading. The market value of $360 million is about 50% below year-ago levels.

Clean Energy took a 3Q charge of $73.8 million, which included costs related to closing 42 stations and repositioning its compressor business in an effort to benefit from consolidation in the segment.

The company raised $450 million in 2011 as part of its effort to build “America’s Natural Gas Highway,” a network of natural-gas stations spread out about every 250 miles along major transportation arteries in California, Texas, the Midwest, Southeast and Northeast.

Its network has grown to more than 575 stations nationwide. The closures are a bid to “streamline our operations, facilitate a focus on what we believe are our most profitable opportunities, and improve our overall financial performance,” Chief Executive Andrew Littlefair said in a released statement.

The company delivered 91.5 million gallons of liquefied and compressed natural gas in the third quarter, up from 84.5 million gallons in the same period last year.

Legendary oilman and corporate raider T. Boone Pickens co-founded Clean Energy more than 25 years ago as a small part of his Dallas-based Mesa Petroleum. He split it off in the late 1990s.