2011 Volkswagen Jetta SportWagen TDI
Fuel economy: 34 mpg (7-8 mpg better than the gas engine)
Annual fuel cost: $1,394
Annual CO2 emission: 6.2 tons
The most fuel-efficient station wagon on the market in 2011 is the Volkswagen Jetta SportWagen, and while the clean diesel TDI costs about $5,000 more than the base gas engine model, it gets significantly better fuel economy.