One factor that not many folks talk about or just completely ignore when it comes to these unique and energy efficent/environmental friendly fuels system - CNG, electric passenger cars, even ammonia based zero emission powered machines etc. etc. is the residual value of the lift ruck, machine, automobile, at the end of it's economic life and the retail price in the second hand market.
Things that help destroy the value for example is that the CNG powered machine that tank has a an expiration date & will need to be replacing (10 years I believe by Fed. law), the fuel system takes unique training to work on, or for added cost it can be converted back to LPG for a gost. The used truck buyer is very unlikely have a refill system handy. Passenger cars/truck/SUVs - hybrids or electric - you pay more for them to start with - those batteries will need replacing some time down the road - and they ain't cheap - I'm certain some one will come along and market another "snake oil" product that will rejuvenate those batteries too of course at a fraction of the cost of a new battery. To me an all electric car is just a toy to show around town 'cause you ain't going to take a trip to Yellow Stone National Park from say Chicago or Bismark, North Dakota in it or take a trip out to West Texas from Forth Worth, TX to watch the mesquite bushes grow on ground dryer than a rock and hope you don't get caught in a dust storm but if you do you might see a tumbleweed blow around. In a nut shell they just ain't practical for the everyday Joe or Joanne plus not very affordable for them either. Heck a good Soccer Mom can burn thru one battery charge in a day and the recharge stations just ain't every where. have a neighbor that has a BMW electric - she says it is a "fun" car- range 200 miles, charge time 7 hours - price tag $44K (USD) for a fun car - my second house only cost $40K on a 1/2 acre lot in 1974. Last week recently had to go to Atlanta to a hospital - 50 miles away - our son had a kidney transplant - all is good so far. Had to make two round trips in one day or 200 miles. Glad I had a fossil fueled Chevy Impala. Don't think that BMW would it have made it the full 200 mph with all the stop and go traffic. My last trip took only 2.5 hours (one way - rush hour). Should take 59 minutes one way per Mapquest - Ha!