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By Robert Rapier on Jul 21, 2009 with 4 responses

Behind the Costs of CNG Conversions

Tags: CNG, natural gas

In my recent post – How Much Natural Gas to Replace Gasoline? – I mentioned that it is quite expensive to convert a gasoline-powered vehicle to natural gas. If you drive a tremendous number of miles each year – as many fleets do – the conversion will pay for itself relatively quickly. For most of us, the savings wouldn’t be enough to justify the conversion.

Today I received an e-mail from Marc J. Rauch, Exec. Vice President/Co-Publisher of The Auto Channel, who shed a bit more light on why the conversion is so expensive. I found this information quite useful, and I received his permission to post his e-mail, seen below.


Hi Robert -

Thanks for the work you did on figuring out how much natural gas we actually seem to have (according to current knowledge) and for the related cost comparisons. It’s a great and value tool for those of us that believe in CNG (and propane) as a viable engine fuel alternative.

One thing that I would like to add (assuming that you didn’t already know this or learn it since posting your piece), is that the cost of CNG conversions for existing vehicles is as high as it is because of EPA licensing requirements. For an individual (or shop) to be licensed to do a conversion, the person must pay $10,000 per year, per engine type, per year of manufacture. So that if a conversion shop wanted to do conversions in 2009 for Camrys for the years 1995 to 2005, the shop owner would have to pay the government $100,000 in licensing fees. Then, if he wanted to do conversions on the same models in 2010, he would have to pay the $100,000 again, even though they are the exact same models and engines that he has been licensed on already. And if there is more than one engine involved, i.e., a 6-cylinder and 8-cylinder, the cost would double.

Therefore, if a shop owner wanted to do 10 model years of Camrys and Corollas and Celicas, and well as Honda Accords and Civics, unless there were common engines being used in these five models the licensing cost (for just one engine per) would be a half million dollars, which would have to be paid again in 2010. These fees are, needless to say, ridiculous and are only there to ensure that many don’t get done (thanks to the gasoline lobby). The cost of the conversion kits are actually relatively inexpensive. If there was a sensible licensing fee (or no fee) the cost for the work could be just a few hundred dollars.

To be fair, there is a second part of the cost equation that has to be addressed: trained CNG conversion mechanics. An argument is typically made by those that want to make argument against CNG that there aren’t enough trained mechanics. This is somewhat true, but of course there really is no shortage of new and old mechanics that would be willing to learn. So the issue is where can they be trained? The University of West Virginia has a great automotive program that they’ve “syndicated” to other colleges around the country. In California, two schools (Rio Hondo in So. CA and Yuba College in No. CA) teach the UWV curriculum. They can and do teach CNG conversions.

I hope the above wasn’t too redundant for you. If you have other information or newer information I would love to hear of it.


Marc J. Rauch
Exec. Vice President/Co-Publisher

  1. By VINCE SCHIFANO on March 8, 2012 at 3:42 pm


    • By Sonny Red on September 10, 2012 at 3:47 pm


      answer: Nothing. See oil price. More money in refining crude to gas than well head Nat gas to cng


      thanks Big Oil Lobby


    • By John Galt on September 19, 2012 at 8:08 am

      This has been changed.  See the EPA ruling:


  2. By Ramrod on August 28, 2013 at 11:54 pm

    My friend just completed a CNG course on installation of the CNG kit on vehicles. He said the highest priced part is the CNG Tank because it has to be tested to withstand such high pressure. He had to buy a license from the state that cost $ 150.00 after taking and passing a state’s test. CNG is a very cheap commodity and can be burned in a vehicle straight out of the ground after it is compressed. No need for a refinery only a compressor with a filter element. That is why you can buy a home compressor and fill up your CNG vehicle from the natural gas line running into your house. The state and federal government will give you a tax incentive to convert your vehicle to CNG not a rebate as some people assume.
    The fiber wrapped tank is expensive but it is light weight. A steel tank would have to be very thick and very heavy to withstand the pressure you need to have CNG in a vehicle most cars and trucks suspension couldn’t support the weight of a steel tank. You can order a complete CNG Kit for around $ 6000.00 That is about as cheap as you can go for kits.
    I never heard anything about the federal government assessing the $ 10,000.00 fee on the mechanic/installer for installing the kit on every engine. That would make the cost at $ 22,000 per vehicle if that was true. Someone got the wrong information on the assessment fee. You can buy a brand new Pickup truck with CNG installed for $ 10,000 more than a gas powered pickup of equal options. In Oklahoma the price of CNG at some stations is as cheap a $ 1.25 per gallon vs. $ 3.45 for gasoline.
    You would have to buy a annual stamp and have it placed on the vehicle to show you are burning CNG because of the state and federal highway tax just like on a vehicle converted to propane. These tax stamps use to cost me $ 50.00 annually for the stamp for my propane powered truck.

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