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I’ve been interested in alternative fuels for a while. I installed a pellet stove to supplement my gas forced air home heating. I installed a gas tankless water heater. I’ve begun installing hydronic radiant heat in my floors.  I’ve done a number of solar and wind power experiments. I’ve also been doing some Brown’s gas experiments. Do I consider myself a tree hugger? A environmentalist? A green-freak? No, not really. I’m interested in environmentalism that’s practical and reasonably convenient or can be made convenient.

I’d planned on converting my Pontiac Fiero to run on LPG, commonly called propane. I purchased all the components, but there were a number of reasons I didn’t follow through with the conversion, time constraints was a big reason, another was convenience and price of fuel. LPG is pretty widely available, but fill locations are usually at a U-Haul, Co-Op or similar because of the need for a specific fill adapter required. The fill setup is the same as for RVs that have permanent mounted onboard tanks. These locations aren’t self-serve like a conventional gas station, which means at each fill, each day, I’d have to pull up to the pump, go in and get the attendant, wait for the attendant to fill my tank, and go in to pay. All combined, not convenient.

While purchasing the equipment and prepping for my LPG conversion, my evil friend Matt planted a seed. What about CNG? This is compressed natural gas. At the time I didn’t think it’d be as easy to convert, as easy to find, or as practical. I was mostly wrong. It’s more convenient where you can find it, most of the pumps are self-serve credit card units available 24/7 so it’s no different than pulling up to a gasoline pump. Big plus. CNG isn’t quite as widespread as LPG, stations have to invest in more expensive pumping equipment and cater to a lower demand. Usually you’ll find CNG available from Natural Gas companies, but there are some regular gas stations that offer CNG. Check here for locations near you, or check here for an interactive station locator where you can post and check your local prices.

The price of CNG is the most attractive part. It generally runs from 1/3 to 1/2 of the price of gasoline. Yeah, I thought that would get your attention. Another major convenience is that you can buy a home refueling appliance like the Fuelmaker Phill, which plumbs into your natural gas supply just like a water heater or furnace and allows you to refuel your vehicle at home for even less cost, and greater convenience, than fueling at a CNG fuel station.

I was right about one thing, it’s not as easy or inexpensive to convert an existing vehicle to CNG as it is to convert to LPG. CNG tanks in particular are more expensive, the LPG tanks operate at a pressure of up to 150psi, CNG tanks operate at a pressure of 3000psi or 3600psi, depending on your system. Obviously CNG tanks need to be quite a bit more robust than an LPG tank, thus more expensive. Depending on your system, the rest of the components may be quite a bit more expensive too. And finally, CNG conversions are more highly regulated, so they’re not very convenient.

Fortunately, due to the Clean Air Act of 1991 which required that all vehicle fleets over a certain size be comprised of 10% alternative fuel vehicles, there is an abundance of factory converted former fleet vehicles, which are generally low mileage and good condition. Most of these vehicles are Dual Fuel, so the CNG fuel system was added to the original gasoline fuel system. This is a good thing, and a bad thing. If you run out of CNG you will fall back on gasoline, but that convenience means the engine isn’t optimized to run most efficiently on CNG, so you will have lower gas mileage than if you had a CNG only vehicle. You also have less mileage on CNG than when using the gasoline side of the system. These factory converted dual-fuel vehicles are selling at a premium now though. Utah residents have the lowest CNG prices in the country right now, at about 64 cents per GGE (gallon of gas equivalent), and they are also enjoying a hefty tax rebate that applies to any alternative fuel vehicle, new or used, put in service that was not previously titled in the state through the end of 2008.

So, after a bunch of research and searching, I finally decided to buy a dual fuel CNG vehicle, a 2001 Chevy Cavalier. You can see it here.