It’s fairly obvious why densely populated states would be interested, especially since natural gas is a readily available source of heating fuel for many parts of the country. Most importantly, the Civic is the Eagle Scout of emissions certifications: it qualified for the California Air Resources Board’s Advanced Technology Partial Zero-Emission Vehicle (AT-PZEV) status, which means that it’s a Super-Ultra-Low-Emission Vehicle (SULEV) with zero-evaporative emissions. To qualify for AT-PZEV, the Civic must also carry a 15-year/150,000-mile warranty on emissions equipment. It also meets EPA’s strict Tier-2, Bin-2 and ILEV certification.

Despite getting the equivalent of a good but not quite amazing 36 MPG highway/24 MPG city, the American Council for an Energy-Efficient Economy (ACEEE) awarded the Civic the green ribbon as the greenest vehicle of 2008. That’s the fifth consecutive year it’s taken the top prize.

So what’s the downside?

Drawbacks to the Civic GX and other Compressed Natural Gas Vehicles

Earlier this week I was clued-in to the explosion in popularity of compressed natural gas (CNG) vehicles in Southern Utah, and their potential to overwhelm the 91 refueling stations already in place there.

That’s the biggest drawback to NGVs:

One way to get around this is to buy your own natural gas refueling station. Since a large number of us burn natural gas for heat, this doesn’t require much more than setting up a pump. The refueling kits, made by FuelMaker, will set you back about $3,500, but that can be offset by substantial tax credits.

  • Second drawback: since natural gas is a compressed fuel, the tank takes up some trunk space, and only holds the equivalent of 8 gallons of gasoline. Honda estimates the vehicle’s range to be 220 to 250 miles, although Consumer Reports claimed it was closer to 180 miles.

NGV enthusiasts are getting around range limitations (and vehicle scarcity) by converting their own vehicles to run on natural gas and adding spare tank capacity. Throwing extra tanks in the bed of a truck, for example, can boost driving range to around 600 miles. The best part about converting a vehicle (as opposed to the Civic GX) is that if you run out of CNG, the system automatically switches back to gasoline.

  • Third drawback: NGVs don’t provide that great of a reduction in greenhouse-gas (GHG) emissions when compared to their gasoline counterparts.

According to the industry group Natural Gas Vehicles for America (NGVA), the reduction is only 20%, which is about the same GHG reduction you get from corn-based ethanol. That doesn’t sound too impressive, but it’s still a reduction, and clean air could be worth it.

The big question mark is natural gas supply. If large amounts of biomethane can be produced from biomass (which is probably already done at your local landfill), the emissions reductions would be much greater.

What about Natural Gas Supply? See Page 3: