What Is CNG?

The answers to all your questions!

Why should I care about compressed natural gas?

 What is CNG?

You keep hearing about natural gas and CNG, but what is CNG and why should you care about using CNG instead of gasoline or diesel fuel for transportation in America today?  In the clip below, from CNGnow, you will hear a few of the environmental, economic, and geopolitical benefits of making the switch to compressed natural gas.

Why use natural gas?

Environmentally Clean

  • Compressed natural gas is the cleanest burning fuel available today.
  • CNG vehicles produce the fewest emissions of all vehicle fuel types.
  • CNG vehicles emissions contain significantly less pollutants than gasoline.
  • Natural gas vehicles give off little or no emissions during fueling.

Maintenance Advantages

  • Intervals between tune-ups for natural gas vehicles can be extended by up to 50,000 miles.
  • Intervals between oil changes can be extended by up to 20,000 miles.
  • Pipes and mufflers last longer in natural gas vehicles because the CNG does not react with the metals.

Cost Advantage

  • Natural gas is less expensive per equivalent gallon than gasoline. In Minnesota, on average, natural gas is ½ the price of gasoline.

Performance Advantages

  • Natural gas gives the same mileage as gasoline and in some cases mileage can be increased up to 20%.
  • CNG running engines are superior in performance to gasoline engines because CNG has an octane rating of 130.
  • Because CNG is already in a gaseous state, natural gas vehicles (NGV) have superior starting and driveability even under severe hot and cold weather conditions.
  • NGVs (Natural Gas Vehicles) experience less knocking and no vapor locking.

The Safety Advantage

  • The fuel storage tanks on NGV’s are thicker than on gasoline or diesel vehicles.
  • NGVs are as safe or safer than those powered by other fuels. An American Gas Association (AGA) survey of more than 8,000 vehicles found that with more than 278 million miles traveled, NGV injury rates per vehicle mile traveled were 34% lower than the rate for gasoline vehicles. There were no fatalities reported–even though these vehicles were involved in over 1,800 collisions.

CNG 101

Answers to 10 introductory questions about natural gas as a transportation fuel.

1. What is Natural Gas?

Natural gas primarily consists of methane (around 90%), with small amounts of ethane, propane, and other gases. Methane is a simple gas molecule made up of one atom of carbon and four of hydrogen (CH4). It is lighter than air and burns almost completely with by-products of combustion being carbon dioxide and water.

3. How do you use natural gas as a transportation fuel?

Compressed Natural Gas or CNG is the most common form of natural gas used in vehicles. Natural gas is stored in the vehicles by being compressed to 3600 psi.

5. What kinds of vehicles can use natural gas?

Natural gas vehicles are available in all classes of gasoline and diesel vehicles.

7. How do you fuel a natural gas vehicle?

It is similar to the way you fuel any car or truck. The dispenser looks about the same, but the nozzle is different. We can easily educate you on how to fill a CNG vehicle. Because natural gas is under pressure, the storage systems must be designed so that no fuel escapes when the vehicle is being fueled. Natural gas nozzles lock onto the receptacles and form a leak-free seal similar to the coupling on an air compressor nozzle. The receptacles are designed so that when the nozzle is removed the gas is prevented from escaping.

9. How long does it take to fill a natural gas vehicle?
  • There are basically two types of fueling equipment for CNG vehicles: fast-fill and time-fill. In fast-fill, the combination of a large compressor coupled with a high-pressure storage tank system, called a cascade, fills the tank in about the same amount of time it takes to fuel a comparable gasoline or diesel vehicle.
  • A time-fill system does not have a storage system and has a much smaller, and less expensive compressor. It typically refuels CNG vehicles overnight at a rate of about one gallon per hour. Time-fill works for vehicles that remain idle overnight such as refuse trucks and school buses.
  • There are also home refueling options for individuals that own a CNG powered vehicle and are looking for the convenience of being able to fuel at home. The units connect to a residential gas line and typically hang on a garage wall. These systems can fuel a single vehicle at the rate of slightly more than one gallon per hour.
2. Why use natural gas as a fuel?
  • Engine, urban, and greenhouse gas emissions are inherently lower than gasoline or diesel engines emissions.
  • Natural gas decreases our reliance on foreign fuel sources (more 98% of the natural gas used in the United States comes from North America)
  • Natural gas costs less per energy unit than gasoline or diesel.


4. Who provides the natural gas?

The local utility provides the natural gas.  It is piped to the location where the gas will be compressed before being dispensed into the vehicles.

6. Are your CNG conversions dedicated or bi-fuel vehicles?

We provide vehicles that are bi-fuel.  This means they can run on either gasoline/diesel or natural gas.

8.How is the fuel stored in the vehicle?
  • Most NGVs operate on compressed natural gas so the fuel takes up less space. CNG is stored on board vehicles under high-pressure (3,600+ pounds per square inch) in tube-shaped cylinders that are attached to the rear, top, or undercarriage of the vehicle. The cylinders meet very rigorous safety standards. They are made of high-strength materials designed to withstand impact, puncture and, in the case of fire, their pressure relief devices (PRDs) provide a controlled venting of the gas rather than letting the pressure build up in the tank.
  • Natural gas may also be stored on-board in the form of liquefied natural gas or LNG. To become LNG, natural gas must be cooled to –260 degrees Fahrenheit. The biggest advantage of LNG over CNG is space requirements. LNG requires only 30 percent of the space of CNG to store the same amount of energy. In order to keep the LNG cold, LNG is stored on-board vehicles in thermal storage tanks.
10. Are natural gas vehicles safe?

Absolutely! Compressed natural gas is stored on-board vehicles in tanks that meet the most stringent safety standards in the world. Some of the tests that these tanks must pass are the drop test, the bonfire test, and gunshot test.

Visual Learning Lab

Explore the latest information on Compressed Natural Gas (CNG) with several videos we have collected from around the web.

Driving change with natural gas.

Concerned about U.S. dependence on foreign energy?  What if we could make a change and start now?  Communities across our nation and leading U.S. companies are driving change with American natural gas.

Whats under the hood of a CNG vehicle?

Natural gas vehicles have horsepower, acceleration, and carrying capacity similar to that of their diesel and gasoline counterparts, but there are big differences as well. In part four of our CNG Now! education series, we show you how CNG tanks can actually be safer than those used in gasoline-powered vehicles and how dedicated NGVs and bi-fuel vehicles can have a lower rate of maintenance and cost less to repair. *Since this video was created, CNG Bi-Fuel Conversions in some cases now cause vehicles to gain better mileage & power compared to regular gasoline vehicles. Plus, we no long re-program the factory computer.  We install a stand alone computer that works along side of your vehicles computer.

Natural Gas: Versatile Energy
  • Most people know natural gas can be used for stove top cooking and grills. However, many don’t realize just how versatile this abundant, domestic resource really is. The same energy source you use to grill your steaks is also used to generate electricity and is increasingly being used to power vehicles, including fleets of taxis, city buses, and even heavy duty garbage trucks.
  • Utility companies are more often choosing natural gas for a number of economic and environmental reasons. When used for electric power generation, natural gas emits half the carbon of coal. It has virtually no emissions of other pollutants such as mercury or sulfur dioxide that impact air quality in our local communities.
  • We are seeing natural gas being used more and more to power vehicles as well. It’s far cleaner than traditional fuel options and supplies enough power to fuel even the heaviest vehicles on the road. It is also more affordable and produces less wear and tear on engines thus reducing maintenance costs.
  • That’s not the only good news. Consider that natural gas is found in abundance in North America. In fact, the Unites States is now seen as having more natural gas than Saudi Arabia has oil. Producing and utilizing this valuable natural resource would mean more environmental benefits, more domestic jobs, and less reliance on foreign energy. The best part is that this resource is ready now!
  • Hear about more of the applications and positive benefits of natural gas in this segment of Nat Gas Now.

Market Development For Natural Gas Vehicles

With lower fuel cost and less emissions, many automakers and fleets are turning to compressed natural gas (CNG) as a vehicle fuel. Even though the fuel has been used in this capacity for decades, increasing prices of gasoline and growing concern for the environment has reignited interest. In this video we talk with Kathryn Clay, the executive director of the Drive Natural Gas Initiative, and Stephe Yborra, the director of market development at NGV America, about the growth, development, and future of CNG in America.

The safety of compressed natural gas.

Compressed natural gas (CNG) is a clean, affordable fuel that has been used in vehicles for decades. With its popularity surging among fleet owners and consumers, more people want to know about the safety aspects of CNG. In this video Stephe Yborra from NGV America navigates through the safety and realities of driving a natural gas vehicle.

Technology of compressed natural gas.

The technology behind compressed natural gas (CNG) as a vehicle fuel is easy to implement. Along with the economical and environmental benefits new innovations are increasing public interest in the fuel.

Natural Gas: Clean Transportation
  • Americans have always been driven, especially when it comes to taking to the open road. Every day Americans drive or ride 250 million cars, buses and trucks – and those vehicles use a lot of fuel. In fact, our nation imports more than 10 million barrels of foreign oil a day. It’s used, in no small part, for transportation. Some of this oil comes from countries with interests that run counter to our own. This makes a compelling case for each of us doing our part to advance greater U.S. energy independence.
  • How do we drive this change? A key part of the answer is cleaner vehicles that use domestic fuel, including abundant American natural gas. With 98% of the natural gas used in North America found in North America, it makes sense to use this domestic energy to power more of our nation’s transportation needs. Natural gas can make an especially significant difference among large transportation fleets that operate some of the busiest and heaviest vehicles on our roads today.
  • When used for transportation, natural gas is 25% cleaner and 40% cheaper than gasoline or diesel. It also reduces smog-producing particulates by up to 90%.
  • Now, natural gas filling stations are popping up all over the country as more cities and leading U.S. companies embrace natural gas vehicles. A cleaner environment, growing energy independence, and less money spent at the pump….natural gas is a smart choice to help our nation go the distance for a cleaner and more secure energy future. It’s just one more reason it’s time for natural gas now!

Frequently Asked Questions

If you have questions, we have the answers!  Select your question below to view the answer.

What does CNG stand for?

CNG stands for Compressed Natural Gas. CNG is a fuel alternative to gasoline or diesel fuel.  The United States has large reserves of natural gas and these reserves are the reason CNG vehicles are growing quickly.  CNG is low cost and the source of the fuel is not subject to politics elsewhere in the world.

Will a CNG conversion void my warranty?
There’s a reason this is #1 on our FAQs page; we get this question all the time. Many dealerships/salemen and shops like to tell/intimidate people that CNG conversions will void your warranty. This is a bold and broad statement, since performing warranty work on a blown headlight has absolutely nothing to do with the aftermarket installation of a bi-fuel CNG system.
Here are the facts: Drivers are protected by something called the “Magnuson-Moss Warranty Act of 1975″. This says a manufacturer cannot void the warranty just because of your aftermarket parts. If your transmission fails under warranty and you have a CNG conversion, then your transmission is still under warranty. This act goes on to clarify that the burden of proof is with the manufacturer or dealer if there is any argument over what caused the failure. Example: Your engine throws a rod under warranty and you have a bi-fuel CNG conversion kit. Well, if the CNG system was not properly installed by a licensed installer, then maybe the dealer has a legitimate argument… however the burden is on the dealer to PROVE that the CNG kit (whether installed properly or not) was the direct cause of the engine failure.
The reality is that when properly installed by our trained technicians your sequential CNG conversion will not void your warranty. Even an extensive search on the internet will not find any legitimate cases where a CNG car conversion has resulted in engine failure or warranty issues. Lots of people like to talk about it, but the fact is CNG conversions are widely accepted around the world as aftermarket parts and modifications. As long as you have a professional and qualified installer then you will be all good.
Get warranty help straight from the government.
What are some advantages to converting my vehicle to CNG?

In Minnesota, CNG is less than ½ the cost of gasoline, result is saving 50% of the current gasoline budget.  In addition to saving money, CNG is a natural resource the United States has.  Using CNG helps to minimizing our dependency on foreign oil.  Burning CNG is also good for the environment.  It is fourteen times cleaner than gasoline. Maintenance and oil changes are also extended 4-5 times due to the cleaner operation of a vehicle powered by CNG.

Will using CNG be harmful to my engine?

No, the opposite is the case. The usage of CNG can extend the life of the engine. This is due to the clean combustion of CNG and the fact that no carbon is generated during combustion. The engine components and oil are not subject to the contamination produced by using gasoline or diesel as fuel.

What is the life expectancy of the CNG components?

With our conversion system properly installed by one of our certified installers and properly maintained, it should outlast most vehicles. The tanks however do have a 20 year life span.

Can I switch back to gasoline while I am driving?

Yes, with our conversion you have an LED fuel gauge with a touch on – touch off switch conveniently located on the instrument panel. This can be done at any time during operation; however most times it is not used. The reason being all CNG-gasoline switching is done automatically and seamlessly by the CNG computer. All the driver has to do is drive and enjoy the savings. Your vehicle can switch from CNG to gasoline while driving 70 mph and you will never know unless you see the gauge light change colors.

Will mileage or performance be affected?

Natural Gas is rated at 130 octane and gasoline is rated at 85-90 octane. With our conversion technology allowing precise distribution giving each cylinder the same amount of energy in Natural Gas as gasoline, the performance will remain the same at 5% (+/-). Most drivers can expect up to a 20% increase in fuel mileage with the higher quality CNG providing more saving.

I don't live near Minneapolis. Can you install at my location, or can I just by the components?
To have a vehicle converted to run on CNG it needs to be brought to our shop in Minneapolis.  If you have a fleet of vehicles, we do have a mobile installation team that can come to your location.  Pricing may vary depending on location and vehicle quantity.  If you live away from Minneapolis, we can arrange for you to get a discounted hotel & rental car rate while we convert your vehicle.  Depending on the vehicle, it usually takes 2-3 days for us to do a full install and test of the system.
WE CANNOT SELL CNG SYSTEMS OR COMPONENTS TO NON-LICENSED INDIVIDUALS.  If you are not a licensed & insured Alternative Fuel Technician, by law, we cannot sell you any CNG components.  It doesn’t matter what state or country you live in. It is illegal for any individual who is not licensed by the state to be in possession of a CNG system.  If a system is not installed by a licensed installer, your vehicle warranty can be voided and your vehicle impounded by the state.
Most Importantly: Is CNG Safe?
Yes, CNG is stored in a cylinder comprised of steel and or very strong polymers, in fact they are literally bullet proof, and are mounted to withstand an 80 mph crash and 8G force in all directions. Gasoline tanks are formed out of a very thin sheet metal and are much more subject to leaks. Natural Gas is lighter than air and rises if a leak occurs; gasoline however pools on the ground and is more subject to ignition. Most all home and business heating and cooking appliances utilize Natural Gas because of safety, dependability, and cost effectiveness. Natural Gas is the safest, cheapest, cleanest burning, and most abundant fuel available in the market today. In some countries, over 50% of vehicles use Natural Gas as transportation fuel and have dramatically reduced their dependency on foreign oil!
Can you convert my vehicle to CNG?

With our HYBRID conversion technology almost any 4, 5, 6, 8 or 10 cylinder gasoline vehicle, domestic or foreign, car, van, SUV, or truck can be successfully equipped for the operation of HYBRID BI-FUEL (CNG or gasoline) regardless of mileage. SUGGESTION:  Don’t settle for a vehicle you don’t like. The conversion can be done on the vehicle you prefer to drive and the benefits and cost savings will be the same.

Can the CNG system be removed/transferred to another vehicle?

Yes, our system can be removed at any time without affecting the gasoline system. Usually the only time this would be done is when the vehicle owner wants to sell the vehicle and feels he/she could not recover the conversion cost with the sale.  In other cases the owner chooses to reinstall the system on a new vehicle. Our conversion is a totally standalone system, meaning it is separate and does not use nor require any portion of the original vehicle components.  We utilize a fully programmable ECM (on-board computer) and this technology allows programming for any 4, 68 or 10 cylinder engine.

Are there vehicles that cannot be converted to CNG?

Yes, there are a small number of vehicles that cannot currently be converted to CNG.  The list below is NOT all inclusive; we add to the list as we discover non-CNG compatible vehicles.

- Ford EcoBoost vehicles

- Chevy EcoTec vehicles (2014-present)

- Chevy/GMC Direct Injection Engines

The list of vehicles that can be converted to CNG far out weighs the number of vehicles that cannot be converted.

How much is it to fill up my CNG tank?

CNG is almost always significantly cheaper than gasoline.  If you look at our CNG station map, you will find that prices can range from as little a $1.00 to $2.00 per gallon. Natural gas prices fluctuate, but are always cheaper than gasoline.

Will my vehicle experience any negative effects?

Not if the installation is completed, inspected, and maintained by our certified installers and inspectors; there is no need for concern.  Our system manufacturer has been in business for more than 65 years in 17 countries with conversions of thousands of vehicles.  The CNG system is specifically designed for U.S. vehicles.

Do you have to remove my vehicle's gasoline tank?

No, the CNG system uses its own storage tank; usually mounted in the cargo area or underneath the vehicle, depending on available space and driver-owner preference.

Can I fill my CNG vehicle at home?

Yes. Homeowners with an existing natural gas supply line may be able to purchase a home refueling system designed to fill their vehicle. Gas from the same supply line that feeds your house is compressed and pumped into your vehicle.  Most pumps have automatic shutoff, so you do not have to stay with your vehicle while it is fueling.  Simply connect the nozzel to your vehicle, start it, and walk away.  As CNG is becoming more popular in the U.S., more options for home fueling are becoming available.  Contact us for more information.  952-944-2808.