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Compressed Natural Gas (CNG)

Heritage Gas offers natural gas delivery service by using CNG trucking. Through CNG transport, Heritage Gas enables large energy users that are currently outside our pipeline distribution network to realize the benefits of natural gas.

 

Trucking CNG to areas that do not have natural gas access allows businesses to remain competitive, reduce energy costs, and maintain jobs during times of economic distress through the utilization of an affordable source of energy.

 

Heritage Gas is a Nova Scotian leader in CNG distribution and currently provides natural gas through CNG delivery to two industrial customers.

 

To find out if CNG delivery can help your business, please call us at 1-877-836-7427.

 

Compressed Natural Gas (CNG) Q&A

1. What is CNG?

CNG is a commonly used acronym for compressed natural gas. It’s natural gas under pressure, enabling a given volume of natural gas to be stored in a small space, which makes for easier transport.

CNG remains clear, non-corrosive, and retains that unique “rotten egg” smell, an odorant that is added by Heritage Gas. This odor makes it easier to detect a leak.

2. How is CNG made?

CNG is made by compressing natural gas to a pressure of 200–248 bar (2900–3600 psi), in cylindrical pressure tubes. Through compression, the natural gas volume that can be transported is multiplied by a factor of 200 times.

CNG is then depressurized to normal “pipeline” operating pressures, so the natural gas can be consumed for manufacturing or space & water heating.

3. How is CNG stored and transported?

CNG is stored and transported in cylindrical tanks (tubes) of various sizes. Heritage Gas’ tube-trailers are manufactured by Fiba Canning. Combined maximum weight for these tractor and trailers units cannot exceed 55,500 kg. Each trailer of 14 tubes contains approximately 315 Gigajoules of energy.

4. Is CNG safe?

CNG is one of the safest fuels available. CNG is a combustible fuel and must be handled cautiously, as is the case with any fuel.

Several factors contribute to CNG’s safety:

  • Flammability/Explosiveness – CNG has a high ignition temperature of 649°C (1,200°F), compared to gasoline at 316°C (600°F). CNG has a narrow range of flammability, requiring a concentration ratio of 5% to 15% of CNG in air. The high ignition temperature and limited flammability range makes accidental combustion of CNG very unlikely.
  • Detecting Leaks – In its natural state, natural gas is odourless. As a safety measure, the gas is odorized with a chemical agent called Mercaptan (rotten egg odor) to provide a ready means of leak detection.
  • Non-Toxic – Natural gas has no known toxic or chronic physiological effects (it is not poisonous).
  • Cylinder Strength – CNG cylinders are much stronger than gasoline tanks. The design of CNG cylinders is subject to a number of “severe abuse” tests such as heat and pressure extremes, gunfire, collisions and fire. The systems are also fitted with valves and other safety devices to monitor and control leakage.
  • Lighter than Air – CNG is lighter than air. Unlike other fuels such as diesel, petrol or propane, which are heavier than air, CNG does not pool on the ground and does not create a fire hazard, potential soil contamination, or pollution to waterways. If a CNG leak were to occur, the gas will disperse rapidly upwards into the atmosphere and dissipate.

5. What are the risks from CNG truck transport?

The risks are very few but, as with any fuel, safe handling and transport are key components and must be well understood. Trucks that deliver CNG must comply with ‘Transportation of Dangerous Goods’ Federal regulations that include meeting federal requirements for the CNG cylinders themselves.

To add some perspective, bear in mind that we fill our cars and trucks with gasoline and diesel and use liquid propane to heat our homes and light our BBQ grills hundreds of millions of times each day — and serious safety incidents are rare. These fuels are routinely transported over provincial roads and, again, safety and security incidents are rare.

6. What if a truck is in a road accident and CNG starts leaking?

If a CNG tank were to be involved in a serious road accident, the first line of defense is the robustness of the equipment. CNG cylinders have very thick walls and are subject to extensive testing including a number of “severe abuse” tests such as heat and pressure extremes, gunfire, collisions and fire.

In the extremely unlikely event that one tank would be breached as a result of an accident, leaking CNG would dissipate rapidly into the air rather than pool like liquid petroleum fuels. Plus, because of the narrow range of conditions needed to ignite CNG and natural gas, chances for ignition are low compared with petroleum fossil fuels. CNG has a high ignition temperature of 649°C (1,200°F), compared to gasoline’s 316°C (600°F), meaning it’s harder to ignite. CNG has a narrow range of flammability, requiring a concentration ratio of 5% to 15% in air, also making it harder to ignite. Together, the flotation/dissipation, high ignition temperature, and limited flammability range contribute to the safety of CNG.

Under the Transportation of Dangerous Goods regulations, Heritage Gas has an Emergency Response Assistance Plan in place with skilled professionals trained to respond quickly to any incident involving CNG delivery trucks 24 / 7.

7. How do you know if CNG starts leaking from a truck?

In addition to the various gauges used to monitor pressure and temperature, a special odourizing chemical (Mercaptan) is added to CNG to make leak detection easier.

A high pressure leak is also quite noisy. Smell and sound are quite dependable leak detectors for CNG.

All operators of facilities and trailers are trained to recognize and respond to these indicators promptly and will have methane detectors as part of their standard equipment.

8. What other liquid and gaseous fuels are already being transported in the area?

Several companies routinely transport petroleum products, such as oil, gasoline and propane, throughout the Maritime Provinces. As with any fuel, proper precautions and understanding of the safety of each fuel must be rigorously maintained.

9. Is CNG transport really the best option for providing natural gas to communities/areas beyond its pipeline infrastructure?

Yes, we offer CNG because we believe it to be a sound business decision for our customers. Our studies show that trucking CNG to areas that otherwise have no access to natural gas allows businesses to become more competitive, reduce energy costs, and maintain jobs in economically strapped areas. It’s also good for the environment – natural gas is the cleanest burning fossil fuel.

10. Did Heritage Gas consider building pipelines rather than adding trucking equipment and dozens of tanker trucks?

Where potential customers are located close to existing pipeline facilities, we recommend connecting to a pipeline as the best long-term solution, but initial expansion costs can be quite high. As the distance increases from existing pipeline facilities, trucking CNG becomes the more cost-effective alternative.

11. Are the trucks powered by CNG? Could they be?

We contract with a trucking firm to do the hauling of CNG and their trucks are currently fueled with diesel. Also, the type of trailer being used is very heavy and trucking-industry power units (tractors) that run with CNG as a fuel do not have engines powerful enough to pull these trailers. The opportunity to operate these tractors on CNG will be re-evaluated as new products arise and operating conditions change to support this choice of tractor fuel.