Solid Waste & Recycling

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Compressed Natural Gas

Natural gas is moving into the waste and recycling truck market in Canada. From only five trucks two years ago, Canada will have an estimated 325 compressed natural gas (CNG) refuse trucks by the end of 2013. Fueling these trucks are eight...


Natural gas is moving into the waste and recycling truck market in Canada. From only five trucks two years ago, Canada will have an estimated 325 compressed natural gas (CNG) refuse trucks by the end of 2013. Fueling these trucks are eight private on-site stations across Canada where the trucks plug in and are filled overnight. Natural gas refuse trucks are the fastest-growing part of the natural gas for transportation market in the U.S. where an estimated half of all new trucks ordered are now natural gas trucks.

What is driving this change?

Lower cost fuel, reduced environmental impact, simpler technology compared to 2010-compliant diesel trucks, and municipal sector interest are all major drivers supporting greater natural gas use. Delivering these benefits are factory-built vehicles from major manufacturers that incorporate improved engine technology providing the power, torque, and performance expected from a diesel truck. Natural gas is well suited for return-to-base and regional operations fleets.

Natural gas has not always enjoyed the strong market interest it is attracting today. Early technology challenges left fleets disappointed in natural gas as an alternative. Whether it was fuel consumption, the use of heavy steel fuel storage tanks or the aftermarket conversion of existing trucks, intentions were good, but execution was not always up to the standard that fleet operators expected.

That has all changed now.

Fleets that are looking to reduce their fuel costs and environmental impact as well as municipalities seeking greener contracted services are behind the increasing demand for natural gas refuse trucks.

Natural gas

Natural gas is an abundant Canadian energy resource. Canada has more than 100 years supply at current demand levels and is the world’s third largest natural gas producer. Natural gas is found as a mixture of gases in underground rock formations. Once extracted, natural gas must be processed and purified before being delivered to market via an extensive underground pipeline network.

Natural gas has a low energy density by volume. This means that it has to be either compressed or liquefied for use on a vehicle. CNG is natural gas that is compressed and stored on the vehicle in durable fuel storage tanks. CNG is the most common form of natural gas used for waste trucks. Some American waste fleets use liquefied natural gas (LNG) instead of CNG. LNG is natural gas that has been cooled to its liquid state at a temperature of minus 162 degrees Celsius. LNG fuel storage tanks are like a sturdy thermos with insulation to keep the fuel at a very low temperature. LNG takes up about half the amount of space as CNG because it has more energy per litre. This is why LNG is favoured for high mileage applications like on-road trucking. In Canada, access to LNG is limited at present, while CNG can be used wherever there is a natural gas distribution network.

CNG is typically about 30 per cent less expensive than diesel fuel. This savings is on an energy equivalent basis, so if diesel is $1.15 per litre, the savings with CNG are $.35 per diesel litre equivalent (dle). A natural gas refuse truck costs about 10 per cent more than a diesel truck. Using 35,000 litres of diesel per year, the payback on a natural gas truck would be about three years.

The engine used in all North America factory-built natural gas refuse trucks is the Cummins Westport 8.9 litre ISL G. This 4th generation engine provides comparable power and torque to a diesel engine. As a spark-ignited engine, the ISL G uses about 12 per cent more fuel than a diesel engine. Natural gas refuse trucks have similar maintenance compared to diesel. Combining these factors with lower cost fuel means reduced operating cost per kilometre using natural gas.

Impacts and interest

Natural gas is the cleanest burning fossil fuel. For many years, natural gas had a major advantage over diesel in reducing particulate matter and smog-related NOx emissions. Changes in diesel technology to comply with 2007 and 2010 emissions standards mean that natural gas and diesel now have similar regulated tailpipe emissions. Where natural gas maintains an advantage is in the area of greenhouse gas emissions (GHG). The estimated GHG benefit is about 20 per cent on a well-to-wheels basis according to Natural Resources Canada, so each truck operating on natural gas provides an estimated 17 tonne carbon benefit based on driving 60,000 km per year. Natural gas trucks are also significantly quieter with up to 10 decibels less noise at idle providing noise reduction benefits for drivers and communities. 

Some municipalities have started to add requirements for the use of lower emission technologies for public sector tenders involving vehicles. For example, in 2008, Seattle, Washington issued a request for proposals for municipal collection services requiring bidders to bid on the basis of natural gas, hydraulic hybrid or 20 per cent biodiesel. Bidders could select the technology. The contract was split between two companies — Waste Management and Cleanscapes — both of whom bid on the basis of natural gas trucks.

In Canada, Surrey, BC, is the first municipality to require the use of natural gas trucks as a condition of municipal tender. Prior to issuing its tender, Surrey did its own research to assess lower emission options. They determined that requiring the use of natural gas trucks would not only reduce emissions, but would also lower the cost of collection services. Taking this one step further, Surrey also has a project to upgrade biogas produced from municipal green bin waste in anaerobic digesters and use the renewable natural gas for the refuse collection fleet. Renewable natural gas can provide near zero vehicle emissions.

Refueling stations

An obstacle for fleets interested in using natural gas has historically been access to fueling. While temporary small stations or mobile refueling may be an option for fleets with only a few CNG refuse trucks, larger private on-site stations can be built for fleets buying at least 15-20 CNG waste trucks.

Several companies offer design, build, maintenance, and financing services for CNG refueling stations. In some cases, the station cost can be built into the fuel supply contract with the all-in cost per litre being below the cost of diesel. The station type that is most commonly used for refuse fleets is a time fill CNG station where trucks are plugged in at filling posts overnight and all vehicles are refueled simultaneously over about eight hours. CNG stations require regular visual inspection and compressor maintenance.

With more than 25 years of technology development behind it, natural gas is finally ready to move into the mainstream as an affordable, lower emission option for waste and recycling truck fleet owners in Canada. With lower cost fuel, reduced environmental impact, simpler technology compared to 2010-compliant diesel trucks, and municipal sector interest, this time natural gas is here to stay.

Alicia Milner is President of the Canadian Natural Gas Vehicle Alliance in Ottawa, Ontario. Contact Alicia at
alicia.milner@cngva.org


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