With the transportation sector contributing the largest portion of greenhouse gas (GHG) emissions in Canada, renewable natural gas (RNG) from food waste and organic material is the next game-changer in vehicle fuelling and the biggest opportunity for near-term, cost-neutral sustainability.
RNG can be generated from any source where organics undergo anaerobic digestion, such as landfills, residential source separated organics treatment facilities, and wastewater treatment. RNG is cost-competitive with diesel fuel, interchangeable with natural gas, and carbon neutral.
“Farms and municipalities are well-positioned to convert their biogas to RNG, a locally produced alternative fuel suitable for on-farm use and for trucking fleets,” says Jennifer Green, executive director of the Canadian Biogas Association.
Fuelling with RNG is an excellent opportunity for the solid waste sector, as they can locally produce vehicle fuel on-site for their fleets. “For the waste industry, RNG just makes sense,” says Bruce Winchester, executive director of the Canadian Natural Gas Vehicles Alliance. “Fifty per cent of fleets in North America are natural gas powered anyway, taking the product they carry around and making it a fuel is the perfect way to close the loop.”
Environmental Benefits of RNG
Generating biogas from landfill gas (LFG) and diverting organics to biogas facilities has several environmental benefits. The 2013 Canadian Biogas Study by Kelleher Environmental found that converting just half of the food waste discarded in Canada into biogas would avoid 2.2 million tonnes of CO2 emissions per year, the equivalent of taking 490,000 cars off the road. The biogas process recovers nutrients from organic waste and returns them to the soil, resulting in improved soil health. Water sources are protected by destroying pathogens in organic material, which reduces the risk of potential environmental impact.
Organizations with sustainability goals can consider using a blend of CNG, a competitively priced fuel that generates fewer atmospheric pollutants than diesel, and RNG for their trucking needs. Blending 10 per cent RNG with 90 per cent CNG offers lifecycle GHG emissions reductions of over 31 per cent compared to diesel or gasoline, and when 100 per cent RNG is used to fuel vehicles lifecycle GHG emissions can be reduced by 90 per cent. There is no technical barrier to blending RNG and CNG, and the ratio is site-specific depending on the availability of RNG.
Consider the Business Case for RNG Production
When studying the business case for producing RNG, consider the gas volumes the material can produce and the cost to do so compared to the cost of current fuelling methods. While RNG is more expensive than CNG, it is about the same price as diesel or gasoline. Blending RNG with CNG makes sense economically, allowing businesses to be green and still save money.
According to Union Gas analysis, blending 10 per cet RNG with 90 per cent CNG adds five cents per litre to the price of CNG, which maintains the strong economic advantage of using CNG/RNG over crude oil-based fuels.
However, there are many variables with RNG production that limit generalizations that can be made about the business case. When considering producing RNG, it is recommended to connect with consultants, technology suppliers, and representatives that have direct experience with these systems.
Generate Biogas and Upgrade it to RNG
Biogas can be generated from landfills, source separated organics (SSO), wastewater treatment, or a combination of these organic sources. Landfills produce a relatively large amount of biogas, and while some sites generate electricity and sell it to the grid, several landfills are not able to connect. Many of these sites offer sufficient economies of scale to produce RNG fuel for fleet vehicles, creating closed-loop energy systems.
Biogas includes carbon dioxide, contaminant gases, and moisture, which need to be removed prior to using it in a vehicle engine to increase the methane content in a process called upgrading. There are several widely used technologies for biogas upgrading including pressure swing adsorption, water scrubbing, chemical absorption, membrane separation, and cryogenic separation. For government permits and approvals required for biogas and upgrading systems, consultation with the province’s Ministry of Environment and provincial safety authority is recommended since regulations vary from province to province.
Transition your Fleet to CNG Vehicles
To capitalize on the RNG opportunity, the fleets must be converted to compressed natural gas (CNG) vehicles. New CNG vehicles typically cost between $15,000 and $35,000 more than conventional diesel fleet vehicles, however the higher initial investment is offset by the substantial fuel savings. Many municipalities and businesses are transitioning their fleets to CNG vehicles to save money and reduce GHG emissions. New CNG vehicles can replace older fleet vehicles, or existing vehicles can be upgraded. RNG is easily integrated into CNG fleets and the vehicles aren’t reliant on returning to the RNG source as they can be refuelled at any natural gas fuelling station.
Choose a Fuelling System
How the vehicles are re-fueled is another factor to consider. The cost for a typical CNG refuelling station ranges from approximately $600k to $1.8M depending on the number of trucks and site specific requirements and conditions. Slow fill, fast fill, and combination fuelling systems are available and the chosen fuelling system is unique for each situation. Solid waste fleets most commonly use slow fill stations allowing the vehicles to be refuelled simultaneously overnight. The slow fill stations have lower capital costs due to a smaller compressor and little or no storage and can benefit from off-peak electricity for compression.
Challenges and Concerns
Certain perceptions of CNG vehicles need to be overcome to facilitate wider adoption of the technology. It can be challenging to convince perspective fleets to use another type of fuel since diesel is a well-established fuel with a developed market and supply chain. Switching fuels may not be an attractive option for some depending on the current business model of the organization, given the capital costs for vehicle conversions and fuelling stations. However, CNG is competitively priced compared to diesel and over ten years an annual average savings of $125,650 per truck can be realized. Additional economic benefits from local renewable energy production include green job creation and local energy security.
In addition, while some business owners may be concerned about the range of natural gas vehicles given the lower energy density, the distance is predictable and heavy duty vehicles can use an array of tanks to provide comparable distance to diesel. There are plenty of options to refuel with about 100 points in Canada where you can refuel a natural gas vehicle. With over 11 million CNG vehicles in use over 30 countries, there is no fundamental challenge to fuelling with CNG and the technology is quite straightforward.
The production of RNG offers an attractive waste management solution for closing the loop between organic waste and fuel. Converting organic materials to RNG captures energy from waste, reduces odour, and produces local renewable fuel for solid waste fleets. More information on making the transition to RNG is available in the Canadian Biogas Association’s Closing the Loop Primer for Municipalities, Food Processors, and Fleets on Fueling Vehicles Using Renewable Natural Gas. Visit www.biogasassociation.ca to access this resource and learn more about the Canadian biogas industry.
Municipalities interested in learning more about fuelling their fleets with RNG can contact Jennifer Green at email@example.com.