Energy, Government, North America, Water
water + energy
Setting New Standards
Creating Valuable Resources at Treatment Facilities
The biogas plan evaluated several alternatives to maximize the use of biogas—and determined that vehicle fuel provides the highest overall value.
Wastewater treatment plants contribute to human and environmental health—they also consume large amounts of energy. EPCOR, owner and operator of the Gold Bar wastewater treatment plant in Edmonton, Alberta, Canada, is working to be more sustainable by maximizing the use of renewable energy and putting into action what they already know—treatment facilities can be valuable resource centers.
Priding itself on treatment excellence and emerging technologies, EPCOR operates the Wastewater Research and Training Centre at the Edmonton Waste Centre of Excellence—research, demonstration and education facilities located at the Gold Bar site.
The facility is reclaiming several million gallons of wastewater per day for industrial process use and is fueling boilers with biogas for space and process heating. Looking to maximize the benefits of biogas, EPCOR partnered with CDM Smith to develop a biogas plan that would meet quadruple bottom line objectives—environmental, social, economic and operational.
Value Without Compromise
The plan considered boiler fuel, cogeneration and biomethane as potential uses for Gold Bar’s excess biogas, and compared them on an economic and non-economic basis. While using biogas for boiler operation is beneficial, a majority of the biogas is still being flared during the summer. To fully realize the beneficial use of biogas, the plan identified several offsite uses. A value-based approach compared the improved value of the biogas to the required investment by EPCOR, never losing sight of the fact that Gold Bar’s primary purpose is to treat wastewater.
The biogas plan evaluated several alternatives to maximize the use of biogas—and determined that vehicle fuel provides the highest overall value. The plan determined that the option with the most value would be to upgrade the biogas into biomethane and compress it for use as vehicle fuel. Gasoline and diesel fuel cost more than electricity and natural gas on a cost-per-energy unit basis, making the ability to generate fuel from a renewable energy source an economical and environmental solution. Generating biomethane from biogas requires gas scrubbing equipment to remove impurities and carbon dioxide. Distribution methods for the biomethane include a private pipeline, a wheeling agreement with the local gas utility, and trailer-mounted compressed natural gas storage vessels that could be trucked to the point of use.
The plan also suggests integration with the Clover Bar waste management centre by diverting organic waste from the landfill to Gold Bar for codigestion, increasing the production of biogas and improving solid waste management.
Making a Case
According to Vince Corkery, EPCOR director of wastewater operations in Edmonton, “This process involved more than writing a biogas plan. We had additional steps to properly integrate this plan with Gold Bar’s overall master plan.” A business case analysis considered capital and operating expenses, as well as future biogas production, current and projected biogas consumption, costs of offsetting natural gas if heating demand exceeds supply, potential carbon footprint impacts, and the potential effects of changing energy rates.
Gold Bar is currently planning for capital expenditures to improve solids handling and optimize liquid stream and digestion processes. The biogas plan analyzed how its recommendations would affect non-biogas assets. In addition, it gave EPCOR a framework to consider future biogas upgrade equipment without compromising the planned construction of solids-handling equipment. Changes in air, land and water regulatory drivers were also considered in the plan.
A Strong Position
“The biogas plan shows off the value of integration, considers our sustainability objectives, and contributes to our mission of being an innovative wastewater treatment facility that recovers resources,” says Corkery. “We want to be a good neighbor, producing a valuable product, and this plan positions us to do that.”