By JAMES NOBLE
March 13, 2014
Despite big uptake in Europe and parts of North America, anaerobic digestion has played a tiny role in British Columbia's renewable energy production. For a proven technology that produces energy from waste and reduces greenhouse gas emissions, its appeal should seem obvious.
Yet it has one significant drawback: It’s not cheap.
Anaerobic digestion (AD) is uncomplicated; essentially, it’s a waste-to-energy technology that heats animal manure and/or food processing waste to 30 degrees C and converts it into a biogas that can be used to generate heat, electricity and fuels. A typical anaerobic digester system can cost between $1.5 million and $4 million to build and requires five to seven years to pay off.
AD projects typically earn revenue from three sources: converting the biogas into electricity for sale to the grid, charging tipping fees for the processing of the organic waste, and selling the digestate byproduct as bio-fertlizer. Selling electricity through a power purchase agreement is the most lucrative and essential to a project's success.
Europe boasts more than 8,000 AD installations and could have nearly 25,000 by 2020. European governments provide long-term power purchase agreements to AD project proponents at a price that guarantees the economic viability of those projects. Ontario has approximately 50 digesters, owing largely to progressive legislation by the provincial government. The Feed-In Tariff Program pays between 16 to 26 cents per kw/h for biogas produced in any of the province’s on-farm digesters.
In British Columbia, BC Hydro pays only 10 cents per kw/h for renewable electricity. A feasible AD system requires at least 13 to 14 cents per kw/h, which is largely why BC has only two on-farm digesters in operation, both in the Fraser Valley.
On-farm AD systems have proven to provide significant environmental, social and economic benefits. However, without an electricity tariff or higher paid rates, the development of on-farm AD systems in BC will continue to lag.