A recent letter to the editor provided information about local gasification projects that produce synthetic gas or “syngas”. These were excellent examples of the hundreds of gasification projects around the world. However, it should be noted that about 98 per cent of the syngas produced by worldwide gasifier projects is made from coal or other fossil-fuels. These feedstocks are consistent, predictable and easy to handle.
Gasifying “biomass” to produce syngas is somewhat more difficult. Biomass refers to plant- or animal-based organic materials such as wood chips, sawmill residuals, straw and other agricultural byproducts. Because they are industry byproducts, some of them are called “wastes”. But they should never be confused with the municipal solid waste generated in households and businesses.
Most waste gasification experts (including a colleague who helped fact-check my information) agree that, relative to fossil fuels and biomass, it is much more difficult to gasify solid waste because it is so variable and contains high levels of contamination. These contaminants lower the solid waste’s heating value, reduce the “quality” of the gasifier ash and affect air emissions. It is also worth noting that many solid waste gasification facilities use a supplemental fuel such as natural gas or diesel to start, and in some cases sustain, the gasification process.
Most industry experts also agree that solid waste gasification is still in the early stages of development. In fact, there are relatively few gasifier projects that use municipal solid waste as a feedstock, and fewer still that use unsorted solid waste as is being proposed by the City of St. Albert. Just-released industry statistics show that solid waste gasifiers make up less than 0.5 per cent of the world’s operating and planned syngas production capacity. Most thermal treatment of solid waste is done using conventional incinerators. These systems, which exist in Canada, United States, Germany, Austria, Switzerland and Sweden, are sometime misreported as being gasifiers.
It is not fair to say that solid waste gasification is unproven; there are a handful of commercial facilities in North America. The Enerkem project, which processes solid waste that has been highly pre-sorted and refined by the City of Edmonton, is a good example. But there are also many solid waste gasifier projects that failed to deliver on their promises. These include the Plasco facility in Ottawa; a system installed by the Regional Municipality of Wood Buffalo that never operated; and (most recently) a small waste gasifier project in southern Manitoba. The technical challenges and high failure rate of waste gasification projects are among the reasons that myself and other solid waste industry professionals consider them to be so risky.
Gasification is also among the most costly of landfill diversion options, even when electricity sales and spin-offs that might (or might not) occur are factored in. The City’s own data, presented to Council earlier this year, shows that diverting solid waste to a new gasifier could increase the cost of the brown cart garbage program by between three and five times.
Scott Gamble, St. Albert
