Cleaning up Coal Power
June 8, 2011
By Gordon Murray
European utilities co-fire wood pellets with coal to reduce CO2 and other emissions. From about 1 million tonnes in 2000, European wood pellet consumption will reach 10 million tonnes in 2011 and is expected to exceed 100 million tonnes by 2020.
European utilities co-fire wood pellets with coal to reduce CO2 and other emissions. From about 1 million tonnes in 2000, European wood pellet consumption will reach 10 million tonnes in 2011 and is expected to exceed 100 million tonnes by 2020. The Wood Pellet Association of Canada (WPAC) has been promoting wood pellet co-firing to the Canadian coal power industry and regulators, so far without success. Here’s why.
- Coal is cheap and plentiful. Canada produces nearly 70 million tonnes annually, of which about 60 million tonnes are consumed domestically. It has 8.7 billion tonnes of coal reserves and 193 million tonnes of known deposits.
- Coal power is well entrenched in Canada. It has been around for about 100 years. The coal power industry is conservative and resistant to change and has powerful, well-funded lobbyists.
- The coal industry is huge. Canada’s 22 mines provide 5,000 direct jobs and thousands of indirect jobs. Coal is top in commodity volume handled by Canadian railroads and ports, which are opposed to anything that could be perceived as a threat, i.e., substituting wood pellets for coal.
- If the cost of environmental damage is not taken into account, coal power is extremely cheap. In fact, many Canadian coal power plants are located right beside the mines that fuel them.
- Canada’s federal and provincial governments are unwilling to implement policies to reduce emissions from coal.
Nevertheless, WPAC is starting to see a glimmer of hope. It has begun dialogue with the Canadian Clean Power Coalition (CCPC), a group of coal power producers who think that coal power is here to stay but needs to be cleaner. CCPC’s purpose is to research technologies to reduce coal power plant emissions, and members include Basin Electric Power Cooperative, Capital Power, Nova Scotia Power, SaskPower, Sherritt International, and Trans-Alta. WPAC recently became a collaborative partner.
CCPC is considering both coal and biomass solutions. Some coal-based solutions being researched include:
Carbon capture and storage: CO2 and other emissions are removed from flue gas and pumped deep underground for permanent storage, a technology that’s still under development and hugely expensive;
Amine scrubbing: Flue gases are passed through an amine solution to absorb CO2 and concentrate it for more efficient storage;
Oxyfuel combustion: Coal is burned in oxygen, rather than air, resulting in flue gas that’s mostly CO2 and captured more readily by amine scrubbing;
Integrated gasification–combined cycle: Coal and steam produce syngas (hydrogen and carbon monoxide), which is burned in a gas turbine with secondary steam turbine (i.e., combined cycle) to produce electricity (if the gasifier is fed with oxygen, the flue gas contains concentrated CO2, which can be captured post-combustion);
Coal beneficiation: Coal is cleaned using water, chemicals, or biological means before combustion to remove impurities; and Supercritical and ultrasupercritical technology: Pulverized coal boilers operate at higher temperatures and pressures and to achieve higher efficiencies.
CCPC views these technologies as long-term permanent solutions requiring substantial resources to commercialize. Such solutions could not be justified in older power plants with limited life. Thus, CCPC sees biomass co-firing as a potential short-term solution that could extend the life of older power plants. However, before the members embark on biomass co-firing, they plan to study it in some detail. Study topics include: economics of co-firing; pros and cons of various forms of biomass fuel, e.g., briquettes, wood pellets, chips, agricultural residues; review of the design, benefits, and costs of feedstock and co-firing configurations on a few coals at specific sites; and burn tests of torrefied material.
As a collaborative partner, WPAC will help to ensure that CCPC obtains an accurate picture of biomass co-firing and will also promote the benefits of wood pellets over other forms of biomass. Although WPAC would prefer to see the Canadian power industry adopt co-firing like its European counterparts, if we are successful with this process, we may finally see the practice adopted in Canada.
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