Pellet Power

Canadian coal-fired power plants don’t co-fire with wood pellets because it would cost more than coal combustion. Despite the substantial environmental benefits of pellets, power companies have no incentive to reduce emissions of greenhouse gases (GHGs). Even Ontario Power Generation is now considering a switch to natural gas, rather than biomass.

In January 2010, Canadian environment minister Jim Prentice announced that Canada would reduce emissions by 17% from 2005 levels by 2020. In late April, he met with chief executives of energy companies to propose that coal-fired power plants be phased out over the next 10 to 15 years. He said that Ottawa also plans to impose absolute emission caps on existing coal-fired power plants and establish a market-based system so utilities can buy credits to meet those targets.

“The approach that we've been working toward involves a cap-and-trade system relating to thermal coal, and the requirement of phasing out those facilities as they reach the end of their useful, fully amortized life,” Prentice said.

Currently, wood pellets are not even on the radar. Canada’s 30 wood pellet plants now produce about 1.5 million tonnes/year, with about 90% exported. The vast majority go to European power companies, which co-fire pellets with coal to reduce GHG emissions. In contrast, no Canadian power companies co-fire. Thus, the domestic market for pellets is virtually non-existent.

Fully replacing coal with pellets can reduce GHG emissions by 91% for a coal plant and by 78% for a natural gas combined-cycle power plant. It also reduces emissions of nitrous oxides by 40–47% and sulphur oxides by 76–81%. Even co-firing a mix of 10 or 20% wood pellets with coal provides a significant reduction in GHG emissions. These numbers were determined by a recent Canadian study (Zhang et al. 2010, Life cycle emissions and cost of producing electricity from coal, natural gas, and wood pellets in Ontario, Canada, Environmental Science & Technology 44:538–544).

Canada presently consumes 60 million tonnes/year of coal. If Canadian utilities began co-firing with 10% wood pellets, it would create a six million tonne domestic market, quadruple the Canadian wood pellet industry, create more than 1,500 jobs, and eliminate 9% of CO2 emissions from Canadian coal power plants. Experience shows that coal power plants can co-fire up to 30% pellets without burner adjustments.

The European Union has rules requiring member countries to generate 20% of electricity from renewable sources by 2020. For at least a decade, power producers in Europe have been co-firing wood pellets with coal, with more than 100 such plants running currently.

Co-firing is the lowest risk, least expensive, most efficient, and shortest-term option for electrical power generation. Unlike coal or natural gas, wood pellets are renewable and carbon lean, meaning that CO2 released during combustion is offset by CO2 captured during subsequent plant growth. The energy in wood pellets (17.2 gigajoules/tonne [GJ/t]) is about the same as that in the lignite coal (16.3 GJ/t) mined in Saskatchewan. Wood pellets burn much like coal and are a consistent size. They break into small particles when processed, which means that they can be mixed with coal without needing a separate system.

The barrier to co-firing in Canada is that it’s more expensive than dedicated coal systems. However, as the Europeans have found, the environmental benefits far outweigh the costs. Implementing co-firing in Canada will require government regulatory support for lowering GHG emissions. In the 1980s, the Canadian government successfully regulated the introduction of unleaded gas to reduce lead emissions into the environment. Implementing of the use of wood pellets for co-firing with coal is a similar initiative that needs government support.

In a February 1, 2010, speech Prentice said, “For those of you who doubt that the government of Canada lacks either the willingness or the authority to protect our national interests as a ‘clean energy superpower,’ think again. We do and we will.”

The government should convince Canada’s major electricity producers of the benefits of co-firing wood pellets with coal so that our country can make immediate progress toward the goal of 17% emissions reductions.

Gordon Murray is executive director of the Wood Pellet Association of Canada. He can be reached at 250-837-8821 or gord@gordonmurray.ca.