I attended a tour of the Genesee Coal-Fired Power Plant near Warburg, Alberta on October 13, 2015. The focus of this trip was the newest generator at the plant, G3, which uses supercritical coal combustion to generate electricity. Supercritical coal combustion uses driver water at higher temperatures and pressures than subcritical combustion. This means that more power can be produced per tonne of coal, reducing overall emissions through improved efficiency (on a kW/tonne basis). G3 also uses injected granular activated carbon, atomized lime slurries (flue gas desulphurization), efficient burners and industrial filter bags (there are 11 000 filter bags at G3) to reduce Criteria Air Contaminant (CAC) emissions. These technologies are important because they put G3 and Keephills 3 (the other supercritical coal-fired power plant in Alberta) head and shoulders above other plants, in terms of emissions per tonne of coal burned. The only emissions from the power plant that are not directly addressed by technologies is carbon dioxide.
An interesting part of the coal-fired process train is the production of fly ash. Fly ash is produced by traditional coal-fired plants (not including flue gas desulphurization), and then sold to cement producers and used as a feedstock. In this way, the end products of electrical production can still be useful. One drawback of using flue gas desulphurization is that the lime in the slurry reacts with fly ash to create gypsum, which cannot be used in concrete production. Because of this, reducing air emissions creates additional waste for the electrical production process. This sucks, since the fly ash that is produced from G3 can’t be used in other industries. Lafarge is working to see if they can use the gypsum in some concrete mixes. The trend in electricity production means that desulphurization is probably going to become common place. This might become an issue for the cement industry in the next decade or so.
I was also at the UofA Energy Club Panel on the Future of Coal in Alberta on October 19, 2015. Randy Dobko, from Alberta Environment and Parks, represented the Albertan Government Ministry’s position on coal-fired electricity generation.
Mr. Dobko touched briefly on the extensive approval process that may be faced by projects in the electricity industry. They may need to apply for permits around air emissions, wastewater, groundwater, solid waste, soil and reclamation activities. This is very extensive, and requires a strong partnership between regulators and industry, as well as folks who have a solid grasp of the regulation they interact with. These regulations are focused on sustainably utilizing the environment, and providing utilities to the citizens of Alberta.
Mr. Dobko also talked about the prevalence of coal fired electricity in Alberta. Coal fired power plants provide almost 40% of the electricity in Alberta. By contrast, Ontario only operates 1 coal fired power plant, to provide during peak demand – they don’t runt the plant 24/7! There are drawbacks to all forms of energy production, but the major drawback of coal fired electrical generation is the emissions. There are mitigating technologies that are being installed at existing and new coal power plants to mitigate CAC emissions, like at G3. One emission that Mr. Dobko specifically mentioned was mercury. Coal reserves in Alberta can contain elemental mercury, which is more likely to be directly emitted. Because of this, Alberta was one of the first jurisdictions in North America to legislate the reduction of mercury emissions. Alberta has been ahead of the game on some emissions, but coal fired power plants still present a serious risk to Alberta’s overall emissions. Let’s talk about Greenhouse Gases.
Carbon dioxide is one of the most important greenhouse gases, and it is produced in large amounts at coal fired power plants. There is Carbon Capture and Storage (CCS) technology that can be operated at power plants but at present there are no major drivers to install these systems. There is currently one system in operation in Saskatchewan at a coal fired power plant. You can look at the logistics of it here: http://www.saskpower.com/our-power-future/innovating-today-to-power-tomorrow/capturing-carbon-and-the-worlds-attention/. Because of regulations that are in place to reduce greenhouse gas emissions, many of the older, less efficient coal fired power plants will most likely be closed, as it is no longer viable to operate them. This would reduce the overall emissions of CO2, but it isn’t a sustainable system for providing electricity to Albertans and protecting the environment.
Overall, it seems like coal fired electricity production needs something pushing a reduction of CO2 emissions before it can be considered environmentally friendly. The major concerns around other emissions are manageable through flue gas treatment, and other environmental impacts like thermal pollution and mining operations can be mitigated through proper operations. But greenhouse gas production still presents a major cost of coal powered electricity. As long as there is a major supply of coal in Alberta, and technologies haven’t been developed that can surpass the cost effectiveness of its electrical generation, it will keep being used. In the meantime, let’s all hope that CCS becomes more viable!