What is coal?
Coal is the world’s most plentiful fossil fuel. It is formed from the remains of land-based plants buried hundreds of millions of years ago and subjected to long periods of heat and pressure.
Coal consists of a complex range of materials and varies greatly in quality from deposit to deposit, depending on the varying types of vegetation from which the coal originated, the temperatures and pressures exerted on the deposit, and the length of time the coal has been forming.
There are various stages of coal development: peat (organic matter, not yet coal) – lignite (the lowest quality coal) – subbituminous – bituminous – anthracite (the highest quality and hardest coal). The coal mined in Alberta is primarily bituminous or subbituminous. Other coal properties include moisture content - coals high in carbon and low in moisture are ranked the highest, and composition – the major elemental components of coal are carbon, hydrogen, and oxygen. Sulphur and other elements can also occur in coal in small, varying amounts. The sulphur content of Alberta coal is considered low, typically less than 0.5 per cent. Other elements can also occur in small, varying amounts.
Canada is ranked eleventh in the world in total proven coal reserves, according to the BP Statistical Review of World Energy from June 2013. Alberta’s coal reserves represent approximately 70 per cent of Canada’s total reserves. Alberta’s coal reserves contain more than twice the energy of all other non-renewable energy resources in the province, including conventional oil and pentanes, natural gas, natural gas liquids and bitumen and synthetic crude.
Alberta’s energy industry started with coal mining in the late 1800’s. Today, Alberta produces 25 to 30 million tonnes of coal each year from its ten mines. The combined total of Alberta, British Columbia and Saskatchewan coal production makes up almost all of Canada’s mined coal.
Alberta's coal is produced mainly by surface mining, either strip mining or open pit. Strip mining is employed to develop the sub-bituminous deposits found on Alberta's plains, using draglines and large stripping shovels to remove overburden and expose a relatively horizontal coal seam. The name strip-mining, is a sub-type of open pit mining and refers to the technique of mining in distinct strips. Other open pit mining techniques are used most in the foothills and mountain regions to develop bituminous coal seams, which are irregular and localized, and where mining can be an almost vertical operation. Coal seams in the foothills and mountains are within the Rocky Mountain Fold and Thrust Belt and are often extensively folded; seams orientation ranges from horizontal to vertical, sometime is only a few tens of metres. Although underground mining has been abundant in Alberta’s past, currently only the Grand Cache coal mine operates an underground operation, in addition to surface mining.
Use of Coal
Coal has been burned for centuries as a source of heat and energy. According to the US Energy Information Administration, worldwide coal consumption is expected to grow by more than 40 per cent between 2001 and 2025. New technologies are making it possible to use coal more cleanly and efficiently. Coals in Western Canada are generally low in sulphur and therefore burn cleaner than coals found elsewhere around the world.
Coal fuels approximately 43% of the installed electricity generating capacity of Alberta’s power plants, making it an integral part of the province’s electricity system. Over two-thirds of the coal produced in Alberta is used as fuel for electricity generation in the province, to heat buildings in agricultural operations and as an important source of energy in cement manufacturing and other industrial processes. Sub-bituminous coal does not require processing or upgrading for use as a fuel for electricity generation in the province. Most of the remainder of Alberta's coal, including both metallurgical coal and thermal coal, is exported to international markets – Japan, South Korea and China mainly. Most bituminous coals must be upgraded or processed by a preparation plant to meet customer specifications.
Coal has other uses. For example, gases, oil and tars extracted from coal can be used in the manufacture of products ranging from gasoline and perfumes to mothballs and baking powder. Coal can be processed many different ways to create a wide variety of products, from carbon filters to pharmaceuticals.
Another potential use is In Situ Coal Gasification (ISCG). The ISCG process includes injecting water and oxidants more than one kilometre deep into the coal seam and igniting it. Under high temperature and pressure, methane, carbon dioxide, hydrogen and carbon monoxide are produced and can be collected. The produced methane can be used in gas-fired electricity generators or as a feedstock for the petrochemical industry. The carbon dioxide may be sequestered underground or used for enhanced oil recovery in the oilpatch.