|April 18, 2007|
Is 'clean' coal possible?
|Vancouver, Canada (GLOBE-Net) - Coal is the world's most commonly used fuel to produce electrical energy, and will continue as such for some time. Yet it is one of the 'dirtiest' of all fossil fuels. It is a major source of toxic air pollutants and the leading source of energy-related greenhouse gas emissions. Many believe 'clean coal' technologies will improve the energy efficiency of coal's use and help eliminate releases of toxic pollutants and carbon dioxide. But there remain many unanswered questions about whether coal can ever be a truly 'clean' source of energy and whether clean coal technology will be ready in time to help slow the impacts of climate change. |
Coal is plentiful, accounting for more than 60% of global fossil fuel reserves. It is also relatively cheap, currently delivering power at a per-kilowatt cost that is lower than natural gas, nuclear and most renewables.
Canada has a fairly strong presence in the global market as the 6th largest coal exporter in the world. Our national reserves account for less than 1% of the world total, but the amount of coal available to us (mostly in Alberta) could supply Canada's needs for another 230 years at current extraction rates, says the Calgary-based Canadian Coal Association.
Coal-based energy production contributes significantly to Canada's electricity supply (16.5% in 2004). Alberta, Saskatchewan, Ontario and Nova Scotia are particularly dependent on coal for electricity, though Ontario plans to phase out its coal fired generation plants by 2014.
Coal is generally regarded as an environmental villain. It has the highest greenhouse gas (GHG) emissions intensity of all combustible fuels, and is a major contributor to Canada's rising GHG profile, producing 12.6% of total emissions in 2004. Four of the country's five largest single emitters are coal-fired electrical generating stations. Coal plants also emit significant amounts of sulphur dioxide, nitrogen oxides, particulate matter, and a variety of heavy metals such as mercury.
Coal mining also has a relatively poor environmental and safety track record. In 2006, over 4,000 Chinese coal miners were killed in a variety of accidents, and many miners (and the communities close to such mines) suffer from serious health problems. In the Appalachia region of the Eastern United States, a particularly harmful mining technique known as 'mountaintop removal' literally involves blasting off the top of mountains to get to coal seams inside. This practice dumps millions of tonnes of rock into adjacent river valleys and streams.
But there may yet be hope for coal. Many believe reducing its environmental impacts may be one of the most important contributions in worldwide efforts to combat climate change and cut air pollution. Most energy experts forecast that coal will continue to be an important energy source worldwide, and this has led to huge investments in technologies that might help to make coal energy 'clean'.
The 'Clean Coal' vision
Coal proponents say part of the answer to the fuel's environmental impacts is the application of technologies to make coal combustion more efficient and less polluting. Several technologies have already been deployed in commercial plants to reduce the releases of air toxics and greenhouse gases. Building on that is the ultimate goal of capturing and storing all carbon dioxide, in effect making coal combustion GHG neutral.
One efficiency improving technology, known as 'supercritical pressurized pulverized coal', has been deployed at EPCOR's Genesee 3 plant west of Edmonton, Alberta. According to the company, the improved combustion method and other technologies such as flue gas desulphurization and low nitrous oxide burners, have eliminated 99.8 percent of particulate matter, 77 percent of sulphur dioxide, 54 percent of nitrous oxide, and 18 percent of carbon dioxide emissions compared to conventional coal plants. EPCOR says "Genesee 3 is the most technologically advanced coal-fired plant built in Canada", and the technology is the best available today.
However, the 495 megawatt station remains the fourth largest single-facility GHG emitter in Canada, illustrating that while coal technology is improving, it is far from 'clean' at the moment. Acknowledging this, EPCOR has pledged to offset Genesee's emissions to the level of a more efficient natural gas combined cycle plant, and is pursuing even cleaner combustion.
Other technologies, including Integrated Gasification Combined Cycle (IGCC), Pressurised Fluidised Bed Combustion (PFBC), and Integrated Gasification Fuel Cells (IGFC), are in various stages of development and deployment, with a few IGCC and PFBC plants operational in the United States, Japan and Europe. These combustion methods seek to maximize the efficiency of coal use, pushing energy-recovery rates higher than the 40% currently achieved by many conventional plants.
However, many believe the route to truly 'clean coal' is through the capture and long term storage of carbon dioxide. Advanced combustion methods such as those listed above lend themselves to this emerging technology. If successful, carbon capture and sequestration (CCS) could become a major tool for reducing greenhouse gas emissions while allowing for the continued use of coal as an energy generating fuel.
CCS allows carbon emissions from fossil fuel combustion to be extracted, transported, and stored deep underground in geological formations, in depleted oil wells to improve recovery rates, or at the bottom of the ocean.
A recent report from the Massachusetts Institute of Technology (MIT) argues that CCS is the critical enabling technology to help reduce CO2 emissions significantly while also allowing coal to meet the world's pressing energy needs. The two key factors needed to ensure its deployment are a significant charge for GHG emissions (a 'carbon price'), and "large-scale demonstration projects of the technical, economic and environmental performance of CCS", says the expert panel behind the report.
CCS has been pilot tested, with three industrial-scale storage projects in operation worldwide. At the Weyburn project in Saskatchewan, 3000--5000 tonnes of CO2 per day are injected and stored underground in an oil well, improving oil recovery rates concurrently. The CO2 in Weyburn comes from a lignite coal gasification plant in North Dakota which produces natural gas. So far no commercial coal power plant has been built with CCS. Currently, several public-private efforts are underway around the world to demonstrate large scale carbon capture and storage at a coal plant.
One of the most advanced is FutureGen, a $1 billion, 10-year demonstration project led by the United States. A shortlist of locations for the facility was announced in 2006, and it is expected that the plant could come online around 2012.
American Electric Power plans to install carbon capture on two coal-fired power plants, the first commercial use of technologies to significantly reduce carbon dioxide emissions from existing plants. The first project is expected to complete its product validation phase in 2008 and begin commercial operation in 2011.
Clean coal in Canada
Canada's first facility aimed at producing zero-emissions coal power will likely be built in Alberta. The Canadian Clean Power Coalition (CCPC), a group of electric utilities and coal mining companies, are planning a full-scale, 400-500 MW IGCC coal plant with CCS, to be constructed at EPCOR's Genesee Generating Station.
From the Alberta government, the group has secured one-third of the $33 million in financing it requires for Font-End Engineering and Design (FEED) work, one-third funding from EPCOR, and is awaiting for decision on one-third funding contribution from the federal government.
Work has already begun now that the type of coal and the plant site have been narrowed down, says David Lewin, Senior Vice President of IGCC Development for EPCOR and Chair of the CCPC. The group has identified four likely gasification technologies, and is determining the suitability of each with the intent of making a decision later this year.
They are also engaged in discussions with the provincial and federal governments on options to transport the captured CO2 for storage. Professor David Keith, a member of a federal-provincial task force charged with deploying CCS in Canada, has stated that carbon capture at a coal plant could be a more cost-effective method of reducing emissions than the $5 billion CO2 pipeline that the Alberta government has proposed for the oil sands industry.
If EPCOR's plans proceed, the FEED study will take around 18 months, with capital investment beginning in 2009-2010. Allowing four to five years for construction, Lewin envisions the plant could be up and running by 2015, capturing all of its carbon dioxide emissions.
The cost of the plant was originally estimated at around $1 billion, but rising prices for steel, concrete, and labour will likely push it higher. It is still too early to talk about specific financing, but Lewin sees a consortium of utilities as likely partners. "We're at the preliminary stages of this technology, and there is a lot of perceived risk," he notes, adding that any government policy which placed a value on greenhouse gas emissions would help make the project more attractive.
"We consider this a very positive step forward in terms of solving our CO2 emissions problems for coal using technology. It is a shift from the type of energy we used in the past to the technologies of the future, and could lend longevity to our utilization of coal," says Lewin.
Implementation of the technology in Canada, which is still a decade or more away, is only a first step towards addressing the emissions associated with global coal consumption. Deploying it in countries where it is needed most, such as China and India, will be even further down the road.
But even the optimists admit that 'clean coal' is not a reality at present and countries will continue to expand their use of coal until more economical alternatives can be found. The search for viable alternatives will continue, of course and renewable energy sources, increased energy efficiency, and the deployment of other technologies will form part of the solution. But the simple reality is that coal will continue to play a major role in meeting our needs for energy well into the future. So the quest for 'clean coal' will undoubtedly be part of the world's overall clean energy strategy.
For More Information: Massachusetts Institute of Technology