The Search for Clean Coal

The Search for Clean Coal

Many countries and companies are pursuing with vigour the concept of "clean coal," where toxic emissions of are reduced by over 90 percent and sulphur and greenhouse gas emissions are rendered virtually non-existent. Research is underway in Europe, North America and Asia on how to make use of the world's most abundant fossil fuel in ways that are environmentally and socially more acceptable.

While no one doubts coal will be with us for many generations to come, many are grasping at the quick fixes that would appear to make coal a "clean fossil fuel." But to date, the solutions remain elusive. In addition to unproven technologies -- at least on a scale that would make a real difference -- there is the thorny issue of costs, most of which would have to be borne up front.

The 2007 World Energy Outlook estimated that coal use, despite potential greenhouse gas emissions, will rise 70 percent by 2030 and will surpass petroleum as the dominant energy source. This poses a significant problem in reducing greenhouse gas emissions to levels that will avert the worst impacts of climate change.

Already there are thousands of coal fired power plants around the world which account for 40 percent of global greenhouse gas emissions and are the world's largest source of mercury, sulphur and nitrogen oxides.

There are over 600 coal-fired plants in the U.S., which has plans to develop at least 60 new coal plants in the next 10 years. European countries will put into operation about 50 coal-fired plants over the next five years.

Australia, the third highest emitter of greenhouse gases on the planet, receives 80 percent of its energy from coal. "Coal is set to play a big role in future Australian prosperity," said the architect of Australia's climate change review, Professor Ross Garnaut.

China has medium-term plans to build more than 500 coal-fired electricity plants and is opening one coal-fired plant each week. China receives 80 percent of its power needs from coal and India receives 65 percent.

In total over 1000 proposed coal-fired plants will be built in the next decade -- almost at the rate of one new plant every month for the next 10 years.

What are Clean Coal Technologies?

When burned, coal releases mercury, sulphur dioxide (which contributes to the formation of acid rain), nitrogen oxides (which forms smog) and carbon dioxide.

In developed countries, removing impurities from coal, such as mercury, through chemical washing is already common practice. Remaining contaminants including sulphur dioxide and nitrogen oxides are removed from flue gases via scrubbers and steam treatment.

Using a process called integrated gasification combined cycle (IGCC), which turns even the dirtiest coal into gas, 99 percent of the sulphur dioxide and nitrogen oxide emissions can be removed. The technology also removes up to 90 percent of mercury emissions.

Another 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 sulfur 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.

With 90 percent of coal plants utilizing some level of flue gas cleaning technology more recent approaches to clean coal have been focused on capturing and storing the large volume of carbon dioxide that is released to the atmosphere on combustion.

The most common approach being researched for Carbon Capture and Storage (CCS) is sequestering the carbon dioxide from coal-fired emissions and inserting the gas underground into stable, geological formations or beneath the ocean. It is believed that CCS is capable of reducing coal fired emissions by over 90 percent.

CCS is not yet commercially available, but according to Rhona DelFrari, EnCana's Media Relations Advisor, results from the Weyburn Carbon Capture and Storage project in Saskatchewan suggest that CCS is safe and that more than 99 percent of the CO2 sequestered at Weyburn will remain in the ground for at least 5,000 years.

CCS has been pilot tested, with three industrial-scale storage projects in operation worldwide. At the Weyburn project, 3000-5000 tons 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.

The Cost of Clean Coal

Cost is a major limiting factor to the widespread use of clean coal technologies. An IGCC coal plant can cost upwards of $2 billion. The cost of a full scale CCS coal-fired power plant currently runs in excess of $1 billion. A recent pilot plant to be developed by GreenGen was canceled when costs exceeded $1.8 billion. Virtually all of this cost has to be incurred up front.

Gerard Protti, Executive Vice-President of Corporate Relations and President, Offshore and International Division of EnCana, who spoke at GLOBE 2008, said clean coal technology is ready, safe and proven but requires a price on carbon and proper climate change regulation to become commercially accepted.

For a typical new CCS power plant CO2 will need to be priced at $30 per ton emitted for CCS to be considered economically feasible. The current price of carbon is $9 per ton. Pricing carbon would also create an additional operational cost which would likely be transferred to the consumer, increasing energy prices for those in developed countries relying on coal power.

Developing countries that are heavily reliant on coal and remain outside the Kyoto accord, such as China and India, are not subject to such carbon pricing. Thus clean coal technology for the thousands of coal-fired plants in these nations is not a likely scenario.

The cost of using cleaner coal technologies isn't just a monetary issue, but also an energy investment issue. Carbon capture and storage itself is a very energy intensive process. CCS could double the operating cost of power plants and lead to electricity price hikes estimated between 21 and 91 percent.

According to a recent Greenpeace report, between 10 to 40 percent of a power plant's energy capacity would be required for carbon sequestration. For every four CCS-equipped coal-fired power plants, a fifth would have to be added to make up for the new energy demands.

Development Doesn't Measure Up

Considering the sheer number of coal plants around the world, only a minuscule percentage will burn clean coal in the next decade. For example, China plans to build one major emissions-free coal burning power station by 2015. In the meantime the country will build several hundred plants using conventional technology.

On May 5, 2008, the Australian government announced $275 million for just 6 new clean coal plants. Twelve of Europe's 50 proposed future plants will utilize clean coal technology.

The United States has invested $3 billion into 8 clean coal-fired plants which will be developed in the next decade.

Mining Coal Remains a Dirty Business

Coal mining itself results in adverse environmental impacts. Open pit mines leave areas of land that are no longer usable, and difficult to rehabilitate.

Mine tailings are still a significant environmental problem for coal mine operations, but disposal and storage processes are improving. Methods include underground storage, dry stacking in deep pits or depositing them deep within the ocean. Unfortunately each of these options still carry environmental consequences.

Underground mining also takes its toll on the health of its workers, particularly in developing countries, where health and safety policies are often absent. In 2004 China reported over 6,000 coal mining related deaths and 10,000 new cases of black lung, a severe respiratory disease.

As demonstrated by developed nations, efficient health and safety regulations can significantly decrease the risk to worker health. In 2004 the United States reported only 28 coal mining related deaths. Since introducing the Federal Coal Mine Health and Safety Act of 1969, occurrence of black lung in U.S. coal miners has decreased over 90 percent.

The Verdict

Although burning coal more cleanly through IGCC and CCS is possible, the numbers don't add up. Clean coal is far too expensive to achieve at the scale that is required. Indeed, for the vast majority of coal fired plants, clean coal will be out of reach.

By all definitions, clean coal is an oxymoron. It will always be extracted with harm to human health and the environment and it always emit CO2, pollutants and toxins.

This isn't to say that clean coal should not be pursued. There is no changing the fact that coal will be a crucial component of the energy mix for years to come and any facility that can utilize clean coal technology should make use of it.

Cleaner coal may not be the silver bullet that so many hope for; but it surely will be part of whatever solution is eventually developed.

Power plant photo licensed under the Creative Commons by jan kooi.