19.6 Can coal’s emissions be cleaned up?

Of course it’s not just the mining and processing of coal that pollutes the environment.

When coal is burned to produce heat energy, it releases a range of toxic substances that damage the environment and threaten human health: gases (sulphur dioxide, carbon monoxide, nitrogen oxide, and planet-warming carbon dioxide), heavy metals (such as mercury and arsenic), radioactive material (uranium and thorium), and particulate matter (soot) with particles small enough to irritate lung tissue or even enter the bloodstream if inhaled. The EPA’s new Mercury and Air Toxic standards of 2011 will reduce emissions of some of the less well-addressed toxic substances by 90% and will save up to $90 billion in human health costs by 2016 (while only costing $9.6 billion to implement).

Coal-fired power plants also generate tons of toxic fly ash—fine ashen particles made up mostly of silica. Some of that ash is diverted to industry, where it’s used in concrete production. But the majority of it is buried in hazardous waste landfills or stored in open ponds like the ones used to contain the slurry waste from mining. In 2008, following a heavy rain event, a 15-metre-tall dike from a pond holding coal fly ash from the TVA Kingston Fossil Plant in Tennessee failed, releasing more than 4 billion litres of fly ash into nearby rivers and coating vast expanses of riverside land. The EPA estimates that cleanup will cost $1.2 billion—more when property damage and lawsuit settlements are factored in. Federal regulators have since identified more than 100 other U.S. ash ponds at risk for breach. [infographic 19.6]

In 2011, public health researchers from Harvard University tallied up the costs of mining and using coal. The analysis took into account many (but not all) of the external costs from mining, shipping, burning, and waste production —that is, the costs that are not currently reflected in the market cost of coal. They estimated that coal costs the U.S. public between $300 and $500 billion a year in externalized costs (health, environmental, and property costs). This amounts to an extra $0.10 to $0.26 per kWh in external costs—in some cases more than twice what consumers actually pay.

So what can be done? On the one hand, coal provides necessary power. On the other, the processes of mining and then burning it are harming people and the environment as much as they are sustaining lifestyles.

One potential solution is clean coal technology—technology that minimizes the amount of pollution produced by coal. For example, scientists and engineers around the world are working on ways to capture the gases emitted from burning coal. We already have the capacity to capture some emissions like particulate matter and sulphur (see Chapter 21).

The next big challenge is carbon capture and sequestration (CCS)—the capture and storage of CO₂ in a way that prevents it from reentering the atmosphere. There are many approaches to CCS; some of them promise to capture more than 90% of CO₂ emissions from coal-fired power plants. But most are still in the research and development stage, and so far, progress has been hindered by the cost of capturing the carbon and by a dearth of good storage options. The extra energy needed to implement CCS must also be considered: estimates for the additional energy needed range from 25% to 40%—this means 25% to 40% more coal that must be mined, processed, transported, and burned. [infographic 19.7]

Another emerging clean coal technology involves chemically removing some of coal’s contaminants before burning it. While it still contains some toxic substances, the final product (a liquid or gaseous fuel, depending on the process used), is cleaner than the original coal. Of course, this process requires energy (thus lowering coal’s EROEI) and generates hazardous waste (from the toxic substances found in the coal) that still has to be dealt with.

In fact, as critics are quick to point out, coal can never be truly clean. Each of these “clean coal” technologies produces its own toxic by-products, and none of them eliminates the need to mine coal from deep within Earth’s surface.

But if we can’t easily avoid using coal, or make it totally clean, we can certainly try to use less of it. One way to accomplish this is to design and use more energy-efficient appliances. Less than 40% of the energy from coal is converted to electricity, but the amount of that energy that goes toward powering appliances depends on how efficient those appliances are. We can also reduce our coal consumption through simple conservation efforts like turning off lights and electronics when we’re not using them. Every kilowatt-hour of electricity conserved means roughly 0.45 kilograms less of coal being burned. And a growing number of public utilities now offer “green power” programs in which users can choose to buy electricity that has been generated by solar or wind power instead of coal (for more on energy efficiency and conservation, see Chapter 24).