Clean Coal Technology

Even the most ardent anti-environmentalist will acknowledge that coal is among the dirtiest of all fossil fuels. It produces emissions that are believed to have some impact on climate change, create acid rain, and pollute water. Given the recent positive resurgence of interest in nuclear power, hydropower, and various forms of renewable energy sources, one might deduce that coal will soon be marginalized and removed from the overall energy portfolio of viable options. However, this is not a reasonable or viable view because:

• Coal currently generates almost half of the electricity in the U.S. and given its lower costs and plentiful supply will likely to have a major role in the U.S. energy supply for many years to come.
• Clean coal technology, aimed at addressing the harsh environmental effects of coal, provides a potential solution to the dilemma around our strong reliance on an energy source that causes such potential damage to our environment.

Available Clean Coal Technologies

According to the Energy Information Administration (EIA) over 92 percent of the U.S. supply of coal goes towards the production of electric power. It is the burning of coal to make steam that turns turbines that generates electricity. During combustion, coal releases carbon dioxide and other emissions in flue gases. There are a number of clean coal technologies available to improve this process and lessen the impact to the environment. They include:

• Coal Washing removes undesirable minerals by mixing the crushed coal with a liquid, thus separating the impurities and allowing them to settle.
• Wet Scrubbers minimize the occurrence of acid rain by spraying the flue gas with limestone and water, thus removing sulfur dioxide.
• Low Nitrogen Oxide (NOx) Burners reduce ground-level ozone by restricting oxygen and adjusting the combustion process.
• Electrostatic Precipitators remove the particulates that can contribute to respiratory challenges such as asthma.
• Gasification, produce syngas as part of an integrated gasification combined cycle (IGCC) process, and thereby avoids burning coal altogether.
• Carbon Capture and Storage catches and isolates carbon dioxide emissions from the power plant, applying a number of developed carbon capture processes:

-   Flue Gas Separation separates the carbon dioxide from other flue gases, resulting in a commercially viable product for other applications.

-   Oxy – Fuel Combustion creates a flue gas primarily of carbon dioxide and water by burning the fuel in pure or enriched oxygen.

-   Pre – Combustion Capture removes the CO2 prior to burning.

With respect to the actual storage, containers are used to prevent or delay its reentry into the atmosphere at least until peak emissions subside hundreds of years from now, using one of two options:

• Geologic storage where oil gas fields and deep saline aquifers contain the CO2
• Ocean storage where liquid CO2 is injected into deep waters and dissolved under pressure.

With the acceptance that alternative forms of energy are not yet able to replace coal within the realities of price and generating capacity, the continued adoption and integration of clean coal technologies offers a potential way to mitigate the environmental effects of coal emissions. There are still some economics challenges to resolve, most notably issues around a tax or value of carbon emissions, but as these issues come into focus and are resolved through public policy these concepts around CO2 emission reduction will become more viable.