All coal firing plants emit thousands of of (tons) of carbon dioxide (a greenhouse gas), sulfer dioxide (an acid rain ingredient), nitrous oxide and mercury into the air. Clean-coal technology proposes storing some of the carbon dioxide underground in a liquefied form. The technology is called carbon capture storage. It is anticipated that this will take an additional 25 percent more energy above and beyond what is being produced for normal use. Also the mountain top removal issue which is a disaster all it's own. The cost of constructing such technology would double the cost of a new plant. Storing this liquefied CO2 is setting the table for additional environmental problems. This technology is not environmentally wise, since there is no guarantee that the underground storage will not leak. The technology can not be retrofitted to an existing plant, at least not economically. Thus, current coal-fired facilities will run until their 50 year retirement age is reached.