In 2002, the state passed a law meant to curb acid rain. The new law meant coal plants had to figure out how to trap sulfur in their smoke stacks, preventing it from entering the air. Eight years later, Charlotte's Shaw Power Group and Alstom Environmental Control Systems, of Tennessee, are working to help Duke Energy meet the state's 2013 deadline at its coal plants. There are at least three coal plants in the Charlotte area, one in Belmont, one on Lake Norman and another on Mountain Island Lake.

The Mecklenburg Times' Sam Boykin reports:

Duke Energy’s four largest plants in North Carolina, which operate around the clock, needed radical filtering implants.

In 2003 Shaw Power Group formed a consortium with Alstom Environmental Control Systems of Knoxville, Tenn. The consortium won Duke Energy contracts to retrofit the four with flue gas desulfurization units, known by a much less lofty title: scrubbers. They are designed to reduce such harmful emissions as sulfur dioxide.

Jim McCarthy, Shaw Power Group’s chief mechanical engineer, said the company opened its Charlotte offices in 2004.

“Initially it was because we had contracts with Duke Energy, but Shaw Power realized there would likely be other opportunities and projects,” McCarthy said. “There was a lot of potential in the power industry in general, not just in the environmental retrofit sector.”

That project will bring Duke Energy into full compliance with the CSA 2013 deadline, Thompson said. “Overall,” he said, “we expect by the end of 2010 to reduce our system (sulfur dioxide) emissions by 70 percent in our five-state territory, and total (sulfur dioxide) reduction for North Carolina will be 75 percent by 2013 over 2000 emission levels.”

Read the entire article here.

According to the U.S. Environmental Protection Agency, acid rain is harmful because it can make it difficult for people with asthma or other respiratory issues to breathe. It can also corrode buildings, statues, monuments and cars, peel paint, damage waterways and forests and cause ground-level ozone.

Yesterday, Charlotte experienced it's first Code Orange day of the year due to elevated levels of ozone.

Get daily updates on Charlotte's air quality on Twitter from the North Carolina Division of Air Quality.

How burning coal leads to acid rain: