Measuring emissions to monitor abatement efforts requires sophisticated instrumentation in a very unsophisticated environment.
　　American Electric Power (AEP) may not be one of the most familiar corporate names to the public, but it has minute-by-minute importance to millions of customers throughout the country. Columbus, OH-based AEP, which celebrated its 100th anniversary in 2006, owns seven public utilities that are household names in Arkansas, Indiana控制工程网版权所有, Kentucky, Louisiana, Michigan, Ohio, Oklahoma, Tennessee, Texaswww.cechina.cn, Virginia and West Virginia. In additionwww.cechina.cn, AEP operates one of the world’s largest transmission and distribution systems, with more than 38,000 circuit miles of transmission lines and more than 186,000 miles of distribution line.
　　Like most electric utilities in the U.S., AEP generates a significant portion of its electricity by burning coal. That means the company faces increasingly strict government regulations aimed at limiting harmful emissions控制工程网版权所有, including the U.S. EPA’s new Clean Air Mercury Rule (CAMR). In response, the company is making substantial investments in new continuous emission monitoring systems (CEMS) at more than three-dozen of its plants. Products from Weed Instrument Co. play a significant role in the reliable operation of those monitoring systems by isolating delicate monitoring equipment from potentially destructive power surges.
　　The coal-mercury issue
　　Mercury is a toxic, persistent pollutant that can be transported thousands of miles through the atmosphere into waterways, where it makes its way into the food chain. In 2005, the EPA responded to the problem by issuing the CAMR, which is intended to cap and gradually reduce mercury emissions at coal-fired plants. The first-phase cap, which takes effect in 2009, mandates a reduction of mercury output nationwide from the current estimated level of 50 tons annually to 38 tons. The second phase, due in 2018www.cechina.cn, is intended to reduce emissions to 15 tons.
　　AEP plans to reduce its mercu