Selecting BTA in the Real World

Although the National Rulemaking for Section 316(b) has yet to be finalized, several state regulatory agencies have been moving ahead to establish BTA for existing cooling water intakes within their jurisdiction.  One of these regulatory agencies is the New York State Department of Environmental Conservation (NYSDEC), and one of the early facilities to have completed the BTA selection process is located on Long Island.  Entrainment and impingement at this facility is dominated by common inshore marine species of Long Island Sound, including tautog, cunner, and Atlantic menhaden.  The selection of BTA began with a screening of all reasonable intake and operational alternatives to determine those feasible at this facility that also will reduce current levels of entrainment and impingement.  One key factor in selecting BTA at this facility is the load-following (cycling) operation during the warmer months when entrainment is expected to be highest and low anticipated operation during the colder months when impingement is expected to be highest.  This operating mode opens the door for considerable reductions in cooling water flow when generating load is low.  A detailed review of the potential for both entrainment and impingement survival also was conducted to include in the evaluation process.  Analysis of the potential benefits of each of the feasible alternatives revealed that variable-speed drives (VSDs) on the existing cooling water pumps and continuous screen operation, coupled with entrainment and impingement survival, would reduce entrainment to more than 90 percent of the level of cooling towers and impingement to a level equivalent to cooling towers.  Further, when taking into account installation times, VSDs actually would provide greater reduction in entrainment than cooling towers for more than 40 years into the future.