Potential impacts of 316(B) regulatory controls and their affects on existing power plant cooling

Nearly half of the US utility-owned steam electric generating capacity is cooled by once-through cooling systems. These plants withdraw cooling water primarily from surface water bodies. Section 316(b) of the Clean Water Act requires that the location, design, construction, and capacity of cooling water intake structures reflect the best technology available (BTA) for minimizing adverse environmental impacts. The selected BTA is likely to be Modified Traveling Water Screens (TWS) for many of the affected plants. Of large concern to these plants is not only the compliance with 316(b), but the adverse impact it will have on the plants O&M. The new rule will require plants to continuously operate Traveling Water Screens, whereas they are typically run off of pressure differential or on timers they currently run intermittently. The overall effect on the plants O&M budget could be significant.  Over the past several years, several different types of modified TWS technology have been developed, specifically for improving fish mortality rates.

This paper will provide history of the development of modified screens and fish return systems, a technical overview of different modified TWS technologies, review applications where those technologies are applicable, and discuss compliance alternatives available for plants to comply with 316(b).