One of the most important issues facing all types of power plants in the future is what to do about cooling of condensed steam. Currently, the most common method for cooling is water withdrawn from a well, river, lake or ocean following once through a heat exchanger and then discharging the water back into the source. A typical 500 MW fossil-fueled power plant uses over 12 million gallons of water per hour for cooling and other process requirements. However, water is becoming scarcer and power plants are facing new regulations on the intake and discharge of cooling water.

Water scarcity and intake/discharge regulations will drive those seeking to construct a new power plant and current plant owners to consider new water management strategies and alternatives to the "once through approach."  Tighter air pollution rules may also drive utilities to upgrade cooling water systems to help reduce SO₃ and particulate emissions.

Among the options to consider are improving the efficiency of existing cooling systems and plant wide conservation and recirculation of wastewater, new technology such as air-cooled condensers, hybrid air/water cooling systems and zero liquid discharge systems, the use of reclaimed municipal wastewater for cooling water systems and co-generation cooling options that use waste steam for recirculating aquaculture systems, ethanol production and drying sewage sludge. All of these options offer different benefits as well as challenges depending on the type and location of the power plant, water requirements, make up or quality of the water available and applicable local regulations.

The following speakers will address the challenges facing power plant operators relative to cooling water use and the various options available for cooling steam with a discussion of the benefits and problems associated with each, the capital and operating costs of each, economic factors promoting or discouraging water conservation and regulatory compliance issues affecting power plant water intake, use and discharge.  Current and developing technologies to minimize water consumption, enhance water quality and increase reuse of water during all phases of the power generation process will also be addressed.

Brad Buecker, Process Specialist at Kiewit Power Engineers, will present "The Influence of Tightening Regulations on Cooling Water Treatment." Once-through cooling is no longer a consideration for new and planned power plants, primarily due to pending 316a and 316b regulations.  Rather, we almost exclusively see cooling towers or air-cooled condensers as the choice for steam condensation at combined cycle plants.  However, tightening regulations on the quality, and sometimes quantity, of power plant wastewater streams are influencing cooling tower treatment programs.  This presentation examines several of the most prominent trends in the cooling water treatment industry.

Brett DeRousse, National Account Manager for Hydrolox, will present "Potential impacts of 316(B) regulatory controls and their affects on existing power plant cooling water intakes."  Nearly half of the US utility-owned electric generating capacity is cooled by once-through cooling systems. These power 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 power plants. Of large concern to these power plants is not only the compliance with 316(b) but the overall financial affect it will have on the power plants O&M. The new rule will require power plants to continuously operate Traveling Water Screens (TWS), whereas they are typically run off of pressure differential or on timers. The overall affect on the power 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 presentation will provide a brief history of the development of modified screens and fish return systems, as well as a technical overview of several different modified TWS technologies, and review applications where those technologies are most applicable. Finally, he will discuss the compliance alternatives and their long term financial affects on power plants.

Daniel M. Cicero, Senior Industry Development Manager Power Group, Water & Process Services Division of Nalco Company, will discuss how power plants can reduce their environmental impact by using good water chemistry. Every power plant wants to be a good corporate citizen of the community in which it resides.  Every power plant wants to minimize its environmental impact.  Those desires must be balanced with the needs of the community for low-cost power.  This presentation will discuss three cases where power plants achieved that balance.  In one case, using water chemistry modeling allowed a power plant to reduce withdrawals from a stressed waterway.  In another, changing water chemistry reduced the impact of the power plant on the local community.  In a third, the ability to respond to changing water quality reduced water costs and demands on the local water supply.

Trent T. Gathright, Sales & Marketing Manager Cooling Water Products at Ovivo USA, LLC Energy Group – Americas, will briefly address different type water intake screens and 316(b) alternatives. Numerous factors affect power plant cooling water at both once-through and closed cycle types. Various methods have been developed to deal with debris at both type power plants including indigenous debris, foreign blown in material and element disintegration. Pending 316(b) may also affect how make-up water intakes are handled.

Andrew Howell, Senior System Chemist for Xcel Energy, will discuss several technologies that are available for condensing steam in power plants.  Increasing difficulty with obtaining adequate cooling water supply for new generating units has required some power plant designs to use dry or hybrid (wet + dry) cooling systems. While necessary in some cases, these options have significant downsides that must be considered in planning for construction and operation.

(This webinar will be free to all participants.) To register for the Hot Topic Hour on "Power Plant Cooling Towers and Cooling Water Issues" May 23, 2013 at 10:00 a.m. (DST), click on:  http://www.mcilvainecompany.com/brochures/hot_topic_hour_registration.htm