Development and Demonstration of a Modeling Framework for Assessing the Efficacy of Using Mine Water for Thermoelectric Power Generation

Thermoelectric power plants use large volumes of water for condenser cooling and other plant operations. Traditionally, this water has been withdrawn from the cleanest water available in streams and rivers. However, as demand for electrical power increases it places increasing demands on freshwater resources resulting in conflicts with other off stream water users. In July 2002, NETL and the Governor of Pennsylvania called for the use of water from abandoned mines to replace our reliance on the diminishing and sometimes over allocated surface water resource. In previous studies the National Mine Land Reclamation Center (NMLRC) at West Virginia University has demonstrated that mine water has the potential to reduce the capital cost of acquiring cooling water while at the same time improving the efficiency of the cooling process due to the constant water temperatures associated with deep mine discharges. The objectives of this project were to develop and demonstrate a user-friendly computer based design aid for assessing the costs, technical and regulatory aspects and potential environmental benefits for using mine water for thermoelectric generation. The framework provides a systematic process for evaluating the hydrologic, chemical, engineering and environmental factors to be considered in using mine water as an alternative to traditional freshwater supply. A field investigation and case study was conducted for the proposed 300 MW Beech Hollow Power Plant located in Champion, Pennsylvania. The field study based on previous research conducted by NMLRC identified mine water sources sufficient to reliably supply the 2-3,000gpm water supply requirement of Beech Hollow. A water collection, transportation and treatment system was designed around this facility. Using this case study a computer based design aid applicable to large industrial water users was developed utilizing water collection and handling principals derived in the field investigation and during previous studies of mine water and power plant cooling. Visual basic software was used to create general information/evaluation modules for a range of power plant water needs that were tested/verified against the Beech Hollow project. The program allows for consideration of blending mine water as needed as well as considering potential thermal and environmental benefits that can be derived from using constant temperature mine water. Users input mine water flow, quality, distance to source, elevations to determine collection, transport and treatment system design criteria. The program also evaluates low flow volumes and sustainable yields for various sources. All modules have been integrated into a seamless user friendly computer design aid and user's manual for evaluating the capital and operating costs of mine water use. The framework will facilitate the use of mine water for thermoelectric generation, reduce demand on freshwater resources and result in environmental benefits from reduced emissions and abated mine discharges