The process for generating electricity is simple: a boiler fired by natural gas burns fuel and air and water is converted to steam. The steam, under great pressure drives turbines generating electricity. Steam is condensed by thermal exchange with cooling tower water, then repumped to the boiler to repeat the process. The heated water during this thermal exchange step is cooled by evaporation in cooling towers, producing the vapor clouds seen often at power generation facilities. There are three types of cooling water systems:
- One-pass cooling
- Closed recirculating systems
- Open recirculating systems
One issue regarding each of these cooling water systems is that various contaminants may enter the cooling water. If cooling water is discharged from the power plant to either a public treatment works or to a surface water, then water pollution control regulatory requirements may be applicable to your power plant.
As you may know from having visited other locations on the virtual tour, the United States Environmental Protection Agency (EPA) regulates the discharge of water from facilities through provisions of the Clean Water Act, including provisions of the National Pollutant Discharge Elimination System (NPDES) program. EPA has authorized many states to implement and monitor the NPDES program. NPDES permits establish the level of performance the discharger must maintain and specify monitoring, inspection, and reporting requirements and other actions necessary to achieve compliance. NPDES permits set specific requirements regulating the characteristics of the discharged water based on national technology-based effluent limitations and applicable water quality standards.
Applicability of NPDES requirements to a typical college or university power plant vary greatly depending on the activities or discharges associated with the facility and the interpretation by the state regulatory agency charged with enforcing the federal NPDES program (in states where that is the case; not all states have been delegated with this authority).
Although the NPDES regulations include steam electric power generating facilities as an “industrial activity,” activities conducted indoors do not typically impact stormwater quality, and therefore, do not generate “stormwater associated with industrial activity.” If you have an NPDES permit for surface water discharges or for stormwater discharge or believe one is required for your power plant, continue on to the expanded content to learn more about NPDES permit requirements.