The primary purpose of the central plants is to generate and distribute steam which is used for heating, humidification, domestic hot water heating, sterilization and making distilled water. During the cogeneration process, the steam passes through a 34 MVA double automatic controlled extraction pressure and condensing steam turbine generator. As a result, up to one-third of the electricity used on campus can be produced as a byproduct. This combination results in an overall thermal efficiency of twice that of any plant built solely for the purpose of power generation.
In addition to maximizing energy efficiency, cogeneration significantly minimizes the impact to the environment. Coal, the most plentiful and economical fuel available, is used primarily; however gas and fuel oil can be used as backup. The facility relies on advanced technology called circulating fluidized bed (CFB) and continuous air emissions monitoring equipment ensures compliance with all State and Federal air quality regulations.
Steam is generated in circulating fluidized bed boilers. The main advantage of CFB technology is the reduction in the emission of acid rain producing components, primarily sulfur dioxide and nitrous oxides. Sulfur dioxide is reduced by the addition of calcium containing products, such as limestone, to the combustion chamber. The limestone reacts with the sulfur dioxide to produce calcium sulfate, which is removed from the combustion process with the remaining ash. Nitrous oxide production is minimized by maintaining the combustion temperature at approximately 1,600 degrees Fahrenheit; a level much lower than conventional fossil fuel combustion temperatures which normally exceed 2,200 degrees Fahrenheit. The fly ash waste produced is sent to a local company which reuses the ash for structural fill and treatment.
Steam is distributed through an extensive network of underground steam and condensate return piping in excess of fifty miles.Annual Emissions Inventories
In 2000, our Cogeneration Facility was awarded a Certificate of Recognition by the US Environmental Protection Agency and Department of Energy for superior environmental performance.
In 2001, we were recognized by the US Environmental Protection Agency as a CHP Founding Partner for our significant contribution in increasing the use of combined heat and power.
In 2002, we were recognized by the US Environmental Protection Agency and The International District Energy Association for continued efforts to improve environmental performance by promoting pollution-preventing district energy and combined heat and power.
In 2003, we received the Energy Star Award presented by the US Environmental Protection Agency in recognition of the significant fuel savings realized by our campus.
And for each subsequent year to date, we continue to be recognized for emission reductions compared to separate heat and power plants.
Energy Services Maps
- All Utilities
- Chilled Water
- Whiteway (Lights)
- Wastewater & Reclaimed Water
- Energy Dashboard
- Customer Billing Portal
- Policies and Procedures
- Employee Portal
- Climate Action Program
925 Branch St.
Chapel Hill, NC 27599