In Pennsylvania, the Municipal Authority of Westmorland County (MAWC) is required by the Pennsylvania Department of Environmental Protection to comply with a continuous discharge mandate. The minimum flow rate from Beaver Run to Beaver Run Creek must be 6.5 million gallons a day (MGD). With a rising cost of electricity and removal of rate caps, the MAWC was faced with the challenge of meeting the discharge requirement while non-invasively recovering energy for behind-the-meter use. The pre-existing system consisted of two parallel pipes, one 8-inch diameter and one 12-inch diameter. Both of those pipes lead from the industrial raw water main to the Beaver Run Creek. Rentricity used existing pump and turbine technology to create a unique energy recovery system to fit MAWC’s needs.
By August 2010, Rentricity installed a new underground vault to house a 30kW turbine generator. In addition, Rentricity replaced the 8-inch line with a 12-inch bypass line to accommodate the mandated 6.5MGD release in the event that the turbine generator goes offline. In normal operation mode the turbine generator operates continuously. For added convenience, a control panel in the pump house allows for local or remote startup. The system is recovering energy for MAWC that was previously lost. The system is estimated to be producing over 250MWh per year. This will save approximately $40,000 for MAWC. Electricity costs make up one-third of their production budget.