Public-Private Partnerships Result in Sustainable Energy Project at MMSD

Energy costs in the form of natural gas and electricity are a significant portion of the Milwaukee Metropolitan Sewerage District's (MMSD or District) operating budget. Through a unique set of public-private partnerships, the District is implementing a project that utilizes landfill gas in lieu of natural gas. The landfill gas is used in turbines to generate electricity for plant purposes, and the resultant waste heat is used to dry biosolids and create a commercially available fertilizer Milorganite©. The purchase price of the landfill gas is less than half the cost of natural gas, resulting in significant energy savings to the District and its customers. Further, the energy savings result in a net savings to the District, with consideration of the capital costs. However, it is difficult to quantify future savings, as there are factors (gas prices and landfill gas quantities) that are quite variable. In addition, the change in fuel results in a 95% reduction in District's greenhouse gases from stationary combustion sources. The public-private partnerships have their own set of challenges from contractual perspectives.