Distributed generation as a solution for demand waiver heating loads

Minnkota Power Cooperative (MPC) is a generation and transmission utility providing electric power to 11 distribution cooperatives and 12 municipal power agencies in eastern North Dakota and northwestern Minnesota. Cass County Electric Cooperative (CCEC) is a distribution cooperative member of MPC. In the mid 80's, MPC created a program whereby its member cooperatives could market electric heating energy without a demand charge in order to utilize excess energy production. As energy supplies have tightened up, this program was discontinued. The distribution cooperatives had to find a means to offset the electrical demand created by the heating loads which were added under this program and not included in the MPC load management program. In a joint effort, MPC and CCEC have worked to install ten diesel powered generation modules at the distribution level totaling 18.25 MW of peak electrical capacity. These units will he operated synchronously with the grid system during periods of peak electrical demand to offset the non-managed load created by the demand waiver heating program. This paper will detail some of the electrical and mechanical design and installation challenges and solutions for this project. Of special consideration for the project are the cold-weather climate conditions, design aspects for the interconnection, joint monitoring and control requirements, and operational guidelines incorporated into the completed project.