Public Service of New Mexico (PNM) installed an energy storage system for simultaneous voltage smoothing and peak shifting associated with a 500 kW photovoltaic system. The energy storage system is comprised of two elements: a 0.5 MW smoothing battery utilizing UltraBatteries and a 0.25 MW/0.99MWh peak shifting battery using advanced lead acid batteries. The two battery systems, combined with a single 0.75 MW power conditioning system, are co-located with a separately installed 500 kW solar photovoltaic (PV) plant. The battery system was funded by the U.S. Department of Energy American Recovery and Reinvestment Act (ARRA) program. Also, part of the project is a PNM-EPRI collaborative effort to implement smart grid technology at the Mesa Del Sol development near Albuquerque, New Mexico.
This case study provides information on the development of the data acquisition system and optimization of the smoothing and shifting algorithms. Results from tests of smoothing and shifting functions from September 2011 through the first half of 2012 are presented, along with lessons learned.