Cat Microgrid Reduces Power Costs For Off-Grid Tucson Proving Ground

The Green Valley area outside of Tucson was an ideal testing location for Caterpillar’s mining division, but the site is too remote to be easily connected to the local utility grid. To generate electricity, Caterpillar relied on three Cat C15 diesel generator sets that ran continuously all year long, using approximately 250,000 gallons of diesel fuel each year. It was clear the facility needed an alternate power solution to reduce costs and align with the organization’s sustainability efforts. At the Tucson Proving Ground (TPG), facility managers worked with local Cat dealer Empire Power Systems to install 528 kWp DC (500 kWp AC) of photovoltaic (PV) solar panels and 500 kW of short-term energy storage in the form of batteries and ultra capacitors to supplement the power generated by the existing generator sets. Empire Power Systems was the original installer of the generator sets at TPG and is responsible for complete microgrid maintenance at the site. With the addition of solar panels and energy storage to its microgrid, TPG expects to reduce its diesel fuel use by 33 percent and its generator set operation by 25 percent.