Three-part image showing Cat energy storage products and Tucson Proving Ground gatehouse
Three-part image showing Cat energy storage products and Tucson Proving Ground gatehouse

Off the grid, On the money: TPG Gatehouse Gets Sustainable Microgrid, Realizes Major Benefits

Overview

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Power Need

The Tucson Proving Ground (TPG) is a 6,500-acre off-grid mining and training site operated by Caterpillar in the Sonoran Desert located 40 miles south of Tucson. For decades, a guarded gatehouse was reliably powered by a diesel generator set, which had logged over 150,000 hours. It was the perfect time for a more sustainable solution.

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Solution

In February 2025, Caterpillar installed a compact hybrid microgrid. Components of the system include 58 solar panels (on a carport-style canopy), a Cat® XES60 battery storage system (24 kW with a built-in microgrid controller), while retaining the diesel generator as a backup power source.

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Results

The microgrid powers the guard gate 24/7 with minimal generator use. In the first month of operation, it used 50 kWh and saved an estimated $6,000 on diesel fuel, not including maintenance costs. It also resulted in improved working conditions – quieter and more comfortable – for the guard who serves at the gate.

Summary

Caterpillar’s Tucson Proving Ground in Arizona upgraded its decades-old, diesel-powered guard gate with a compact hybrid microgrid system in February 2025. The installation – featuring 58 solar panels, a 24 kW Cat XES60 battery storage unit, and a backup diesel generator – now powers the site efficiently and quietly, saving approximately $6,000 per month in fuel costs. This off-grid solution reduces emissions and improves working conditions while serving as a scalable model for remote or noise-sensitive applications.

Overhead view of TPG gatehouse with solar panels
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Key Statistics

24 kW
Power rating of the Cat XES60 battery storage unit that serves as the system’s energy hub.

$6,000
Average amount saved in diesel fuel consumption per month.

TPG gatehouse showing a guard speaking to a person in a car
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The Impact

  • Lowered overall GHG emissions by replacing nearly continuous generator use with clean solar power.

  • Enhanced energy reliability with battery storage and generator backup.

  • Improved operational insight through real-time data monitoring and solar forecasting.

  • Maximized solar potential with 330 days of sunshine annually in the region.

Quotable

“We’re seeing a lot of interest in hybrid microgrids—on-grid or off-grid. Anywhere customers want to save money on energy, or where power access is limited, this kind of system makes economic and environmental sense.”

Thomas Schwartz
Project Systems Engineer
Caterpillar Electric Power

Closeup of Cactus at Tucson Proving Ground
Closeup of Cactus at Tucson Proving Ground

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    XES60 (60 Hz)

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