When Tucson Electric Power added a solar boost system to our largest local power plant in 2016, it was an opportunity to evaluate an innovative green energy technology.

The system used sunlight to boil water, producing steam to help drive a turbine at our natural gas-fired Sundt Generating Station. The system, one of the first of its kind, was designed to boost the plant’s output by up to 5 megawatts without added emissions.

Over time, though, the system proved increasingly unreliable. While it was supposed to provide more power per square foot than conventional solar technology, its shutdowns left it lagging behind the low-maintenance output of a conventional photovoltaic array.

Now that we know other more conventional technologies work better, we’re repurposing its parts to produce a comparable amount of energy at a lower cost, with reduced water use and maintenance costs.

Steam piping from the original system is being retrofitted to capture exhaust from two RICE units to fuel a pair of heat recovery steam generators that will be used to preheat asphalt for local road projects. The system’s ground elevation components, meanwhile, are being reused to mount PV panels.

“Over the last decade, the renewable energy sector has seen unprecedented growth and a rapid expansion of technology,” said Dylan Bearce, Director of Tucson Power Production. “It’s important that utilities embrace innovation around alternative technologies as we shift away from traditional resources. As technology changes, we also need to be nimble and respond to evolving efficiencies and improvements. This retrofit is the best option for our customers by allowing us to build on our earlier investment to produce a better outcome.”

Watch a time-lapse video showing the dismantling of the system, which weighed 2,400 pounds and included more than 500 74-foot long steel mirrors.

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