Sundt Power Lines

Tucson Electric Power is moving forward with plans to install new local generating resources that will support the company’s plans to deliver more renewable power to customers.

TEP already has more than 330 megawatts (MW) of community-scale renewable energy resources, enough to meet the annual electric needs of about 115,000 homes. The company is working to deliver at least 30 percent of its power from renewable resources by 2030.

Although solar arrays and wind turbines are great options for meeting customers’ energy needs, they can present challenges, too. Their variable energy output can cause voltage instability and other problems if TEP can’t quickly compensate for the fluctuations.

That’s why TEP is preparing to install modern, flexible natural gas generating resources and planning for other improvements at its largest local power plant. The company recently signed an agreement for 10 reciprocating internal combustion engines with a combined capacity of up to 200 megawatts. These natural gas-fired units can run efficiently and cost-effectively even while making frequent adjustments to power output levels. They also can enhance reliability during periods of peak energy demand.

“As we add more solar and wind, we’ll also need a resource that can respond quickly and reliably to the variable production of renewable resources,” said Conrad Spencer, a TEP Power Production Director overseeing the project. “If a cloud passes over a solar array, production drops rapidly. When the sun shines again, production will ramp up again. These reciprocating engines can adjust quickly to help fill in the gaps.”

As the new units become available, TEP will shut down two less efficient steam generators that were built in the 1950s and are nearing the end of their useful lives. TEP also will build a new substation and make other improvements to support the project, which will result in fewer emissions and lower water usage.

The new facilities are expected to come online in 2019. More information about these and other improvements are available at

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