Construction began this week on a pioneering hybrid solar and fossil-fuel power generation project at Tucson Electric Power Co.’s H. Wilson Sundt Generating Station.

California-based Areva Solar is building the Sundt Solar Boost Project, which will use a system of focusing reflectors to concentrate sunlight on tubes to produce steam for direct use in one of Sundt’s existing generating turbines.

TEP says the installation at the Sundt plant on East Irvington Road, expected to be operational by October, will add up to 5 megawatts of emissions-free power generating capacity to Sundt’s mainly gas-burning Unit 4 generator during peak-demand periods.

The steam-boosting project is among a handful of similar installations in the world and the only one of its kind in the nation.

A larger U.S. plant built by Florida Power & Light Co. in Martin County, Florida, is of a different design, using a heat-transfer fluid instead of directly generating steam and trough-style parabolic reflectors.

Areva’s “compact linear Fresnel reflector” technology is a system of nearly flat mirrors, arranged in louverlike arrays and motorized to track the sun, to heat up water passing overhead through a linear absorber.

The Sundt project was originally planned to go into operation in early 2013, but permitting delays pushed back construction, TEP spokesman Joe Barrios said.

Over the course of a year, the system will help Sundt produce enough added power for more than 600 Tucson homes, said Areva Solar, part of a leading French energy company.

The total cost of the project, which qualifies for federal tax credits and funding through renewable-energy subsidies funded by TEP ratepayer surcharges, is being kept confidential, Barrios said.

In testimony before the Arizona Corporation Commission when the panel initially approved the project in 2012, the project’s total cost was estimated at $7.8 million.

Contact Assistant Business Editor David Wichner at or 573-4181.