Roseville electric officials say damaged combustion turbine will be rebuilt and plan national lineworkers event

Roseville Electric Chief Operating Officer Sean Matchen told the City of Roseville Public Utilities Commission on Jan. 28 that one of two combustion turbines at the Roseville Energy Park suffered significant internal blade damage and will be rebuilt using replacement parts ordered from the original equipment manufacturer.

“It's a little over $5,000,000,” Matchen said of the current cost estimate for parts and repair, adding that Siemens technicians dismantled the unit in January and confirmed the damage was substantial but repairable. He said staff expect parts to arrive over the next month and Siemens will return in late March to reassemble the unit, with the plant back to full capacity in late April or early May.

The repair path follows an on-site inspection that narrowed the city’s options from a full module replacement to a parts-and-rebuild approach. Matchen said the city engaged its insurance broker, a root-cause analysis firm and the equipment manufacturer to document damage and pursue insurance recovery; the city is treating the work as an insurance claim. He emphasized the timeline is preliminary pending delivery of parts and completion of the root-cause report.

Why it matters: the Roseville Energy Park provides firm capacity to the city’s resource portfolio ahead of summer peaks. Matchen told commissioners that, with the unit offline, Roseville’s system has continued to meet community demand and that the timing of the outage is preferable to a summer failure. He said the department has acquired additional capacity through other resources and would procure more short-term capacity if needed.

Matchen described early investigative findings that point to the variable frequency drive (VFD) control logic used during start-up as the likely cause, but he said the city will wait for the formal root-cause analysis before assigning liability. “We believe … the logic or the programming that controlled when the VFD released the turbine may not have been working correctly,” he said.

In the same presentation Matchen outlined other department items: the electric department will host the American Public Power Association Lineworkers’ Rodeo at the county fairgrounds in late March, a free, public event designed to showcase lineworker skills and safety and to attract several thousand visitors; and the department is consolidating management and administrative staff into renovated space at 116 South Grant Street next week, while the 2090 facility will remain the operations and field crew hub.

What commissioners asked: they pressed for details on the turbine’s age (Matchen said the unit began operation in 2007 and the plant was built in 2005) and on insurance coverage; Matchen said the city is pursuing full recovery through its insurance program but was still early in that process. Commissioners also asked whether the department expects summer shortfalls if this or other older units become unavailable; staff said Roseville has options to secure replacement capacity and recently added approximately 50 MW via an acquisition from the Department of Water Resources.

Ending: Matchen said the department will return with updates as parts arrive and the Siemens reassembly proceeds, and that staff will share the root-cause report when available.