Siemens Energy Lands Third HL-Class Contract with AECI for 420 MW Oklahoma Peaker

Why Is Associated Electric Cooperative Building a New Peaking Plant in Oklahoma?

Associated Electric Cooperative, Inc. (AECI), a member-owned, not-for-profit electric cooperative serving rural Missouri, Oklahoma, and Iowa, has selected Siemens Energy's SGT6-9000HL gas turbine for its 420-megawatt Bristow Energy Center natural gas peaking plant in Creek County, Oklahoma. [1] The cooperative has been contending with rising peak demand on both ends of the calendar. "We continue to see growing summer and winter peaks on our system," said Sean Wright, Vice President of Engineering and Construction at AECI. "To protect reliability today and into the future, we have a real need for quick-start, peaking capacity to serve our member-owners." [1]

What Makes the SGT6-9000HL Well-Suited for Peaking Duty?

Fast ramping is a defining characteristic of the HL-class, with the SGT6-9000HL capable of achieving up to 85 MW per minute and reaching full capacity in world-record time — enabled by an optimized thermal management system and internally cooled rotor passages that allow free thermal expansion during fast transients, supporting both cold and hot starts. [1] For a unit that may sit idle for extended periods before being called on hard, that thermal flexibility matters. Alongside the turbine, Siemens Energy will supply an SGen6-2000P generator and a dilution SCR system to meet emissions compliance requirements at the site. [1]

How Does Bristow Fit Into AECI's Broader Generation Strategy?

Bristow is the third SGT6-9000HL contract Siemens Energy has signed with AECI, following two agreements in 2023 for the Ripley Energy Center in Oklahoma and the Turney Energy Center in Missouri, both currently under construction. [1] The repeat purchases point to a deliberate build-out of fast-response gas capacity across AECI's territory — a pattern reflecting the pressure Midwest cooperatives face as electrification and industrial load growth push reserve margins tighter.

What Is the Status of the HL Fleet More Broadly?

As of March 2026, Siemens Energy has sold more than 55 HL-class turbines, with 16 already in commercial operation. [1] Josh Kovac, HL Product Director at Siemens Energy, pointed to the fleet’s track record as central to the value proposition: "The HL provides flexible, reliable power with fewer resources — translating into long-term cost and emissions benefits for our customers." [1] Pending regulatory approvals and permitting, AECI expects construction at Bristow to begin in 2027, with the unit commercially available in 2029. [1]

References

• [1] Siemens Energy. "Siemens Energy to supply HL turbine to Associated Electric Cooperative for new peaking plant in Oklahoma, USA." June 8, 2026.