The Challenge
By 2022, the 20 Frame 7B/7E units across these four facilities had accumulated 20 to 30 years of service, and the operational clock was running out. Tightening environmental regulations had rendered the fleet non-compliant with current NOx permit limits. Without a viable path to emissions compliance, forced retirement was not a long-term risk; it was a near-term operational reality.
The conventional solution would have meant full turbine replacement. For a fleet this size, that path required a capital commitment of hundreds of millions of dollars, not including the collateral scope that comes with it. Converting 7B frames to 7E configurations, the standard OEM approach to achieving modern emissions performance, triggers new Heat Recovery Steam Generator requirements. For facilities with existing HRSG infrastructure built around 7B configurations, that is not a modification. It is a rebuild.
The utilities needed to comply with emissions requirements without dismantling the infrastructure they had already built around these units. They needed to preserve output and availability, not trade them away during a multi-year capital program. And they needed a solution that could be implemented simultaneously at multiple sites, across units with varying operational histories, without compromising the safety record of their workforce or Hanwha Power's project teams.
The financial and operational stakes were concrete: approximately 1,200 MW of generation capacity across four operating facilities, with no tolerance for extended downtime or noncompliance.
The Solution
The utilities evaluated their options against a clear set of constraints: achieve sub-5 ppm NOx, maintain existing frame configurations, avoid HRSG modification scope, and preserve output capacity. The OEM path required 7B-to-7E frame conversions, which triggered new HRSG requirements and significantly expanded project cost and execution risk. Hanwha Power's LEC III system offered a different path.
LEC III is a drop-in Low Emissions Combustion retrofit designed for Frame 7B and 7E turbines. Rather than requiring a frame change, it operates within the existing hardware configuration, eliminating the downstream HRSG implications entirely. For these facilities, that distinction translated directly into a reduced project scope, lower capital outlay, and a faster path to compliance, without compromising the existing plant's balance-of-plant infrastructure.
The retrofit scope extended beyond combustion alone. Each unit received an Inlet Bleed Heat system to maintain combustion stability under varying load conditions, upgraded exhaust frame cooling, and selective component replacements for rotors, stators, hot-gas-path parts, and fuel system components. The program was sequenced across individual unit outages ranging from 45 to 150 days, with Hanwha Power field teams of 3 to 8 specialists per site.
Project execution ran concurrently from March 2022 through July 2026 across all four facilities. The scope required coordinating outage windows, logistics, and personnel across PGE Beaver, Duke Madison, AEP Riverside, and AEP Mattison simultaneously, while maintaining fleet availability throughout the multi-year program.
As one project stakeholder at a participating utility noted:
"Partnering with Hanwha Power gave us confidence our aging fleet could perform like new again, meeting modern standards while preserving the value of our existing infrastructure."
The Results
The 20-unit fleet retrofit program delivered measurable outcomes across every performance category that matters to plant operators and asset owners.
On emissions, the program's primary objective, every unit achieved sub-5 ppmvd NOx at 15% O2, an 18% reduction from the pre-retrofit baseline. CO emissions came in below 25 ppmvd fleet-wide. The units now meet current permit requirements with margin, eliminating the near-term compliance risk that had placed forced retirement on the table.
Output and efficiency improved alongside compliance. Hanwha Power guaranteed 58,850 kW per unit, representing a 3.2% increase in output across the fleet. Heat rate improved to 12,970 BTU/kWh HHV, a 2.5% efficiency gain that compounds over the extended operational life of each unit. Post-retrofit availability reached 99.8%.
The strategic outcome is the number that anchors the program's return on investment: 10 to 15 years of life extension per unit, across 20 turbines, preserving approximately 1,200 MW of generation capacity. The alternative was full replacement at a capital cost in the hundreds of millions of dollars, plus the additional scope of HRSG modifications. The LEC III retrofit path delivered compliance, performance improvement, and fleet life extension without triggering that replacement scope.
Across all project sites, over the full duration of a multi-year, multi-site program with teams of up to 8 field specialists per location, Hanwha Power recorded zero recordable safety incidents.
