Gasturb 13 May 2026

A 14-stage axial design, but with a trick: the first four rows of blades were made from a titanium-aluminide alloy that United Turbine had licensed from a bankrupt Swiss metallurgy firm. This allowed the compressor to swallow dirty air (paper mills are full of fibrous dust) without eroding the blades for at least 35,000 hours. The distinctive whine of a Gasturb 13 at start-up—a rising, almost mournful howl that peaked at 7,100 rpm—was known as the “Vinter Scream,” after its creator.

A two-stage, free-power turbine (separate from the gas generator spool) that turned at a fixed 3,600 rpm for 60 Hz grids. This was the genius of the dual-shaft design. When the generator breaker tripped or the grid frequency dipped, the gas generator spool could overspeed by up to 15% without destroying the power turbine. A GE Frame 5 would have shed its blades. A Gasturb 13 would simply howl louder, then settle back. One operator at a Louisiana chemical plant reported that his unit survived 47 grid disturbances in a single hurricane season—and still started the next morning. The Operational Reality Owning a Gasturb 13 was like owning a vintage sports car: exhilarating when running, but requiring a sixth sense to keep it that way. The turbine’s Achilles’ heel was its magnetic thrust bearing . Because of the cold-end drive arrangement, the entire 8-ton gas generator spool was supported on a single, oil-lubricated magnetic bearing at the compressor inlet. When it worked, it was frictionless perfection. When it failed—usually due to contaminated lube oil—the spool would walk forward, grinding its blades into the stator. A “spool walk” event was the stuff of nightmares: a deep, guttural grinding noise followed by a cloud of atomized titanium and the smell of burned ester oil. Gasturb 13

Facing bankruptcy, United Turbine’s chief engineer, Dr. Alena Vinter, made a radical bet. Instead of competing with the American giants (GE and Westinghouse) on pure megawattage, she proposed a for the emerging deregulated power market. The goal was not to run 24/7 for 40 years (the coal plant model), but to cycle daily, follow volatile renewable output, and provide both electricity and process heat to paper mills, refineries, and district heating networks. A 14-stage axial design, but with a trick:

Then came the crash. United Turbine AB, never financially stable, was gutted by the post-9/11 industrial recession. In 2004, the consortium declared bankruptcy. Spare parts dried up. Siemens and GE, sensing weakness, began offering aggressive retrofits: replace your Gasturb 13 with a “modern” single-shaft machine, they said, and gain 8% efficiency. Thousands of owners took the deal. The Gasturb 13s were scrapped, or sold for parts, or left to rust in place like industrial ghosts. A two-stage, free-power turbine (separate from the gas

The result, after 13 compressor redesigns—hence the name—was the GT-13/2. It was a 42-megawatt, dual-shaft machine with a pressure ratio of 16:1 and a turbine inlet temperature of 1,230°C (2,246°F). Unremarkable on paper. But its soul was in the details: a configuration that placed the generator at the air intake side, allowing the hot exhaust to be ducted directly into a heat recovery steam generator without awkward bends. And a variable inlet guide vane (VIGV) system so precise that operators joked the turbine could “read a newspaper” at 50% load. Anatomy of a Legend To walk around a Gasturb 13 in its natural habitat—say, the boiler house of the Holmens Bruk paper mill in Norrköping, Sweden—was to experience industrial design as art and menace. The machine was 11 meters long, painted a heat-faded battleship gray, with the telltale orange-brown staining around every bolted joint that signaled years of leaky, righteous operation.