Steam Turbine Modernizations Driven by the Need for More (Green) Power and Reliability

At Turbo Expo 2025, Michael Smiarowski, Manager Steam Turbine Modernizations at Siemens Energy, shared with Turbomachinery International what’s driving steam turbine modernizations, and how have these drivers have changed in recent years. He spoke about decarbonization efforts impacting steam turbine modernization projects, particularly those regarding efficiency upgrades and fuel flexibility.

What are the primary drivers for steam turbine modernizations, and how have these changed in recent years?

Our nuclear customers are really focused on optimizing their output. It starts with a thermal uprate to increase steam production. With that, you need to look at the steam turbine to determine if it can handle the additional steam. Sometimes, you must change out turbine components to support that. The overriding driver for our nuclear customers is the need for additional power, as well as green, carbon-free power generation.

For fossil units, mainly combined-cycle units on the steam side, we're seeing customers whose equipment is reaching 25 years of operation, where they encounter lifetime and reliability issues. They are looking to modernize the turbine to extend its lifespan for another 25 to 30 years, trouble-free. There are obviously options for this; you can continue repairing and maintaining what you have, but that comes with an increasing risk of future problems.

How are decarbonization efforts impacting steam turbine modernization projects, particularly regarding efficiency upgrades or fuel flexibility?

For nuclear plants, any increase in output is a carbon-free contributor to power generation, so that helps our overall greenhouse gas reduction, which a lot of nuclear customers are focusing on right now.

When you talk about the fossil fleet, specifically gas turbines, and even some existing coal-fired steam turbine plants, you run into some challenges. We're involved in working with customers on unique designs to support carbon-capture and sequestration efforts driven by the need to decarbonize, which have been funded by the government. We're taking care of the steam turbine portion. Overall, steam turbine modernization focuses on increasing the efficiency of operating units—increasing efficiency essentially allows you to generate more power with less fuel. So, overall, it helps with the decarbonization focus.