Siemens Energy Highlights Alternative Fuels to Power Gas Turbines, Decrease Emissions, Boost Decarbonization Efforts

Last week, Siemens Energy and Net Zero Technology Centre (NZTC) reported the successful operation of an SGT-A35 gas turbine on methanol. It demonstrated a decrease of up to 80% in NOx. Tyler Clifford—Senior Technology Engineer of Fuel Flexibility, Hydrogen, and Carbon Capture at Siemens Energy—spoke with Turbomachinery International about the company’s partnership with NZTC and its recent demonstration using an alternative fuel to decarbonize a gas turbine. Siemens Energy manufactured and installed the new components needed for the methanol-fuel conversion using 3D printing techniques.

TURBO: What are the main drivers for using methanol as an alternative fuel?

Clifford: Diesel-fueled gas turbines are commonly used as emergency backup power sources in industrial applications and power generation or marine propulsion. They are favored for their reliability, efficiency, and quick start-up capabilities, making them ideal for various critical and remote applications.

Methanol can replace diesel as backup fuel or provide a lower emission alternative for power generation e.g., in remote locations where pipeline supply of gas is not available. Methanol is also an attractive fuel for the marine industry to replace fuel oils, due to its ease of storage onboard and global availability in numerous ports.

Methanol has a well-established global supply chain, and its methods of storage and transportation are well-understood, making it attractive from a supply-chain perspective. The production of green methanol is rapidly growing due to demand in the marine industry, which can simply be ‘dropped’ into this existing supply chain.

TURBO: During this demonstration, what percentage of methanol was used, and what type of methanol(s) was used?

Clifford: For this demonstration, 100% conventional methanol was used.

TURBO: What are the advantages of using 3D-printed components to retrofit a gas turbine? How long does a retrofit take? How long did it take to retrofit the turbine used in this demonstration?

Clifford: 3D printing allowed for rapid prototyping of multiple concept designs. These concepts were subjected to flow testing at atmospheric conditions, allowing us to down-select the designs based on the most promising results for the full engine demonstration. It took around one week to install and commission the retrofit for this demonstration, which included gas turbine combustion components and auxiliary systems such as:

• a fuel system
• fuel pump
• fuel tank
• nitrogen blanketing system
• fire and gas detection
• suppression and control system modifications

This was specific to this demonstration test on a test bed; implementation at commercially operating sites may vary.

TURBO: What are the benefits of methanol in terms of decarbonization? Does it increase fuel costs or is it comparable to natural gas?

Clifford: Methanol can be produced from various feedstocks. Conventional methanol is typically made from natural gas but can still offer a 10% reduction in CO₂ emissions compared to diesel. Methanol can be made from lower-carbon sources such as biogenic (bio-methanol) or renewable hydrogen and captured CO₂ (e-methanol), offering up to 95% reduction in CO₂ emissions.

From a cost perspective, conventional methanol is competitive with diesel. Of course, cost will increase using methanol with a lower-carbon intensity such as bio- or e-methanol. Methanol, in all its forms, reduces NOx emissions by up to 80% as well as reducing other pollutants such as SO2, particulate matter, and smoke.

TURBO: What other practical steps can gas turbine manufacturers take to reduce CO₂ emissions in difficult-to-decarbonize industries?

Clifford: There are several pathways available to decarbonize gas turbines. Firstly, by increasing the efficiency of the gas turbine by upgrading with more efficient parts or digital plant optimization solutions resulting in lower fuel consumption and therefore fewer emissions. Secondly, reducing the use of carbon-based fuels by blending in lower carbon fuels such as hydrogen. For full decarbonization, the switch to 100% carbon-free fuel is required. Fuels considered by Siemens Energy for use in its gas turbines are hydrogen, methanol, biofuels, and ammonia. Alternatively, traditional fuel (i.e., natural gas) can continue to be used with carbon capture and storage (CCS) to capture the CO₂ emissions generated from the plant.

TURBO: What other decarbonization efforts is Siemens Energy involved with?

Clifford: Siemens Energy supports decarbonization in each of its four business areas. The wind business with its subsidiary Siemens Gamesa is at the forefront here. The solutions provided by the Grid Technologies business area ensure that climate-neutral electricity is transported to where it is needed. Transformation of Industries is dedicated to the decarbonization of energy-intensive industries and the production of PEM electrolyzers for hydrogen production. The decarbonization of gas turbines falls within the remit of the Gas Services business area.