WEC Energy Group (WEC) determined additional natural gas capacity was needed to meet the growing demand on the coldest days in southeast Wisconsin. To meet the demand, WEC received regulatory approval to build two peak-shaving LNG plants adjacent to separate natural gas pipelines in the region – one in Bluff Creek, Wisc. and one in Ixonia, Wisc.

This project is specific to the Bluff Creek location, which received first liquid in November of 2023 and is home to a 12,000,000 gallon double-wall, single-containment liquefied natural gas (LNG) storage tank, compliant with API 625, API 620, and NFPA 59A standards. The scope included the engineering, procurement, fabrication, and construction of the tank foundation, outer carbon steel tank, and inner 9% Ni steel tank. Along with EPFC of the tank itself, the tank insulation system, piping to grade, piping insulation, structural steel, electrical, instrumentation, jib crane, and shop priming work was included in the project scope. Field painting is also part of the project scope and will be completed in 2024 following emergence from winter weather.

The tank design included space for five in-tank pumps to send LNG out of the tank and a jib crane to service the pumps. Fitting everything on the roof created some design and construction challenges, but the design and construction teams pushed through these challenges to execute the project on schedule.

The project was bid and awarded during the toughest times of the Covid epidemic. Project execution followed suit and persevered through the “supply chain” fallout from Covid. Through all these challenges, we were able to execute the project safely with zero incidents and finish on time to meet the client’s goal of storing LNG for the 2023-2024 winter heating season.

Award Name

API 620 Low Pressure Liquid Storage Tank

Company Name

CB&I Plainfield

Award Year


Product Details

  • Wisconsin LNG Project
  • WEC Energy Group
  • Bluff Creek, Wisc.

Date Completed

November 2, 2023

Construction Standard

API 620

Overall Height


Column Height






Steel Tonnage Used


Steel Thickness

0.25” - 1.4’

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