The new assets will be split between the existing Cass County Station and Turtle Creek Station, which is currently under construction.

OPPD chose Siemens Energy to provide the new assets, including four SGT6-5000F combustion turbines, capable of producing 225 MW each. Three would be built at OPPD’s existing Cass County Station. One would be built at Turtle Creek, where the plant’s two original turbines are scheduled to come online later this year. They are expected to be online by 2030.

“These engines are part of the larger system expansion our community is demanding – from more high voltage transmission to more generators, including the Platteview Solar facility in Saunders County and our Standing Bear Lake Station in Douglas County, which will come online in 2024,” aid OPPD Vice President of Systems Transformation Brad Underwood. “That doesn’t include the potential K Junction facility and other generation pursuits we have underway. The totality of all of it is truly amazing.”

OPPD anticipates its load will grow by 100 MW each year for the foreseeable future. As a member of the Southwest Power Pool (SPP), OPPD is required to have enough capacity to meet not only its own customers’ peak energy usage, but also a 15% reserve margin.

OPPD also said the new generation will not impact its commitment to net-zero carbon emissions by 2050.

“We modeled all types of generation and energy storage options that are consistent with that commitment without sacrificing affordability and reliability for our customers,” Underwood said. “The new combustion turbines are part of that journey. A diverse energy mix is crucial to ensuring the critical services of energy supply are not compromised.”

The plants are part of the utility’s Power with Purpose initiative, which is planned to add 1,200 MW of solar and natural gas generation. The natural gas generation plants will be used as needed, per market conditions (estimated to be about 15% of the time). 

Specialized large equipment movers were used for the moving effort, which took place over nine nights in September.

Loaded on a trailer, the engines measure around 248’ long by 14’ wide and 19’ tall. The trailer and engine combined will weigh in at 796,000 pounds. The engines were shipped from Italy and then by rail to Nebraska.

In late fall, two Siemens simple-cycle combustion turbines and generators will be moved to the other new natural gas generation balancing station location, in Sarpy County. Both plants are slated to be completed by 2024.

The public power provider said the delay is only until the utility’s new natural gas generation balancing stations are fully approved for grid interconnection service by the Federal Energy Regulatory Commission and administered by the Southwest Power Pool.

“This is one of those moments where we need to slow down our present path to achieve our future goals,” said OPPD President and CEO Javier Fernandez. 

OPPD’s board previously had approved that the changes occur by the end of 2023, when the new natural gas generation balancing stations – Standing Bear Lake (SBLS) and Turtle Creek (TCS) — were planned to come online. Grid interconnection delays are blamed for the revised schedule. The new natural gas-fired power plants are now expected to enter service by 2026. 

The new capacity includes two simple cycle combustion turbines and six to nine reciprocating engines. 

The utility’s Power with Purpose plan aims to bring around 1,200 MW of new natural gas and solar capability online. OPPD said that once the new gas-fired stations are online, it would look to retire North Omaha Station units 1-3 and refuel units 4-5 from low-sulfur coal to natural gas. 

In 2016, OPPD retired North Omaha units 1-3 from coal operations. Today, these units are available to run on natural gas, serving as peaking units. The station has a total generating capacity of 577.9 MW, according to OPPD.

SBLS and TCS are under construction now. However, the Southwest Power Pool must conduct a grid interconnection study before they can be connected to the grid. In addition, the two new natural gas generation projects have experienced what OIPPD said were “some siting and grading delays,” as well as supply chain issues. The new solar generation projects have also experienced challenges with siting of projects and supply chain challenges, including impacts from recent tariff and related trade actions.

OPPD said it secured in 2020 a slot in the SPP interconnection review schedule. At the time it expected the review process to take around 30 months. Since then, it said that the interconnection queue backlog has doubled the expected time to complete studies and transmission expansion options are being studied. SPP is not expected to complete the OPPD interconnection study before 2024. For planning purposes, OPPD said it will keep the coal-fired North Omaha Station on its books through 2026.

OPPD said that the delays will not affect its commitment to achieving net zero carbon by 2050.