Wartsila engines arrive at Pioneer Generation Station

A Wartsila engine leaving the railyard on its way to Pioneer Generation Station.

Construction continues at Pioneer Generation Station Phase IV (PGSIV) with the recent arrival of six Wartsila reciprocating engines. The engines, weighing in at approximately 450,000 pounds each, arrived at the jobsite from Finland on Dec. 15. “The engines were transported via ship through the St. Lawrence Seaway and into Duluth, Minnesota,” says Darrell Slavick, Basin Electric construction coordinator III. “From there, they were transported by rail to Williston, North Dakota, where they were transferred to a truck and eventually brought to the site.” 

A lot of people, planning, and organization went into delivering the engines to the site. The transportation crew alone included eight drivers for each truck, ground men, and pilot cars. Those working at PGSIV cleared the site making sure there wasn’t any equipment in the way or other trucks coming into the area. “With every move comes different tasks and processes. Permits need to be applied for and routes need to be carefully planned,” Slavick says. Before departing the railyard, one final call was made to check on permits and clearances from local utilities to make sure everything was in place. 

Each engine took about two hours to travel from Williston to the PGSIV construction site. The engine sat on an 18-line trailer connected to a pull truck and a push truck. “Navigating the truck route through town was probably the trickiest part,” Slavick says. “Getting around the streetlights and low-hanging utilities with these tall loads was a slow process, and then the maximum speed to site was only about 20-25 miles per hour on the open highway.” The process of getting all six engines to the site took five days to complete. 

The engines, consisting of the block, pistons, crankshaft, and heads, were staged in the laydown yard. “All the pieces are laid out and will get moved into the assembly tent as needed, where a big gantry crane will lift them off the trailer or into place on top of the block,” Slavick says. “All of the pieces get uncrated, cleaned, and attached, such as the turbo, the air receiver, some miscellaneous piping and tubing connections, and the oil pan/sump, which also serves as the bottom frame of the unit.” From there, the finished product is re-tarped and brought back out to the laydown yard. 

Once the building is ready to accept the engines, they will move from the laydown yard by a self-propelled trailer to their final resting place. “The trailer will drive each engine over to the building and back it in where they will be set on a “jack and slide” rail system. The engines are hydraulically slid down the length of the engine hall on rails,” Slavick says. Once the heavy-haul contractor places the engines and generators on location, they will be aligned and coupled to each other. Crews can then start working on all associated piping and electrical work to make the engines functional. 

The 18-megawatt engines are a larger version of the twelve existing nine-megawatt reciprocating internal combustion engines (RICE) at Pioneer. The engines can respond to load changes quickly and are very flexible. The engines will sit side by side and run at approximately 520 revolutions per minute. “It’s a very slow-moving engine, similar to a train engine,” Slavick says. 

The next major delivery to PGSIV is scheduled for early February, with the arrival of the first combustion turbine generator. The associated turbine will arrive a couple weeks later. 

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