By Mary Schmidt
The real power behind the new generation station in Rochester, Minnesota has nothing to do with megawatts and everything to do with collaboration and transparency. The Westside Energy Station can generate 47 MW of power for customers in and around Rochester, and it is a study in teamwork and pre-planning.
When Rochester Public Utilities (RPU) decided to replace its 1949-vintage Silver Lake coal-fired plant, part of the plan was to add a new generation station designed for additional peaking power capacity, increased efficiency, and significantly lower carbon emissions. Design engineering of this new plant began in spring of 2016 and construction began that fall; the $62.6 million facility was fully operational in early 2018. It is the largest power development project ever undertaken by RPU.
“This natural gas power plant will help meet RPU’s capacity obligation with reliability and reduced emissions, and keep prices low by being able to hedge against the risk of volatile electricity prices,” said Jeremy Sutton, Director of Power Resources at RPU.
“We had to develop a level of trust and rapport with the owner and Wartsila.” – Tony Densmore, Boldt
The project was on an aggressive timeline. Engineering firm Sargent & Lundy and construction firm The Boldt Company formed a joint venture called The Westside Energy Partners to fast track planning. The project faced construction issues early on; later crews had to base all planning on the shipment date of five 20V34SG natural gas fired reciprocating internal combustion engines (RICE) supplied by technology group Wärtsilä.”
Before one shovel broke the dirt, the contract between owner, engineer, and construction company was written to meet unique challenges. The agreement fixed prices for design and general conditions on the project, it provided a fixed margin structure for the work, and it provided an open-book approach for the balance of the plant delivery. Under this agreement, the owner allowed flexibility in how work was performed and materials were sourced to best meet the project requirements.
“We had to develop a level of trust and rapport with the owner and Wärtsilä,” said Tony Densmore, Boldt project manager. “We had a budget and within that, incremental savings were used to create contingency funds which were used to provide additional scope to enhance the facility.”
Construction and engineering teams executed the project with maximum transparency. “We had an obligation to provide clarity,” said Nelson Rosado, engineering project manager for Sargent & Lundy. “When we made decisions on design features and materials, we were completely transparent and gave the owner a chance to weigh in.”
Construction and design collaboration: start early
Pre-construction planning began early with weekly meetings between Sargent & Lundy engineering, Boldt construction management, engine manufacturer Wärtsilä, and the owner’s management team leaders. All parties reviewed balance of plant engineering, procurement, constructability issues — and all players made decisions in a transparent environment.
“Early collaboration is key,” Rosado said. “It allows us to clarify the technical issues and incorporate the owner’s requirements for local siting and permitting, sustainability, reliability, and ongoing operation of the facility. At the end, the owner gets what they want and need.”
The collaboration was tested early on when the owner indicated the site was on a floodplain and needed to be elevated and stabilized. Boldt and Sargent & Lundy crews persuaded the owner to start construction six months early in order to meet the end deadline that required stabilizing the earth under equipment foundations and working through a complicated local permitting process. Crews also had to beat oncoming winter weather. Boldt teams raised the site five feet using more than 900 gravel piles to support the weight of the equipment across the power island footprint. Construction closed 2016 with earthwork complete and resumed work in spring of 2017, thus saving the owner time and money.
Construction involved complicated scheduling and critical path planning spearheaded by Boldt/Sargent & Lundy, but was entirely dependent on delivery of the five 150-ton engines. The RICE units are designed to provide quick-start power generation in regions needing energy on short notice and ancillary power services to maintain grid stability. Their flexibility is becoming a high value characteristic for power customers due to the increasing reliance on intermittent renewable energy.
“They have the ability to be at full load extremely quickly and come off-line rapidly.” – Josh Klopp, Wartsila, on the flexibility of reciprocating engines.
“They’re the ultimate, flexible technology,” said Josh Klopp, business development manager for Wärtsilä. “They have the ability to be at full load extremely quickly and come off-line rapidly. Reciprocating engines are designed to be maintained on site and are an excellent complement to renewable energy.” The units installed at RPU can go from sitting idle to providing power to the grid in less than ten minutes, but in other installations engines have achieved full load in two minutes.
The foundations and balance of plant tie-ins had to be completed quickly to set the massive engines when they arrived in June of 2016.
“You need close cooperation between Wärtsilä, the construction company, and the owner to ensure there’s a proper laydown area and proper coordination,” Klopp said. Each engine arrived fully assembled at the site on flatbed transports and supporting equipment for each engine arrived at the site in 12, 40-foot conex shipping containers.
Construction built on transparency
“One of the best aspects of this project was the owner created a culture that allowed us to get the job done as a team,” Densmore said.
It was a tight time frame to get the building completed enough to set the engines. Densmore managed more than 25 subcontractors, but had the flexibility for Boldt crews to self perform most of the construction. Boldt teams did concrete work, erected steel, installed the exhaust system, installed all major equipment systems, and built out the control room and admin building. Key subcontractors installed the electrical systems for the engines, and provided insulation and specialty mechanical tie-ins. Constant review of the work process between Boldt, Sargent & Lundy, and the owner helped save time and money.
“By self-performing work we had fewer subs to manage and flexibility in shifting resources,” Densmore said. “We could identify the work that made the most sense on any one day and juggle workers and schedule tasks to meet our goals without waiting for subcontractors.”
The exacting work of installing the RICE units required adhering the to the tight tolerances of the manufacturer and Wärtsilä technical advisors were on site to oversee all work.
“Allowing a good engineering and construction team to create an open, collaborative environment allows the owner to have input on the overall design and make key decisions during construction,” Rosado said.
The project also has these unique features:
• The structure features a building envelope around the engine structure that reduces sound impact to the adjacent community.
• There is a 60-kilowatt solar array adjacent to the engine building to provide renewable energy to the plant office
Increased collaboration allowed the engineering and construction teams to complete the project two months ahead of schedule and RPU saved more than $2 million through construction cost efficiency. Teams say the project “moved at the speed of construction” primarily because of the transparent, collaborative environment created before any crews moved on site.
Mary Schmidt is an independent writer and communications consultant specializing in construction, manufacturing, and business topics.