Priming a Man-made Masterpiece
When Eric Johnson, contracts project manager at Fagen Inc., drives off the American Renewable Gainesville Renewable Energy Center job site early this fall, he’ll be completing the final task in a master construction schedule bearing nearly 30,000 individual line items. He will be the last to leave of approximately 1,400 civil engineers, crane and bulldozer operators, boilermakers, millwrights, pipefitters, electricians, ironworkers and hundreds of other laborers directly employed by Fagen, or working under their supervision, who are responsible for building this 100-MW biomass power plant.
The asphalt road that will ultimately carry Johnson off the project did not exist just 26 months ago. While the project was certainly in development when talks between project owners American Renewables and Granite Falls, Minn.-based Fagen Inc. were underway, the 130 acres where the facility now sits was an undeveloped pine bog. All of that changed in late March 2011, when American Renewables awarded the construction contract to the Fagen team and issued them a notice to proceed.
Upon authorization to proceed, a team of foresters and loggers descended upon the site and began preparing it for the civil engineering work that needed to be completed to support the coming influx of people, equipment and material necessary to build the facility. Site preparation continued through early summer, with deployment of specialized equipment that sifted the site’s sandy soils to remove tree stumps and roots, leaving a pristine base for construction to begin.
After preparing the site, the Fagen team moved into their first civil engineering phase of the job—construction of the truck receiving infrastructure and the facility’s woodyard. Monumental in size and scope on its own, this phase was identified early in the scheduling process as important to get underway as soon as possible. “That was big,” notes Tim Griffin, project manager at Fagen Inc. and the ranking Fagen team member. “That was our first civil phase of the job. We poured concrete on July 6, 2011.”
For the truck receiving building, pilings were driven around the perimeter of what would become the structure, and the dirt inside of the pilings was removed. In this void, a 5-foot thick slab of concrete was poured, and walls were formed to create a giant hopper that would be the first stop for biomass entering the site. The importance of completing construction of this component was not lost on anyone. “We knew it was a critical path project, so that was the first thing we asked engineering to release to us,” Griffin adds.
With construction of the truck receiving area and woodyard well -underway, similar work began on the pad and foundation where the facility’s boiler, turbine, and baghouse would ultimately rest. A boiler and steam turbine capable of generating 100 MW of electrical power are massive pieces of machinery and require an immense, burly slab of concrete to support them. The facility’s immense size may best be understood by considering the sheer volume of concrete that was poured into the gargantuan slab.
Griffin paints a picture of the slab’s size, saying, “The pad for the baghouse was about 1,800 yards, a 3-foot thick slab. The boiler pad is 5-foot thick and that was about 5,600 yards. We poured the boiler slab not monolithically, but in four different pours.”
Considering that a standard concrete truck carries only 10 yards of concrete and measures nearly 40 feet from bumper to bumper, a hypothetical line of trucks needed to pour this slab would stretch nearly six miles.
To minimize congestion on the roads and avoid the hottest portions of the day, work on the slabs was conducted during the overnight hours. The resultant slabs are a source of pride for both Griffin and Evan Fagen president and chief operating officer of Fagen. “We have a very good team here, and our crews did just a stellar job just getting us out of the ground,” says Fagen. “The slabs, they are beautiful, there are no bird baths in them. It is just very, very nice work…the civil team sets the tone for the job.”
With completion of the dirt and concrete work in the woodyard and boiler, baghouse and cooling tower pads, the project’s various components were ready to “go vertical,” an industry term that denotes when structures begin to rise visibly from the ground.
The structural steel skeleton that now houses the facility’s boiler, steam turbine and baghouse rises more than 190 feet feet from its concrete base. On the east side of the facility, an elevator has been installed to allow ready access to the boiler, day bins, steam turbine, baghouse and other vital components that will have to be monitored and maintained throughout the life of the facility. This structural skeleton was the result of a planned, carefully orchestrated effort by multiple crews working in concert to complete the assignments needed for the next phase to proceed, while staying out of one another’s way. “We had the pipe rack up and erected first,” says Griffin. “That’s the equivalent to a couple of floors high of the main boiler. We could start on our pipe rack, and with Metso ready to go vertical with their steel, we could be out of their way. So that was the first vertical structure on the site.”
In early spring 2012, the structure was built out enough for the boilermakers to begin the construction and erection of the facility’s boiler. “Then Metso came on the site,” Griffin recalls. “They came on Feb. 2, and by March 15 they were setting their first steel, and began going vertical.”
The vast majority of the work on the Gainesville site has been performed by Fagen personnel, but Fagen left the fabrication of the facility boiler to Metso’s boilermakers. Metso crews installed thousands of tons of steel, more than 19,000 feet of pipe of all sizes, and performed more than 10,000 individual field welds, nearly all X-rayed to ensure they were perfectly completed. This meticulous attention to detail paid off as the boiler was just recently put through its first significant test. “We got our hydrostatic test off last week, which was a big milestone for the project,” Griffin beams. “We filled it full of water and some oxygen scavengers and then brought the pressure up to 2700 pounds. Generally, on new boilers, there are a few leaks. On this job, just about all piping was X-rayed, and we had zero leaks. That is not very common at all.”
With that milestone met, the facility is in the final stages of construction. “Right now, there is a lot of mechanical, electrical and instrumentation activities going on but the big push now is the commissioning of the plant,” says Fagen.
While commissioning awaits, the process of handing the facility over to owner American Renewables and its contracted operations and maintenance provider, NAES Corp., is well underway. The facility’s plant manager has been on the project site for nearly six months, and in late March the remaining NAES staff will join him to begin their site specific-training.
The facility was to begin receiving biomass shipments in March to ensure that the woodyard’s 11 conveyors, stacker and reclaimer are all correctly balanced and capable of delivering the fuel the boiler will require when the boiler is first fired in June.
Later this summer, the facility will begin emerging from its construction chrysalis and take flight toward its operational life. Once operational, the site will join a sister facility in Nagodoches, Texas, developed by American Renewables, built by Fagen, and now owned and operated by Southern Power company, as one of the two largest woody biomass power facilities in the country.
When asked about the completion date for the facility, Griffin explains that completion is actually broken into two project milestones. On Aug. 30, the project will be classified as having entered “substantial completion.” Once in this phase, Griffin says that boiler performance and emissions profiles are taken at different output levels in a series of final tests, before meeting a guaranteed completion date of Nov. 30.
Pondering the approaching completion date, as well as the end of Fagen’s day-to-day presence on the site, Fagen has much to reflect on. “I was on the road with this company for eight years, and when you finish a job and you’re headed out—you have all your stuff in your vehicle and your headed home or to the next project—and everything is turned over, and the customer is happy, it’s a very good feeling.”
Griffin likens that final moment on site to the experience of leaving his home for a long vacation, noting one significant difference. “The good thing here is you just leave everything on.”
Author: Tim Portz
Executive Editor, Biomass Magazine