The Niagara Region Wind Farm has been recognized as one of 10 exceptional projects at the annual Ontario Concrete Awards banquet, held as part of the Ontario Buildings Show/World of Concrete Pavilion. Developed by ENERCON Canada and Boralex, and engineered by WSP Canada, the project was supported by Niagara based Rankin Construction, which acted as project manager and precast producer.
The project features 77 wind turbines on a 43,200 hectare area that extended over six municipalities and that will generate 627.4 GWh/year. Precasting work began in August 2015 and was completed in May 2016. Site construction began in July 2015 and was completed in October 2016 when the site was officially commissioned.
Although there are other windfarms in the province, a write-up summarizing the project notes that this was the first to be constructed using concrete towers. These reportedly allow for taller heights and additional wind power generation. Concrete components include ready mixed concrete for the 77 wind turbine bases totalling 967m3*77=74,459 m3 and precast concrete components for 1740 cast concrete tower segments totalling 35,859 m3.
Sto Tritchew, senior vice-president, Rankin Construction, says his team had worked with ENERCON on a previous windfarm project but from a foundations and field work perspective. “ENERCON has a plant in Quebec that would normally handle the precast work but with a requirement for an Ontario-based component, contracted us to handle this for them.”
He says the proprietary nature of the design required a 12-member delegation to spend three weeks in Europe preparing for the work.
Without the benefit of using one of Enercon’s state of the art facilities, specifically constructed for this purpose, accommodations and creativity came into play. Production for the large concrete segments, constructed using 23 different molds, was setup in the old Port Weller Dry Docks facility which hadn’t been used in some time, was not designed for winter use and whose L-shaped configuration, rather than a lineal plant design, required the use of specialty equipment to move materials from one plant to the other without compromising production.
Tritchew says the space only allowed for the storage of two days pouring and then components had to be moved so work could continue. In the summer, this was not an issue, but once winter hit, he says, this became more challenging.
To resolve the issue a tent, 400 ft. by 100 ft. by 400 ft. high was erected and pumped with 12 million BTUs of heat.
“We would pour, paint, and ship to the tent and the components would sit for a week to cure before they were moved to the field.”
He says European standards also presented challenges in the early days. For the concrete tower segments, for instance, tolerances included no bug holes greater than the size of a dime due to needed surface treatments; tight dimension and smoothness tolerances due to stacking/connecting/post-tensioning; and strict temperature control to avoid thermal cracking.
“Grout rings had to be installed to within a 0.3 mm tolerance. We’ve never done anything quite that fine before. By the new year, the team had gotten into a rhythm but the first few months took time, learning and adjusting.”
He says the project required a concerted team effort, with frequent meetings to ensure everyone was moving in the same direction.
“There was the work going on in the plant and then the outdoor curing, then moving the pieces to the site to be sure the teams in the field could keep moving forward. To have been able to accomplish all of that with teams that were new to the process and the design and to have met the tight time lines is an achievement we are all very proud of.”
“Not enough can be said about the team and the teamwork it took to make this project a success. We are grateful to ENERCON for putting their trust in us to take on this challenge and to all of the key teams who made the project’s success possible.”
Other project credits go to: Concrete supplier, Lafarge Canada Inc.; steel supplier, Salit Steel; precasting pump supplier, Pumpcrete; heavy-lifting solution provider, Mammoet; general contractor, Borea Construction; and construction pump supplier, Degrandis Pumping.