When you think of wind farms, you often think of the large structures stretching into the sky, but what about what lies below?
An extraordinary amount of planning and thought goes into the design and construction of each wind farm. Preplanning for these projects often happens more than a year in advance before any ground is broken for the construction. Several factors need to be considered for each project, such as the wind farm’s location, the number of turbines being installed, and even the location of the underground utilities and infrastructure.
This is why wind farm developers often enlist GPRS services to make sure that there are no subsurface hazards below the construction sites. Protecting your crew from subsurface damage can save you time, money, and needless worksite injury.
Subsurface utility lines are in widespread use across the United States. These unseen lines include electric, communication, water, sewer, storm drain, irrigation lines, and many unknown or abandoned pipes. Many lines within the public infrastructure are mapped out. However, many private utilities are not. Because we cannot be entirely certain where utilities lie underneath the ground, ground penetrating radar is often used to verify the absence or location of utility lines to excavate safely.
GPRS utilizes some of the most advanced equipment in the industry, but ground penetrating radar remains one of the most critical implements in our Project Managers’ arsenal.
Ground penetrating radar uses three primary components: a control unit, a transmitter, and a receiver. The transmitter sends electromagnetic waves into the ground while the antenna is being rolled over the surface. The waves reflect back to the receiver when they encounter different materials and the reflections generate an image on the screen for a utility scanning professional to decipher, mark on the surface, and add to a map. GPR can even detect non-metallic objects and can be used to locate utility lines, subsurface voids, and much more.
We asked Sam Dittmar, an Electrical Field Construction Coordinator working for a private renewable energy contractor, how important it was to use utility scanning prior to breaking ground for a wind farm. In response, he told us that it was of the utmost importance, “if there is a live gas line that’s struck, that’s potentially fatal.”
Many underground utility lines carry gas and electricity for municipal or commercial use. If a construction company breaks ground before knowing if the earth underneath is clear of subsurface hazards, they risk a potentially fatal accident occurring.
We asked Brian Barlow, a GPRS Project Manager, to describe the process of working for a wind farm from the utility locating perspective. Brian said:
“[The] pre-construction phase is when utility locating is vital for planning and design. Locating companies are used to verify that the proposed turbine locations [can] be used. From there the proposed collection lines can be set into play. Utility location companies then scan for known and unknown utilities along the path, as well as for the access roads and crane paths. Locating companies also scan the concrete on the turbine bases for borings that are used to test the slab to prevent damage to the rebar.”
But these large projects usually will experience design changes over time, so adjustments are frequently required.
The wind farm owner is responsible for ensuring that the area designated for construction is scanned for utility lines before the subcontractors arrive on-site to break ground. However, between the design phase and construction phase, the geographical location of the wind farm can change. This means that some areas may go completely unscanned because the preliminary scans were conducted before the changes to the location adjustments. So, construction companies will often have to hire private utility scanning companies to ensure that all the area being built upon is clear of utilities.
Utility line strikes are rare on wind farm construction sites, even with all this complexity. Sam Dittmar reported having no issues with utility line strikes due to the thoroughness of companies like GPRS, who make sure that all areas are completely clear of subsurface obstructions.
This attention to detail is only becoming more necessary. Sam Dittmar told us that the team utilized an automated excavator on his most recent excavation. He told us large trenchers are used in rocky conditions and informed us that a lot of manpower and mechanical helpers are required to break ground in these less-than-ideal geographical conditions. And now construction companies are using automated trenchers that have a computer interface in an excavator bucket, allowing the excavator to dig and install the cables automatically. He told us that this automated trencher was only used for a small portion of this last project as a proof-of-concept, but it demonstrated the potential for making wind farm installations more efficient in the future.
We’re excited to see the wind farm construction process become safer and more efficient than ever before. Building a wind farm is long and complex, but the companies involved are often comprehensive and diligent. It’s interesting to see how many seemingly innocuous variables contribute to these new wind farms’ design, planning processes, and construction.
GPRS performs utility locating, leak detection, and concrete imaging for projects of all sizes. Contact us today at https://www.gp-radar.com/contact/schedule-service to schedule a service with us.