Colorado-Based Solar Installers Technology Shift Delivers Full Site Benefits
Customer Profile: New Energy Structures Company (NESCO) is a contractor that specializes in commercial solar installations.
Business Challenge: Improve tolerances and find new efficiencies on solar field construction projects, especially considering today’s tight labor market.
Solutions:
Benefits:
- Faster, more accurate piles
- 50% labor efficiency
- 95% post accuracy
- Less than 2% misalignment
- Improved transparency
For Longmont, Colorado, U.S.-based New Energy Structures (NESCO), the construction of one of the largest distributed solar projects in the City of Westminster, Colorado has become a hot spot for exponential improvements in workflows.
As a subcontractor to Namaste Solar, an employee-owned, fully integrated solar energy company, NESCO is tasked with installing the solar arrays for Trimble’s Westminster, Colorado headquarters. Incidentally, Trimble is a provider of construction technology, including a solution specifically for piling required on solar field installations. Winning the Trimble project gave NESCO the perfect chance to try out the company’s machine control system, which has the potential to yield big benefits on this - and future - projects.
Trimble’s new 1.7-megawatt solar array includes ground-mounted solar arrays, setup in the adjacent open land and raised structures with solar panels to form 170 carports for employees and visitors. The solar panels are projected to offset more than 100 percent of the energy consumed by the company’s two-building campus in the Westmoor Technology Park.
Vernon White, field supervisor for NESCO, said, “We’ve worked all around the country doing fixed tilts, dual axis trackers. Pile driving on a solar field is the bread and butter of our business. We know, if those piles don’t go in right, the solar array performance will suffer.”
That need for assured accuracy is one reason why NESCO opted to test out Trimble’s Groundworks Machine Control System and Trimble Business Center on the project. Groundworks is purpose-built specifically for drilling, piling and dynamic compaction operations. With some support from the Trimble team, NESCO installed the software on its GAYK HRE5000 pile driver and got to work. The team used Trimble Business Center to create pile plans in the office that are sent to the machine.
Ensured Alignment
Solar panel piles, and thus pile driving, is foundational to any successful ground based solar site. These posts must be accurately positioned both horizontally and vertically, any misalignment could result in additional stress and torque on the racks. As well, in many cases, the solar panels cannot be installed until the posts are re-sunk.
“On a fixed tilt system, we want to make sure our tables are squared out before we put racks on them,” said White. “Piles have to be placed and vertically aligned with precision. Our more conventional workflow is to use stakes and stringlines to ensure alignment.”
The manual process they have been following until now is effective, though very time (and labor) consuming. He and his crew rely on multiplane lasers to stake a few rows at a time, the operator completes a series of piles, and then repeats for the next set of rows. “That methodology gets especially tedious and time consuming when the ground is contoured. We don’t have to do any of that with Groundworks,” he said.
With Groundworks, the installers have all post locations from the pile plan on the display in the machine. The pile driver navigates without stakes using the solution’s high accuracy real-time kinematic (RTK) positioning.
“Tolerances for solar are around 1-inch in each direction, and we get much closer than that across every pile with Groundworks,” he said. “On any given day, we might drive 100-200 piles. I was most impressed by the pile location accuracy. On this project, we had a 95 percent post accuracy.”
Besides post positioning accuracy, White and his team dove into some of the other capabilities within the Groundworks software, which is built to support the entire pile driving process, including alignment and depth.
“One thing I especially like about the system is embedment depth notifications,” White said. “When we hit the assigned depth for the pile, the pile position on the display turns green. If something went wrong and the operator didn’t hit specified depth or hit a refusal, the dot goes red. And it includes an Auto Stop that stops the pile driving process when you’ve reached the specified elevation.”
The pitch and role features within Groundworks provided additional time saving. The easy-to-visualize screen makes it very clear when the pile is level. “Just keep the hourglass green,” he said. “In our post quality check, I only had to adjust six out of 244 piles, and those adjustments were very minor.”
Documented Efficiency, Transparency
As the supervisor on the project, White’s job is to quality check every pile’s directional (north, east, south or west) and embedment depth. That detail is automatically recorded and easily visualized in the software.
“I typically walk around the site handwriting notes about pile positions that were of concern,” he said. “Now, I can pull that information from each machine at the end of the day, plug it into the computer and look through those maps. It saves me a lot of walking.”
He said the daily data log on the work completed by the machines is big, too. “The ability to upload the number of piles sunk in a day by one machine, embedment depths, tolerances, degrees in and out, up and down, certainly streamlines my job,” he said. “I’m more efficient and better able to respond to issues when they arise in the field.”
He sees another advantage of the machine control system in terms of customer relations. “From a transparency standpoint, the more information that I can give clients and the general contractor the better,” he said. “The ability to automatically log refusals, work rates, production rates and embedment depths provides our customer, in this case Trimble (and Namaste Solar), confidence in our work quality.”
With Groundworks, White now even provides end-of-day reports showing how many piles were installed, along with embedment depths at every location. In his mind, it’s all about visibility and transparency to a job well done.
When asked about productivity, White noted that he has five guys doing the work of 10 on the Westminster job. “It’s that kind of efficiency that allows our team to spend more time on other parts of solar installation, such as bracket bolt-ups, so we get jobs done faster. From a supervisory standpoint, with GNSS and Groundworks implemented, I’m saving more than 80 hours on my post quality control budget.”
He also sees some additional benefits in training. Like many other contractors, labor availability is tight. This system will help, he believes, because they don’t have to teach new people how to do stringline and site layout. “The learning curve for the technology in the pile driver is quick and easy,” he said. “Our operators needed maybe 15 minutes to get up and go.”
White and the NESCO team are also looking to better tie the Groundworks data to their construction management software. That connection will allow him to automatically share reports with the construction manager, project manager and customers. “I can also better support my guys in the field,” he said. “As I review the daily logs, I can immediately see if piles are coming in out of tolerance and check on my crew before they get too far along. It’s just better accountability and visibility for better decision making.”
Now, he’s imagining how he can put this system to work on a 50MW site.
“I’m excited to add more Trimble technology to our rigs,” he said. “We just bought two HRE5000 pile drivers that are going to Wisconsin, where we’re getting ready to start on a very large solar job. The surveying alone can push costs upwards of $30-40K. Now, with Groundworks, we’re gung ho about setting up our own CAD files to layout solar fields. This solution really is a game changer for us.”