In the modern age of solar 4.5 MW is not a big power plant, generally occupying less than 50 acres of land. But from the perspective of a field technician, size is all relative.
A Needle in a Haystack
“A plant that size has about 18,000 panels,” says Rick Lavezzo, the owner of ArrayCon, one of the nation’s largest builders of utility-scale solar power plants. “And trust me, if you’re trying to find a bad panel out there it can be like looking for a needle in a haystack.”
Rick should know; his firm was recently hired by a plant owner to find and replace a run of bad solar panels on a 4.5-MW power plant. “If we had to do this the traditional way, it literally would have taken us weeks. I’m not even sure the plant owner would have decided to do it if that’s the path we’d taken.”
Fortunately, they were able to take a different path — they used a drone service provider (or DSP in the lingo of the age of the drone) to spot the bad panels for them before they serviced the plant. Using a thermal sensor and a sophisticated flying robot that looks vaguely like something from a Batman movie, PrecisionXYZ was able to fly the entire site in under 40 minutes and provide ArrayCon with the results the next day. Not only did they spot the bad panels, they identified a number of strings that were offline and an entire subarray that was tracking incorrectly.
Thermal imagery combined with drones are a real game changer for maintaining these assets. Because energised assets like solar panels generate heat, a drone equipped with a thermal camera allows you to quickly assess the site and easily spot the problem areas. It’s almost like that ‘needle in haystack’ has a blinking light attached to it. It really accelerates the entire troubleshooting process.
Accelerating Build Times
But drones can have an impact on solar economics long before the power plants are even built; by accelerating build times they are driving costs out of the entire structure for the solar industry. Tom Werner, SunPower’s CEO recently told investors that drones could reduce their power plant construction costs by up to 30 percent. When you consider that a 100-MW power plant can cost up to $200 million, that’s a big a deal. The question asked by many is simple; how?
Consider that 100-MW power plant — $200M doesn’t just fall out of a tree. A bank or other investment vehicle sets that money aside in order to create that cash-producing asset called a solar power plant. And the moment the bank sets that money aside the clock starts ticking. Every day in which that money isn’t earning returns for an investor translates into opportunity costs.
“That whole saying about ‘time is money’ — that’s the construction industry in a nutshell,” Lavezzo said. “It’s about how quickly you can build a quality project so the bank can start making money off that asset. So project velocity isn’t just important, it’s everything.”
For solar power plants, that clock starts ticking with something called a site assessment. Think of this as pre-screening of a site’s viability for project development. Historically these were done with Google Earth or an equivalent online or subscription service. The challenge with these tools is that the imagery and accuracy can be very course, requiring project developers to spend more time assessing the site.
With high-resolution drone imagery, every detail of the site is visible within days. SunPower estimates that by using drones, they can cut 90 percent off the time it normally takes to build a proposal ready site assessment. Of course, once a site is deemed favourable for a project, you still need to actually build it. And here too, drones play a big role in accelerating the entire process.
Traditionally, land surveys for projects are conducted once a project is approved. Even with modern survey-grade GPS technology, the process is labor-intensive, and it can easily be more than a month before a survey is completed. That’s critical time when capital is sitting on the table. In contrast, drones flying over a site use a process called photogrammetry to build highly accurate maps very quickly.
Photogrammetry itself is not new and was used extensively during World War II for aerial bombing mission planning and post bombardment assessments. In general, the higher and faster you fly, the lower your detail and accuracy. Conversely, flying “low and slow” gives you greater accuracy and detail. This is why drones are the ideal solution for building extremely accurate topology maps across large areas.
At PrecisionXYZ, we’re very comfortable building topology maps across a thousand acres. Drones are an ideal use case for large, utility-scale solar power plants.
Not only does this accelerate the front end of the project, but it also provides design and engineering teams centimeter-level fidelity. This allows them to more accurately estimate resource utilisation at the project site, further reducing project costs. And since the information is provided in the form of a digital model, construction organisations can now integrate that information into their project tracking, which leads us to yet another area where drones help drive out costs.
A New Perspective on Project Management
Tracking project velocity across a 100-MW to a 200-MW site is not easy; you are tracking work crews across literally hundreds of acres, and each crew has their own set of challenges. For the overall project manager, this can create a situation where information is disjointed, and without the context of the overall job site, it can be difficult to assimilate for quick decision making. This can end up hindering their ability to manage the site effectively.
Drones re-establish site context, delivering images of the entire project site in real time, allowing a manager to see at a glance the status of the overall project. More importantly, it enables them to address a host of issues that might not otherwise be obvious — be that manpower, material or safety, all of which can impact project velocity and ultimately delivery. Because all the information is now digitised and stored in the cloud online, this also allows project management teams to more easily analyse the results of not only the current project but of projects conducted in the past. Lessons learned can then be applied for better results in future projects.
The net result is an immediate improvement in project velocity and continuous improvement in project velocity over time. In an industry that is constantly trying to find another $.01/watt of savings, the potential savings drones represent huge.
At the end of the day, drones are a robotic tool designed to extend the capabilities of people, teams, and managers. And while the first era of drone technology was simply about making drones reliable, consistent and functional, the second era — the era of data collection — is having a much more profound impact. In the age of automation, drones are the front-line forces driving value creation in construction economics.