As photovoltaic (PV) projects have evolved over time, the industry has focused on reducing costs to increase the adoption of solar power. This reduction has been dramatic, and the corresponding increase in solar PV projects is exciting, with new records in project size and overall deployments announced nearly every year. As solar project costs drop so, too, have racking costs through the utilization of improved engineering analysis, appropriate and efficient material selection, and improved manufacturing approaches. Knowing that racking continues to play an integral role in solar installations, savvy project integrators are paying more attention than ever to products and solutions available to reduce costs and create job site efficiencies. To help end-users optimize PV installations, the following breaks down the project development and construction process, from start to finish.
1. Integrated Design & Delivery Solutions (IDDS) in Solar
The single most important determinant in the efficient construction of a solar project is the selection of the racking system itself. The civil work / foundation design, material logistics, racking installation, system adjustment and alignment, and module mounting. Each step is based on the design of the racking system, and should be given full consideration when evaluating different options. The Integrated Design and Delivery Solutions approach uses collaborative work processes and enhanced skills, with integrated data , information, and knowledge management to minimize structural and process inefficiencies and to enhance the value delivered.
2. Pair the Racking System to the Foundation
For a racking design to be effective, it must be optimized for a given foundation. This often times requires different solutions for different soil conditions. For example, sites with challenging soils that require extensive groundwork may benefit from larger foundations.
In other cases, ground conditions may have limited bearing strength, or may have depth limitations such as bedrock or boulders that make installation of a larger foundation more challenging. In this case, a rack designed with a smaller base requirement could provide more flexibility at the project site.
On site testing can support the selection of an optimized foundation and might reveal soil issues or helps to reduce the foundation embedment depth.
3 .Streamline Materials Logistics
It may seem obvious, but ensuring the correct materials arrive to a job site on time, and in the correct order, is paramount to an efficient installation. Once on the job-site, these materials furthermore need to be systematically distributed where needed in order for the project to operate smoothly. To mitigate this problem, it doesn’t hurt to select a racking system with a minimal amount of loose hardware and components to begin with.
Fully assembled or partially pre-assembled racking systems may further reduce the material count, but it may also necessitate larger equipment and greater logistical challenges. In evaluating racking products, review the number of components, the flexibility in placement of components, and any equipment that may be necessary to move system parts.
4. Monitor operational sequencing
The aerial of this project shows a typical sequencing issue where some racks couldn’t be built due to the fact that trenching for the home runs started late. The efficiency of the project can plummet, and the additional on-site complication may increase the likelihood of accidents or material damages. An honest project plan and communication between project participants is key to avoid sequencing issues and related cost.
5. Consider Pre-Build Racking Solutions
Many basic products have several loose pieces, including nuts, bolts, and other hardware. Products with quick connections and pre-assembled hardware are quite common, and will help minimize the handling of loose hardware.
Most manufacturers of racking solutions tout their installation speed, so it’s important to consider how those installation features translate to benefits in real-world project conditions. Newer racking solutions sometimes provide hardware that’s not only pre-assembled, but also pre-located on the racking system. This not only eliminates the need to handle of loose hardware, but also eliminates the need to measure and adjust components. With connection points established in a quality controlled, factory setting, racking can be built quickly and correctly the first time.
6. Think Ahead and Avoid Costly Site adjustments
No two sites are ever the exact same, so it’s important to consider the variation of job-site features ahead of time to avoid potential time consuming adjustments.
Although all connections should allow for adjustment, infinite adjust-ability can become a major challenge to a rack being built in a timely manner. Rather than trying to adjust an entire rack after it’s assembled, it can be helpful to utilize a product that allows the installer to establish and lock each adjustment during a single step in the assembly. Using this approach, the installer can adjust the racking to a fixed height in one step, and then adjust to a fixed front-back position in the next step, and so on. Minimizing the number of connection points that are tied to the adjustment of the rack will also save installation time.
7. Leverage the Racking Solution for Efficient Module Installation
Many newer racking solutions include time saving features for proper module positioning, such as module retention ledges, built directly into the racking. This allows the installer to quickly rest a module in perfect alignment with the rack each time. As an added benefit, the module can be supported hands-free until the clamps can be positioned. Ultimately, this reduces the number of installers required to complete what was formerly a painstaking process. Advancements have also been made with regards to clamping, with products offering faster connections that take over the role of traditional bolted connections. What about thinking outside the box ? Why not using rivets? No torquing – no torque marks ….! No theft – a little more work if they have to be exchanged!
8. QA procedures
After delivery of materials, a batch testing/verification should be conducted to identify perceptible deviations. These should be addressed immediately before they influence the project itself. It is also critical to establish sign-off procedures that incorporate the IDDS philosophy, where QC procedures are discussed and implemented by all project participants in the pre-construction phase.
Ultimately, the foundation for a successful Quality Assurance program is the quality control maintained by the manufacturer to ensure that all delivered materials delivered conform to the contract requirements.
9. Safety – a team effort
Safety procedures are not only for workers, or for installers, or for helpers – no – they are implemented foreverybody to protect everybody on the job site, which means that superintendents , project managers, fence contractors, electricians, installers – everybody has to follow them! Safety procedures should be clearly communicated and enforced! The lower the incident rate the smoother the project.
10. Plan B& Communication
There is always something – storm, burglary, vandalism, refusals, missing holes ….. – be prepared, and have a plan B in place to reduce the impact of disturbing changes during construction and conduct your risk analysis up front to minimize disruptions.
Communication is key. A weekly construction meeting is the minimum, and the larger the project the more coordination meetings are necessary!
Bottom line : Client + Supplier + Installation partner = One Team
Designing a structurally adequate racking system is relatively straightforward. However, with ongoing pressure to bring down the cost of solar systems, there’s a fine line between material optimization and risky design. The evaluation of the complex structure to identify the most valuable solution for a Ground-Mount project requests the participation of client(layout,expectations,goals), supplier(sound, valuable system) and the installer(schedule, efficiency). The more all parties are involved the better they can achieve the overall project goal!