Delays are just about the worst problem for a developer or EPC working on a commercial solar project. Slowdowns cause project costs to quickly accumulate and potentially spiral out of control which can have ripple effects, leading to even further delays. This is a vicious cycle that can jeopardize solar + storage project success.
One of the most significant causes for potential delays is the information flow between project developer and engineer:
“Not having specific information and having to keep digging for it can delay a project by weeks or even months,” says Marvin Hamon, Senior Electrical Engineer Manager at Pure Power.
Technical Information is Essential for Engineering
To complete PV system design documents, the engineer of record needs certain information from the developer, who in turn must gather it from other project stakeholders. This process can take a lot of time and hold up the engineering process. Delaying engineering means delaying the rest of the project, which has substantial implications for project costs.
Clients in the C&I solar space are generally less knowledgeable about the intricacies of PV systems. They often just want to sign the papers and return to a fully installed and operating rooftop or carport system. Gathering and delivering technical information that the engineer may need is nowhere near to making their task list.
Kicking-off a Successful PV Development Process
“We often work with developers who install PV systems on big box stores. They come to us for the engineering work, so we help them by delivering the system design documents,” says Hamon.
However, managing a project with any given number of sub-contractors can be a challenge for the developer. Information flow is crucial for project success, and if clients do not recognize the importance of providing the needed information to advance the engineering design, it can lead to significant delays.
To simplify the process of gathering technical information, Pure Power has identified three categories: Utility contribution data, Civil cornerstones, and Equipment specifications. By applying these principles and gathering the information in a timely manner, developers, EPCs and project stakeholders can set themselves up for success.
Utility Contribution Data
Collecting the needed utility contribution data requires the client to contact the utility. The engineer or developer can help by putting together a request letter that lists all the information needed from the utility. Different projects will require varied information, but the commonalities are usually the following figures:
• Fault Current Contribution: The engineer needs to know the fault current at the point of interconnection, the point at which the utility service ends.
• System Impedance: The impedance of the utility system.
• Service Voltage: The actual voltage of the service line.
• Transformer Rating: If there is a service transformer, the engineer needs to know its rating.
Utility contribution data are used in engineering calculations and have an impact on equipment and system component rating, making them a foundational input for the system design. For example, if the fault current is 25,000 amps, then the rating of the equipment has to be at least 25,000 amps.
Civil Cornerstones
Commercial solar projects often include structures. For example, a big box store that wants to install solar panels in its parking lot will have to build the canopies that hold up the solar modules. A third-party provider will usually be hired to design such a structure. However, the electrical engineer needs to be informed of the specs in order to design an effective and stable PV system.
The most common information that needs to be exchanged is:
• Which grounding system does the structure require?
• Which PV mounting system will be installed on the structure?
• Which type of foundation will the structure have?
The crucial part lies in the communication of the developer with the structural engineer to gather the technical details as early in the project as possible. The sooner the electrical engineer has the data, the earlier the system design can be finalized. Uniting both structural and electrical engineering under the same roof, as is the case with Pure Power, streamlines communication.
Equipment Specifications
Typically, the developer or EPC will let the engineer know which equipment they want to work with. They may have a preferred manufacturer or they may be dependent on the availability of certain components when sourcing them. Knowing the equipment specs for modules, inverters, and the racking system, the engineer will work on the design, establish where conduit runs and tray cable systems will be located, and specify conductor sizes.
While these specifications are usually communicated to the engineer early on in the process, the main cause for delays can be the following often overlooked components:
• Switchboards
• Power Panels
• Circuit Breakers
• Fuses
“The specifications of all equipment that the developer intends to use must be submitted to the engineer. This requires the developer to ask their distributor to put together an exact list of manufacturers and models of each component. The list has to be reviewed by the engineer to make sure it is appropriate for the design,” says Hamon.
In other words, the system design cannot be finalized without the equipment specs, so it is crucial to gather the information as early as possible after the project kick-off. Due to availability constraints, many developers will be tempted to buy certain equipment before getting engineer approval. However, this equipment may not be compatible with the system requirements, and it may not be able to be used on the project.
Streamlining the Flow of Information
The exchange of information serves as the foundation for accurate engineering design and ensures that all PV system components are compatible and compliant with safety and performance standards. Without it, engineers face uncertainties that can stall the design process, resulting in cascading delays across procurement, installation, and commissioning. A timely and precise flow of data makes the difference between a smoothly executed project and one stuck in costly setbacks.
Get in touch: Talk to one of our engineering professionals for more insights on the technical information needed for commercial PV system design. For more information, please visit www.PurePower.com or email info@PurePower.com.