Design Solutions in Alternative Energy Projects Given Procurement Challenges
Global supply chain disruptions due to the COVID-19 pandemic as well as a concentration of supply chain within Southeast Asian markets have had significant impacts in the renewable energy industry. Supply chain delays result in business interruption (BI) days in which projects experience downtime with regards to procurement, commissioning, and energization. According to a market trend report prepared by GCube Insurance Ltd, sector-wide average BI days have increased by 38% in comparison to 2016 levels  . The solar industry itself has experienced the largest increase in BI days with an average increase of 95% . The increase in these downtime days underscores the need to diversify renewable energy supply chains amid a rapid push towards clean energy initiatives. Moreover, there are several design methods that can be implemented to reduce BI days, increase procurement options for clients, and keep projects on schedule. This post will give three examples of how Flux has proactively limited project delays through creative engineering solutions.
Ground mount solar project site
1. Specify equipment to allow flexibility in procurement
Medium voltage conductors have several electrical parameters that are critical to specify during the design phase of alternative energy projects. However, stringent design specifications can be a hindrance to procurement due to potentials for manufacturer unavailability or shipment and processing delays. As a result, specifying key electrical parameters provides clients with flexibility to procure cables that suit project schedules and costs.
Flux designed a ground mount solar project in which simplified specifications for the medium voltage conductors allowed for the construction schedule to remain on track. The minimum parameters that were specified included appropriate voltage rating, ampacity, and UL certification. There were several properties that were deliberately not specified as it was either not critical to the design or the conductors had been designed to satisfy minimum conditions.
First, the insulation of the conductor was not specified. Typical medium voltage conductors have either XLPE or EPR insulation. In the case for this design, it was not critical to specify the insulation as the lower costs, reduction in dielectric losses, or electrical treeing impacts did not need to be considered. Medium voltage conductors also need to specify some form of shielding whether it be a tape, wire, or braid. In the case for this design, a bare copper ground conductor within the MV trench was implemented thus eliminating the need for shielding that is capable of carrying ground fault currents. Finally, the jacket of the MV cable was specified for an operating temperature of 90°C. Having the cable specified at a lower temperature rating allowed for procurement flexibility for 90°C or 105°C rated cables. If the cables had been specified at 105°C, then the use of 90°C rated conductors would have had lower ampacities thus resulting in dangerous over-heating situations.
MV Cable at a Project site
Overall, the use of a generic cable specifications allowed for maintaining project schedules while providing the procurement team adequate flexibility for obtaining the relevant project components. Moreover, it allowed the client to bid to multiple vendors to obtain medium voltage conductors which were most in line with the desired price point and delivery schedule.
2. Plan for expedited commissioning schedules during the design phase.
Commissioning requirements are critical to consider during the design process to avoid overall delays with energization. Flux designed a battery energy storage project with several SCADA enclosures. These communication enclosures were fed from a dedicated auxiliary power panel that was fed from the utility point of interconnection. Due to equipment delays, the site was ready to be commissioned prior to energization of the main switchgear. Since Flux had incorporated a generator plug into the communications power panel board, testing and commissioning of the SCADA system could occur. Additionally, a mechanical interlock was placed between the main panelboard circuit breaker and the generator plug circuit breaker. The interlock would also provide a safety measure which would prevent the plug from being removed while the power was still on. Planning for proper sequencing of installation becomes key for mitigating delays in commissioning and energization and allows for commercial energy storage projects to come online more efficiently and effectively.
3. Anticipate and respond to changing client goals.
Client needs are continuously changing given market conditions as well as legislative orders. The recent extension of the 2018 solar tariffs on imported solar cell and modules has had far-reaching impacts on a variety of solar projects in their ability to reach completion due to increased hardware costs and extended delivery schedules. As a result, flexibility and adaptability becomes key components of the design process.
Flux designed a solar carport system which had already started the permitting process when the client requested a change in the modules that were being used on site. Procurement delays would have prevented the client from being able to commence construction. The design warranted switching from using monofacial modules to bifacial modules, which are exempt from the 2022 extension of the solar tariffs. Flux responded promptly to accommodate the equipment change in order to meet client deadlines. We as a team were able to respond quickly and diligently to ensure overall site power requirements and module counts were being met per the owner’s requirements. The flexibility of our design team allowed the project to re-enter the permitting process without causing further impediments to the client.
Flux Energy Systems has a wide range of experience in the alternative energy industry. We are client focused and always seek to deliver the best quality of product to ensure ease of construction. We are quick to adjust to changing goals and will always serve as the technical support and expertise to ensure the permitting and construction process works smoothly.
Blog written by Ahana Mukherjee, Design Engineer at Flux.
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Alison Brown, PE, PMP