In order to get the most out of your solar system, it is important to implement ongoing monitoring, detailed reporting and system maintenance. This case study summarises a performance review completed by Beam Solar for one of our clients, and shows how solar can outshine when installed and serviced correctly.
This Victorian abattoir installed a 1.356 MWdc solar PV system at their plant in the end of 2018 to supply electricity to the site. The system is a ground-mounted, 30-degree fixed-tilt array with 4110x 330W Jinko panels and 44x 27 kVA Fronius ECO inverters.
Beam Energy Labs were engaged to review the performance of the system and provide recommendations to improve performance if necessary. To review existing performance, actual solar generation data was provided by the VIC plant for the period Jan 2019 to Jul 2021. This was compared to Solcast® solar irradiance data for this location from Jun 2020 to Jul 2021. The Solcast® irradiance data was converted to expected PV generation data using appropriate loss factors for each timestamp.
Performance
The system performed well compared with the calculated expected generation data. The table below shows that the system outperformed by approximately 2.7% over the period Jul 2020 – Jun 2021.
The comparison in monthly generation data below shows that the system performed particularly well during July through to December.
A comparison between the real and expected solar generation for the site over a 3-day period in December 2020 is shown below.
Solar production at this VIC plant closely matched the output expected from this kind of system and showed a slight over-performance compared with the expected values for most months in the sample period analysed. Based on the loss values used in the calculation of the expected generation, it is unlikely that excess soiling, panel derating or other system inefficiencies were present with this system.
Inverter size and clipping
The site was concerned about inverter sizing and potential ‘clipping’ of solar output by the inverters. A review of solar production on the two largest generation days over the dataset, January 1st, 2020, and November 8th, 2020, did show some evidence of clipping. The chart below shows solar output for both days. Clipping is observed for a short period during the peak solar period and solar production reaches the 1,188 kW inverter limit.
Significant clipping would not be expected given the high inverter (AC) to solar (DC) ratio of 0.88 for this system. Excessive clipping is typically observed in systems with a much lower ratio such as 0.75 which is the minimum ratio mandated to generate Small-scale Technology Certificates (STC) for small solar systems (<100 kW). Upon review of the data, the impact of clipping on this system only attributed to a reduction in generation of ~0.1% per year.
About Beam Solar
At Beam Solar we aim to assist our customers in making the best business decisions for their solar investment projects. That includes providing guidance not only through the early stages of the project (feasibility, energy assessments, and quoting), but also through procurement and ongoing service.
In order to ensure you get the most out of your new solar system, we will complete a post-install system inspection to identify any defects with the system and arrange for rectification. We can also provide a performance and savings assessment on the system several months after install to confirm if the system is performing as expected. This is to provide additional trust and ensure that your system is providing the maximum benefit to you and your business.
If you are wondering what solar can do for your sites, start a Beam Solar assessment by clicking the button below.