Technical Specialist BTY Group Mississauga, Ontario, Canada
PV solar facilities are typically designed using an industry-standard DC/AC ratio of 1.2. This study examines the hypothesis that due to steadily decreasing module costs the optimum DC/AC ratio may be higher than 1.2. This has implications for Developers trying to maximize financial returns. Capital and operating cost estimates were developed for representative fixed-tilt ground-mount designs. AC output was kept constant, and DC/AC ratio was varied from 1.0 – 3.0. Energy output was modeled using commercial energy modeling software. CO2 offsets were included in the analysis. Two locations were studied: Alberta, Canada (good solar resource), and Wexford, Ireland (poor solar resource) to study if solar resource quality had any impact. NPV and LCOE were calculated for each site at each ratio. Our primary conclusion is that for AC-constrained sites, Developers should perform a through investigation of the benefits of using higher DC/AC ratio. We feel this has particular significance for sites coupled to energy storage, and locations where high power prices prevail in late afternoon. The results also indicate that “overbuilding DC†may be even more beneficial at locations where output is often limited by heavy cloud cover, such as Ireland, the UK, and NW USA.
