Geographic potential of shotcrete photovoltaic racking: Direct and low-concentration cases

Relentless cost declines in solar photovoltaic (PV) modules have radically reduced system costs, but the result is that racking costs have become more important. In this study a new open source racking method using earth and shotcrete-based ground mounts is investigated in two geographic regions: (1) Boa Vista, Brazil, where PV rows have an optimized shallow tilt angle and can be close-packed and (2) Kingston, Canada, where racks can make use of low concentration in the required inter-row spacing. Models are developed for both locations with single, double and triple vertical stacked shotcrete-based ground-mounted PV racking systems. Using these models bills of materials and energy simulations are produced to provide a cost benefit analysis specifically for the shotcrete racks. The results show that for utility-scale PV systems near the equator, a shotcrete racking system could reduce racking costs by 18–22% from the least expensive conventional racking and as much as 47% reduction for more expensive commercial racking. Economics is less clear for shotcrete-based racking at higher latitudes that incorporate low-concentration reflectors as they can be both lower and higher costs than conventional racking, but would be expected to produce at least 18% more electricity per installed Watt. Overall this novel racking concept was found to be promising, particularly for desert regions where it could reduce soiling losses. The results of this study indicate a need for future work to fully evaluate the potential of shotcrete racking to reduce solar electricity costs at the utility scale.