Open-Source Vertical Swinging Wood-Based Solar Photovoltaic Racking Systems

Abstract

Vertical bifacial solar photovoltaic (PV) racking systems offer the opportunity for large-scale agrivoltaics to be employed at farms producing field crops with conventional farming equipment. Unfortunately, commercial proprietary vertical racks cost more than all types of conventional PV farm racking solutions. To overcome these cost barriers, this study reports on the development of a new wood-based PV racking design. The open-source design consists of a hinge mechanism, which reduces mechanical loading and enables wood to be used as the main structural material, and is the first of its kind. This open-source vertical wood-based PV rack is (i) constructed from locally accessible (domestic) renewable and sustainable materials, (ii) able to be made with hand tools by the average farmer on site, (iii) possesses a 25-year lifetime to match PV warranties, and (iv) is structurally sound, following Canadian building codes to weather high wind speeds and heavy snow loads. The results showed that the capital cost of the racking system is less expensive than the commercial equivalent and all of the previous wood-based rack designs, at a single unit retail cost of CAD 0.21. The racking LCOE is 77% of the cost of an equivalent commercial racking system using retail small-scale component costs, and is 22%, 34%, and 38% less expensive than commercial metal vertical racking, wood fixed tilt racking, and wood seasonal tilt racking costs, respectively. Overall, wooden vertical swinging PV racking provides users with a low-cost, highly available alternative to conventional metal vertical racking, along with a potential increase in energy yield in high wind areas thanks to its unique swinging mechanism.

Maximizing Biomass with Agrivoltaics: Potential and Policy in Saskatchewan Canada

“…For wheat farmland (e.g. Figure 5), a vertical 2700 W PV mini-array with a width of 4.8 m [108] was used for vertical PV simulations, while a 15,000 W single-axis tracking system with a width of 23 m and depth of 4 m [109] was used as the second system type for PV simulations. To calculate the number of arrays in a single row, the length of one side of the land was divided by the width of the array.…”

Solar photovoltaic wood racking mechanical design for trellis-based agrivoltaics

“…Aluminum, one of the most commonly used construction materials for PV racking structures, has more than 5 times embodied CO 2 e/kg of wood [26], giving wood a distinctive edge. Wood has already been shown to be a cost-effective racking material for fixed tilt [20], variable tilt [27], vertical PV [28] and awning designs [86]. Previous work has shown that the economics of wood vs aluminum racks varies widely by geography [87], but it is superior in most of North America.…”

“…Responsibly-sourced wood is considered sustainable [25], and it has a negative embodied energy when compared with other PV racking materials [20,26]. Several low-cost open-source wood racks have been designed previously for fixed-tilt [20], variable-tilt [27] and vertically-mounted PV systems [28]. No open-source wood racks have been developed for trellis-based crops despite the fact that trellises are often constructed with wood [29].…”

Ballast-Supported Foundation Designs for Low-Cost Open-Source Solar Photovoltaic Racking

“…One approach to reducing costs of small-scale PV systems is to use do-it-yourself (DIY) development of open source technologies [35]. This approach is well developed and there are open source hardware designs for the distributed production of PV racking of the following types of systems: (1) low-tilt angle PV racks for mobile arrays [36], (2) steel cable-based cross X-wire PV racking systems for flat commercial rooftops [37] and groundmounted near the equator [38], (3) tensegrity-based solar PV racking [39], (4) after-market adaptions of conventional modules to allow for building-integrated PV (BIPV) [40], (5) fixedtilt ground-mounted wood-based racks [41], (6) variable-tilt wood-based PV racks [42,43], (7) vertically mounted (sign-based) wood PV racks [44], (8) fence-based PVs for agrivoltaics on existing farm fencing [45], (9) aftermarket adaptation to make floatovoltaics (FPV) [46], (10) trellis-based agrivoltaics wood-based PV racks [47], (11) cable and pipe-based mobile photovoltaic racking [48], (12) cable based variable tilt racks [49], and (13) earth and shotcrete-based racking [50]. There are also many community-developed racking systems made from wood.…”