Citation: Vandewetering, N.; Jamil, U.; Pearce, J.M. Ballast-Supported Foundation Designs for Low-Cost Open-Source Solar Photovoltaic Racking. Designs 2024, 8, 17. https:// doi.org/10.3390/designs8010017 Academic Editor: Julian D. Booker Received: 5 January 2024 Revised: 30 January 2024 Accepted: 1 February 2024 Published: 4 February 2024 Copyright: © 2024 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). Article Ballast-Supported Foundation Designs for Low-Cost Open-Source Solar Photovoltaic Racking Nicholas Vandewetering 1 , Uzair Jamil 2 and Joshua M. Pearce 3,4, * 1 Department of Civil & Environmental Engineering, Western University, London, ON N6A 5B9, Canada; nvandew@uwo.ca 2 Department of Mechanical & Materials Engineering, Western University, London, ON N6A 5B9, Canada; ujamil@uwo.ca 3 Department of Electrical & Computer Engineering, Western University, London, ON N6A 5B9, Canada 4 Ivey School of Business, Western University, London, ON N6G 0N1, Canada * Correspondence: joshua.pearce@uwo.ca Abstract: Although solar photovoltaic (PV) system costs have declined, capital cost remains a barrier to widespread adoption. Do-it-yourself (DIY) system designs can significantly reduce labor costs, but if they are not attached to a building structure, they require ground penetrating footings. This is not technically and economically feasible at all sites. To overcome these challenges, this study details systems designed to (1) eliminate drilling holes and pouring concrete, (2) propose solutions for both fixed and variable tilt systems, (3) remain cost effective, and (4) allow for modifications to best fit the user’s needs. The ballast-supported foundations are analyzed for eight systems by proposing two separate ballast designs: one for a single line of post systems, and one for a double line of post systems, both built on a 4-kW basis. The results of the analysis found that both designs are slightly more expensive than typical in-ground concrete systems by 25% (assuming rocks are purchased at a landscaping company), but the overall DIY system’s costs remain economically advantageous. Sensitivity analyses are conducted to show how modifications to the dimensions influence the weight of the system and thus change the economic value of the design, so users can trade dimensional freedom for cost savings, and vice versa. Overall, all wood-based PV racking system designs provide users with cost-effective and easy DIY alternatives to conventional metal racking, and the novel ballast systems presented provide more versatility for PV systems installations. Keywords: open source; photovoltaic; racking; solar energy; biomaterials; wood; photovoltaic; mechanical design; balance of systems; renewable energy 1. Introduction The primary impediment to a solar photovoltaic (PV)-powered society has been economics [1], but fortunately PV technology has enjoyed price declines for decades [2,3], so solar is now generally the lowest-cost electricity generation technology on both the small and large scales [4,5]. These new low costs and the fact that PV systems provide carbon- free electricity have enabled PVs to be the most rapidly-expanding electricity source [6,7]. At this point, PV systems are the dominant source of new power [8]. The PV industry continues to be primarily driven by large-scale centralized systems as these have been where energy policy is largely focused [9], but to achieve the U.N. ‘Sustainable Energy for All’ goals, it is clear that small-scale home-power PV systems can play a huge role [10,11]. These smaller systems can be both driven by the economic advantage for small prosumers to save money [12], but recent life cycle analysis also makes it clear that smaller systems are better for the environment [13]. Although even at the small-scale, PV systems are an economic benefit to the prosumer, the up-front investment for PV systems presents an economic barrier to consumers in the developing [14,15] and developed economies [16,17]. Designs 2024, 8, 17. https://doi.org/10.3390/designs8010017 https://www.mdpi.com/journal/designs