Integrated tube-based photovoltaic panel system optimized for co-location with crops

US agricultural cropland covers 349 million acres, approximately 18% of the land area in the lower 48 states. The historical challenge to adding solar over crops has been an inherent conflict between each one’s need for sunlight. Standard solar panels cast large shadows which take substantial time to pass over any given point on the land surface. While many plants are shade- tolerant, deep shade induces plants to shut down as if experiencing nighttime-like darkness. Compromised plant growth makes co-location of solar and crops undesirable. So solar arrays typically just displace crop production, which compromises US food security, negatively impacts rural economies, and can violate land-use restrictions, such as zoning regulations. Taka Solar, a recipient of the DOE American-Made Solar Ready! and Set! prizes, will design, build and test the first tube-based photovoltaic (PV) solar panel and mounting system fully optimized for agricultural applications. The key differentiator for Taka’s design is the use of narrow solar tubes in arrays with significant spacing between them, which avoids deep shadows and allows for overall adequate light passage to support plant growth. The panels can be economically made with different spacing options, so the light level below can be set to the ideal balance of photosynthesis and cooling via shading. Plants like corn or grapes that require higher light levels would use panels with more widely spaced tubes, whereas plants like alfalfa benefit from shade, so would use panels with tubes arranged with a higher density. Moreover, Taka panels provide solar tracking with no moving parts to increase energy production. Additionally, mounting system and balance of systems costs are lower due to reduced wind loading. The proposed project will demonstrate the feasibility of co-locating Taka solar panels with crop cultivation to enable commercialization. In Phase I, Taka will build panels for a pilot test and plant study at UC Davis with Dr. Heiner Lieth’s group. Dr. Lieth has more than 10 years of experience studying plant performance under various types of PV panels, including solar tubes. Previous research indicates that the Taka design will produce energy while improving growth of economically important crops such as alfalfa and grapes. The crops to be studied under Taka’s panels represent >18 million acres of US farmland (USDA), which is an areas larger than West Virginia. Assuming 200 kW per acre, Taka’s panels have the technical potential to provide over 3,600 Gigawatts. This growth in solar capacity has a roughly $5 Trillion market potential (@$1.50/watt). Additionally, this new capacity could generate over $250B in annual energy revenue (@$.05/kWh) while maintaining or boosting food yields. Taka panels can also enable the electrification of farm equipment, such as tractors, to reduce farm operating costs, improve air quality and reduce carbon emissions.