Researchers present here a novel ecosystems approach—agrivoltaics—to bolster the resilience of renewable energy and food production security to a changing climate by creating a hybrid of colocated agriculture and solar PV infrastructure, where crops are grown in the partial shade of the solar infrastructure. They suggest that this energy- and food-generating ecosystem may become an important—but as yet quantitatively uninvestigated—mechanism for maximizing crop yields, efficiently delivering water to plants and generating renewable energy in dryland environments. We demonstrate proof of concept for agrivoltaics as a food–energy–water system approach in drylands by simultaneously monitoring the physical and biological dimensions of the novel ecosystem. We hypothesized that colocating solar and agricultural could yield several significant benefits to multiple ecosystem services, including (1) water: maximizing the efficiency of water used for plant irrigation by decreasing evaporation from soil and transpiration from crop canopies, and (2) food: preventing depression in photosynthesis due to heat and light stress, thus allowing for greater carbon uptake for growth and reproduction. An additional benefit might be (3) energy: transpirational cooling from the understorey crops lowering temperatures on the underside of the panels, which could improve PV efficiency. We focused on three common agricultural species that represent different adaptive niches for dryland environments: chiltepin pepper (Capsicum annuum var. glabriusculum), jalapeño (C. annuum var. annuum) and cherry tomato (Solanum lycopersicum var. cerasiforme). We created an agrivoltaic system by planting these species under a PV array—3.3m off the ground at the lowest end and at a tilt of 32°—to capture the physical and biological impacts of this approach. Throughout the average three-month summer growing season we monitored incoming light levels, air temperature and relative humidity continuously using sensors mounted 2.5m above the soil surface, and soil surface temperature and moisture at 5-cm depth. Both the traditional planting area (control) and agrivoltaic system received equal irrigation rates, and we tested two irrigation scenarios—daily irrigation and irrigation every 2d. The amount of incoming photosynthetically active radiation (PAR) was consistently greater in the traditional, open-sky planting area (control plot) than under the PV panels. This reduction in the amount of incoming energy under the PV panels yielded cooler daytime air temperatures, averaging 1.2+0.3 °C lower in the agrivoltaics system over the traditional setting. Night-time temperatures were 0.5+0.4 °C warmer in the agrivoltaics system over the traditional setting (Fig. 2b). Photosynthetic rates, and therefore growth and reproduction, are also regulated by atmospheric dryness, as represented by vapour pressure deficit (VPD) where lower VPD indicates more moisture in the air. VPD was consistently lower in the agrivoltaics system than in the traditional growing setting, averaging 0.52+0.15 kPa lower across the growing season. Having documented that an agrivoltaic installation can significantly reduce air temperatures, direct sunlight and atmospheric demand for water relative to nearby traditional agricultural settings, we address several questions regarding impacts of the food–energy–water nexus system.
Tag Archive for: Agrivoltaics
The specific intent of this study was to draw insight about solar development from participant experience, and responses indicate that the most considerable opportunities and barriers center on social acceptance and public perception issues. Perspectives about the opportunities and barriers to agrivoltaic development were captured via interviews with solar industry professionals, and inductive analysis revealed that interviewees were most focused on opportunities and barriers that correspond with Wüstenhagen et al.’s three dimensions of social acceptance: market, community, and socio-political factors.
Worldwide, water is becoming scarcer and more expensive due to the effects of climate change. Significant adaptation will be necessary to ensure adequate supply and efficient use of a diminishing resource. This reduction in the supply of water will affect agriculture and will require a change in focus from increasing productivity of land to increasing productivity per unit of water consumed.
Community-based Stormwater Strategies and Vegetation Management for Sustainable Solar PV Development
Solar photovoltaic (PV) technology is being deployed at an unprecedented rate. To this end, we investigated critical soil physical and chemical parameters at a revegetated photovoltaic array and an adjacent reference grassland in Colorado, United States.
This study, performed by a research group that includes AgriSolar Clearinghouse partners Greg-Barron Gafford and Jordan Macknick, describes an integrative approach for the investigation of the co-location of solar photovoltaics and crops, and the potential for co-located agrivoltaic crops in drylands as a solution for the food-energy-water nexus impacts from climate change.
The research focused on three common agricultural species that represent different adaptive niches for dryland environments: chiltepin pepper, jalapeño, and cherry tomato. The researchers created an agrivoltaic system by planting these species under a PV array—3.3m off the ground at the lowest end and at a tilt of 32°—to capture the physical and biological impacts of this approach. Throughout the average three-month summer growing season, researchers monitored incoming light levels, air temperature and relative humidity continuously using sensors mounted 2.5m above the soil surface, and soil surface temperature and moisture at 5-cm depth. Both the traditional planting area (control) and agrivoltaic system received equal irrigation rates, with two irrigation scenarios—daily irrigation and irrigation every 2ays.
The researchers found that shading from the PV panels can provide multiple additive and synergistic benefits, including reduced plant drought stress, greater food production and reduced PV panel heat stress. The agrivoltaic system conditions impacted every aspect of plant activity, though results and significance varied by species. The total fruit production was twice as great under the PV panels of the agrivoltaic system than in the traditional growing environment
Cumulative CO2 uptake was 65% greater in the agrivoltaic installation than in the traditional growing area. Water use efficiency was also 65% greater, indicating that water loss to transpiration was equal between the treatment areas. The increased productivity in the agrivoltaic system is probably due to an alleviation of multiple stress interactions from heat and atmospheric drought.
Because PV panels are sensitive to temperature, the cooling of panels below daytime temperatures of 30 °C positively impacts their efficiency. In this study, researchers found that the PV panels in a traditional ground-mounted array were significantly warmer during the day and experienced greater within-day variation than those over an agrivoltaic understory. Researchers attribute these lower daytime temperatures in the PV panels in the agrivoltaic system to a greater balance of latent heat energy exchange from plant transpiration relative to sensible heat exchange from radiation from bare soil. Across the core growing season, PV panels in an agrivoltaic system were ~8.9+0.2 °C cooler in daylight hours. This reduction in temperature can lead to an increase in PV system performance. Using the system advisor model (SAM) for a traditional and a colocation PV system in Tucson, AZ, researchers calculated that impact from temperature reductions from the agrivoltaic system would lead to a 3% increase in generation over summer months and a 1% increase in generation annually.
These results show the additive benefits of agrivoltaics, to both crop production and energy production, as well as the impacts to ecosystem services such as local climate regulation, water conservation, and drought resiliency.
This guide provides information that can assist both lenders and consumers in financing solar energy systems, which include both solar electric (photovoltaic) and solar thermal systems. It also includes information about other ways to make solar energy systems more affordable, as well as descriptions of special mortgage programs for energy-efficient homes.
The program provides guaranteed loan financing and grant funding to agricultural producers and rural small businesses for renewable energy systems or to make energy efficiency improvements. Agricultural producers may also apply for new energy efficient equipment and new system loans for agricultural production and processing.
This document is the first of a three-volume series designed to support electric cooperatives as they explore and pursue utility-scale, utility-owned solar PV deployments. It includes examples of business models for implementing utility-scale solar projects including details of full and partial ownership.
This paper discusses that the HomeStyle Energy mortgage loan is designed to support homeowners efforts to increase energy and water efficiency and reduce utility costs as well as create home resiliency for environmental disasters or to repair damage from such disasters. The document shows that HomeStyle Energy may be a more affordable financing solution than a subordinate lien, home equity line of credit, Property Assessed Clean Energy (PACE) loan, or unsecured loan.