Wavelength-Selective Photovoltaic Systems (WSPVs) combine luminescent solar cell technology with conventional silicon-based PV, thereby increasing efficiency and lowering the cost of electricity generation. WSPVs absorb some of the blue and green wavelengths of the solar spectrum but transmit the remaining wavelengths that can be utilized by photosynthesis for plants growing below. WSPVs are ideal for integrating electricity generation with glasshouse production, but it is not clear how they may affect plant development and physiological processes. The effects of tomato photosynthesis under WSPVs showed a small decrease in water use, whereas there were minimal effects on the number and fresh weight of fruit for a number of commercial species. Although more research is required on the impacts of WSPVs, they are a promising technology for greater integration of distributed electricity generation with food production operations, for reducing water loss in crops grown in controlled environments, as building-integrated solar facilities, or as alternatives to high-impact PV for energy generation over agricultural or natural ecosystems.
Tag Archive for: Solar greenhouse
The use of renewable energy in modern greenhouse management is important to achieve efficient and sustainable food supplies for a world with increasing population. This study assessed the performance of a blind-type shading regulator that can automatically rotate semi-transparent photovoltaic (PV) blades installed on the greenhouse roof in response to sunlight variation. The PV blind oriented parallel to the roof partially blocked intense sunlight penetration into the greenhouse, but it transmitted sunlight during cloudy time by turning the blind bearing to be perpendicular to the roof. A stable irradiation environment is therefore producible in the greenhouse under variable sky conditions. Annual operations demonstrated that the blinds’ own generated electrical energy can sustain PV blind operation and produce surplus electrical energy. The PV blind electricity generation and sunlight availability for crops below the PV blind roof were calculated based on a mathematical model developed using theoretical sunlight parameters and the experimentally obtained PV blind system parameters. Assuming cloudless skies and threshold irradiance for blind rotation set at 500 W m−2, 13.0 and 12.3kWh m−2 yr−1 surplus electrical energy can be generated, respectively, by north–south and east–west oriented model greenhouses. Cloudy skies reduce surplus electrical energy production by 50%, but PV blinds can supply greenhouse electrical energy demands partially or completely, depending on the degree of greenhouse electrification. Below the PV blinds, 8–10 MJ m−2 day−1 of insolation is expected to irradiate crops under actual sky conditions. This insolation is sufficient to cultivate major horticultural crops. Regulating the threshold irradiance level for PV blind turning can control the sunlight apportionment ratio for cultivation and electricity generation, thereby enabling sustainable energy–food dual production in a greenhouse.
This report reveals that increasing the sustainability of food production will require development of new mixed-use technologies. Also discussed is that novel electricity-generating windows (Wavelength-Selective Photovoltaic Systems, WSPVs) are suitable for use in greenhouses for growing plants. Results show minimal lasting effects of growth under WSPVs on plant physiology and development, thus WSPVs represent a new wedge for decarbonizing the food system.
This AgriSolar Best Practices Guide is intended to assist farmers, PV developers, regulators, and other stakeholders in developing high quality Agrisolar projects. The guide provides Best Practices for Agri-PV systems, PV on agricultural buildings, and open-field applications. Also included in this guide are discussions of trends and innovations in the AgriSolar community. This guide defines the key actions required of all parties involved in project development to maximize the sustainability of Agrisolar projects, from an agronomical, ecological, and financial perspective.
This study assessed the climate conditions inside a greenhouse in which 50% of the roof area was replaced with photovoltaic (PV) modules, describing the solar radiation distribution and the variability of temperature and humidity. The distribution of the solar radiation observed in this study is useful for choosing the most suitable crops and for designing PV greenhouses with the attitude for both energy and crop production. The study also includes suggestions for a better agronomic sustainability of agrivoltaic systems.
The long-term analysis in this study demonstrated a good capability of the numerical model to predict the shading effect inside a photovoltaic greenhouse combining the daily calculated exposed percentage with measurements of solar radiation. Photon flux daily values inside a PV greenhouse were calculated and measured from April 18th to June 8th in 2014. Commercial software was used to calculate the exposed percentage values for the greenhouse being studied. This study shows that modern software can be utilized in optimizing PV greenhouse operations.
Overall, this study demonstrated that the use of semi-transparent OPVs as a seasonal shade element for greenhouse production in a high-light region is feasible. However, a higher transmission of PAR and greater OPV device efficiency and durability could make OPV shades more economically viable, providing a desirable solution for co-located greenhouse crop production and renewable energy generation in hot and high-light intensity regions.
This study investigated the feasibility of a greenhouse roof with an integrated semi- transparent PV-blind system to provide moderate shading conditions to greenhouse crops along with simultaneous electrical energy generation. The results in this study can be used to optimize variations of agrivoltaic operations and their development in the future.
This study shows that adding semitransparent organic solar cells (ST-OSCs) to a greenhouse structure enables simultaneous plant cultivation and electricity generation, thereby reducing the greenhouse energy demand. To lower the energy footprint of greenhouses, there has been growing interest in integrating solar cells onto the greenhouse structure. In this approach, a portion of light is captured by the solar cells to generate power, while the remaining light transmits into the greenhouse for crop production. The results of this study can benefit development of agrivoltaic operations by maximizing the amount of sunlight reaching plants grown in greenhouses.
This article aims to demonstrate the viability of a greenhouse that integrates, as a novelty, semi-transparent amorphous silicon photovoltaic (PV) glass (a-Si), covering the entire roof surface and the main sides of the greenhouse.