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Possibilities of Using Semi-Transparent Photovoltaic Modules on Rooftops of Greenhouses for Covering Their Energy Needs
摘要： Semi-transparent photovoltaic cells allow the transmittance of solar irradiance through them and they have been used in building’s skylights and facades. Their use on rooftops of greenhouses can result in electricity generation which can cover part or all of their energy needs without affecting the growth of the plants. This also results in the decrease of cooling requirements during the summer since less solar irradiance is entering the greenhouse and lower CO2 emissions due to energy use in it. However, their current prices are high compared with the prices of opaque PV cells. The purpose of the present work is to investigate the possible use of semi-transparent PV modules placed on the roof of energy intensive greenhouses in Crete-Greece in order to cover their energy requirements and sell the surplus electricity into the grid. Two different cases have been studied where greenhouses of 1,000 m2 each cover their high heating needs using heat pumps and solid biomass. PV modules of 42.5 KWp can be placed on their roofs covering slightly less than 50 % of their surface allowing enough solar irradiance to enter the greenhouse. In the first case the generated electricity can cover more than 80 % of total energy needs and in the second all the energy needs offering the possibility of selling the surplus electricity to the grid. However, the current high prices of semi-transparent PVs do not favour their use by farmers since their installation costs are high. Future financial support from the government could increase their attractiveness for commercial applications in greenhouses.
关键词： greenhouses,electricity generation,cost,environmental impacts,Semi-transparent photovoltaics,energy
更新于2025-09-23 15:19:57
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Economic Assessment of Solar Photovoltaics Use in Agricultural Greenhouses in Greece
摘要： Modern greenhouses can utilize renewable energy sources for covering their energy requirements and reducing their carbon footprint. Solar photovoltaics use for power generation is currently a reliable and cost-effective technology which is used in many applications. The purpose of the current work is to investigate the possibility of using solar photovoltaics in agricultural greenhouses in Greece and to assess their profitability compared with the profitability of their use in households. Semi-transparent and opaque photovoltaic cells can be used for electricity generation with the net-metering regulations covering all their annual electricity needs. Existing studies in various countries concerning their use in greenhouses have reported a payback period of the investments of 4-10 years. In Greece the cost of electricity in the agricultural sector is subsidized while economic incentives are offered regarding the use of this technology in greenhouses. Economic assessment of the investment of solar photovoltaics in greenhouses for a period of 25 years in Greece indicates payback periods of 7.2 and 14.4 years, depending on capital subsidies obtained, while positive net present values are achieved. Their use in households in Greece has a payback period of 10.4 years while the net present value is also positive. The current study indicates that the use of solar photovoltaics in modern greenhouses in Greece supported financially by the government according to the net-metering regulations is profitable, offering economic and environmental benefits to the farmers.
关键词： profitability,solar energy,net-metering,agricultural greenhouses,photovoltaics,Greece,pay-back period,net present value
更新于2025-09-11 14:15:04
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[Sustainable Energy Developments] Geothermal,Wind and Solar Energy Applications in Agriculture and Aquaculture || Chapter 7: Fundamentals of solar energy
摘要： Modern agricultural systems are characterized by the intensive and optimal use of land and water, turning agricultural exploitation into a semi-industrial concept. Greenhouses are systems suitable both for zones with unfavorable climatic conditions – allowing crop growth regardless of the ambient temperature – and for regions with less restrictive weather – with the aim of increasing crop productivity and improving fruit quality. In this context, a secure and environmentally friendly energy supply must be considered, for any power range or circumstance, including for stand-alone installations. Crop growth is primarily determined by climate and the amount of water and fertilizers applied through irrigation. Therefore, greenhouses are ideal for farming because they allow one to optimize these physical parameters, via the photosynthetic process (Ramírez-Arias et al., 2012), to enhance biomass production. This manipulation requires energy consumption, depending on the crop’s physiological requirements, and the production patterns adopted for yield quantity and timing. The present general concern on the development of more efficient and sustainable productive activities has increased interest in the evaluation of alternatives to the conventional energy sources in the sector; presently many are involved in processes for assessing the environmental feasibility and technological development of such alternatives (Antón et al., 2007; Bojacá et al., 2014; Martínez-Blanco et al., 2011; Page et al., 2012; Romero-Gámez et al., 2012; Torrellas et al., 2013; van der Werf et al., 2014). This work aims to provide an overview of the existing options for the integration of renewable sources in greenhouses located in semi-arid regions where, for example, the high availability of solar radiation facilitates its use for the fulfillment of a certain percentage of the heat and/or electricity loads of greenhouses. Accordingly, this overview contains the basic technological aspects of the main renewable technologies applicable in greenhouses, some simplified design tools and criteria for their selection. Finally, it includes a summary of selected experiences in this field. The main objective is to contribute to a better understanding of the technologies that should support the promotion and development of projects for the implementation of renewable energies in agriculture.
关键词： biomass,geothermal energy,wind energy,semi-arid climates,crop growth control,renewable energy,photovoltaic,greenhouses,energy efficiency,solar energy
更新于2025-09-04 15:30:14