| Work Detail |
Scientists from Turkey, Qatar and Egypt have designed a greenhouse system that includes a battery energy storage system, hydrogen production and storage, and a semi-transparent photovoltaic array. The system has been optimized for maximum net present value and minimum grid dependency. A research team led by scientists from Turkey’s Final International University has developed a self-powered greenhouse that uses a semi-transparent photovoltaic (STPV) system, a battery energy storage system (BESS) for short-term energy storage, and hydrogen for long-term storage. The proposed system size was optimized to maximize the net present value (NPV) and minimize the energy dependence (ED) on the grid. “Previous studies highlight the potential of STPV systems, which serve a dual function by allowing sunlight through for photosynthesis and generating electricity simultaneously. Despite this advantage, there is a recognized lack of energy availability during the winter months in greenhouses,” the team explains. “By incorporating both BESS and hydrogen as part of a hybrid energy storage solution, this research provides a comprehensive approach to address seasonal energy dependency and optimize year-round energy management.” The system was designed to use STPV with 7% efficiency, costing $100 per 32W panel. The BESS is lead-acid based, with 80% to 90% charge and discharge efficiency and priced at $500/kW. The electrolyzer is 80% efficient and costs €388 ($408)/kW; the hydrogen storage system is 90% efficient and costs $10/kW; and the fuel cell is 60% efficient and costs €395/kW. The assumed grid electricity rates are $0.43 per kWh for peak demand, $0.12 for off-peak demand, and $0.3 for intermediate demand. The GBO algorithm optimizes the system based on three scenarios: the first prioritizes financial profitability, i.e. higher NPV; the second seeks a balance between profitability (higher NPV) and energy independence (low DE); and the third attempts to achieve maximum energy independence, i.e. as low DE as possible. Summer and winter solar irradiation data from Qatar were collected and used. “GBO is an efficient and powerful algorithm that uses two basic search strategies: exploitation and exploration. The exploitation search technique focuses on finding local optima, ensuring detailed and refined searches within a specific region of the search space,” the academics explained. “In contrast, the exploration search technique aims to discover global optima by searching broadly across the entire solution space.” The scientists found that the first scenario requires an STPV area of ??8,500 m2, a BESS capacity of 150 kW, an energy output of 240 kWh, and a hydrogen storage of 4,436.4 kg. In this case, the NPV would be $1,584,800, with an initial investment of $1,304,006. The system will have a ED rate of 15.07% and will import 19,200 kW of energy from the grid in summer, 62.76% and 86,851 kW in winter, respectively. The second optimization scenario required a STPV area of ??12,750 m², a BESS capacity of 225 kW, an energy output of 360 kWh, and hydrogen storage of 8,763.6 kg. In this case, the NPV would be $1,483,500 with an initial investment of $2,007,900. The system will have a DE rate of 10.64% and will import 15,000 kW of energy from the grid in summer. In winter, the DE rate will be 40.09% and will import 50,595 kW. Finally, the third scenario requires a STPV area of ??27,200 m², a BESS capacity of 480 kW, an energy output of 768 kWh and a hydrogen storage of 23,476 kg. In this case, the NPV would be $98,223 with an initial investment of $4,401,100. The system will have a DE rate of 10.31% and will import 14,760 kW of energy from the grid in summer. In winter, the DE rate will be 1.56% and it will import only 1,078.7 kW. “Scenarios that emphasize minimal ED result in negative NPVs, highlighting the trade-off between achieving energy independence and maintaining financial viability,” the team concludes. “This dual-approach optimization not only improves the economic viability of greenhouse energy systems, but also promotes sustainability and energy independence, providing valuable guidance for the development of sustainable and financially viable greenhouse energy management strategies.” The results were presented in “ Towards a self-powering greenhouse using semi-transparent PV: Utilizing hybrid BESS-hydrogen energy storage system,” published in the Journal of Energy Storage . Researchers from Final International University in Turkey, the Ministry of Municipalities and Qatar University, and Arish University in Egypt carried out the study. |
