عنوان مقاله [English]
Increasing the global population requires food security, especially in developing countries. In this regard, greenhouse systems have significantly increased efficiency due to resource constraints and advantages such as the possibility of more than one harvest per year. This issue is vital in arid and low rainfall areas such as Iran. These systems require higher energy consumption than traditional methods due to their greater sensitivity to environmental conditions such as temperature and humidity. It is predicted that in the next 50 years, energy shortages and how to supply them will be one of the most fundamental issues and one of the ten most important challenges in the world. As a result, energy supply is considered an essential indicator for the development and progress of industrial greenhouses.
On the other hand, urban development includes economic, social, and environmental approaches that must align with sustainable development. Management problems in this process always exist between the urban space, stakeholders, and urban infrastructure. This complexity requires multidimensional approaches and specific quantitative or qualitative methods for analyzing and combining different aspects.
In this study, by modeling grid-connected renewable power generation systems in Homer software, an optimal hybrid system has been introduced to reduce greenhouse gas emissions. In addition to examining environmental and technical parameters, economic parameters have received much attention in this research. The crop under cultivation in the greenhouse was cucumber; the main reason for choosing it was the significant number of cucumber greenhouses in this city and easy access to the data of the cucumber greenhouses. Of course, the data related to other agricultural products were also generalized, and even regardless of the type of product, each greenhouse can obtain the current net cost of its greenhouse only by estimating its bioelectricity. This can be a good guide for all greenhouses in the same climate with any product. Sensitivity analysis on inflation and interest rates also helps farmers and the government work with full awareness in this area, thus providing the necessary conditions for sustainable urban development.
Materials and Methods
This research includes studying energy systems in greenhouses located in Robat Karim city. Based on this, the renewable energy sources in the area have been studied and evaluated. According to that, the corresponding components in Homer software have been designed and modeled as connected to the network. Homer software is used to power many items such as buildings, hotels, and villages, by simulating energy consumption and performing economic and technical analysis on hybrid systems. In addition to analyzing economic parameters, it Analyzes and examines environmental parameters and how to generate optimal power.
After examining different scenarios in Homer software, each of which includes two or more primary components, three scenarios have been selected as the top scenario, the optimal scenario including solar panel, wind turbine, and battery. In this scenario, the net present cost is $ 215,626, and the energy cost in this scenario is $ 0.084 kWh. Then the second scenario includes a solar panel, diesel generator, and battery, with a net present cost of $ 238,135 and a cost of energy of $ 0.094 kWh. Finally, the solar panel, wind turbine, and diesel generator scenarios were considered the last, with a net present cost of $ 240,626 and an energy cost of $ 0.094 kWh. The share of the renewable sector in the first to third scenarios is equal to 6.59, 6.47, and 4.59 percent, respectively.
As mentioned, the primary purpose of this modeling is to reduce the emission of pollutants, which in the optimal scenario to prevent the emission of 66 tons of carbon dioxide, 18 tons of unburned hydrocarbons, and 200 kg of sulfur dioxide per year. These values are for a greenhouse with an area of 0.2 hectares. Meanwhile, the area under cultivation of greenhouses in Tehran province is about four thousand hectares. If only ten percent of the area of greenhouses in the province uses a combined system, it can prevent 132,000 tons of carbon dioxide. That is equivalent to the amount of carbon dioxide absorbed by 6,300 trees.
Tehran province is one of the most strategic parts of Iran in the greenhouse industry. The construction of new greenhouses is considered an urban development, which must be in line with sustainable development to be considered a suitable solution. In this way, renewable energy is considered an inevitable action. The inexhaustibility and non-production of pollutants are two crucial factors for the global acceptance of the use of renewable energy. In this research, an attempt has been made to model an optimal system by reducing the emission of greenhouse gases, especially carbon dioxide, by modeling renewable power generation systems connected to the grid in Homer software. Furthermore, to consider the project’s future possibilities, inflation and interest rates have been examined using the sensitivity analysis of Homer software. The investigation’s most significant findings include the following:
• The best scenario includes a solar panel, wind turbine, and battery with a net present cost of $ 215,626 and an energy cost of $ 0.084 kWh. By providing subsidies and guaranteeing the purchase of renewable electricity, the government can encourage the use of hybrid systems and the grid connection, thereby providing part of the goal of reducing emissions. Solar and wind energy are the most suitable renewable sources due to easy access throughout the country, which play an influential role in reducing energy costs.
• Using a hybrid system of solar panels, wind turbines, and batteries in grid mode can reduce carbon dioxide emissions by about 61%. In this way, we can take action to combat climate change for sustainable development and commitment to international treaties.
• It is possible to increase the share of the renewable sector by increasing the capacity of solar panels, allocating more space, and in some cases, even supplying greenhouse energy without connection to the grid. Of course, it is recommended to use a network-connected system as much as possible to reduce costs.
Finally, according to the studies conducted and the problems facing the use of renewable resources, it is recommended to create a significant change in the agricultural industry and control the emission of greenhouse gases in the country. Maximum government support should be provided through loans and facilities, appropriate policy-making, raising farmers’ awareness, encouraging the private sector.