Renewable energy generation, particularly from solar power, is on the rise to lower carbon emissions. However, solar photovoltaic plants require vast tracts of land, leading to competition with agricultural land use. Agrovoltaics offer a solution by integrating solar PV systems with farming on the same land. This involves using elevated structures for the solar panels, allowing agricultural activities to continue beneath them.
Electricity, which is required for many farming operations (like irrigation pumping and post-harvest cold storage), can be produced using solar energy. According to the Fraunhofer Institute for Solar Energy Systems (ISE) [1], agrivoltaics is a system technology that attempts to maximise the synergistic benefits and potentials of primary agricultural produce and secondary solar power generation on the same area of land.
However, there are concerns that the shadow of the solar system on agricultural lands may restrict plant development, growth, and yields. Therefore, it is critical to pick the right type of solar system and crops for successful agrivoltaics projects. A suitable system layout should be selected for agrivoltaics where elevated solar systems will use direct sunlight to generate power while plants will use the diffused light to grow [2].
This study ‘Economic indicators evaluation to study the feasibility of a solar agriculture farm: A case study’ mainly aims to choose between the surface-mounted solar system and the agrivoltaics system on the existing land (agricultural land) which is already available for the installation of solar plant.
An economic analysis is conducted to compare ground-mounted and agrivoltaics systems of the same capacity to support the concept of dual land use for farming and energy generation. The use of solar power in agriculture operations is out of the scope of this case study. Both systems had the same production capacity. Two different hypothetical situations were used for each system.
Data collection parameters for the agricultural operation included, among others crop types, cropping seasons, land preparation techniques, harvest quantity, food crop processing activities, post-harvest management, local market economics for the agricultural products, market pricing, and sales, and costs for farming activities.
Data collection for the solar systems included the cost of the solar system installation and operation (capital costs), power generation, and energy sales market prices (surplus and self-consumption), among others. Energy variables captured included net present value (NPV), payback period (PB), and levelized cost of electricity (LCOE) for surface-mounted and elevated solar systems. Two scenarios were used for the economic factors.
The agrivoltaics system is comprised of 19 raised solar panel support structures, each of which has 32 solar panels with a 345 W power output. Each raised solar panel produced 11 kWp of power. In the first situation (Case Study A), the assumption was that solar power performance would remain constant during operation. In the second situation (Case Study B), the assumption was that annual performance would be reduced by 0.5 %.
In this agrivoltaics project, vegetable selection is based on its market potential, investment potential, irrigation requirements, protection and sheltering, and profit margin. Vegetables are grown organically using biological fertiliser, composted animal waste, and green manures, principally cow dung.
The crop output showed negligible impact from the shadow of the elevated structure because the total vegetable yield is ten metric tons which is greater than India's average national vegetable yield on the same land area [3]. The various expenses related to fixed and variable costs of agricultural production. Given that solar power plants are built on already-existing land; land costs are not taken into account in the study. Fertiliser costs are low since the Institutes' dairy cow compost is utilised. The 200kWp elevated solar power plant exports its electricity into the distribution system. This experiment uses drip irrigation and uses just 1 kW of power for irrigation of the farmland. Therefore, irrigation activity is done by either solar or the grid and has little impact on the total power requirement.
Results and discussion
The results for the agriculture parameters are - Farm profit (INR 161, 907), Gross margin (INR 316, 907), and Benefit-cost ratio (1.5). The results show that agrivoltaics is better than the surface-mounted system because there is no significant difference between the payback periods of agrivoltaics and surface-mounted systems; the net present value of agrivoltaics is greater than the surface-mounted solar system for both the study case A and case B and the levelized cost of electricity of agrivoltaics is 55 % less than that of the surface-mounted solar system.
Economic parameter results for agricultural farm
Surface-mounted and agrivoltaics economic parameter results net present value comparison: A higher net present value indicates that a given investment will earn more than its expected costs. This means that the investment will generate a higher cash flow than the amount invested. The study indicates that the case A net present value for the surface-mounted became positive in the 9th year with the value of 4915,762 INR at the end of the project life time. For the agrivoltaics case, it became positive in the 10th year with the value of 5822,544 INR at the end of the project life time. The net present value for the agrivoltaics project exceeds the surface-mounted net present value.
Payback period comparison
A shorter payback period is a better investment choice as it denotes lower investment risk and faster profitability. The study shows that there is no significant difference between the payback period of surface- mounted system (5.9 years) and agrivoltaics system (6.03 years) in both the study cases.
Levelized Cost of Electricity comparison
The total cost of the system is 57.35 INR/Watt for surface-mounted solar and 66.75 INR/Watt for agrivoltaics, respectively. The cost of operation and maintenance is 1500 INR/ kilowatt for surface-mounted solar, and the gain from vegetable production is 2484 INR/year-kW is also included in operation and maintenance for the calculation of levelized cost of electricity in agrivoltaics because this was used in the maintenance of agrivoltaics system.
An inflation rate of 3%, life span of 20 years, and a power purchase rate of 6 INR /kWh are similar for both power plants. The cost of energy for agrivoltaics plants (1.44 INR/kWh) is 55% less than the surface-mounted LCOE (3.24 INR/kWh).
Land equivalent ratio (LER)
Land equivalent ratio greater than 2 is achieved in this case study. Power generation ratio is set to one because the generation capacity of surface-mounted and agrivoltaics is considered same in this case study; crop yield in dual land use (agrivoltaics) is ten metric tons which is greater than India's average national vegetable yield on the same land area. This value of land equivalent ratio indicates that in agrivoltaics the use of land is double as compared to the use of land in surface-mounted solar systems. In this case study, the government subsidies are not applicable, and the electricity generation cost is calculated by local government regulations.
This study indicates that the concept of solar agriculture farm allows the multiple use of the land with several benefits such as increased net yield, reduced power evacuation costs, and steady income for farmers.
The full paper can be accessed here
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