Abstract:
The idea of agri-voltaic system was brought in keeping with the needs of food and energy in future, in which both crop and electricity can be produced in a single land use system. The western part of Rajasthan is a very suitable place for solar energy, where there is abundant sunlight for about 300 days in a year. Commercially available photo-voltaic panels have an efficiency of 12-15% and are an excellent choice for future potential energy needs and environmental protection.
Keeping in view the above facts, a 105 kW capacity agri-voltaic system was established at Central Arid Zone Research Institute, Jodhpur. In the overall system, photo-voltaic modules were installed in three types of designs in three different blocks (36 x 36 m) for testing for field cultivation between photo-voltaic arrays, in which distance of 3, 6 and 9 meters was placed between the two photo-voltaic rows. In the established agri-voltaic system the rainwater was harvested from the solar panel top, collected through a rectangular gutter/ channel and conserved in a rainwater harvesting structure (Tanka) of 1 lakh liter capacity along with crop and electricity generation.
The agri-voltaic system was designed in such a way that suitable crops can be taken between the two solar rows. Crops were selected preferably of short height and requiring less water under this system. Keeping this in view, moth bean, moong bean and clusterbean crops were raised in kharif season of 2017, while moth bean, moongbean and cowpea crops were raised in kharif season of 2018, which yielded good yields. Shankhapushpi, Ghritkumari and Sonamukhi were raised in 2017 while brinjal and chilli were cultivated in 2018 between two rows of agri-voltaic arrays.
Solar energy is available for about 4-5 hours per day for electricity generation in Jodhpur. Accordingly, a 1 kW photo-voltaic system can provide 4-5 kW electricity per day and a 105 kW capacity agri-voltaic system will generate 420 kW of electricity in a cloudless day. The grid connectivity is done by the net meter of the agri-voltaic system. On an average 10,000 kWh of electricity was produced each month in the year 2018.
The total surface area of installed solar PV modules is 651 m2. Construction of rainwater harvesting structure (Tanka) was done on 70% annual rainfall probability of 280 mm. In the rainy season of 2017 rainwater was harvested from the actual surface area of 431.4 m2. During 20 July-15 September 2017, a total of 202.9 mm rainfall was recorded and 62,583 liters of rainwater could be collected. Thus, system efficiency was found to be 69.2%. Similarly, in the year 2018, the entire area of solar PV panel 651 m2" used and against received rainfall of 213.1 mm, 71,300 liters of rainwater could be stored with 64.3% system efficiency during the period June 1- August 31.
