The Solar Pumps Tool has been developed by aggregating and analysing district-wise data for more than 600 districts across India. The tool uses 20 parameters affecting the deployment of solar for irrigation in varying scenarios.
Based on objectives defined by the user, the tool helps to:
In order to conveniently analyze the relative standing of different districts in a given scenario, multiple parameters have been collapsed into one numeral, the overall score. In order to do so, the parameters were normalised, through unity-based normalisation, to make them dimensionless and align the range from 0 to 1 to eliminate range specific biases before applying a weighted sum average as shown below:
Composite score = n1*w1 + n2*w2 + …………………… + n10*w10
Where, ni = normalised score for a parameter = (x-xmin)/(xmax – xmin); [0,1]; wi = weight; and x = parameter value
The choice of the basic unit of assessment was influenced by data availability, minimum heterogeneity within the selected unit of geographical area, and administrative ease of implementation based on insights from this tool. The parameters were chosen for the assessment display wide intra-state variation and there are gaps in the availability of block-wise data. Hence, the district was preferred over the state and the block, as the basic unit of assessment for this tool.
This tool makes use of 20 parameters, which in varying configurations, affect the suitability of:
The deployment of solar for irrigation should be governed by ensuring environmental sustainability, economic viability, and social equity. In this regard, five criteria, with 10 corresponding parameters (described below) were identified for this tool. These are applicable as ‘weights’ across all scenarios. The rest of the parameters pertain to specific deployment approaches and policy objectives and are covered under the respective headings.
A. Potential demand for solar pumps – Inadequate access to affordable and reliable irrigation
B. Economic viability of solar-based irrigation
C. Purchasing capacity of farmers:
D. Access and subscription to institutional credit
E. Farmers’ attitude towards progressive farm technologies
Parameters can be applied in two ways in the tool: as ‘filters’ to select/de-select districts, and as ‘weights’ contributing to the overall score of a district.
‘Filters’ are used in the tool to define a maximum or minimum cut-off point for a parameter or multiple parameters to help focus on only the districts meeting such criteria (say, districts appearing in the bottom 25th percentile under Number of cultivators reporting use of diesel pumps), based on the objectives of the user.
‘Weights’ are used in the tool to determine the contribution of a certain parameter towards the overall score of a district (explained below), being calculated for each district for every scenario.
This tool measures the suitability of four deployment approaches (mentioned below) for any given district. The district’s suitability is assessed based on the performance of its ‘Affecting’ parameters on their filtering criteria.
A. Individually owned off-grid solar pumps: Solar for irrigation has been largely promoted through this approach so far, i.e. farmers purchasing-stand-alone solar pumps of varying capacities with significant subsidy support from the government. Ownership of pumps provides easy and reliable access to irrigation.
B. Solarisation of feeders: Changing the source of power at the feeder level will ensure a rapid and cost-effective transition to solar-based irrigation on a large scale.
C. Water as a service: This model has the potential to improve irrigation equity as it avoids a prohibitively high upfront cost of technology for small and marginal farmers:
D. Promote 1 HP & sub-HP pumps: 1 HP and sub-HP pumps could help marginal farmers meet their needs and could also be put to use for lift irrigation, provided there is access to surface water.
This tool recommends a set of policies for each district, for the implementation of which solar could be leveraged as a potential source of irrigation, a capital investment, or a way to further climate resilience. The suitability of a policy for a district is evaluated based on the performance of a set of pre-identified ‘Affecting’ parameters.
A. Har Khet ko Pani – Pradhan Mantri Krishi Sinchayee Yojana: Solar-based irrigation could improve access to groundwater irrigation.
B. Per Drop More Crop – Pradhan Mantri Krishi Sinchayee Yojana: Solar pumps can be deployed along with precise water application devices such as drip irrigation to promote efficient irrigation practices.
C. Doubling Farmers’ Income – Capital Investment: Encourages investment in farm technologies, such as solar pumps, by small and marginal farmers.
D. Doubling Farmers’ Income – Crop Diversification: Solar pumps help achieve diversification towards high value crops; in turn enhancing the economic viability of solar pumps.
E. Doubling Farmers’ Income – Crop Intensity: Solar pumps to ensure irrigation access to help grow crops beyond rabi and kharif.
F. National Mission on Oilseeds and Oil Palm (NMOOP): Solar pumps to help provide reliable irrigation for oil crops.
G. Sub-Mission on Agricultural Mechanisation – Farm Power Availability: Solar pumps to improve farm power availability.
H. Climate Resilient Farming for Small Farms: Solar pumps to advance the cause of low-carbon agriculture and improve climate resilience.
i. The choice of filters and weights has been kept the same across states, while in reality, the influence of parameters will vary with geographic locations and states.
ii. The default weights and filters have been decided based on CEEW research and consultation with a set of experts, which could reflect the biases of the group. The tool tries to correct this by allowing the user to change weights and as per their discretion, with almost no restriction.
iii. The tool as of now only captures the potential of solar-based irrigation for groundwater sources. In the future, it might incorporate variables corresponding to surface water availability to enhance its scope.
iv. Given water availability is an important criterion when it comes to the sustainable deployment of solar pumps, it would have been useful to integrate India’s aquifer (hard rock) map to its political map. But, this could not be done due to the unavailability of a usable format of such a map.
v. Certain deployment approaches, like the community ownership of solar pumps, and a few policy objectives could not be incorporated in the tool due to the unavailability of data.