How Is India Using its Solar Pumps for Irrigation?

Key Highlights

• There is a significant divergence in the general data quality and pump usage pattern across multiple years. The most likely reason for this divergence is the difference in the device quality. Due to this issue, the study has treated the data sets from the two years as separate datasets.
• A significant number of pumps are underutilised in terms of hours of usage. Almost 24 and 54 per cent solar pumps from 2016-17 and 2017-18 respectively were used for less than 550 hours annually. Within them, 5 per cent and 14 per cent pumps respectively have been used very rarely. This represents a colossal waste of publicly funded assets.
• The average annual usage shows two distinct seasons in a year - one season coinciding with the Kharif season (July to November) and the other with the non-rainy season (December to June). The Kharif season shows a double peak - one in the beginning and one in the end. This pattern fits well with the irrigation cycle of paddy, which is the dominant crop in the state. The non-rainy season usage pattern displays a gradual increase and decrease post-March. The solar pumps are most likely used for non-cereal crops in these seasons.

The overall pump usage follows a pattern of two distinct irrigation periods in a year



Source: Authors’ analysis
Note: The top line of the chart represents the average sunlight hours available on that particular day. The seasonality of sunlight hours is clearly visible. The blue portion represents the average number of hours of usage, and the green portion represents the number of hours for which an average pump was unutilised on a given day.

• The usage pattern shows an alarming trend of decreasing annual usage hours over the years. This is true for pumps sanctioned in both the years as well as across different classes of users (categorised based on intensity of usage).
• The same trend is also seen in the energy generation data of the pumps. This signifies that the decrease in usage hours is not due to a shift in the irrigation timing.

The annual operational hours of pumps is decreasing over the years



Source: Authors’ analysis

• Assuming a 16 per cent maximum energy generation potential, the study estimates that, on an average, only 27 per cent of the total potential is utilised. This represents poor social return for public investment.
• The exercise has purely been based on the data available in the portal and is vulnerable to data quality and device quality issues that may have gone undetected. To firm up the conclusions from the data, the state needs to carry out a well-designed survey with the same beneficiaries. Particularly, the findings on decreasing usage over the years has not been highlighted by any extant studies. Hence there is a need to complement this study with a survey.

Key Recommendations

Assuming the findings are not due to any systematic data errors, the study recommends that:

• Assess the social returns from the publicly funded solar pump schemes.
• Improve the utilisation of the solar pumps. States should re-evaluate the designs of existing schemes. Promoting smaller capacity pumps along with supporting farmers to make the shift to horticulture or other less water-intensive crops could improve overall economic outcomes from the pump. Sharing pumps, community deployments, and encouraging non-pumping use of the solar asset for other complementary livelihood activities could be the way forward.