Sustainable deployment of solar irrigation pumps

Key Findings

Groundwater depletion is a major problem in several countries of Asia. More than 60 per cent of irrigated land in India relies on groundwater resources, with levels decreasing across most parts of the country. Given below are key determinants for successful adoption of solar pumps:

Key Determinants for Economic Sustainability

• The capacity and capital costs of solar pumps are dependent on the peak daily water requirement of a crop. The use of solar pumps would be more economical for crops having high revenues per unit of peak water requirement.
• Discharge rates from a solar pump declines linearly with increasing pumping head. Thus, regions with lower water table will need solar pumps with higher capacity and capex, ceteris paribus.
• To ensure long-term economic sustainability of SIPs, it would be essential to link their deployment with water management and harvesting schemes.
• Daily variation in solar radiation can limit pumping hours, particularly in regions with fewer peak sunlight hours or higher incidence of cloudy cover.
• SIPs are cost-effective as compared to diesel pumps on a lifetime basis. However, farmers’ ability to fund high capital costs would be a critical factor in their adoption.
• Scale of farming may not directly determine economic viability of SIPs, it influences the possibility of SIP adoption, particularly for smallholder farmers. Therefore, utilization could be improved through use of surplus electricity from solar panels for household/productive purposes.

Key Determinants for Environmental Sustainability

• SIPs could considerably reduce greenhouse gas (GHG) emissions and other pollutants as compared to electric or diesel pumps, both of which are highly carbon intensive.
• Replacing just five million diesel pumps in India with SIPs could help abate 26 million tons of CO2 emissions.
• Effective management strategies for each component (such as solar panels, controllers and invertors) at its end of useful life would be imperative to ensure environmental sustainability of SIPs from a lifecycle perspective.
• It would be essential to promote additional water-management mechanisms in regions with limited water resource. These may include use of drip and sprinkler kits, mulching, conservation farming, etc.

Key Determinants for Social Sustainability

• Key determinants of social acceptability and adoption of SIPs would be awareness about the technology through intensive awareness campaigns, technology demonstration, and training exercises for farmers and other stakeholders.
• Agricultural planning and water resource management would be crucial for a long-term sustainability of water resources as well as the use of SIPs.
• Measures such as fencing, security fasteners, anti-theft bolts, alarms and system monitoring tools are being used to secure solar panels against risks of theft.
• SIPs could offer multiple co-benefits, which make them attractive on both economic and social dimensions, for users as well as other stakeholders. They are often used to supplement drinking water requirements, particularly in water scarce regions, such as Rajasthan in India.

Key Recommendations

• Build awareness about solar pumps through information campaigns and field demonstrations by policymakers and solar pump suppliers.
• Target key supporting stakeholders, including financiers and local knowledge networks, in education drives. This could facilitate wider acceptance and adoption of SIPs.
• Prioritise areas with rising use of diesel-powered irrigation, availability of crop inputs, and market linkages. Such areas would find more takers for SIPs.
• Facilitate access to credit for farmers as well as suppliers and service providers, while being sensitive to the needs of different business models.
• Design a regulatory framework to manage SIPs and maintain water harvesting strategies to enable a long-term sustainability of solar powered irrigation.