Overcoming barriers to solar dryer adoption and the promise of multi-seasonal use in India

Abstract

Food and income loss caused by conventional open-sun drying of crops could be reduced through the use of protected solar drying equipment. Yet, solar dryers have not been widely adopted among the majority 470 million smallholder farms worldwide. Combining primary survey and field data on dried chili harvests collected in India, this paper demonstrates for the first time how technical, financial, and operational barriers combine to limit smallholder ownership of commercially available hoophouse tunnel dryers. It then addresses those barriers using a systems-level approach. First, economic loss due to degradation of chilies in open-sun drying is quantified, averaging 34% of potential revenue. Despite demonstrated revenue gains of 22% based on improved quality, technoeconomic analysis indicates that seasonally stranded solar dryers are not profitable enough to overcome capital and operational cost barriers: cumulative income parity with open-sun drying is not reached for 3–7 years. Second, to address this major adoption barrier, complementary multi-seasonal revenue streams are introduced that incorporate both drying of crops and growing of seedlings in the same dryer structure for year-round revenue generation. Together with service-based operation to support smallholder access, payback time is decreased by at least 50% relative to single-season usage. Adding available financing schemes, multi-season dual-use dryers could reach payback in 1 year versus 6.5 years for drying-only usage, reducing the financial adoption barrier by up to 85%. This suggests that multi-season utility can drive solar dryer adoption. Finally, a sensitivity analysis of single- and dual-use solar dryer operations is provided and their practical implementation by smallholder farmers is discussed.