Solar-powered irrigation increases crop yields

A new study, led by the International Institute for Applied Systems Analysis (IIASA) under the research project Renewables for African Agriculture (RE4AFAGRI), published in Environmental Research Letters, finds that standalone solar photovoltaic (PV) irrigation systems have the potential to meet more than a third of the water needs for crops in small-scale farms across sub-Saharan Africa.

The RE4AFAGRI study – which is also part of the Long-Term Joint European Union-African Union Research and Innovation Partnership on Renewable Energy initiative – has developed an open-source modeling framework that used various datasets related to agriculture, water, energy, expenses, and infrastructure to help envision requirements for solar PV irrigation systems.

The framework calculates local irrigation needs, determines the necessary size and cost of technology components such as water pumps, solar PV modules, batteries, and irrigation systems, and assess the economic prospects and sustainable development impacts of adopting solar pumps.

In sub-Saharan Africa 80% of agricultural production is produced by smallholder farmers who face constraints in increasing farm productivity, resulting in a large yield gap.

Extensive rain-fed agriculture (90% of all cropland) under unpredictable and erratic rainfall pattern is the leading cause of the low productivity and food insecurity in Africa, together with a low degree of mechanisation. This has been reinforcing a persistent poverty trap, triggered by cyclical famines that are jeopardising local development opportunities.

Lead author of the study and a researcher in the IIASA Energy, Climate and Environment Programme’s integrated assessment and climate change research group Giacomo Falchetta says the institute estimates an average discounted investment requirement of $3-billion a year, with the potential to generate profits of over $5-billion a year from increased yields to smallholder farmers, as well as significant food security and energy access co-benefits.

Falchetta explains: “Reducing the irrigation gap with cost-effective solar pumps can boost food production and improve nutrition, contributing to Sustainable Development Goal 2 (SDG 2), equating to zero hunger. Further, surplus electricity generated by these systems could serve other energy needs, aligning with SDG 7, [namely] Affordable and Clean Energy.”

Crucially, the authors of the study demonstrate the great importance of business models and investment incentives, crop prices, and PV and battery costs, in shaping the economic feasibility and profitability of solar irrigation.

IIASA Transformative Institutional and Social Solutions Research group leader Shonali Pachauri notes that using a business model that spreads out all initial expenses more than doubles the number of workable solar irrigation systems, and presents huge potential for achieving the SDGs in the process.

“The study also highlights that without strong land and water resource management infrastructure and governance, a widespread deployment of solar pumps may drive an unsustainable exploitation of water sources and reduce environmental flows. “Consequently, investing in infrastructure such as reservoirs for water management during seasonal variations, and enhancing water resource governance, are critical factors for ensuring the sustainability of widespread solar pump deployment.”

The analysis and the novel open-source modeling framework can support public and private actors working along the water-energy-food economy nexus in identifying economically feasible areas and quantifying the potential net economic benefit of developing solar irrigation, and can thus foster investment in the sector, Pachauri concludes.