The benefits and risks of solar-powered irrigation - a global overview

Sep 22, 2018

Source/author : Food and Agriculture Organization of the United Nations

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1. Introduction


Agriculture is the single largest employer in the world, sustaining the livelihoods of 40 percent of the world’s population, many of whom continue to live in poverty (United Nations, 2015). Irrigation is among the measures that can improve yields, reduce vulnerability to changing rainfall patterns and enable multiple cropping practices (FAO, 2011). As such, irrigation is often seen as the engine that helps to ensure food security, generates incomes, provides jobs and drives rural development. Energy is a key input for irrigation services.

As investment costs for solar powered irrigation systems (SPIS) are coming down and subsidy schemes for SPIS are being rolled out, solar technologies are becoming a viable option for both large and small-scale farmers. SPIS provide reliable and affordable energy, potentially reducing energy costs for irrigation. In rural areas where diesel fuel is expensive or where reliable access to the electricity grid is lacking, they can provide a relatively flexible and climatefriendly alternative energy source. SPIS can be used in large-scale irrigation systems as well as for decentralized, small-scale irrigation.

Some countries are promoting SPIS in the framework of national action plans regarding climate change as a way to reduce emissions from agriculture. The operation of solar pumps does not produce any greenhouse gas (GHG) emissions. Life cycle assessments of SPIS, accounting for emissions in a cradle-to-grave scenario, indicate a potential reduction in GHG emissions per unit of energy used for water pumping (CO2-eq/kWh) of 95 to 97 percent as compared with pumps operated with grid electricity (global average energy mix) and 97 to 98 percent as compared with diesel pumps (GIZ, 2016).

Nevertheless, it is important to note that SPIS – if not adequately managed and regulated – bear the risk of supporting unsustainable water use. Once the systems are installed, there is no cost per unit of power and thus no financial incentive for farmers to save on fuel or electricity for water pumping. This can lead to wasteful water use, over-abstraction of groundwater, and low field application efficiency. In some cases, farmers sell water to their neighbours at a profit, increasing the overall water withdrawals. Recognizing the water-related risks and addressing those from the beginning – especially in the financing and design stages – will be crucial to ensure the sustainable use of SPIS technology.

In light of the rapid expansion of SPIS, there is an opportunity to not simply introduce a clean, climate-smart and innovative energy technology, but to think strategically about how this technology can be used to encourage more sustainable use of groundwater resources, to create more inclusive finance and management structures and to foster more integrated thinking about solutions around the water-energy-food nexus.


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