Is solar irrigation set to take over Africa?

Ohrigstad, South Africa. Photo by Wynand Uys on Unsplash.
Mar 2019

An Agriculture Climate Letter from the CGIAR Research Program on Climate Change, Agriculture and Food Security (CCAFS) blog.

The Water-Energy-Food Nexus Blog Series

Delivering water, energy and food for all in a sustainable and equitable way is a major challenge faced by society. The water-energy-food nexus concept aims to address this by better understanding how interactions between water, energy and food are shaped by environmental, economic, social and political changes and how the synergies and trade-offs among them can be better planned and managed. The Water-Energy-Food Nexus Knowledge-Action Network is a network of people and organisations which fosters transdisciplinary research and communicates the importance of holistic system approaches across water, energy and food systems. Acknowledging that the nexus concept is often described as overly academic and not practical on the ground, the Water-Energy-Food Nexus Knowledge-Action Network is organising this blog series to illustrate the role of the nexus concept in addressing local and national challenges of sustainable and equitable access to resources. Understanding the perceptions and entry points with which local and national stakeholders can engage with the nexus concept is key to further implementing nexus approaches, especially in the Global South.

Learn more about the Future Earth Water-Energy-Food Nexus Knowledge-Action Network. 

Is solar irrigation set to take over Africa?

By Bruce Campbell (CCAFS), Frank Rijsberman (GGGI), and Mark Smith (IWMI)

Republished with permission from CGIAR Research Program on Climate Change, Agriculture and Food Security (CCAFS) blog

Against a backdrop of plummeting electricity costs of solar energy and expanding solar energy generation (see Figure 1), the World Economic Forum hosted Keith Breen’s blog back in 2016: “Is solar set to take over the world?” We ask that question for African irrigation, and query whether Africa’s abundance of sunlight can help the continent leapfrog to a different food future. Recent scientific articles in the energy and agriculture literature suggest solar has a major role to play, but also point to challenges.

Figure 1: Electricity cost Ritchie, H. & Roser, M., 2019. Energy Production & Changing Energy Sources.

Globally, 20% of cropland is irrigated, but only 5% in Africa (FAO 2016); and yet Africa has the greatest food insecurity, partly due to unreliable growing seasons. Growing seasons will become more unreliable with climate change, while expanding and urbanizing populations will be needing more and different foods as diets and demand change. Can irrigation be a strategy for both climate adaptation and helping smallholders enter expanded markets?

Hua Xie et al. (2018) have estimated that irrigated land area in the drylands of Sub-Saharan Africa (SSA)—home to about 425 million people—can be expanded by 6–14 million hectares, 84% of which is small-scale irrigation. Modelling estimates that food import dependency can be reduced from 54% under business-as-usual to 17–40%; and that hunger and undernutrition can be reduced. Previously, it was estimated that across 13 African countries studied, groundwater could expand irrigated land area by 13.5 million hectares, but with strong differences in potential amongst countries (Pavelic et al. 2013). Thus, the potential for expanding irrigation in Africa is there.

Shah et al. (2018) write that “South Asia’s groundwater economy stands at the threshold of a revolution in adoption of solar irrigation pumps”. In India, the Farmers Energy Security and Empowerment Program will install more than 2 million solar pumps through a USD 22 billion fund. Can solar be the cornerstone of Africa’s groundwater development? Wazed et al. (2018) in their recent prospectus for solar irrigation technologies for SSA are highly positive about the future of solar, noting that photovoltaic “powered water pumping technologies are well developed, easily accessible and require almost no maintenance over the course of the lifetime of the technology”. In addition, what is feasible today will be outstripped by multiple technological innovations in the not too distant future (Brunet et al. 2018).

However, there are challenges, and here we briefly mention four:

  1. Inequality in irrigation schemes and water provision is widely reported from research, e.g. women having lower access than men to water, information and credit  (Sinyolo et al. 2018).
  2. Underperformance of irrigation schemes has been a challenge in many developing countries because of poor participation of smallholders in infrastructure maintenance (Sharaunga & Mudhara 2018).
  3. Over-abstraction of groundwater, amounting to a “global groundwater crisis” (Famiglietti 2014). Searching “groundwater depletion” and “irrigation” on Google Scholar yields about 990 English language articles since 2018, indicating the scale of the problem. Solar pumping comes with almost no marginal costs; thus, pumps can keep running even when water is not really needed or is used for low-value or water-loving crops. So, if diesel and electric pumps have caused a crisis, solar has the potential to exacerbate it.

Shah et al. (2018) suggest that linking irrigators into electricity grids may be an answer. In a pilot scheme in India, when farmers were not connected to the grid, they used all of their solar-generated energy for irrigating their own and neighbours' fields; but when connected to the grid, they sold as much power as they could and used only 35% of what they generated for pumping. Solar power sales thus became an additional source of income for farmers, contributed to the national grid, and could reduce the current fossil fuel subsidies for irrigation.

  1. High initial investment costs coupled with inconsistent energy policies (e.g. subsidies to fossil fuels, high import taxes on photovoltaics) and the economic issues faced by many developing countries (e.g. low foreign investment, high interest rates, limited agricultural credit) can be prohibitive (Brunet et al. 2018). Given high up-front costs for solar irrigation, private investment needs to be fostered through, for example, farmers being connected to the grid while also tapping into high value agricultural markets (with good connections to input and output markets).

Blessed by sunlight, African countries can greatly benefit from solar energy to make use of groundwater resources, but there are implementation challenges that must be overcome. Capital costs must become more affordable and better water governance is needed to help reduce inequalities and improve water management. As in Asia, preventing groundwater overuse is critical, but is possible with incentives created by linking solar irrigation to development of national, or perhaps local, grids. Solar irrigation can be a win-win for climate change adaptation (less reliance on rainfall, increased and diversified incomes) and mitigation (renewable energy to grids, less reliance on diesel and electricity pumps). If we get it right, solar irrigation can create a win-win-win-win for food, water, energy and climate.