SDG 17 underscores the pivotal and interconnected role of water, including its energy implications, in addressing challenges related to human well-being and sustainable development. Solar water pumps (SWPs) offer an important technological innovation exemplifying this water–energy–food–society nexus. As a comparatively new and eco-friendly approach to irrigation, SWPs have the potential to substantially benefit millions of smallholder farmers in sub-Saharan Africa (SSA). With costs for solar products steadily reducing, the small-scale SWP market is expected to grow in sales and expand into new territories. Overall, the region’s groundwater resources are known to be greatly underutilized and hence enable greater SWP adoption. This study assesses the possible risks to groundwater resources from SWP expansion to the year 2030. The current market environment is extremely heterogeneous across regions and countries. It is conservatively estimated that up to 10,000 units are sold each year, with the strongest markets found in East Africa. Around 100,000 SWP units are estimated to be in operation. For projected rates of annual growth spanning from 6% to 18%, along with intentionally high estimates of groundwater pumping, the upper limit on the quantity of available groundwater pumped by small SWP development to 2030 would vary from 0.4% to 0.6% at the SSA scale. Values in the regions vary from a low of <0.1% for Central Africa through to a high of 1.6%–2.1% for Southern Africa. Specific countries may generally support additional SWPs ranging from tens of thousands up to millions of units without negatively impacting on groundwater availability. Countries characterized by greater recharge and lower current groundwater use can accommodate greater numbers of SWP systems. Short-term threats to the availability of groundwater are assessed to be low over the short and medium terms. Over the long term, risks to groundwater may be greater than evaluated in this study should SWP growth rates exceed the projected range or if improvements in technology allow for stronger, small-capacity pumps to flood the market. To address long-term groundwater management challenges, key action areas have been defined that recognize the diverse conditions across the regions.

Using water-energy-food-environment (WEFE) nexus as the prism, this review explores evolution of groundwater governance in Iran, Saudi Arabia, Mexico, China, Bangladesh and India – which together account for two-thirds of the global groundwater-irrigated area. Global discourse has blamed widespread water scarcity squarely on supply-side policymaking and advocated a broader template of water governance instruments. Integrated Water Resources Management (IWRM) presented just such a template – with pricing, participation, rights and entitlements, laws, regulations, and river basin organizations – as additional water governance tools. However, the IWRM template faced disillusionment and pushback in many emerging economies. WEFE nexus, the new paradigm, prioritizes system-level optima over sectoral maxima by harnessing synergies and optimizing trade-offs between food, water, energy, soil, and eco-system sustainability within planetary boundaries. Realizing this vision presents a complex challenge in groundwater governance. Global groundwater economy comprises three sub-economies: (a) diesel-powered unregulated, as in Nepal terai, eastern India, Bangladesh, Pakistan Punjab and Sind, and much of Sub-Saharan Africa, where use-specific energy subsidies are impractical; (b) electricity-powered regulated, as in North America and Europe, where tubewells are authorized, metered and subject to consumption-linked energy charges; and (c) electricity-powered unregulated, as in geographies covered by our review – barring China, Bengal and Bangladesh – where unmeasured electricity subsidies have created a bloated groundwater economy. This last sub-economy represents the heartland of global groundwater malgovernance, least equipped to meet the sustainability challenge. It has an estimated 300 million horsepower of grid-connected electric pumps that are either unauthorized and/or unmetered and/or use free or heavily subsidized or pilfered power for irrigating 50–52 million hectares, nearly half of global groundwater-irrigated area. In (a) and (b), groundwater scarcity inspires water-energy saving behavior via increased energy cost of pumping. In sub-economy (c), users are immune to energy costs and impervious to groundwater depletion. Here, the WEFE nexus has remained blind to the irrigation realpolitik that catalyzes or constrains policy action. We explore why the political costs of rationalizing subsidies are prohibitive and exemplify how a smart transition from fossil to solar energy for pumping may offer an opportunity to turn the perverse WEFE nexus into a virtuous one.

Solar irrigation pumps (SIPs) are emerging as a popular technology to address water, energy, and climate change challenges in South Asia while enhancing livelihoods and food security. SIPs are deemed to be a women-friendly renewable energy technology (RET) due to their design, operating system, and safety. While the gender dimensions of natural resources are well documented, the extent to which the water, energy, and food (WEF) policies—including policies to promote SIP technologies in the countries of South Asia—conceptualize and operationalize gender equality and social inclusion (GESI) is not well understood. Therefore, in this study, we reviewed 39 WEF sectoral policies of Bangladesh and Nepal by adopting a gender-transformative analysis approach to rank the policies on a continuum ranging from a scale of 0–3 (denoting gender-unaware, gender-aware, gender-responsive, and gendertransformative). We found that the governments in both countries commit to gender equality and women’s advancement in their WEF sector policies, institutions, and decision-making by ensuring gender and justice principles in their constitutions and national development frameworks. However, these higher-level aspirational principles are not always operationalized in the WEF sector policies. We found that the WEF policies are aware of the need to include GESI and social equity in sectoral programming, yet operational rules for their implementation often fail to challenge structural barriers. Such barriers hinder women and marginalized groups from participating in and benefiting from WEF policies, including the deployment of SIP technologies. This calls for a transformation not only in project implementation but also in the policymaking processes of WEF sectors in the South Asian region.

Irrigation plays a crucial role in enhancing food production, increasing land productivity, and improving the livelihoods of smallholder farmers in Sub-Saharan Africa (SSA). Solar pumps and water harvesting ponds have emerged as promising technologies for sustainable agriculture for smallholders in SSA and beyond. The socio-economic impacts of these systems are less studied in the existing literature. This study examined the agricultural productivity of solar pump and water harvesting irrigation technologies and their impacts on income and food security among smallholder farmers in the Central Rift Valley, Lake Hawassa, and Upper Awash sub-basin areas in Ethiopia. Data were collected from 161 farming households that were selected randomly from woredas where solar pump and water harvesting pond irrigation systems had been implemented. The sample size was determined using the power calculation method. Bio-physical observation and measurements were also conducted at field levels. The benefit–cost ratio (BCR) and net water value (NWV) from the use of solar pump and water harvesting pond irrigations were analyzed to assess the viability of these systems. The household food consumption score (HFCS) and household dietary diversity score (HDDS) were calculated to measure food security, while the revenue from crop production was used to measure crop income. An endogenous switching regression model was applied to address the endogeneity nature of the adoption of the irrigation technologies. The counterfactual analysis, specifically the Average Treatment Effect on the Treated (ATT), was used to evaluate the impacts of the irrigation technologies on income and food security. Results indicate that the ATT of crop income, HFCS, and HDDS are positive and statistically significant, illustrating the role of these irrigation systems in enhancing smallholder farmers’ welfare. Moreover, smallholder farmers’ solar pump irrigation systems were found to be economically viable for few crops, with a BCR greater than 1.0 and an NWV ranging from 0.21 to 1.53 USD/m³. It was also found that bundling agricultural technologies with solar pump irrigation systems leads to enhanced agricultural outputs and welfare. The sustainable adoption and scale-up of these irrigation systems demand addressing technical and financial constraints, as well as input and output market challenges.