An IWMI study finds solar irrigation can cut diesel emissions and energy costs in Bangladesh without raising water use, but warns safeguards are needed to protect groundwater as adoption grows.
In Goalia village, Barishal, Bangladesh, 60-year-old farmer Mohammed Nurul Islam carefully sets up his portable solar irrigation pump. Provided to a local farmers’ group by the Bangladesh Rice Research Institute, the micro solar pump aims to reduce reliance on diesel and improve irrigation access for small-scale farmers. For Nurul Islam, this new technology represents not only cleaner energy but also a more reliable way to grow his crops.
Bangladesh relies on around 1.6 million groundwater irrigation pumps, 80 percent of which run on diesel. Most of this water is used for Boro rice, a highly water-intensive crop grown in regions already under stress from climate change. Diesel pumps deplete groundwater and contribute significantly to greenhouse gas emissions.
A new study by the International Water Management Institute (IWMI) shows that solar-powered irrigation can reduce emissions, lower costs and support farmers while protecting groundwater if implemented carefully. Conducted under the Solar Energy for Agricultural Resilience project and supported by the Swiss Agency for Development Cooperation, the research examined how farmers in northwest Bangladesh used water after switching from diesel to solar pumps.
Researchers observed a small increase in dry-season paddy cultivation as some farmers shifted from other crops due to more reliable irrigation. Groundwater modeling indicated that this minor expansion had minimal impact, with water levels dropping by less than one meter. Experts caution that larger increases in paddy area or water use could threaten sustainability, especially in clay-rich districts such as Rajshahi, Pabna and Bogra.
The study shows that solar irrigation is not only a tool for cleaner agriculture but also a model for a just and sustainable transition in farming, one that balances climate action, economic benefits and resource protection. For farmers like Mohammed Nurul Islam, it offers a practical, cost-effective way to grow crops, reduce emissions and safeguard natural resources for future generations.
“A just transition in agriculture is not just about technology,” said Sohanur Rahman, founder of YouthNet Global. “It is about fairness, climate justice and ensuring that farmers and communities benefit while natural resources like groundwater are protected.”
Between 2021 and 2023, IWMI compared dry-season water use on farms using diesel and solar pumps. The results showed no significant increase in water use after switching to solar. Farmers using solar pumps used slightly more water than diesel pumps, but savings of 20 to 30 percent on energy costs prevented overuse.
The study highlights the success of the fee-for-service model in which private companies install and operate solar pumps with financing from the Infrastructure Development Company Limited and sell water as a service. Farmers pay only for the water they use, creating incentives for efficient distribution.
Darshini Ravindranath, project lead for the Solar Energy for Agricultural Resilience project, added, “Aligning incentives and safeguards is critical to protect groundwater while improving farmer livelihoods.”
Policy measures are key to long-term sustainability. Techniques such as alternate wetting and drying, which allow rice fields to dry periodically, can reduce water use by up to 40 percent, lower costs and cut methane emissions without affecting yields. Linking subsidies to efficient irrigation, using solar suitability maps, improving groundwater monitoring and integrating managed aquifer recharge can further ensure sustainability.
The study provides guidance for policymakers and investors seeking to expand solar irrigation responsibly, promoting climate-smart agriculture, environmental sustainability and improved livelihoods. Similar programs in India, Southeast Asia and sub-Saharan Africa offer lessons for scaling solar irrigation globally.
“Solar irrigation holds tremendous promise for decarbonizing agriculture and improving energy access,” said Mohammad Faiz Alam, senior researcher at IWMI. “But sustainability depends on smart deployment backed by strong governance.”
