Improving energy efficiency in rice field irrigation
Strategies to enhance the adoption of electricity-saving technology in irrigated agriculture
Background, challenges and context
While domestic and industrial users still account for most electricity connections in Bangladesh, they have increased at a slower rate than in agriculture – particularly in the last decade. Indeed, the agriculture sector is emerging as a major user of electricity. But, with most studies of energy efficiency focusing on residential or commercial users of electricity, not much is known about electricity use in agriculture, the dominant source of employment in developing countries.
Groundwater extraction for irrigating rice fields is often fuelled by electricity, and consumption is likely to rise as pumps become more affordable for small-scale farmers. Water extraction, and hence electricity consumption, can be reduced through Alternate Wetting and Drying (AWD) technology, which comprises a simple PVC pipe open at both ends and drilled with holes. Planted in a rice field, it enables farmers to monitor soil moisture and irrigate only when below-ground water levels inside the pipe fall below a 15cm trigger.
The adoption of AWD can have a significant impact on incomes, especially in the winter season, when irrigation is used the most. Farmers profit from using AWD, and, when faced with hourly water prices, rather than seasonal water contracts by the acre, are willing to pay more for it.
However, water is often sold by tube well owners, who mostly price it by area, rather than volume, and they pay the electricity costs. It is also common for farmers to pass irrigation monitoring and management onto tube well owners, who will carry out day-to-day monitoring of water levels in their area and decide when to schedule an irrigation.
Meanwhile, fragmented landholdings and small plots mean farmers sometimes practice joint irrigation, where several plots are irrigated at once. This leads to a coordination problem, where a lack of control over irrigation timing makes it difficult to make decisions at an individual level. But if everybody adopts AWD – rather than just a few farmers in the tube well area – an economic surplus would be created due to the reduced electricity costs of pumping. Anecdotal evidence suggests water sellers would consider sharing some of this surplus with farmers through lower per-acre water prices, meaning that AWD may then become more profitable for farmers.
Research overview and objectives
This study is one of the first to understand if energy efficiency can be increased among agricultural users, and whether electricity use in agriculture can be a target for policy intervention. It investigates how the uptake of AWD can be increased in situations where per-acre water prices do not create appropriate incentives for farmers to adopt the technology.
Experimental evidence will be provided on two alternative policy approaches, relative to the benchmark of targeting AWD directly to individual farmers (who do not always directly benefit from the savings). The team will test whether tube well owners should be the target for AWD adoption, and whether encouraging coordinated adoption can induce farmers to use water (and thus electricity) more efficiently and increase profits via lower water prices.
A randomised controlled trial will be carried out, with the experimental sample comprising all farmers in 360 villages in the Mymensingh area of Bangladesh, where there is extensive evidence of seasonal area-based water pricing, tube wells are mostly privately owned, and water pumping is often fuelled by electricity.
The villages will be randomly divided into three equally sized groups, with AWD being promoted to 1) individual farmers as a ‘business-as-usual’ benchmark, 2) tube well owners, and 3) groups of famers via collective meetings. Each of these groups will be subdivided and will receive one of two prices; one set around the marginal cost of AWD technology and the other subsidised and set at the socially-optimal level.
The effects of these different policy interventions will be tested on several outcomes, including the AWD purchase decision of individual farmers, AWD use, water management, electricity consumption, crop output, and water prices.
The objective is to deliver rigorous evidence on new and scalable approaches to increasing adoption and use of electricity-saving irrigation technology. Ultimately, this will make rice production more energy efficient – reducing water use and electricity costs and leading to enhanced profits at farm level.
Manzoor Dar, International Rice Research Institute, Delhi, India
Muhammad Ashraful Habib, International Rice Research Institute, Dhaka, Bangladesh