Mitigation and beyond: Multiple co-benefits of solar irrigation in Bangladesh

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Summary

Irrigation in Bangladesh depends primarily on imported diesel. The Government of Bangladesh (GoB) has started investing in solar irrigation pumps (SIPs) to replace diesel pumps in off-grid areas. The objective is to achieve energy security and reduce agriculture’s greenhouse gas (GHG) emissions. Results from a representative survey of farmers in the command areas of the SIPs installed by the Infrastructure Development Company Limited (IDCOL) show that beyond effectively achieving the primary objective of reducing the use of diesel (mitigation), these pumps also provide other significant benefits to the farmers. The study found that these SIPs reduce farmers’ cost of irrigation by 20% to 30% compared to diesel irrigation pumps, offer them access to less labor-intensive, time-saving irrigation services, and support their needs for supplementary irrigation in case of delayed monsoons.

Introduction

Bangladesh relies heavily on imported diesel for irrigation, making the country’s food sector susceptible to global fuel price shocks. Domestic farmers bear the brunt of increasing diesel prices if the Government of Bangladesh (GoB) decides not to subsidize diesel in the event of global price rises. The consequences are dire for diesel irrigation-dependent boro cultivation, which is crucial for Bangladesh’s food security. Dependence on imported diesel also puts a heavy burden on the government’s foreign exchange reserves. Substituting diesel pumps with solar irrigation pumps (SIPs) can help achieve energy security while sustaining food security.

Until mid-2022, Bangladesh has installed 2716 SIPs, with a total capacity of 50.4 megawatts (MW) (SREDA 2020). The Infrastructure Development Company Limited (IDCOL), a nodal agency for renewable energy financing in Bangladesh, has financed around 84% of the installed capacity in solar pumps (1523 SIPs with 42.1 MW capacity). IDCOL uses a unique fee-for-service business model, where a private company or a non-governmental organization (NGO) undertakes the installation, operation, and maintenance of the SIPs, and farmers purchase irrigation services from the operators for a fee.

The International Water Management Institute’s (IWMI) Solar Irrigation for Agricultural Resilience (SoLAR) project in Bangladesh conducted a survey covering 900 farmers (both IDCOL SIP farmers and non-SIP farmers) from 60 villages in Rangpur and Rajshahi divisions in north-west Bangladesh for the agricultural year 2020-21. These two divisions cover 70% of IDCOL SIPs installed so far. The study found that transitioning to solar-based irrigation provides various benefits to farmers, besides mitigating diesel-driven carbon emissions in agriculture.

Mitigation benefits

Farmers who receive irrigation services from IDCOL SIPs have substantially reduced diesel use for irrigation. The use of diesel within the SIP command area is just 8% during the boro season (Kharif 1), 3% during the aman season (Kharif 2), and 22% during the Rabi season.

Results from the IWMI survey show that, on average, irrigating one acre for three seasons (Kharif 1, Kharif 2, and Rabi) in a year requires ~ 65 liters of diesel. But the average diesel use is reduced to just seven liters for an acre of land that comes under IDCOL SIP irrigation, leading to a savings of 58 liters per acre. This reduction in diesel use translates to an avoided CO emissions of 2.8 metric tonnes of CO per SIP (EPA n.d.), or 4293 metric tonnes of CO from the 1523 IDCOL SIPs per year.

The average command area of a diesel pump is approximately 5.9 acres compared to 18 acres served by an IDCOL SIP (Buisson et al. 2022). If the GoB replaced all 1.24 million diesel pumps irrigating 2.99 million hectares (Buisson et al. 2022, BADC 2020) with about 400,000 IDCOL-type SIPs, that could translate to reduced emissions of 1.2 million metric tonnes of CO per year. 

Adaptation co-benefit 1: SIPs reduce farmers’ out-of-pocket expenses for buying irrigation water

The plot-level cost of buying irrigation water from IDCOL SIPs is 20% to 30% lower than the cost of purchasing water from diesel pump owners. The savings are higher for irrigation-intensive crops like boro paddy.

Also, in terms of the quantity and quality of water received from the seller, the percentage of water-buyers who disagreed that they were satisfied is comparatively lower when buying from solar pumps (9% for quantity and 2% for quality) vis- à-vis diesel pumps (15% for quantity and 14% for quality). Similarly, in terms of whether irrigation was received at adequate timing, dissatisfaction is substantially higher amongst water buyers from diesel pumps (36%) as compared to solar pumps (only 19%

Adaptation co-benefit 2: Irrigation from IDCOL SIPs saves time and labor costs

Time spent for irrigation is significantly lower when irrigation is bought from a fee-for-service IDCOL SIP (1.3 hours/day) as compared to irrigation using own diesel pump (2.6 hours/day) or hired diesel machines (1.8 hours/day) (Fig. 2).

Adaptation co-benefit 3: SIPs enable supplementary irrigation during late monsoons

Climate change is making rainfall patterns increasingly erratic in South Asia. In the event of delayed monsoons (as in 2022) or long gaps between two rainfall episodes, SIPs are used for supplementary irrigation in Bangladesh. The share of plots (22%) using SIP irrigation in the rainy Kharif 2 season (primarily for aman paddy) is relatively higher than those using purchased diesel irrigation (18%) (Fig. 3). These numbers are likely to be higher in a drought year.

Suggested citation

Mitra, A., Buisson, M.-C., Osmani, Z., Habib, A., Hossain, M., Siddiqui, M. B., & Mukherji, A. (2022). Mitigation and beyond: Multiple co-benefits of solar irrigation in Bangladesh. International Water Management Institute (IWMI).