Can Grid Connected Solar Irrigation Pumps Be The Future Of Irrigation In Nepal?

There are over 1,700 SIPs installed across Nepal, nearly 1,400 of them are installed with subsidy from Alternative Energy Promotion Center (AEPC).

Oct. 14, 2020, 1:36 p.m.

Increasing emphasis on SIPs

Only 31% out of 3.5 million hectares of cultivated land is irrigated so far in Nepal; about one-third of that gets irrigation from groundwater. However, the operational cost of groundwater pumping is relatively high, especially when using diesel pumps. Solar irrigation pump (SIP) technologies can be considered as a solution for enhancing access to irrigation with minimal or no operational cost compared to diesel pumps. SIPs use freely available solar energy to pump water for irrigating farmlands, therefore, are very useful in the areas far away from electricity grids.

The Government of Nepal has been supporting the promotion and development of Renewable Energy Technologies and accordingly solar energy provisions have been embedded in the overall alternative energy plans and policies in Nepal. According to the three-year interim plan 2007-2010, Nepal has the potential to generate 1,132.7 MW of solar energy. The 13th National Plan (2013-2016) incorporated plans for solar energy for irrigation in Tarai. In recent years, it is becoming a major highlight in Tarai with central and provincial governments prioritizing SIP projects as evident from the 14th Plan (2017-2020), 15th Plan (2020-2025) and budget speeches of recent years. For example, the 2018-19 budget speech of the central government allocated NPR 350 million as grants for SIP and pledged additional support to renewable energy production if initiated by cooperatives and local communities in collaboration with the local government.

SIPs are already getting huge attention from all three-tier governments as reflected in the form of resource allocation for the SIPs. There are over 1,700 SIPs installed across Nepal, nearly 1,400 of them are installed with a subsidy from the Alternative Energy Promotion Center (AEPC). With increasing emphasis on-grid electrification programs, there are fears that the investment in those SIPs will be ineffective as the cost for pumping with electricity is cheaper compared to solar with the provisions of subsidized electricity cost for agriculture. However, it is likely that SIPs will continue to be a priority for a foreseeable future because of the fact that electrification would focus on houses than on farms and therefore, even with 100% electricity coverage, farms may be deprived of electricity access and quality of electricity continue to be an issue. Also, the costs of providing grid electricity to each and every farm may be prohibitive and not cost effective. Efforts to expand electricity to those areas increase the cost of irrigation. Similarly, some areas such as Province-2, which has no or limited hydropower potential, may continue to consider solar as a priority for energy security and therefore SIP will continue to be a priority at least for a decade or so. Furthermore, requirements for energy-mix demands for self-produced and green energy, and socio-political circumstances may still drive demands for SIPs. Therefore, appropriate solutions to maximize the use of SIPs and optimizing the return are required. Connecting SIPs to the national grids could be a potential solution.

Benefit from and provisions of the grid connection of SIPs

Most of the SIPs installed so far are generally under-utilized for various reasons. Connecting them to national grids benefits in many ways. They include but not limited to – i) extra income to farmers by selling excess solar energy when not used for pumping water and therefore improves benefit-cost ratio as well as reduces the payback period of SIPs; ii) provides stable power in the system so that cases of pump damage due to voltage fluctuations can be reduced drastically; iii) makes power/energy available to pump groundwater for irrigating during the no sunlight hours, thus reducing evapotranspiration loss and contributing to water conservation; and iv) net metering and connection to the grid also improves sustainability outcomes in the long run by ensuring that stand-alone, off-grid pumps do not get abandoned when national grid reaches these off-grid areas.

Nepal Electricity Authority (NEA) has already approved net metering provisions in 2074 BS. It allows consumers to connect solar panels to the national grid, and then feed energy into and draw electricity from the grids. The consumer then pays only for the net consumption of electricity. NEA purchases solar energy at the rate of NRs. 7.30/Unit. Currently, 2.7 kW of the rooftop solar system is connected to the national grid as per the Net Metering provision. In the case of farmers (or irrigation consumers), the cost of electricity is subsidized to NRs. 4.96/Unit but they can sell energy through SIPs at NRs. 7.30/unit, thus getting NRs. 2.34/Unit profit. Furthermore, the same size solar panel can operate more pumps if they are connected to a mini/micro-grid system by managing the operating time of pumps, thus, optimizing the use of available solar energy.

The concept is already piloted in Chitwan with two Individual solar pumps, each of 2 horse-power capacity. Both have shown a very exciting experience. They have minimized low voltage problem in the pump and have replaced diesel pump by grid connection of SIPs. It has helped the pump owner to reduce the cost of their regular electricity bill by 70%. The cost of connecting individual SIPs to the national grid is unnecessary expensive due to the grid inverter.

Despite several benefits of net metering, AEPC or any of the other organizations that implement SIPs on the ground are yet to implement net metering for SIPs at a larger scale. The probable reason could be a lack of pilot that demonstrates feasibility for SIPs. Therefore, there is a need to explore ways that encourage grid connection of current and future SIPs with national grids in more efficient ways so that it benefits farmers as well and the national grid system. Use of a micro-grid system to connect individual pumps and then connect the micro-grid to the national grid can be considered as a solution in this endeavor.

Realizing the grid connection

The grid-connection of SIPs can be realized by connecting IPs through multiple micro-grid (MG) systems. About 15-30 off-grid SIPs can be connected to an MG system and then to the national grid as shown in the schematic diagram. The MG technology is simply synchronous with the traditional wide area synchronous grid (macro-grid). It is connected to a solar farm, national grid (through net meter), local feeder, and several pumps and end-uses. When there is excess solar power, it supplies to the national grid. The MG system is programmed in a way that it keeps an accounting of all energy evacuated to and drawn from the grid. The entire database can be accessed remotely through the server if we install a 3G sim card in it.

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Schematic illustration of a microgrid (MG) system. P1-Pn are individual solar irrigation pumps

The effectiveness of each MG system can be evaluated from the perspectives of productivity, profitability and sustainability by monitoring indicators such as – i) stability of the system in terms of voltage and eventual breakdown; ii) increase in overall annual earning/profit by virtue of grid connection of SIPs; iii) reduced hours of groundwater pumping and subsequent contribution to groundwater sustainability.

Creating an enabling environment

Though the grid connection of SIPs is gaining attention in recent times, it’s yet to be realized. International Water Management Institute in partnership with the Swiss Agency for Development and Cooperation and government partners (i.e., NEA and AEPC) are considering implementing a demonstration pilot on the grid-connection of SIPs. The aim is to connect a group of existing SIPs to the grid through an MG system in Province 1 and 2 in collaboration with local governments, NEA and AEPC. Its success is expected to drive wide-spread replication in other parts of the country.

For wider replication of SIPs, we may need to promote hybrid pumps which can run with both alternating and direct currents. Connecting SIPs spread over a large geographic area to grids is not efficient as the losses would be higher, therefore, strategies for densifying SIPs at a particular cluster would be a real enabler for promoting grid connection of SIPs.Quality of SIPs (both material and installation) and availability of after-sale services also affect potential benefits, and therefore efforts towards quality control and creating a pool of local technicians are also required for harnessing optimal benefit from SIPs for a long-run. Emphasis on the governance of SIPs is equally important as technical aspects to ensure sustainability and equitable distribution of benefits across different sections of the society. They include but not limited to inclusive access to SIPs; ensuring the availability of extension and training services; awareness-raising of a wide range of stakeholders on potential benefits as well as limitations associated with SIPs in general and grid connection in particular; promoting enabling policies and programs; and ensuring coordinated and synergized efforts of all stakeholders such as farmers, local governments, NEA, AEPC and others.

Though the number of irrigation consumers of NEA is increasing from 132 to 151 thousand from FY075-76 to FY 076-77. The number is very tiny compared to the number of farmers in Nepal. Furthermore, the rate of electricity consumption by irrigation consumers is decreasing from 635 units/farmer/year to 545 units/farmer/year from FY075-76 to FY76-77. As irrigation consumers can get electricity at almost 50% subsidized rate that normal users and can sell energy from SIP at a rate NRs. 2.34 higher per unit than the cost of taking electricity from the grid, it’s a real opportunity for farmers. However, efforts are required to increase the number of irrigation consumers, preferably with higher concentration at specific areas, and arranging dedicated feeders for irrigation facilities, to create an enabling environment for connecting more SIPs to the national grids. Strategies to discourage subsidies to diesel pumps, the practice still prevailing in many local governments in Tarai, would also be helpful in this endeavor.

Though the grid connection of SIPs is beneficial in many ways, some of the unanswered questions are – i) What could be the preferable size of SIPs for grid connection for optimal benefit? Who (group of farmers or local government or NEA) owns the system after grid connection? iii) How to ensure farmers do not incline toward the easiest option of selling electricity by abandoning the primary objective of irrigation and agriculture production after the grid connection of SIPs? iv) What is the best techno-institutional model for the grid connection of SIPs in Nepal? iv) How to make SIP as a preferred option for investment (without subsidy)?

Finally, SIP is certainly a solution for enhancing access to irrigation, but a single solution is certainly not adequate to help achieve the target of 100% irrigation coverage. Therefore, new local governments may consider having a set of solutions consisting of standalone SIPs, grid-connected SIPs, and electricity pumps depending upon the level of access to electricity within the jurisdiction of their political boundaries.

(Dr. Pandey is a Researcher at International Water Management Institute and Mr. Gyawali is an Assistant Director at Nepal Electricity Authority)

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