Grid Connection of Solar Irrigation Pumps for Maximizing Return

The Government of Nepal has been supporting 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.

Grid Connection of Solar Irrigation Pumps for Maximizing Return  
Grid Connection of Solar Irrigation Pumps for Maximizing Return

Dr. Vishnu Prasad Pandey, Sagar Gyawali

Increasing emphasis on SIPs
Groundwater irrigation is covering about one-third of the total irrigated land. However,
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 farm lands,
therefore, are very useful in the areas far away from electricity grids.
The Government of Nepal has been supporting 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 a potential to generate 1,132.7 MW of solar energy. The 13 th
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 14 th Plan (2017-2020), 15 th Plan (2020-2025) and
budget speeches of recent years. For example, 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 resources allocation for the SIPs. There are over 1,700 SIPs installed across Nepal,
nearly 1,400 of them are installed with subsidy from Alternative Energy Promotion Center
(AEPC). With increasing emphasis on electrification programs, there are fears that the
investment in those SIPs will be ineffective as 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 in farms and therefore, even with 100%
electricity coverage, farms will be deprived of electricity access and quality of electricity
continue to be an issue. Efforts to expand electricity to those areas increase cost of
irrigation. Similarly, some areas such as Province-2, which has no or limited hydropower
potential, may continue 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 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
roof top solar system is connected to the national grid as the Net Metering Provison. In 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, same size solar panel can operate more number of pumps if they are
connected to a mini/micro-grid system by managing operating time of pumps, thus,
optimizing 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 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 cost of their regular electricity bill by 70%. The cost of
connecting individual SIPs to national grid is unnecessary expensive due to grid inverter.
Despite several benefits of net metering, AEPC or any of the other organizations who
implement SIPs on the ground are yet to implement net metering for SIPs at a larger scale.
The probable reason cold 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 national grid
system. Use of micro-grid system to connect individual pumps and then connect micro-grid
to national grid can be considered as a solution in this endeavour.

Realizing the grid connection
The grid-connection of SIPs can be realized by connecting SIPs through multiple micro-grid
(MG) systems. About 15-30 off-grid SIPs can be connected to a MG system and then to the
national grid as shown in the schematic diagram. The MG technology is a simply
synchronous with the traditional wide area synchronous grid (macro-grid). It is connected to
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 accounting of all energy evacuated to and drawn from the
grid. Entire database can be accessed remotely through server if we install a 3G sim card in
it.

 

Schematic illustration of a micro grid (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 enabling environment
Though grid connection of SIPs is gaining attention in recent times, it’s yet to be realized.
International Water Management Institute in partnership with Swiss Development
Cooperation and government partners (i.e., NEA and AEPC) are considering to implement a
demonstration pilot on grid-connection of SIPs. The aim is to connect a group of existing
SIPs to the grid through a 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 pool of local
technicians are also required for harnessing optimal benefit from SIPs for a long-run.
Emphasis on 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 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 number of irrigation consumers of NEA is increasing from 132 to 151 thousands
from FY075-76 to FY 076-77. The number is very tiny compared to number of farmers in
Nepal. Furthermore, 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 to farmers. However, efforts are required to increase number of
irrigation consumers, preferably with higher concentration at specific areas, and arranging
dedicated feeders for irrigation facilities, to create 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 endeavour.
Though 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 primary objective of irrigation and agriculture production after grid
connection of SIPs? iv) What is the best techno-institutional model for 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 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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