Grid-connected solar irrigationNepal must diversify its energy sources to meet the nationally determined contributions.
Groundwater (GW) irrigation through shallow tube wells (STWs) powered by diesel pumps has been crucial for farmers in the Terai belt since the 1970s (Asian Development Bank, 2013) due to low investment cost, easy repair, and an established supply chain. However, despite being a prevalent method, diesel pumps are one of the main contributors to greenhouse gas emissions in the agricultural sector.
Solar irrigation pumps (SIPs), on the other hand, are climate-resilient technologies that utilise clean solar energy for pumped irrigation. Research by the International Water Management Institute (IWMI) showed that farmers with access to SIPs experienced a significant decrease in diesel consumption compared to those without access. The Alternative Energy Promotion Centre (AEPC)—a nodal government institution under the Ministry of Energy, Water Resources and Irrigation (MoEWRI) which promotes renewable/alternative energy in Nepal—supports solar irrigation with a 60 percent subsidy to farmers. The AEPC-subsidised SIPs are installed in areas where there are no grid connections.
The Nepal Electricity Authority (NEA), a state-owned utility service provider, intends to expand its grid network as hydroelectricity projects increase in Nepal. With this expansion, the gap between grid-connected and off-grid areas will diminish rapidly, creating an opportunity for grid-connected solar irrigation.
Due to the nature of irrigation water requirements, the farmers use SIPs around 32 percent of the time, resulting in an annual energy waste of approximately 4,521 MWh. Integrating the SIPs into the grid will improve the utilisation of the SIPs to 100 percent by injecting excess energy into the grid.
Since the AEPC-subsidised SIPs come with only two years of after-sales service, farmers are likelier to abandon them due to high repair costs. Additional income from energy sales to the grid would cover the repair and maintenance costs. This will be a good approach to reducing e-waste generated from SIPs and other solar projects in the long term. SIPs’ grid integration would also provide an opportunity for farmers to replace their older DC pumps with AC pumps that are easily repaired locally.
Solar irrigation has gained popularity in the Terai region over time. The demand for AEPC-subsidised SIPs has surged as farmers shift from expensive diesel-based irrigation to SIPs with zero operational costs. In order to address this demand, a scalable business model combining the current subsidies with financing is required. Additional income from net-metering could play a significant role in the scalable business model for SIPs.
Hydroelectricity dominates Nepal’s energy sector, making up over 95 percent of the nation’s installed capacity. However, the country’s seismic activity poses a significant risk to its hydropower plants, and climate change threatens the vulnerability of its river system. Therefore, Nepal must diversify its energy sources to meet the nationally determined contributions (NDC) target of a 15 percent energy mix with other renewable energy sources like solar and wind. A grid-connected SIP can be an ideal solution to help achieve this goal with minimal investment.
In Nepal, grid-connected solar irrigation hasn’t taken off despite net-metering provision for the past few years. There is a lack of national-level institutions to oversee grid-connected solar irrigation. The NEA focuses largely on hydropower projects, and solar irrigation is not on its primary agenda, which creates a gap in the national-level institutions overseeing such programmes. Currently, the NEA is selling energy at Rs2.3 per unit and buying surplus solar energy at Rs5.94 per unit, which does not make financial sense.
Since grid-connected SIP is a new concept, the lack of awareness among local governments or farmers is understandable. Hence, several pilot projects involving the local government and the farmers are needed to confirm proof of concept. Such projects will help generate field knowledge in the local context, capacitate the local stakeholders, and optimally utilise the resources of the local government. Many institutional solar grid-tie projects commissioned with net-metering are mostly limited to industrial and urban areas. The local NEA office in rural and semi-urban areas lacks experience with net-metering and procedural clarity in implementing grid-connected solar irrigation projects with net-metering.
There is a lack of clarity in the process as there is no guiding document to clarify which type of farmer user groups should apply for such connections and where it needs to be officially registered. This leaves the sanctioning of such a system under the discretion of the person in authority.
The primary stakeholders for grid-connected solar irrigation are the local governments, farmer user groups, the NEA, the AEPC, and the private sector. To develop a scalable model for grid-connected solar irrigation, these major stakeholders must join hands and implement several pilots at different sizes (individual, community and institutional levels). The learnings from various pilot projects must be captured to develop guiding policies for grid-connected solar irrigation. Guided by the learnings from these pilot projects, the net-metering guidelines could be tailored for grid-connected solar irrigation that puts a lesser financial and technical burden on the NEA.