Access to clean and reliable water supply is becoming increasingly crucial worldwide. Many regions rely on diesel- or kerosene-powered systems to extract groundwater, which can be harmful to the environment due to carbon emissions, and can incur high costs. Thus, solar pumps, as a technology, have a broad range of applications extending beyond the agricultural and power sectors. These are water-pumping systems that utilise solar energy. They offer long-term and cost-effective solutions for a variety of applications, particularly in areas with limited access to power or conventional sources of fuel. According to a Fortune Business Insights report published in 2020, the global solar water pump market is projected to increase at a compound annual growth rate (CAGR) of 10.2 per cent between 2021 and 2028. This reflects an increase in output production from $2.86 billion in 2021 to $5.64 billion in 2028.
Types of solar pumps
The Fortune Business Insights reports that the solar pump market can be classified based on the type of pump and the type of motor. There are two types of pumps – submersible pumps and surface pumps. A submersible pump is situated beneath the water surface. These pumps are often installed in wells, but they can also be installed in ponds and streams by slightly elevating them above the water level. A surface pump is installed above the water surface and is equipped with an intake line that draws water from the source to feed the pump.
There are two types of motor – AC and DC. A DC controller connects the PV array to a pump assembly with a DC motor. As there is no need for power conversion, DC pumps have longer lifespans and greater efficiency compared to equal-sized AC pumps. However, these pumps have limited head and flow rates, and are often utilised for applications with lower head and lower volume requirements, typically with a maximum power requirement of 4 kW.
Status in India
Being primarily an agrarian economy, India is also deploying solar pumps and is promoting their usage through the Pradhan Mantri Kisan Urja Suraksha evam Utthaan Mahabhiyan (PM-KUSUM) scheme. The scheme was launched in March 2019 by the Ministry of New and Renewable Energy. The primary objective of the scheme is to enhance crop productivity and raise farm income through the solarisation of the agricultural sector. The scheme consists of three components, which include the establishment of small renewable energy plants on barren/fallow land owned by farmers, the implementation of standalone off-grid solar water pumps and the solarisation of existing grid-connected agricultural pumps. As per the PM-KUSUM website, the total number of sanctioned and installed individual solar pumps under Component C, as of June 30, 2023, stood at 121,930 and 1,519 respectively. Under Component B, the total number of sanctioned and installed standalone solar pumps were 947,991 and 244,373, respectively. Meanwhile, under Component A, the sanctioned and installed solar capacity totalled 4,716 MW and 113.08 MW, respectively.
There have been significant developments in the solar pump space at both the central and state levels. In March 2023, the Karnataka state cabinet approved the implementation of the PM-KUSUM scheme in the state, with the objective of delivering solar-powered irrigation pump sets to approximately 10,000 farmers. It will also include Component B under the scheme, which aims to install 1.75 million freestanding (off-grid) solar irrigation pumps with a capacity of up to 7.5 horsepower.
Additionally, in January 2023, the Karnataka Vikas Grameena Bank signed an MoU with Mecwin Technologies India Private Limited, a Bengaluru-based company, to finance the deployment of solar-powered pump sets. In the same month, Bangalore Electricity Supply Company Limited floated bids to install and commission grid-connected distributed solar power systems for the solarisation of agricultural feeders, covering 262,331 pump sets under Component C of the PM KUSUM programme.
The focus on promoting solar pumps stems from their numerous advantages. One, solar pumps offer a significant environmental benefit due to their low impact. Two, they require less maintenance compared to conventional pumps because they have fewer moving components, resulting in reduced operating and maintenance expenses. Three, they are incredibly versatile and can be used in off-grid or rural areas with limited or unstable power infrastructure. Four, solar pumps are scalable and can be sized to accommodate individual water needs. Five, farmers can generate a steady income stream by selling power to discoms at a predetermined tariff. They can also earn revenue by leasing their land to a developer or discom for the establishment of a solar power plant. Six, there are no recurrent power or fuel costs because solar water pumps do not require fuel (diesel/kerosene) or electricity to operate. Despite the promise of various capital subsidies for solar pumps to decrease farmers’ initial capital investment, the adoption has remained fairly limited. One of the key reasons is a lack of awareness among farmers in the country’s remote regions. This is particularly true for small-scale farmers who may be unfamiliar with such programmes. Even if they are aware, they may lack the resources or skills to effectively utilise and benefit from such initiatives.
Another key issue in the sector pertains to the financing of solar pump replacements. Farmers often hesitate to bear the cost of replacements if there is no incentive to reduce usage, particularly under a flat-rate tariff regime. The energy service company model, widely used in India, involves a third-party service provider replacing pumps in feeders on behalf of the discom as a financing approach to boost adoption rates. The discom reimburses the service provider based on the expected energy savings. Furthermore, even if farmers can afford solar pumps, they may have reservations about using them due to a lack of technical understanding.
The International Institute for Sustainable Development’s report titled “Implementing Solar Irrigation Sustainably: A Guidebook for State Policy-makers on Implementing Decentralised Solar Power Plants through PM-KUSUM Components A and C (Feeder-level Solarisation) with Maximum Social, Economic, and Environmental Benefits” highlights that discoms face significant challenges due to seasonal fluctuations in agricultural load. The report suggests that the key solution for preventing upstream power flow during the non-irrigation season is optimal targeting and sizing of power plants. Another concern is the impact on daily load management. As the share of solar power in the grid rises, shifting the agricultural load to the daytime emerges as the most cost-effective strategy for load management. States can utilise initiatives such as the PM-KUSUM to strategically plan the long-term transition of agricultural power.
There are several other concerns in the solar irrigation space. One prevalent issue is power outages caused by the inadequate condition of rural feeder infrastructure. Developers emphasise that the safeguards recommended in the PM-KUSUM guidelines for grid availability do not fully address these concerns. Moreover, developers face an uphill task in identifying and acquiring affordable land for establishing solar plants, as well as in developing the necessary transmission and evacuation infrastructure. Another major challenge for developers is navigating land revenue regulations, which include the timely application of land use and restrictions on land transfers under certain conditions. Furthermore, there are significant financing-related challenges, including the poor track record of discoms in making timely payments of dues and limited access to credit from financial institutions due to the low creditworthiness of developers.
Going forward, there is immense potential for deploying solar-powered pumps in India, and with adequate support from the government, this sector is poised to grow significantly in the years to come.
By Nikita Choubey