MIT Researchers Release Evaluation of Solar Pumps for Irrigation and Salt Mining in India


Groundwater pumps are an essential technology in India, particularly for small farms that count on them for crops irrigation during dry seasons. Due to issues with the electrical grid and the high cost of diesel fuel, solar-powered pumps have great potential to address farmers’ needs while lowering costs and better conserving natural resources.

According to a new report, scientists from MIT and the Comprehensive Initiative on Technology Evaluation (CITE), a program supported by the U.S. Agency for International Development (USAID), recently assessed an array of solar pump technologies accessible in India for irrigation and salt mining to learn more about which technologies can best meet farmers’ needs.

There’s a lot of potential for these technologies to make a difference, but there is a large variance in the cost and performance of these pumps, and lot of confusion in finding the right-sized pump for your application.

Jennifer Green, Study Author and Research Scientist, MIT

Green also said, "In many areas, the only people to turn to for information are the people selling the pumps, so an independent evaluation of the pumps working with our partners provides a third-party, non-biased information alternative."

In the study, scientists evaluated the performance of small solar pumps in a lab setting and examined bigger solar pump systems on the ground in India. The lab setting provided a controlled environment for a more thorough examination, and the field assessment allowed researchers to see how these systems functioned in the environment where they would be implemented. Scientists also used an intricate systems modeling process to study how the pumps affected the social, economic and ecological conditions around them, and how various government policies might influence these conditions.

The study team noted that although these solar pumps are a "clean technology," there is a worry that cheap power will lead to the over-extraction of water, which could have catastrophic effects.

When people are using diesel, they pay by the liter, so they use as little as possible. With solar, once people make the capital investment to purchase the equipment, they’re incentivized to pump as much as possible to get a good return on investment.

Jennifer Green, Study Author and Research Scientist, MIT

In the lab, MIT researchers tested five pumps, which represented a range of price points. Looking at flow price, priming simplicity and total efficiency, lab tests revealed that two of the lower-cost pumps performed the best, and the most costly pump performed rather poorly. MIT scientists also analyzed pump usage, setting up remote sensors in pumps being used in Gujarat, India to make sure that usage was consistent throughout each day, and the systems were functioning correctly.

As solar pumps tend to be too costly for small-scale farms, CITE also performed a financial case study to determine any mechanisms could make solar pump systems more viable for these users.  The CITE analysts looked at potential policies like subsidizing the cost of the equipment and paying for unwanted electricity generation as a pairing that could help farmers make this changeover.

“It will be critical to ensure financing mechanisms are accessible to these users,” Green said. “Coupling solar pump systems with well-thought out government policies and other technologies for minimizing water use is the best approach to optimizing the food-water-energy nexus.”

In addition to conducting the scientific assessment, CITE researchers also created a sizing tool to help farmers figure out what size pump will fit their specific needs.

That gives them more knowledge and power when they go to talk to the water pump manufacturers. If they know what they need, they’re less likely to be talked into buying something too big for their needs.

Jennifer Green, Study Author and Research Scientist, MIT

Brett Smith

Written by

Brett Smith

Brett Smith is an American freelance writer with a bachelor’s degree in journalism from Buffalo State College and has 8 years of experience working in a professional laboratory.

Tell Us What You Think

Do you have a review, update or anything you would like to add to this news story?

Leave your feedback