Transforming the way milk is stored

Published: Oct. 6, 2015

By Anmar Frangoul for CNBC

In 2013,
Promethean Power Systems
(United States) received a Powering Agriculture award for the
Market Growth (Stage 5) of
Energy Efficiency
Solar Photovoltaic
solutions for
Cold Storage
in the production of

About Powering Agriculture

Powering Agriculture: An Energy Grand Challenge for Development supports the development and deployment of clean energy innovations that increase agriculture productivity and stimulate low carbon economic growth in the agriculture sector of developing countries to help end extreme poverty and extreme hunger.

As the global population increases, the issue of food waste is becoming increasingly pressing.

According to the Food and Agriculture Organization (FAO) of the United Nations, 30 to 40 percent of the world’s food production does not even make it to market, with roughly 1.3 billion tons of food—valued at more than $1 trillion—either wasted or lost.

In some parts of the world, the consequences of such wastage can be stark. A 2014 report from the Institute of Mechanical Engineers states a lack of proper storage results in the loss of "up to 50 percent of fruit and vegetables" in Sub-Saharan Africa and India, while 25 percent of milk produced during Tanzania's wet season is also wasted.

An MIT start-up has developed technology that is dramatically improving the way milk can be stored in Indian communities where access to electricity is difficult and reliable refrigeration is limited.

“Most Indian villages have grid power, they have electricity,” Sorin Grama, co-founder and CTO of Promethean Power Systems, told CNBC in a phone interview. “They’re not completely off grid, they just don’t have power 24 hours a day, they don’t have it when they need it,” he added.

“With the dairy industry, it needs to be a very time specific operation: you collect milk early in the morning and early in the evening and you need power at that time to chill the milk quickly before it spoils,” Grama said.

Grama explained that he and his co-founder, Sam White, decided that they would store this intermittent grid energy using what he described as a “thermal battery” that negates the need for costly and unreliable diesel generators.

“When power comes on—it could be any time of the day or the night—we run a refrigeration compressor, very much like a compressor in your home refrigerator, which basically makes ice,” Grama said.

“When the power goes out the ice is still there, it doesn’t melt immediately, it… holds the cool for a while,” he added.

“Obviously this is much more complicated than a home refrigerator, these are industrial refrigeration systems,” Grama explained.

The company’s products include a rapid milk chiller, a conventional milk chiller, as well as a cold storage system. The rapid milk chiller is able to chill milk to four degrees centigrade instantly, and can cool up to 1,000 liters of milk every day using only four to five hours of energy, according to Promethean.

To date, the company has overseen the installation of more than 100 milk chilling systems in rural India. The chillers, which are manufactured and assembled in Pune, India, cost roughly $9,000 according to Grama.

“Individual farmers don’t have enough money for this, but the dairy processors, the companies that buy the milk from farmers and turn it into… butter and other things, these are the companies that have the money for this, they buy the system,“ Grama said.

According to the company, each chilling system serves roughly 20–30 farmers, who can in turn earn a regular, steady income.

Related News & Events: 
Apr. 18, 2017

Indian cleantech startups often struggle to find the talent needed to build an effective team. From "feet on the street" to senior leadership, authentic knowledge of the complex Indian market is key. A leader in this developing market, Promethean is being watched as they negotiate these challenges.

Feb. 22, 2017

Promethean's system allows for chilling milk at source, which is a win-win for dairy plants and farmers. Dairies get milk with less microbial load and spoilage possibility; farmers benefit from a more flexible delivery time and increased herd size. They can also expect to fetch a better price.

Jan. 31, 2017

Word is spreading about the transformative impact of Promethean's milk chiller technology. The company has sold over 500 milk chilling units to its dairy partners in India, Sri Lanka and Bangladesh. Retailers are also using Promethean’s system for refrigerating produce.

Jan. 29, 2017

Sorin Grama and Sam White of Promethean Power are finding their stride in India, where their thermal energy storage technology is making a real difference in the lives of Indian dairy farmers—without using a single drop of diesel.