Sustainable Energy

Transforming the way milk is stored

Anmar Frangoul | Special to
Promethean Power Systems

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. 

Philip Game | Lonely Planet Images | Getty Images

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.