No crying over chilled milk: Promethean Power

Posted By: Leila Karnik, Advisor, ennovent- innovations for sustainability|Dated: December 29, 2011

When Sam White and Sorin Grama of Promethean Power Systems came to India, they had no idea they would double the income of so many villagers. The company has come a long way since to develop a rural refrigeration solution in India. Sam tells us about the challenges they faced and their experiences in India.

The Idea and market

After winning the MIT B-Plan competition, in 2007, Sam quit his job to start Promethean along with Sorin who had just graduated from MIT. “We heard Harish Hande speak at MIT, during the B plan contest and were inspired by him,” says Sam. “He spoke about the structured micro finance infrastructure in India that one does not find in Africa, and that’s what we had hoped to tap into.”

After some research on India, they found out that with over 13 billion kilos of agricultural produce going waste, every year, the country definitely had huge business opportunities!

The Business opportunity

Sam and Sorin started cold-calling for business opportunities. One day, they got a chance to meet the head of Bangalore Dairy to discuss the difficulties faced while transporting milk. The dairies collected warm milk twice a day at a central location from farmers across 10,000 villages. If the milk was not chilled within four hours, it would spoil. The dairies were using diesel generators to chill the milk at the central location. And this was expensive as fuel costs were very high along with other maintenance costs.

The Product

After four years of research, Sam and Sorin developed a thermal battery that stores and releases cold thermal energy and re-charges automatically whenever power is available.

With this battery they created a Rapid milk chiller, thus eliminating the diesel-generator backup. “Once the milk chiller is placed at a central location in the village, farmers can bring in their milk as soon as they have it, and the milk gets chilled instantly. A chiller stores up to 40 liters of milk and it can be put into the market for 15 – 18 days instead of 2-3 days,” explains Sam.

With this chiller, milk got a longer shelf life, the quantity of milk sold increased due to less wastage and the villagers almost doubled their incomes for a lifetime! “We only had plans of a good business in mind, with no specific goal on the social impact,” says Sam.

LEARNING: Sometimes by-products are of bigger value than the business intent. In this case, doubling people’s income was not the main goal but an unexpected result.

The Challenge

Sam and Sorin always wanted to create a source of power with solar to help store milk. “We were stuck to solar and the solar power milk chiller we created was a complicated technology that took electricity from the grid and solar still did not work well enough. But, this forced us to create the new storage technology. And it was only when we let go of our solar dream that we started to do well on the tech front.”

In villages they experienced the most hospitable and gracious people. “When we first installed a chiller, we partnered with a company that measured the milk fat and weight. The scale measuring the milk was broken for the first few days, and the failure was associated with us. The villagers were making a lot less money as the scale was broken. At first, there was an uprising, but then, they gave us a benefit of the doubt, and things went well.”

LEARNING: Don’t expect things to go fine, till it has actually worked out. And you do get a second chance. Always.


Promethean has recently won a grant of USD 500, 000 dollars to adapt this battery for chilling fruits and veggies. They are partnering with Icelings in Mumbai for this. They have shown a lab prototype to 15 dairies and they have a purchase order from Amul India for their expansion project in West Bengal.

They hope to start making their profits once they start executing these orders. “Until now we have been in the trial and error mode but we have done a lot,” says Sam.

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For more stories on innovation at the BoP, you can read ennovent’s Innovations for sustainability blog.

About the Author

Leila has over ten years of experience in both social ventures and high-growth startups.  Most recently, Leila led the concept & launch of ennovent’s online Global Network bringing together entrepreneurs, investors and experts to create impact at the Base of the economic Pyramid

Leila is also the co-founder of the National Entrepreneurship Network (NEN), a non-profit that supports new & future entrepreneurs reaching out to over 400,000 young people in India. At NEN, Leila launched the first web portal for high-growth entrepreneurship resources in India, and the TATA NEN Hottest Startups, the first-ever community award for startups.

With a focus on resource building and communication, she worked in Washington DC and Mumbai with Ashoka: Innovators for the Public. She joined the Wadhwani Foundation’s founding team in 2002 and later took a sabbatical to work on a feature film project. Leila holds a BS in Foreign Service from Georgetown University, Washington DC.

The views expressed above are those of the author, and not necessarily representative of the views of the Mahindra Group. 

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  • Mayank Gupta

    Amazing to see villages getting benefited because of a simple BPLAN Competition. Inspirations can surely fuel people to do anything.  

  • Mayank Gupta

    Amazing to see villages getting benefited because of a simple BPLAN Competition. Inspirations can surely fuel people to do anything.  

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