Learning to chill

Sam White’s Promethean Power has taken a long journey to improve milk collection in rural India.

promethean crop

When Sam White and his co-founder Sorin Grama won second place in the MIT $100K business plan competition, they thought it was a ticket to instant success. Now, after almost ten years of toil, failure, and reinvention, their Promethean Power Systems is finally starting to make the impact they dreamed about in 2007.

Today, 162 of their milk chilling units are in active use across 8 Indian states, Sri Lanka, and Bangladesh. But like all good solutions, it began with finding a real problem. India is the world’s largest producer and consumer of milk – and much of that production happens in small villages far from collection centers with modern systems for preserving and processing the milk. “If you let milk sit for more than four hours without chilling it, it goes bad,” said White in a talk at the MIT Tata Center on Wednesday. “India averages six hours. The country has $13 billion in spoiled food every year. Once we learned that, we had our problem.”

White and Grama discovered that chilling milk at the source, in villages, was a difficult task because of intermittent power supply. Where the grid couldn’t be relied on, owners of small dairies had to use expensive diesel generators, or they had to forgo chilling the milk at all, making it ripe for spoilage.

“We wanted to break apart the whole logistics of milk collection in India,” White said. “Our goal was to let them chill at the village level using intermittent electricity or solar.”

This began an odyssey full of failed ventures and what White described as “crazy technologies.”

Promethean tried a variety of solar-based technologies, none of which could get the milk cold enough. They even tried setting up an ice-delivery service to villages. “It was a logistical nightmare.”

Rock bottom came in 2010, when they brought a full-scale prototype of a solar powered milk chiller to India. It consisted of an enormous 2000 liter chilling tank, which was capable of chilling only 500 liters of milk. Their partner, a managing director at Arun Ice Creams in South India, took one look and pronounced it far too large and inefficient a system to ever be practical at village scale.

Sam White speaking at the MIT Tata Center.
Sam White speaking at the MIT Tata Center.

“A year’s worth of work down the drain in 30 seconds,” White summarized. “That night we were out in the street at two in the morning, smoking cigarettes and talking about what we were going to do. I don’t even smoke. Finally one of our Indian colleagues said, ‘Why are we so focused on solar? Why don’t we get rid of solar and cut our costs in half? We can reduce the size of the chiller and use intermittent grid power instead.”

In reflection, White says that they were so invested in their technology, they had failed to think about the best way to actually solve the problem. “In 2010 we were so committed to solar, we didn’t care what we had to do, we were going to build this.”

Their colleague’s suggestion touched off an intense debate about the identity of the company – were they a solar technology company, or a company trying to solve the milk spoilage problem?

“At the end of the day,” White said, “we didn’t have a choice. We had to move forward and turn this startup that was about to fail into something that could be considered successful.”

They switched to grid power, reduced the size of the chiller, and were finally able to create a product that was attractive and practical for dairy processors to install in the villages where they source milk. Now, milk can be chilled less than 30 minutes after it comes from the cow – as opposed to the six hour national average, and there’s no need for expensive, highly polluting diesel generators.

“We have 162 systems out there chilling milk today, but as you can see from our journey, it could’ve turned out very differently. If we had just stuck it out in the lab for years, without trying things in the field and having all these failures, we’d still be in the lab today.”

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