Thermal Power Storage Saves Indian Dairy Farmers From an Unpredictable Grid

Published: July 13, 2015

By Mike Stone for Greentech Media

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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.

After years of experimentation, Promethean Power Systems finds value in thermal storage for India.

India is the world’s No. 1 milk producer. Unfortunately, rural India is not well served by the electrical grid—creating problems for milk producers who need to keep their product cool.

In much of India, milk is brought by farmers to small, village-based collection centers. If the milk spoils before being collected from the center by the dairy, the farmer won’t get paid. What’s more, if a farmer misses that day’s pickup from the dairy, the product is unlikely to remain fresh without reliable refrigeration.

The milk industry needs reliable refrigeration, but that’s not easy with a highly unpredictable electrical grid.

The collection centers have a choice: risk spoiled product or invest in a diesel generator for when the grid fails. The second option is not only bad news for the environment—it also considerably inflates the operating cost of refrigeration.

Promethean Power Systems has come up with a solution to the problem. The company is manufacturing milk-chilling units connected to a patent-pending thermal battery that uses a phase-change material to store 28 kilowatt-hours of energy in the form of ice.

When electricity is available, ice forms in the thermal battery. When the grid supply is interrupted, the melting ice maintains the temperature of the chilling unit to ensure the milk—up to 2,110 pints of it in each chiller—rapidly drops in temperature. More importantly, it remains cool, and far less likely to spoil, before being picked up by trucks from the dairy company.

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