Ice + Sun: A Clean Power, Energy Storage Combo


Updated: Here’s a yin and yang combo: power a building with the sun and store the energy overnight with ice. Solar panel maker Sunpower (s SPWRA) and Ice Energy, a startup that makes ice-based energy storage and air conditioning systems for buildings, announced on Thursday that they’ve teamed up to build a pilot project combining their technologies.

The project, part of the state-funded California Solar Initiative (CSI) Research, Development, Demonstration, and Deployment (RD&D) Program, will be built in conjunction with utility PG&E, energy consultants KEMA, Sandia National Laboratories and a yet to be name “major national retailer.” Update: According to the PG&E blog that’s Target. SunPower was granted $1.88 million for the project from the California Public Utilities Commission and SunPower says it is working with two other energy storage companies, too, one of those is Xtreme Power.

Here’s how the solar-ice system would work. SunPower’s solar panels will be installed on the roof of a commercial building, and as the sun starts to go down in the afternoon, and less solar power is delivered, the energy stored in Ice Energy’s ice-based energy storage system kicks in. At night the Ice Energy units create ice. Ice Energy’s “Ice Bear” air conditioner units cool a building by circulating chilled refrigerant to the coil of a standard air conditioning system, which is basically moving the cost of cooling to off-peak hours when it’s less expensive.

The point of the solar ice combo system is to cut an energy bill by moving the power generation off-peak, as well as to provide additional power to make up for when the solar system is producing less power. Ice Energy’s founder Greg Tropsa told me in an interview that he expects the solar ice pilot project to be up and running by the first quarter of 2011.

Ice Energy CEO Frank Ramirez once told me that ice is the only really efficient means of storing energy out there. Tropsa said that the technology is fundamentally lower cost than any electro-chemical solution like a battery.

Is the so-called “ice battery,” finally getting its day in the sun? Earlier this year Veolia Energy North America, a subsidiary of massive French energy and water company Veolia Environnement, announced that it had bought a district cooling system that uses ice to lower the cost of cooling buildings from Comfort Link.

For more research on smart grid check out GigaOM Pro (subscription required):

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Image courtesy of Stevendepolo.



reading this makes me wonder at the great lengths we are going to make a buiding energy efficient. People in older times did almost nothing to make their houses efficient. They just used natural,local,durable materials and their hands to build their homes, which kept them warm in winters and cool in summers.

Brad Bergman

This is a completely ridiculous premise. While there is nothing wrong with either technology, there is nothing complementary about then either. The thermal storage aspect of generating ice at night uses extra power at NIGHT, not during the day when the solar cells are making their power. Even if you oversize the solar system, so that there’s enough extra energy being created during the day to power the facility through the night, that excess power is being pushed onto the grid, not into the thermal storage. The effect of both of these technologies is to increase demand on the grid at night; they do not offset each other. If anything they tax the grid connection even more than it would be without either technology, and the combination only exacerbates the arguments the utility makes against net metering. You’re abusing the transmission infrastructure and forcing ratepayers to cover your load-shifting scheme.

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