Here’s a little something you can chew on when you sit down to eat one of the 46 million turkeys Americans will roast this Thanksgiving. The latent thermal storage in all those turkeys could provide 4.32 gigawatt hours (GWh) of energy. According to the Energy Information Administration, theaverage U.S. home used 10,932 kWh in 2014. That means all that thermal storage in Thanksgiving’s main-dish favorite could power some 400 homes for an entire year.
So, how do you tap that energy? You can’t exactly roll into your garage and plug a hybrid vehicle into a turkey. But, you can use a turkey’s thermal storage capacity the same way you tap the energy in a cooler’s ice, which you may be using to keep your beer cold while you’re watching a holiday football game. The mass of the turkey allows the grid to utilize a cold storage facility as an energy storage system.
The company I work for, Enbala, provides ancillary services to the grid by treating cold storage rooms filled with things like frozen turkeys as though they were batteries. When there is an operating reserve event called in the grid area, we can cut the compressors that are cooling the space and rely on the thermal mass of that space – and the turkeys in it – to hold the temperature for several hours until the grid is back in balance. Then we turn back on the compressors.
What I just described is more of an industrial process, but this goes down to commercial levels, as well. In grocery stores, for instance, we could align freezers use to run full out when there’s extra supply in the grid and cut back power use when the grid is constrained.
With the growth of the Internet of Things, aggregators will probably be able to tap thermal storage from the refrigerator or deep freeze in your home, too. Maybe soon, your cold-storage devices – or your hot water heater – will participate in energy markets through an aggregator like Enbala.
If you have a frozen turkey defrosting in the fridge, that will bump up the power of your personal cold storage even more. The average turkey packs 0.0933 kilowatt hours of stored electrical energy.
Take a look at my math. Enjoy! And have a very happy Thanksgiving!
James Shaw, Manager, Mechanical Engineering