Storing Energy The Cool Way

on November 16, 2011 at 6:00 AM

What is the only form of energy whose price has remained relatively stable for the past 40 years?

The answer: Off-peak electricity, CALMAC CEO Mark MacCracken told Breaking Energy in a recent interview. CALMAC is a thermal energy storage company that uses off-peak electricity to freeze ice overnight. During the day, the power is gradually released to replace air conditioning which generally draws power from the grid during peak and most expensive electricity demand hours.

With 4,000 installations in 35 countries around the world, MacCracken said CALMAC is scooping up the “low hanging fruit,” or even “the fruit that’s on the ground already,” by trying to encourage commercial customers in particular to use stored off-peak electricity for cooling.

Technology firm SAP uses pre-frozen ice to cool its buildings during the summer, one of a number of innovative and often low-tech methods used by companies to handle energy demand spikes.

“We have a tremendous amount of energy storage available to us,” CALMAC’s MacCracken said. While demand response programs have existed for decades to similarly shift power during the day based on peak demands–allowing utilities to control load particularly on hot summer days–MacCracken said using off-peak electricity daily can in many casessave commercial building owners much more money.

He said every building has different needs and choosing which program is best really depends on various individual factors. CALMAC’s IceBank Energy Storage systems can be hooked up to demand response mechanisms, but generally are already drawing power from the grid when it is cheapest, making it virtually unnecessary for utilities to shed that user’s load.

MacCracken has been working at CALMAC since 1976, when the company was involved in both solar and energy storage systems. But when various government rebate programs expired and the solar industry lagged, the company decided to focus on an energy supply that was not dependent on passing government whims.

The dramatically lower prices of nighttime, as compared with daytime, electricity have been consistent for decades, MacCracken said. He speculates that even with mass adoption of electric vehicles, many of which will be charged at night, nighttime prices will never reach daytime prices.

And considering the increasing wind developments, some of which are already taking negative prices at night in Texas, nighttime power costs might even drop in the coming years, even as gas, oil and peak electricity prices rise, he said.

But, he said, it is often hard to convince customers that the IceBank systems are worth it because they appear to draw more electricity than conventional air conditioners. The numbers aren’t lying, he said, but because power is so much cheaper at night, utilities and customers end us saving much more power by shifting air conditioning load to the nighttime.

The same is true for refrigerators, which he said some companies are trying to convert to nighttime defrosting. A refrigerator with an internal clock that times defrosting for the night may draw a tiny percentage more of power, but the long term savings for utilities and customers are much more significant, he said.

“Certain people don’t see it as energy savings,” MacCracken said. He said customers don’t realize that power isn’t created a their outlet but at a power plant far away. Changing the mindset about energy is key, he said.

Photo Caption: A CALMAC IceBank Energy Storage tank.