Could a weird ice machine solve California’s energy problems?
Probably not, but it can store energy in the form of ice, which is pretty cool
Chelsey B. Coombs • February 18, 2015
Unlike this one, the Ice Bear is a refrigeration technology helping California energy companies store energy. [Image credit: Flickr user Ukumari Photography]
Meet the Ice Bear. No, it’s not a cousin of the polar bear living in the Arctic. It’s a big machine that uses a system of coils, 450 gallons of water and another evaporator coil. It was created by Ice Energy, tested by the energy provider Southern California Edison and can be added to a building’s air conditioner to store electrical energy as ice. And many of them may be moving to California.
Last October, the California Public Utilities Commission ordered its three big investor-owned electric utilities — Pacific Gas and Electric, Southern California Edison and San Diego Gas and Electric — to start storing electricity.
It’s the first energy storage mandate in the U.S., and it requires the companies to build enough capacity to store 1.3 gigawatts of electricity, enough to power one million homes, by the end of 2020.
Storing electricity is expensive and inefficient because of the energy lost in its conversion from storage to usable form. Design constraints also prevent large amounts of electricity from being stored. Big electric companies have turned to technologies to ease the process, and one of these is the Ice Bear.
The Ice Bear works by freezing water during the night, when electricity is less expensive and in less demand. While the rest of the building is sleeping (or at least not using power) a refrigerant runs through the coils of the Ice Bear to freeze the water. The next afternoon, when air conditioners are most likely at their peaks, a pump in the Ice Bear sends the refrigerant, cooled by the ice it created, into the air conditioner’s evaporator coil. This helps cool hot air that’s coming from the building. This newly chilled air is then pushed into the building, just as an air conditioner would normally do. Eventually, enough warmer room air reaches the Ice Bear’s intake vents to melt all the ice in the device, leaving it filled with liquid water. When that happens, the building’s air conditioning finally kicks on, and runs until the Ice Bear’s water supply is frozen again overnight.
The California Public Utilities Commission mandated the storage plan as a way to smooth out the daily highs and lows of power production and consumption. “There are times during the day when we are producing more electricity than we need, and other times when demand exceeds what is on the grid. This will help us avoid blackouts without having to build new generation,” state assemblywoman Nancy Skinner told the San Jose Mercury News in 2013 when the project was first proposed. Now, electricity produced by power plants running at night when demand is low can be stored and used during the day when demand is much higher. More storage capacity will be especially helpful in encouraging the installation of solar panels and wind turbines, which can provide power only when the sun is out and the breeze is blowing.
Ice Energy estimates that one of its $10,000 units can “shift 72 kilowatt-hours of on-peak energy to off-peak hours.” That’s enough to keep 72 40-watt bulbs running for just over a day.
So far, Southern California Edison is willing to buy 2,500 Ice Bears for the West Los Angeles Basin region, according to the press release announcing the decision. But this is only contributing to a small portion of California’s 1.3 gigawatt mandate. We’ll have to wait and see how much less weight the system will have to bear with these units in place.
This is nothing new. In 2000, when we were renovating our synagogue, Pepco proposed such a system. It turned out to be impractical, because we only conditioned our sanctuary about 10 hours a week
I did not do the calculations, but I doubt that at the proposed price it would have been worthwhile for any duty cycle.
So on a 24 hour basis these things store about 3kw/hr. On a cost per KWh that’s about $3300.
If I am not mistaken that is 3 times the cost of NG including both fuel and capital costs. And the NG figure includes all of the installation costs which I highly doubt is the case with ice bears.
And these units are likely not 100% efficient so let’s assume a very generous 75% efficiency. That would mean 4kwh of NG (or coal) would have to be burned to store 3kwh in the ice bear.
So these units:
1. Cost more than just burning more NG during the day – the NG doesn’t cost more – it just sells for more because there isn’t enough installed gas turbine capacity.
2. Will likely mean more – not less – co2 into the atmosphere from burning NG – if co2 emissions matter to you.
Another near idea that founders on the rocks of reality propped up by politically correct legislation that Californians pay for.
Why not use phase change materials placed in attics like “Infinite R” that is passive and requires no energy but levels the load on the power grid? Material cost about 75 cents per sq ft.
“Public utilities benefit by reducing energy loads and balancing out daytime and nighttime peak energy demands.”
Off-peak power is incredibly inexpensive which begins to explain the profound benefits of demand shifting by daypart. Mr. Tulk may be looking at devices like the Ice Bear too narrowly.
For example, in some regions of the country cooling days far outnumber heating days (i.e.: Phoenix). The ability to reduce the peak demand that occurs at 4PM during summer when temps reach 117+ degrees, and every AC unit is cranking at max capacity by using stored “cold” energy is a game changer.
Let the naysayers not slow the progress of innovation… particularly new application of an old concept that’s been demonstrated commercially by Ice Energy and their Ice Bear units.