In nearly all regions of the United States, peak annual electricity demand comes in the afternoon on the hottest days of the year, when air conditioners in homes and offices are cranked to the maximum. It’s one of the main technical challenges for utilities and grid operators, which must sign contracts with power plants to ensure that they have sufficient capacity on hand to meet only a few hours of demand, and it can be hard to predict just how much they will need.
In Southern California, one company has come up with a solution to marry peak electric demand with cheap overnight electricity prices. And in a field where interconnected software and high-tech chemical batteries dominate, their solution is both simple and oddly tangible: making ice.
Earlier this month Ice Energy completed the first phase of a project to deploy over 1,200 ice-making and cooling machines at businesses and industrial facilities across the territory of utility Southern California Edison (SCE).
And while there have been larger single-site thermal storage projects, such as the molten salt system at the 300 MW Solana Concentrating Solar Power (CSP) plant in Arizona, Ice Energy says that when complete this will be the largest distributed thermal energy storage system in the nation.
The core of Ice Energy’s project is the Ice Bear, a unit that is typically sited on the roof of commercial and industrial buildings along with an air conditioner. The Ice Bear makes ice by drawing electricity at times that electricity prices are low, which is often overnight, and then takes over from the air conditioner when prices and electricity demand are high.
The system has many of the features of standard cooling systems, including a condensing coil, pumps and a heat exchanger. In addition there is a tank to store the water and ice. But it also has data controllers to provide intelligence regarding electricity prices, similar to batteries. As such, the system is something of an air conditioning and energy storage hybrid.
Ice Energy describes its system as a thermal battery, and like batteries the company articulates the scale of its units in watt and watt-hour terms. In the first phase of the SCE project, Ice Energy deployed 100 units, which it says represents 1.9 MW; the full project for SCE will be 21.6 MW in around 1,200 systems. As the company estimates the equivalent of a six-hour rating, this would be around 130 megawatt-hours for the whole project.
Ice Energy also estimates that its units come at half the life-cycle cost of lithium-ion batteries, and key to understanding this is that the company calculates a 20-year life for its products, which is longer than most lithium-ion batteries.
Under the terms of its arrangement with SCE, Ice Energy supplies and installs its units at businesses and industrial facilities free of charge to property and business owners. To pay for the units the company holds contracts with SCE to manage peak demand and load shifting, under which SCE will be able to operate the units as it sees fit to meet system needs.
There is the potential here to assist in the integration of higher levels of renewable energy as well. While the output of California’s vast quantities of solar PV somewhat coincide with peak demand, like in other areas this overlap is not perfect, as the peak of air conditioning use tends to come later in the day than the peak of solar output. Furthermore Ice Bear and other thermal energy solutions can help to mitigate air conditioning demand after the sun goes down, and without some form of energy storage solar PV on its own can not.
This is not the first deployment of Ice Bear in partnership with a utility; the municipal utility in the City of Glendale, California has installed at least 162 Ice Bear units in its service area. Furthermore, Ice Energy has a 5 MW contract with a municipal utility in the City of Riverside, as well as a 1 MW contract with the island of Nantucket in Massachusetts and a 500 kW contract with utility Eversource.
In terms of private installations, the units are deployed in a total of 13 U.S. states, as well as in the UK, Denmark, Saudi Arabia and Singapore.
Ice Bear population growth
Ice Energy notes that not every utility service area is ideal for its products. The company notes that utility rates must align with its ability to deliver peak demand reduction, and that energy storage options must be either accepted by utilities or mandated, such as in California. The company further notes that when partnering with utilities, customers sometimes have difficulty understanding that the technology comes with no cost to them.
But for the markets that can benefit from its technology, Ice Energy notes that it does not have any barriers to scaling its output, noting that its products do not depend upon rare earth materials or other hard-to-find components.
Furthermore, Ice Energy notes that it is poised to benefit from the potential payment for ancillary services under FERC Order 841, which requires utilities to create market structures that allow energy storage devices to participate.
As is the case with all technologies, it remains to be seen what Ice Energy’s future will bring. The United States will need to deploy a truly massive volume of energy storage to rapidly decarbonize its electricity supply using renewable energy, and Ice Bear could be part of this solution.