Storing Energy in the Freezer: Long-Duration Thermal Storage Comes of Age

Jason Dreisbach fields at least half a dozen calls every week
from people trying to sell him a technology to lower his energy
costs. As the owner of Dreisbach Enterprises, a cold-storage
facility owner with operations in Northern California, he’s�a
popular target. Cold storage — from frozen food warehouses to
grocery and restaurant refrigeration — has one of the highest
energy costs of any industry; energy expenditures are usually
second only to payroll.

Dreisbach endures sales pitches that run the gamut of energy
solutions, from LED lighting to rooftop solar to fuel cells. When
Viking Cold Solutions reached out in 2017 with a thermal energy
storage technology, his interest was piqued because, even though he
had many questions, “it was not a foreign concept,†he said.
The battle in cold storage is not keeping things cold, but
rather removing heat. “We are constantly fighting [British
thermal unit] intrusion,†Dreisbach explained. Viking Cold
offered something that aided in the battle.

Cold storage facilities have long been a target for
energy-efficiency and demand-response programs because of their
intense energy needs. And yet, these ubiquitous facilities have not
been fully tapped for their energy savings or potential as flexible
energy resources. Some promising companies with mechanically
complex thermal energy storage solutions targeting the commercial
sectors, including the cold chain, have exited the business or
turned to software-based offerings only.

It’s a tough sell to get any business, especially grocers or
frozen-food warehouses, to give up valuable square footage for any
energy storage solution, or to put their customers’ products in
jeopardy to save on costs. Because of this, Viking Cold has found
that many of its potential clients have had limited success with
demand-management participation. And until recently, most utilities
have not actively sought out long-duration energy storage as part
of their grid flexibility portfolio. Now, that is all changing.

A big target, easily overlooked

Viking Cold Solutions didn’t set out to develop a technology
for utilities to tap as a grid resource. Its founder simply wanted
to move more frozen foods more efficiently between Jacksonville,
Florida and Puerto Rico for clients such as Sam’s Club. The
patented solution leverages thermal energy storage to the benefit
of frozen-food storage providers and utilities.

In simple terms, all thermal energy solutions involve the
heating or chilling of water or another medium, which is then used
to shift energy loads. In the case of Viking Cold’s technology,
it also improves efficiency. Thermal energy storage is currently a
small but growing portion of the behind-the-meter energy storage
market, according to Wood Mackenzie’s energy storage analysts.

Source: Wood Mackenzie Power & Renewables

Viking Cold’s technology for frozen-food warehouses looks like
a radiator that sits atop the frozen-food racking. It’s made of
sealed plastic bottles filled with water and hydrated salt
solutions that act as a phase-change material to absorb heat
infiltration inside the freezers. There are no mechanical system
components, but the phase-change material is paired with an
intelligence platform that optimizes temperatures and energy use
and interfaces with nearly any building or warehouse management
system.

“With our technology, we essentially treat the phase-change
material like a thermal battery,†said James Bell, president and
CEO of Viking Cold Solutions. “We know precisely how much energy
is in there. Prior to thermal energy storage, people had just
guessed.†He further noted that energy-saving practices for this
sector have traditionally used the food or the building as the
energy-storage medium, “but now we have something specifically
designed for energy storage that is safe for both food and the
environment.†The systems can deliver over 12 hours of
load-shifting while improving refrigeration efficiency an average
of 25 percent.

Born in Florida, coming of age in California

Dreisbach Enterprises and San Diego Food Bank are two of the
California-based operations that have invested in Viking Cold’s
technology to run their operations more efficiently. In thermal
energy storage, they have found a powerful long-duration storage
solution that helps them do everything from integrating renewables
more profitably to increasing resiliency during power disruptions,
as well as participating in multiple utility programs in ways they
couldn’t before. Viking Cold is an approved project developer in
California’s Self-Generation Incentive Program, which provides
funds for behind-the-meter energy storage deployments.

The average cold-storage warehouse has approximately 1 megawatt
of energy storage potential, according to Viking Cold. In the case
of Dreisbach Enterprises, in 2017 it installed the technology in a
portion of one of its 100,000-square-foot Northern California
facilities, which now reduces nearly half a megawatt of freezer
load for 13 hours every day. Prior to the installation, Dreisbach
used the conventional cold-storage industry practice known as
flywheeling (also called floating), which consists of sub-cooling
the food and then shutting off refrigeration systems during the
expensive six-hour peak demand-charge period.

“What Viking Cold has allowed us to do is [to avoid]
sub-cooling to the degree that we had, and then ride it out for
much longer,†said Dreisbach. “Instead of six hours, we ride 12
or 13 hours, six days a week, without turning on our more major
compressors.†The result is a 22-month payback period instead of
36. There have been other benefits: It’s simply not as
uncomfortable in the warehouse when employees are working because
the fans are blowing less; operations and maintenance needs and
costs have been reduced, and during a recent 24-hour outage caused
by a nearby Pacific Gas & Electric transformer, temperatures
rose only about 5 degrees, said Dreisbach, compared to the rise of
approximately 15 degrees that would have occurred without Viking
Cold’s thermal energy storage (TES) technology.

San Diego Food Bank’s TES system has allowed the organization to
essentially shut down compressors overnight and leverage its onsite
solar array to power more of the refrigeration during the day. The
facility has also reduced its morning peak, which occurs before the
solar array is generating energy, by about 12 kilowatts. The
overall energy savings have amounted to nearly 40 percent.

San Diego Food Bank was able to shift its runtime to better
leverage its solar generation and eliminate 95% of overnight
grid-sourced refrigeration load. (Source: Viking Cold
Solutions)

A distributed energy resource for the taking

While thermal energy storage has been available for a long time
in various forms, the current juncture seems particularly well
suited to the solution. Lithium-ion batteries, which dominate the
energy storage market, offer about two hours of storage for
utilities to tap. For heavy refrigeration loads, Viking Cold has
found lithium-ion batteries are neither feasible nor economical
when compared to its TES, which has a levelized cost of energy of
less than $0.02 per kilowatt-hour.

At the same time, the need to incentivize load-shifting takes on
new importance as intermittent wind and solar are rapidly added to
the grid, and as peak mitigation increasingly becomes a focus as
utilities look to displace inefficient peaker plants. Regulators
are more frequently tasking utilities with providing
“all-of-the-above†resource plans that include a range of
distributed energy resources, energy storage in particular.
Finally, utilities are looking for opportunities to be proactive
with value-added services for their largest customers to
prevent them from defecting.

Viking Cold’s technology can address these varying utility
challenges, but it is often still viewed through an efficiency
lens. That’s fine with Bell, who says the company is focused
first and foremost on serving its cold-chain customers. That’s an
important distinction, as some other promising thermal energy
providers have prioritized chasing utility and municipal contracts
rather than focusing on end-use customers. If Viking Cold can also
work with energy providers, the company sees that as icing on the
cake.

“A year or two ago, we had maybe one or two utilities that had
incentives for us,†said Collin Coker, VP of sales and marketing
at Viking Cold Solutions. “Now we have dozens.†The very nature
of those incentives is also evolving. A large, investor-owned
Midwestern utility is building a program that will incentivize
the storage capacity of TES systems like Viking Cold’s.

“Overall, the thermal energy storage vendor ecosystem isn’t
crowded today, but may see more competition as more utilities
include incentives for this technology and customers realize the
value proposition offered by TES,†Wood Mackenzie analysts noted
in a 2019 Energy Storage Monitor report.

In the past year, Viking Cold has found that both utilities and
cold-storage companies are approaching the company with their
challenges, rather than simply hoping someone like Dreisbach
returns the sales team’s calls. “Down the road, I see this
looking like insulation did 100 years ago,†said Bell.

“Now you wouldn’t even consider a building without
insulation. Going forward, why would anyone build a
temperature-controlled facility without the efficiency and
resiliency of TES?â€

Source: FS – GreenTech Media
Storing Energy in the Freezer: Long-Duration Thermal Storage
Comes of Age