POWER September 2020 - 22

TOP PLANT
Developing a Solution for
Utility-Scale Storage
Darrell Proctor
ong-duration energy storage is seen
as a key technology to support a
low-carbon power grid. Storage is
particularly important as more intermittent
renewable energy such as wind and
solar power comes online.
The challenge has been implementing
a grid-scale storage technology. Batteries
have proven adept at providing power for
short intervals; a long-duration solution
that can provide power for several hours,
and is cost-effective, has been elusive.
Support for solving the long-duration
L
problem is increasing, though, as more
countries adopt renewable energy goals
and work to integrate renewables onto the
grid. Storage is key to providing reliable
power as baseload electricity units are
retired, so many groups, including government
agencies, utilities, and technology
providers are working to find solutions.
Hydrostor, a private company founded
in 2010 and based in Toronto, Canada, is
one of those groups. The company calls
itself " the world's leading developer of
utility-scale energy storage facilities, "
and is using its proprietary Advanced
Compressed Air Energy Storage, or ACAES,
technology and purpose-built underground
storage caverns to provide a
long-duration solution (see sidebar).
Hydrostor's Goderich facility in Ontario
was officially inaugurated in November
2019 (Figure 1), two years after construction
began, and began commercial operations
for the province's Independent
Electricity System Operator (IESO) in August
2020. It's recognized as the world's
first commercially contracted A-CAES
facility, working with Ontario's IESO for
peaking capacity, ancillary services, and
full participation in the merchant energy
22
market to support grid reliability. The plant
uses no fuel, produces zero greenhouse
gas emissions, and according to Hydrostor,
" helps enable a cleaner, more affordable,
and more flexible electricity grid. "
" We're proud to complete this important
commercialization milestone for Advanced
Compressed Air Energy Storage,
and deliver the significant benefits of our
technology in our own backyard, here in
Ontario, " said Curtis VanWalleghem, Hydrostor
CEO, in comments to POWER.
" This facility serves as an important proof
point for A-CAES on the global stage,
enabling the build-out of Hydrostor's fullscale
project pipeline in Canada, the USA,
Chile, Australia and other markets. This is
the showcase of the A-CAES technology. "
The innovation behind Hydrostor's
Goderich facility makes it a worthy recipient
of a POWER Top Plant award.
First Utility-Scale, Commercial
Application
The Goderich plant represents a major
milestone for Hydrostor, as it's the company's
first revenue-generating commercial
facility. The plant has 1.75 MW
of peak power output; a 2.2-MW charge
rating; and provides up to 15 MWh of
storage capacity. Goderich is a first-of-itskind
utility-scale commercial application
of A-CAES technology, conforming to all
interconnection, uptime, performance,
and dispatch standards as set out by the
IESO, with which it has a 10-year contract
to provide energy services.
" New technologies are changing the
way we keep the lights on for Ontarians, "
said Peter Gregg, president and CEO of
the IESO. " NRStor and Hydrostor's Compressed
Air Energy Storage project is a
great example of the innovation we're
www.powermag.com
seeing in this province, and will help us
further understand how these unique resources
can best integrate with Ontario's
market and system operations, and drive
down costs for consumers. "
Hydrostor told POWER, " The facility
demonstrates the ability of Hydrostor's
A-CAES technology to fully participate
in and deliver a range of valuable grid
services to electricity markets. " It noted,
" [N]ow that it is fully commissioned it
serves as an important demonstration
that the operating principles of A-CAES
as a commercially available, long-duration
storage solution [are valid]. "
The A-CAES Process
There are four steps in the Advanced
Compressed Air Energy Storage (ACAES)
process.
1. Compress Air Using Electricity.
Off-peak or surplus electricity from the
grid or a renewable source is used to
operate a compressor that produces
heated compressed air.
2. Capture Heat in a Thermal
Store. Heat is extracted from the air
stream and stored inside a proprietary
thermal store. This adiabatic process
increases overall efficiency and
eliminates the need for fossil fuels
during operation.
3. Store Compressed Air. Air is
stored in a purpose-built air storage
cavern where hydrostatic compensation
is used to maintain the system at
a constant pressure during operation.
4. Convert Compressed Air to Electricity.
Hydrostatic pressure forces air
to the surface where it is recombined
with the stored heat and expanded
through a turbine to generate electricity
on demand.
POWER | September 2020
Courtesy: Hydrostor
A Canadian company is using its proprietary technology, known as A-CAES,
to provide a long-duration, cost-effective way for energy storage to provide
power for hours at a time.
http://www.powermag.com
POWER September 2020

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