Advanced Compressed Air Energy Storage

Hydrostor’s proprietary Advanced Compressed Air Energy Storage (A-CAES) technology is the leading low-cost bulk energy storage solution. Hydrostor's A-CAES solution uses an emission-free, adiabatic process combined with purpose-built air accumulators that can be sited virtually anywhere — enabling CAES to fulfil its potential. It addresses intermittent renewable generation (solar, wind), reserve capacity, peak shaving, and transmission and distribution deferral. Hydrostor offers a complete solution including financing and warranty through our strategic partnership with AECOM.


Flexible Generation Plants

Zero emission fossil-fuel free peaking or baseload power

Bulk energy storage up to 100’s MW, and 4 hours to multiple day duration

Repurpose coal and once-through-cooling plant assets, leveraging existing infrastructure

Urban power plants providing load shifting, grid balancing and T&D deferral solutions

24-hour voltage support, emergency power, black start, and power quality conditioning

Replace diesel generation with low cost renewable energy

Low cost

Small surface site requirement

Optimizing Wind and Solar

Renewable energy on demand at a lower cost than diesel / HFO power

Time shift generation to maximize project economics

Eliminate renewable curtailment

Baseload or peaking plant designs

Increase distributed renewable generation with single central storage resource

Electrical independence for islands, micro-grids, and off-grid locations

Load levelling

Transmission and Distribution Deferral

New transmission lines have long lead time, are expensive, and challenging to permit

Maximize existing T&D capacity by utilizing capacity during off-peak times to bring power through the transmission bottleneck to charge

During on-peak times, inject storage generation after the T&D bottleneck to supply market on the load side

Emission-free A-CAES can be installed in densely populated urban areas

Provides flexible generation and reliable back-up power for critical areas and infrastructure

24-hour voltage support, emergency power, black start, and power quality conditioning

How A-CAES works



Pressurized to the same depth found in the accumulator



Adiabatic process is emission-free, eliminating the need for natural gas to generate heat



Hydrostatic pressure stores air in an isobaric state



Hydrostatic pressure forces air to the surface, where it drives a turbine generating electricity

1. Convert Electricity to Compressed Air
Electricity runs an air compressor which converts the electrical energy into compressed air. The compressed air stream is pressurized to the same pressure found at depth where the accumulators are located and the air is stored.
2. Capture Heat in Thermal Store
Heat from compression is captured from the airstream and stored to be used during generation, known as Adiabatic CAES. Adiabatic operation increases system efficiency while eliminating the need for additional heat from fossil fuel such as natural gas, avoiding fuel costs and emissions.
3. Store compressed air in accumulator
Compressed air is stored within one of three types of Hydrostor Accumulators. In Hydrostor’s Terra™ and Marine applications, compressed air displaces water in the accumulators at the hydrostatic pressure related to depth. In Cavern applications, an underground geological formation is utilized to store large volumes of air at variable pressure.
4. Convert Compressed Air to Electricity On Demand
To generate electricity on demand, the system reverses the air flow allowing pressure to force the air back to surface. The stored heat is added back into the air stream. The now heated air travels through a turbo expander which drives a generator, efficiently converting the energy in the air back into electricity for the consumer.


Air Storage Options

Hydrostor Terra™

The Hydrostor Terra™ system utilizes a proprietary isobaric purpose-built underground cavern for air storage, which can be deployed at any site within proximity to a body of water, including inner-city and urban areas. Terra™ utilizes hydrostatic pressure from a water-filled shaft to maintain an isobaric (constant pressure) system during charge and discharge, significantly reducing the cavern size required as compared to traditional CAES systems. When charging, compressed air is piped from the surface into the purpose-built accumulator, displacing water up the shaft and back to its source. Conversely, when the system discharges, compressed air flows back up to the mechanical equipment while gravity forces water to flow into the accumulator, displacing the air.

Hydrostor Terra Brochure
Hydrostor Marine

The Hydrostor Marine system utilizes HydroPod, a rigid-walled accumulator structure designed for quick and simple underwater installation at depths of 150+ meters. Hydrostor Marine facilitates bulk storage where deep water is located close to shore. This system is connected via drilled air communication pipe from shore, and utilizes hydrostatic pressure found at depth to maintain an isobaric (constant pressure) system during charge and discharge. Compressed air is pumped into the HydroPods displacing water in the accumulators during charge, with water displacing the air during discharge.

Hydrostor Marine Brochure
Hydrostor Cavern

Utilizing an existing cavern such as a salt dome or existing mine, Hydrostor surface equipment flows compressed air into and out of the cavity, steadily building pressure used for storage. This variable pressure system can repurpose existing infrastructure in stabilizing the grid.

Surface Technology

Surface Mechanical Equipment

Hydrostor systems use utility-grade, bankable Tier 1 OEM compressors and expanders, proven over decades of operation in the power sector. Our systems can be operated with charge rate, discharge rate, and storage capacity set independently, providing maximum design and operational flexibility to suit the application. As an example, our systems can charge an entire night’s worth of solar power during the day, or take full advantage of negative power pricing by quickly charging in a few short hours, then slowly delivering that power over many hours.

Thermal Store

Unlike traditional CAES systems, which rely on natural gas to generate heat required during operation, Hydrostor utilizes a patented adiabatic thermal management system to efficiently recycle heat generated during compression for later use during generation, making it truly emission-free. The proprietary sizing, material selection, configuration, and execution of Hydrostor’s Thermal Store technology increases round-trip efficiency. Eliminating the need for fossil fuel burning during the generation phase significantly reduces operational costs and eliminates harmful emissions.


Utility scale

Up to 100’s+ MW, GWh+, 4 hour to multiple day duration

Green energy on-demand

Environmentally friendly with no hazardous chemicals

Long life

30+ years without efficiency loss on mechanical and up to 100 years on accumulator

Proven components

Mechanical components manufactured by Tier 1 OEM suppliers

Adiabatic Process

Emission-free (no fossil fuel) operation

Maximum flexibility

Decoupled charge, discharge, and storage capacity provides ultimate flexibility

Low cost

Lowest installed cost / kWh available today for bulk energy storage

Roundtrip AC/AC efficiency

~60% or higher

Multiple Air storage options

1) Terra™, 2) Marine, 3) Cavern

Excellent reliability

Tier 1 OEM Supplied mechanical equipment matched with AECOM expertise

Black start & voltage support

Ancillary benefits provided by synchronous equipment

Unlimited cycles

Proven rotating equipment means no limitations or efficiency loss from cycling

Complete Solution

Hydrostor provides turnkey projects complete with maintenance and operation services—the customer just needs to signal Hydrostor how much power to produce (or store) and when.

Fully financed solutions
Full lifetime warranty
Sized to meet clients varying requirements
Operations and maintenance services

Current Projects


Project Name Location Power Rating Storage Capacity Customer Utility Host Status
Toronto Island Toronto, Canada 0.7MW Phased expansion to multi-MWh Toronto Hydro In-service Nov-2015
Goderich Goderich, Canada 1.75MW 7MWh NRStor (to IESO) Under construction
Vader Piet Aruba 1MW 6MWh WEB Aruba N.V. Contracted

Hydrostor is engaged with several utilities around the world to deploy systems rated at hundreds of megawatts, delivering gigawatt-hours of storage at durations ranging from four hours up to multiple days.

Hydrostor CAES Reference Facility

Toronto Island, Canada. Utility Host: Toronto Hydro

Hydrostor inside
Hydrostor Toronto Island map
Hydrostor Toronto facility

Strategic Partners

AECOM logo

Hydrostor and AECOM have partnered to jointly develop, market and construct A-CAES systems globally. Employing 87,000 people in 150 countries on 7 continents, AECOM brings 107 years of multidisciplinary Engineering, Procurement, and Construction experience to Hydrostor projects. This partnership brings reliability, bankability, and longevity to fully warrantied Hydrostor systems. Hydrostor is proud to work with a partner of this caliber to assist in deploying our technology worldwide.

Curtis VanWalleghem MBA, BASc, PMP

Chief Executive Officer, Board Member

Curtis is CEO of Hydrostor, a leader in the compressed air energy storage market. Prior to Hydrostor, Curtis was Sr. Manager in Deloitte's Corporate Strategy Consulting Practice where he advised and consulted for some of the top energy companies globally. He has also held positions at nuclear generator Bruce Power and wind developer Environmental Electric Company.

Cameron Lewis

Founder & Chief Technology Officer

With nearly 15 years of manufacturing experience of oil-field production equipment in Alberta, Mr. Lewis has worked directly with all types of process equipment meeting all types of needs both domestic and abroad. He has prior experience with a number of start-ups including Delaney Energy Manufacturing, Chadco Canada, Armadillo Card Company, and most recently Environmental Electric Company, developing wind farms in Ontario.

Jon Norman MASc, P.Eng

PRESIDENT & Chief Operating Officer

Jon is professional engineer with nearly 20 years experience in the power industry, environmental sector, management consulting and government. Jon previously held senior roles at Brookfield Asset Management, most recently as VP responsible for regulatory policy and government relations across North America for the power and utilities business. In earlier roles he served as project manager for environmental operations and held senior roles in government, where he led grid and networks policy development in Ontario as well as interjurisdictional negotiations. Jon holds an interdisciplinary master’s degree in engineering and economics from the University of Toronto.

Jordan Cole BBA, MBA

EVP & Chief Commercial Officer

Jordan is a senior professional with 15 years of experience in the private equity space. He spent over a decade at Brookfield Asset Management expanding the company’s renewable power, real estate and infrastructure global platforms. Prior to joining Hydrostor, Jordan was the Chief Investment Officer within Brookfield’s district energy platform, Enwave Energy Group. He has experience in renewables and infrastructure project development, and has been involved in a number of key transactions and financings. Jordan holds both honors BBA and MBA degrees from the Schulich School of Business at York University.

Andrew McGillis MSc, P.Eng

VP Engineering & Projects

Mr. McGillis is a coastal and marine engineer. He has more than 10 years of experience working as an engineer in the marine sector, including project management, coastal process investigations, and design. Most of his past work involves site investigations and engineering design of marine structures such as revetments, breakwaters, harbours, offshore wind turbine foundations, and scour protection. He is now focused on managing the design and engineering process at Hydrostor.

Alex Fuentes BASc, MBA

VP Business Development, Marketing & Alliances

Alex has over 17 years of professional experience, including 2 years leading business development and marketing for a global utility-scale solar developer, and over 8 years in renewable energy and corporate sustainability with Bullfrog Power. Prior to that Alex held various engineering and project management roles with companies such as Siemens-Westinghouse, Honeywell, Apotex and Husky Injection Molding Systems. Alex holds a BASc in Mechanical Engineering from the University of Waterloo and an MBA from the University of Toronto’s Rotman School of Management.

Cindy Hung MBA, CPA, CMA

SVP, Finance and Corporate Operations

As an experienced leader with over 20 years of professional experience in finance, accounting and corporate operations, Cindy has a proven track record with strong relationship building skills and knowledge in a fast-paced, cutting-edge environment. She is responsible for oversight of our finance, corporate operations, HR and IT departments. She holds a CPA, CMA, an honours BMath/BA from University of Waterloo and a MBA from Wilfried Laurier University.

Ray Boland

Chairman of the Board

Ray is a corporate advisor who has been engaged at the CEO and COO level to implement corporate change and effect business transitions, particularly to small and medium sized corporations. He is also a senior advisor with the MaRS Discovery District, where he advises on the commercialization of innovation and provides ongoing support for a number of early-stage companies. Previously, he was a Managing Director of Corporate and Investment banking with RBC Capital Markets in New York, and was also head of the Chicago based RBC Global Automotive Business. Born in Dublin, Ray has studied international relations and economics and has a MBA from Trinity College Dublin and holds the ICD.D Designation from the Institute of Corporate Directors.

Tom Rand

Board Member

After a number of years as a successful software entrepreneur Tom now focuses his efforts on carbon mitigation. He's active in Cleantech venture capital, technology incubation & commercialization, and public advocacy. Tom is Managing Partner of the privately-backed MaRS Cleantech Fund, a Senior Advisor at the MaRS Discovery District and sits on the board of a number of clean energy companies and organizations. Tom has two books under publication: Kick the Fossil Fuel Habit (early 2010) and Walking the Frog (Fall 2014). Tom holds a BSc in electrical engineering (U of Waterloo), an MSc in philosophy of science (University of London and LSE) and an MA and PhD in philosophy (U of Toronto) and is an Action Canada Fellow.

Curtis D. Bartlett

Board Member

Mr. Bartlett is a founding Partner of Lorem Partners. He has over 30 years of experience as an entrepreneur and manager, private equity investor and investment banker. Mr. Bartlett is currently a founding director of Parex Resources Inc., a TSX listed oil company based in Calgary with operations in Colombia, which has grown from a start-up to over $2 billion of market capitalization. He is also a founding director of Gravity Renewables, Inc. a private Boulder based company focused on consolidating small hydro power facilities in the United States. Mr. Bartlett has been involved in the start-up, growth and sale of more than a dozen companies in the energy sector. He graduated with a Bachelor of Arts (Honours) degree from Queen’s University, and received a Master of Arts degree from the University of Toronto. Mr. Bartlett served as a Trustee of Queen’s University, and holds the ICD.D from the Institute of Corporate Directors.

Ron Miller

Board Member

Mr. Miller was a co-founder of MHI Energy Partners (2001), a private equity investment firm which then rebranded itself Lorem Partners in 2012. Mr. Miller has extensive experience in strategic and corporate finance matters for both privately held and publicly traded entities including originating, valuing, structuring and negotiating acquisitions, dispositions, and, conventional and non-conventional financings. Mr. Miller is currently a board member of Parex Resources Inc., Rhino Legal Finance Inc., Redress Risk Management Inc., and JDRF Canada; he is also a board observer of Gravity Renewables, Inc.

Mr. Miller holds a Bachelor of Commerce degree (1987) from the University of Alberta and has also obtained his Chartered Professional Accountant (1990) and his ICD.D (2009) designations.


Mining Engineer

Deadline: May 16, 2018
Downtown Toronto, Ontario
Full-Time / Permanent

Senior Electrical Engineer

Deadline: May 04, 2018
Downtown Toronto, Ontario
Full-Time / Permanent

Global Mining Lead Engineer

Deadline: April 25, 2018
Downtown Toronto, Ontario
Full-Time / Permanent

Lead Mining and Civil Engineer

Deadline: Upon filled / ASAP
Downtown Toronto, Ontario


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Hydrostor Inc.
82 Richmond St East, Suite 400,
Toronto, Ontario, Canada
M5C 1P1

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(416) 548-7880