Energy storage systems are technologies that capture excess electrical energy during periods of low demand, storing it in other forms and converting it back to electrical form for the grid during periods of high demand. As such, they play a critical role in overcoming common problems associated with renewable energy, such as their intermittency and non-dispatchable nature. Other than improving the efficacy of renewables, energy storage can provide additional benefits such as power grid decongestion, backup power supply, and load balancing.
Hydrostor – Canada’s first Underwater Compressed Air Energy Storage
Along with a group of 10-15 other renewable energy enthusiasts and professionals, I was offered the unique chance to visit Hydrostor, a proprietary Underwater Compressed Air Energy Storage (UCAES) technology system in Toronto, which I later learned is the first of its kind in Canada. Given the lack of deployment of such large-scale energy storage technology in the market – and knowing the important role that these systems play in the overall success of renewables – I jumped at this opportunity.
Since having access to a large body of water is one of the main requirements of this technology, Hydrostor was strategically built on the Toronto Islands, right next to Lake Ontario. While this is a small-scale (660 kW) pilot project, Hydrostor founder Cameron Lewis and CEO Curtis VanWalleghem informed us that they plan to ultimately expand their operations once the system is sufficiently evaluated. Designed for a lifespan of approximately 30 years, this plant is projected to operate long enough to promise a significant return on their initial investments. Not bad for two renewable energy entrepreneurs who decided to try something different and venture off the beaten path!
Relationship with Toronto Islands and Toronto Hydro
A bit about the logistics of the real estate – Hydrostor’s property on the Toronto Islands was subleased to them by Toronto Hydro, the city’s main utility service provider. As a utility provider serving almost 6 million residents in the city, Toronto Hydro sees great potential in this innovative piece of storage technology – it has the proven ability to hold electricity for weeks without losing power, as well as the potential to be scaled up significantly should electricity demand suddenly increase. Ultimately, Cameron and Curtis expect this operation to be able to provide electricity storage and emergency backup power for our city– at peak output and 60% efficiency, the unit would be capable of powering approximately 330 homes in Toronto!
How does the UCAES technology work?
Essentially, Hydrostor’s plan is to use low cost, off-peak renewable electricity to pump air into large balloon-like bags (similar to those used for marine salvage operations) located 60km underwater. Depth is key – the deeper the bag is under water, the higher the pressure expended on the air in the bags, and the greater the electricity generation potential. Once full, the air in the bag will be stored under constant, intense pressure due to the weight of the lake water surrounding it. As soon as the plant needs to generate electricity, it releases the air out of the bags to drive a generator, which then supplies power into the electricity grid and completing the storage cycle.
Financial support and business development
On the financial front – Cameron expressed with gratitude that this project would not have been as successful as it is today without a generous grant funding from the Sustainable Development Technology Canada (SDTC) program offered by the Government of Canada, and the Innovation Demonstration Fund by the Government of Ontario. He also emphasized that their team is working extra hard to continuously improve and tweak the system, as they have ambitious goals of designing the best possible model, package it, and eventually push it out to the world!
Cameron told me proudly that currently, Hydrostor is the only company in the world with a functioning underwater compressed air facility. One of their target markets for future expansion opportunities include island nations in the Caribbean, evidently due to their proximity and access to large volumes of water. In fact, they’ve already signed a contract with WEB Aruba, an electrical utility on the Dutch Caribbean island of Aruba, to build a 10MW plant that will accompany a 30MW wind farm on the island.
Cleantech innovation is undeniably a key component to kick-starting the low carbon economy and helping Canada reach its 2030 carbon reduction targets. Let’s hope that these two budding clean-tech entrepreneurs can help our country – and the rest of the world – add a new dimension to our energy economy that is not only profitable, but also sustainable and revolutionary!
Other energy storage technologies in Canada:
- Flywheels are mechanical batteries that store kinetic energy in a rotating mass. During times of low demand, flywheels use power from the electricity grid to drive a motor, which spins the wheel at high speeds, allowing it to store excess energy. When demand is high, the momentum of the flywheel allows the motor to act as a generator, slowing down the flywheel and dispatching power back to the grid.
- Thermal energy is stored off-peak energy that can be used to supply heating or hot water needs, consequently reducing electricity consumption during on-peak periods. Examples include solar thermal systems and ice storage systems.
- Electric vehicles (EV) and their batteries can be used as controllable load during periods of low demand, and a source of electricity supply during periods of high demand. By sourcing electricity from EV charging stations, EV users can supply the excess electricity to the grid or use it to meet their own electricity needs.
- Tesla motors is mass producing The Tesla Powerwall, an innovative energy storage battery that can harness solar energy through solar panels to be stored and used by homeowners at a later time. This gives homeowners the opportunity to avoid paying peak-time electricity prices, as well as having access to a reliable electricity source in the event of power outages.
Header image source: Hydrostor website
UCAES process diagram: Hydrostor website
Air storage balloons image: Toronto Hydro website