Located 55 meters below the surface of Lake Ontario is the world’s first underwater energy storage system, featuring a series of colossal balloons filled with compressed air. With the help of these pressurized balloon-like structures, the system stores energy, which can later be used to provide electricity during peak periods. This innovative technology, known for its longevity as well as lost costs, could serve as an alternative to traditional diesel or gas-based back-up power sources.
The underwater system, situated three kilometers off the southern coast of Toronto Island, was recently launched by Canada-based Hydrostor Inc., in collaboration with Toronto Hydro. The result of five long years of research, the technology can be used to store energy when electricity is cheapest. Conversely, it can work in tandem with renewables, like wind and solar power, to collect and store energy on exceptionally sunny and windy days. Speaking about the project, Curtis VanWalleghem, the CEO of Hydrostor, said:
The G20 is talking about getting off fossil fuel by 2050. To do that, our electricity system has to incorporate storage so we don’t need as much backup diesel and natural gas capacity—that’s what this can do.
Central to the technology are huge specially-designed balloons, called accumulators, that are somewhat similar to the materials used to raise shipwrecks from the ocean bed. The system first converts the available energy into compressed air, by means of an advanced compression technique. To prevent energy loss of any kind, the heat produced during the process is also stored up, using heat exchangers. Following this, the air is forced through a specially-built pipeline, and then finally stored inside the accumulators. VanWalleghem added:
Compressed air’s been around for 40 years. It’s finding places to store the air that’s been the problem [and] why it hasn’t been massively adopted. We open it up to thousands more sites because we use hydrostatic water pressure.
During peak times, the system makes use of the lake’s natural pressure to pump the compressed air back through the installed pipe. It can then be used to power a turbine, and consequently, generate electricity. The company’s pilot system, in Lake Ontario, has a total capacity of around 660 kilowatt hours, which is enough to power nearly 330 homes. According to the developers, the system can be scaled up, for the purpose of storing larger amounts of energy.
The technology has several advantages over conventional energy storage systems. It can last twice as long as grid-based battery systems, and costs far less. It is completely non-toxic, and does not depend on diesel or gas. Hydrostor is currently looking for ways to make the technology available to the global market. The company is already in talks with a Venezuela-based utility company for the construction of a larger facility. VanWalleghem said:
We’re now focused on commercializing this technology globally to bring our green energy storage solution to countries around the world… That’s a step-change improvement in storage economics.