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Not All Salt Caverns Are Created Equal

 

 

 

The storage of compressed materials in underground salt caverns is a new concept to many in eastern Canada. However, it is standard operating procedure in other parts of the world. So, let’s explore how these salt caverns work and what makes them special.

There are two main varieties of salt formations: bedded and domal. Bedded formations are inconsistent in thickness and shape, contain deformities that affect stability and are not highly compressed. Domal formations – or salt domes – exist under a dome of highly stable bedrock, which applies an opposing force to the natural tendency of salt to rise toward the surface.

The Fischells Salt Dome is a gulf-style formation, a rare and very high quality geological structure that is typically found much further south, in the Gulf of Mexico and southern United States. Gulf-style domes are massive in size and the Fischell’s dome is larger than most, measuring roughly 5 km square by 2 km deep.

It is possible, with all necessary reservations, to develop suitable salt caverns for hydrogen in bedded salt formations as is the case at the Teeside site in the UK. However, the caverns are smaller in comparison to other caverns and the development and operation costs could be up to 5 times higher considering that the caverns are less deep and the salt is not as thick.

The deposits in a gulf-style salt dome exist under extremely high pressure, which compresses the salt until it is as dense and impermeable as bedrock.

However, unlike bedrock, the salt can be mined and removed relatively easily, by drilling a narrow well – 40 cm or 16″ wide – deep into the salt formation, followed by the injection of fresh water into the hole. This process, called solution mining, softens and dissolves the salt, which is then pumped out of the well, followed by the injection of additional water, and so on. In a process that could take up to two years, we will create a cavern that is 1300 metres deep and 80 metres wide.

The surrounding walls of the salt cavern are highly compressed and impermeable, making it ideal for the storage of various materials under very high pressure. In the near term, we plan to inject compressed, cooled air into the cavern. When power is required on the provincial grid during peak demand periods, this pressurized air can be released into an industrial turbine connected to a generator. In other words, our salt dome can help ensure stability of electricity supply for residents of Newfoundland and Labrador.

Over the longer term, the dome will be key to development of the wind-powered green hydrogen industry, because alternative sources of green energy will be required for those occasions when winds are too high or stop altogether. Hydrogen can be stored in salt caverns to use as a backup fuel source during these periods of inadequate wind supply.

Our salt dome is so large, there is sufficient capacity within the salt deposit to create another 30 caverns, each measuring 1300 metres deep by 80 metres wide. Which means the development potential of the Fischells Salt Dome is virtually unlimited.

As the world advances toward the clean energy transition, it is imperative that we recognize the unique properties of salt caverns as safe and secure storage locations. By carefully identifying and developing the right salt caverns, we can unlock the full potential of compressed air and green hydrogen as clean and sustainable energy solutions, ushering in a brighter and greener future for generations to come.

For more information about the Fischells Salt Dome and/or partnerships and development opportunities please contact the Triple Point team at info@triplepoint.ca.