The hole in Svartöberget is not very big compared to what it can be in Gällivare. Construction began in May and it will be some time before the storage can be tested.

The hydrogen storage should be tested on a small scale to verify that it is functioning as intended before possibly building a much larger storage.

– We believe that the safest method is to store the gas locked in a rock, but it will be a great pressure on the rock, says Mikael Nordlander, responsible for the development of industrial collaborations at Vattenfall.

High requirements for the material to be gas-tight

Gas storage in rock chambers is already done with, for example, natural gas. However, there are two important differences which will now be explored:

– Gaseous hydrogen is a very small molecule, so it requires the material to be truly gas-tight, and we want to make sure of that with this test, explains Mikael Nordlander.

In addition, it must be dynamic storage, that is, you have to fill and empty the warehouse over and over again.

– So we want to make sure that we know what kind of rock is needed if we build on a larger scale next.

Mitigate housing risk

In Gällivare, a warehouse 1,000 times the size is expected to be built when the Hybrit demonstration plant goes live – a warehouse that, in extreme cases, can provide production for 4 to 5 days.

Mikael Nordlander of Vattenfall says they have been working with design and risk analysis for a long time. He says there should be no risk to those who live nearby.

– The risk is extremely low, we put the storage locked up 30 meters inside a mountain and in the event of an extremely unlikely leak, we can detect it and divert the gas to a safe place.

By May of next year, they expect to be ready with the test warehouse and be able to put it into operation. The warehouse will then be tested for two years.