The hydrogen cavern at the HYBRIT Fossil-Free Green Steel Pilot Plant, the site that produced the world's first batch of fossil-free sponge iron. The plant is a joint Swedish investment by steel-maker SSAB, iron ore miner LKAB and electricity provider Vattenfall. 

The lined rock cavern is 30 metres deep with an area of 100 cubic metres and can store around 100 tonnes of hydrogen. 

With HYBRIT technology, SSAB aims to be the first steel company in the world to bring fossil-free steel to the market in 2026 and largely eliminate carbon dioxide emissions from their own operations by around 2030.

In 2016, SSAB, LKAB (Europe's largest iron ore producer) and Vattenfall (one of Europe's largest energy companies) joined forces to create HYBRIT, an initiative that endeavours to revolutionise steelmaking. Using HYBRIT technology, SSAB aims to replace coking coal, traditionally needed for ore-based steelmaking, with fossil-free electricity and hydrogen. The result will be the world's first fossil-free steelmaking technology, with virtually no carbon footprint. Their goal is to reduce Sweden's CO2 emissions by 10% and Finland's by 7%.