Hydrogen is often quoted as future energy carrier as it might offer an alternative for the scarce fossil fuels. Advanced high strength steels, such as TWIP steels, are excellent materials for applications in for example the automotive industry, where weight reduction is essential while dealing with the strict CO2-emissions despite more stringent safety regulations. However, the combination of hydrogen and advanced high strength steels offers a lot of challenges. Hydrogen can cause unpredictable failure. This significantly limits the applicability of these high strength steels. This proposal will look at this phenomenon on a microscopic scale and aims at getting fundamental understanding on how hydrogen affects the mechanical properties of TWIP steels.