Hydrogen generation system, power generation system, hydrogen generation method, and power generation method

A hydrogen generation system configured as a magnesium-recycling hydrogen generation system, the hydrogen generation system comprising:

• a by-product acquisition unit configured to separate a by-product from a post-reaction solution, which is a solution after reacting with a hydrogen generation material containing a hydrogen-containing magnesium compound that generates hydrogen via a reaction with the solution, to acquire the by-product including more than one type of oxygen-containing magnesium compound that contains oxygen produced by the reaction;
• a raw material production unit configured to react the by-product with a halogen-containing substance containing halogen and other atoms than the halogen to produce a raw material containing magnesium halide;
• a hydrogen generation material production unit configured to reduce the raw material with plasma containing hydrogen to produce the hydrogen generation material;
• and
• a hydrogen generator configured to react the hydrogen generation material with the solution to generate hydrogen.