Based on the obtained results, a prototype generator of pressurised hydrogen by the hydrolysis of Mg or MgH2 in the solution of citric acid has been developed and tested. Main feature of the generator is a possibility of reaction control by controlled supply of the acidic solution to hydrolysis reactor. The developed hydrogen generator demonstrated possibility of controlled hydrogen release at the pressure up to 100 bar with H2 yield of 0.79 and 1.42 Nl/g using magnesium and magnesium hydride, respectively, as a hydrogen generating material. At the same operating conditions, hydrogen release when using MgH2 was 2.5 times faster than for Mg.