Hydrogen is a great energy vector to deal with the renewable energy integration. Indeed, use renewable energies to produce electrolytic hydrogen with water electrolysis and then convert the energy stored to produce electricity with a fuel cell is a solution to deal with the stochastic characteristics of renewables like photovoltaic or wind turbine. However, fuel cells and electrolysers need to be used in specific operating conditions. Multi-time-scale energy management systems can be used to ensure that the operating conditions constraints are respected for each unit. This paper deals with a two-time scale energy management system to treat with the fuel cells and electrolyser specifications. The first stage ensures that the technical specifications of each unit are respected and the second stage uses weather prediction to ensure the minimal start/stop time recommendations of the fuel cell and the electrolyser.