SOLARWAY with modularized PEM stack technology manufactures electrolyzers from 5kW to 1MW scale. Instead of a large single cell stack design, we utilize multiple units of modularized stacks in order to manage each stacks individually. For the 1MW electrolyzer, we use 5 of 100kW single cell stacks and if one stack has a problem the rest of four stacks will be still running. In another word, the electrolyzer will never shut down and one bad stack can be simply replaced. For a 1MW electrolyzer, it is combined with containerized and compact design, that can be installed outdoors in any ambient temperature.