In just four months, Plug Power stock rose in value by nearly 300%.Plug Power (PLUG 0.21%) stock has had a number of huge runs over the years. The company is a popular hydrogen stock, a category of business that could grow rapidly as demand rises for renewable energy.This year alone, from trough to peak, Plug Power shares nearly quadrupled in value. Many investors have jumped in hoping that the surge continues. But before you jump in yourself, there are two things you should understand.Can hydrogen power me ...