Investors think Plug Power's electrolyzers might have a growing new market.Plug Power (PLUG 17.70%) shares jumped today, and investors see a path for more gains to come. That's not because of any news directly from the hydrogen power company. Rather, it's what investors see as a potentially very lucrative new market for Plug Power.Shares were 19.9% higher as of 12:40 p.m. ET Monday after reports that the Federal Energy Regulatory Commission (FERC) rejected a request to increase the amount of power from a nu ...