Today, let's compare pure-play hydrogen fuel cell specialist Plug Power (NASDAQ: PLUG) -- shares of which are up 33.8% so far this year -- with renewable energy generalist Brookfield Renewable Partners (NYSE: BEP), which is only up 3%. Its products have found a niche market in industries where extended downtime (to recharge a battery) isn't an option: Mostly warehouse forklifts and airport safety vehicles. Unfortunately for Plug, batteries remain the dominant alternative vehicle fuel, and with gasoline prices so low right now, the economic argument for switching to alternative-fuel delivery vans is likely to take a hit.