Plug Power has powerful growth potential and problems.Shares of Plug Power (PLUG) recently slid under $2 a share, putting them around their 52-week low. The hydrogen stock is now down nearly 60% this year. It's even further below its all-time high. An optimist might say that the stock doesn't have much farther to go before it hits bottom. They could also point to the hydrogen company's tremendous growth potential as a reason to be bullish that shares could stage an epic recovery. However, there are reasons ...