It turned out that PWER was never going to report earnings until the 29th of July. Had I known that at the time I would definitely had been long PWER and been sitting on big gains now! However, there is no sense in dwelling on what could have been but instead focusing lessons learned.
I have learned that I need to be more comprehensive when searching for a stock's earnings announcement date by checking several sources. Hope this helps your own trading.
Good luck and good trading!