<prompt> Translate the following text to EnglishIngawa mifumo hii ya FGD ni ya kawaida, usakinishaji wa FGD ya Homer City ulifanywa wakati huo huo kama usakinishaji wa vitengo vitatu vya SCR.  <response>: 13 Although these FGD system installations are considered typical, the Homer City FGD retrofit installation was performed during the same time frame as the installation of three SCR units. 