This　research　paper　presents　an　experimental　investigation　for　performance　evaluation　and　energy　efficiency　estimation　of　a　specific　grid　connected　photovoltaic　(PV)　power　system　under　real　meteorological　conditions.　The　basic　installation　and　data　of　10　MW　Oryx　photovoltaic　plant　(OPVP)　installed　in　Ma＇an,　Jordan　is　introduced.　The　main　objective　of　this　research　is　to　show　and　examine　the　obtained　results　and　build　a　good　database　for　Ma＇an　in　particular　and　Jordan　in　general.　In　addition,　promote　the　use　of　solar　photovoltaic　plants　as　a　clean　and　cheap　alternative　energy　source,　whether　ongrid　or　standalone.　This　approach　relies　on　a　genuine　atmosphere　conditions　including,　correspondence　system　and　meteorological　station.　The　weather　data　are　obtained　from　three　different　weather　stations　in　Ma＇an,　Jordan　to　compare　and　insure　the　accurate　estimation.　Last　year,　OPVP　supplied　the　national　electric　power　company　in　Jordan　with　24.157　GWh.　This　integration　was　considered　satisfactory　during　this　period,　where　the　annual　energy　efficiency　of　the　OPVP　was　12.1%,　the　average　annual　value　of　the　performance　ratio　was　78.14%,　and　the　average　annual　capacity　factor　was　26.34%.　By　comparing　the　obtained　results　with　the　actual　values,　it　is　ascertained　that　the　proposed　approach　has　the　superiority　over　estimating　the　energy　efficiency　and　performance　of　PV　plants.　Moreover,　the　obtained　outcomes　can　be　utilized　as　rules　for　the　use　of　solar　PV　power　plants　in　Jordan　and　other　comparative　climatic　nations.　©　2019　International　Journal　of　Renewable　Energy　Research.