** Shares of Australia's Amplitude Energy AEL.AX rise as much as 6.7% to A$2.72, their highest level since February 10

** The energy firm says that along with joint venture partner O.G. Energy, it executes Gas Sales Agreement (GSA) with EnergyAustralia

** Co says agreement for supply of 30 petajoules (PJ) of gas from East Coast Supply Project (ECSP) in Australia

** Adds that supply to start in H2 2028

** Despite moves, stock down 8.6% YTD

(Reporting by Aamir Sheik Khalid in Bengaluru)

((Aamir.SheikKhalid@thomsonreuters.com))