(AGI) Rome, Sept 23 - The average purchase price of energy onthe electricity exchange in the week from Monday Sept 15 toSunday Sept 21, was up by 2.06 euro per MWh over the weekbefore, rising to 57.30 euros per MWh. The volume ofelectricity traded on the exchange also rose by 3.5 million MWhor 1.1 percent. The liquidity of the market was 63.5 percent, arise of 0.3 percent. The average selling price ranged between53.33 euros per MWh in the South and 91.21 euros per MWh inSicily. (AGI) .