In view of the tremendous benefits induced by cooperative operation of microgrids, such as reduced power loss, lower operational cost and load peak reduction, this study presents a new energy management strategy for coalition forming microgrids under an electricity market environment. The proposed framework models the time-variant and intermittent attribute of renewable energy sources using a worst-case transaction mechanism. The energy management strategy minimises the net operating cost of the microgrids forming the coalition, which not only includes the cost of distributed generation but a worst-case net transaction cost to account for the intermittency in renewable energy-based sources. Extensive numerical results are shown to corroborate the efficacy of the proposed framework. DOWN ramp up/down rate of DE i SOC i, k, t min /SOC i, k, t max limits on state-of-change (SOC) of ESS i power loss ratio of conversion c , d charging, discharging efficiencies of ESS v ci , v co , v rated cut-in, cutout , rated wind speeds of the WT v i, k, t available wind speed at the location of the WT generator i at MG k at time t Variables Binary variables u k, t , v k, t status (0/1) of MG k's power exchange state with the remaining MGs x i,k,t , y i,k,t status (0/1) of ESS i during discharging/charging w k, t , z k, t status (0/1) of MG k's power exchange state with the grid Continuous variables F i,k,t fuel consumption of DE i