The energy resolution of the electromagnetic end-caps of the future LDC detector has been studied using two methods: the analog method, using the energy deposited in the active layers; and the digital one based on the number of hitted cells. The simulations show that for electron energies above 4 GeV, the energy resolution is better for the analog method while for low energies (E < 4 GeV), the digital method gives a better resolution. Other techniques, i.e. an hybrid method combining analog and digital methods or a modied digital method, have been tested to improve the energy resolution.