Ecodesign of Ever Net-Load Microgrids

The European Union has promoted the process of electrical market liberalization, extended to residential/office/commercial buildings and a strong encouragement towards the rational use of energy. European energetic policy aims to promote the installation of small renewable power sources and the use of high efficient cogeneration. Recently it promotes strongly also the `Nearly Zero-Energy Buildings´ that have to be pursued as much as possible by a local generation sufficient to supply the residual amount of energy. To avoid future chaotic phenomena in the existing distribution network the paper highlights that the power flow of local generators has to be maintained local: the users have to remain net-loads organized in Ever Net-Load Microgrids. The actual distribution network for low voltage customers appears inadequate to comply with these improvements and it has to change in order to accept microgrids organized by the union of customers bunches. The authors suggest the ecodesign of the microgrids able to constitute the Nearly Zero-Energy Buildings and also to accomplish the goals about enhanced safety, high local power quality, d.c. distribution systems, common emergency systems, efficient load shedding, energy management. The microgrids allow to guarantee a reduced impact as ever net load on the net supply.