Microgrids are a relevant way to promote renewable energy sources and to provide electrical power in remote areas where the main grid is weak or inexistent. This is not the only application of microgrids. Indeed, those are now very famous on industrial sites, eco-districts or campus. Once interconnected or connected to the main grid, those microgrids can be real added-value assets. They can take part in voltage dip mitigation or frequency control of a bundle of microgrids or simply to the main grid itself. Microgrids can now be also considered as ancillary services (R1, R2, R3DP). Engie Laborelec is very active on this topic with its Smart Grid Lab and works on several projects which can demonstrate those aspects but also the feasibility of dealing with several energy fluids in one system. The presentation will be also focus on real cases and return on experience from the field.