Because the microgrids you're referring to are stand-alone power systems, they aren't connected to the national grid. Right now, stand-alone power systems in Canada rely mainly on diesel-generated electricity. The idea is to reduce the carbon footprint as much as possible, which means reducing the use of the diesel generator as much as possible, by making the most of available wind and sun, and by storing electricity when there's a surplus of power.
What the research shows us is that we can significantly reduce the use of diesel. Obviously, in the specific context of a stand-alone power system, you can't take advantage of interties with neighbours and the benefits of a larger geographical area.
That means diesel is still required to ensure stability and security, but the idea is to reduce the reliance on fossil fuels as much as possible and benefit from local energy sources, whether the wind or the sun.