  The global climate change creates a dire need to mitigate greenhouse gas
(GHG) emissions from thermal generation resources (TGRs). While microgrids are
instrumental in enabling the deeper penetration of renewable resources, the
short-term planning of microgrids needs to explicitly assess the full range of
impact of GHG emissions. To this end, we propose a novel unit commitment (UC)
approach, which enables the representation of GHG emissions from TGRs, the
specification of GHG emission constraints, and the ex-ante evaluation of carbon
tax payment with all other costs and benefits. We quantify the relative merits
of the proposed approach vis-\`a-vis the classical UC approach via
representative studies. The results indicate that the proposed UC approach
yields lower costs than does the classical UC approach and achieves a greater
reduction in costs as carbon tax rate increases. Further, increasing carbon tax
rates can markedly disincentivize TGR generation under the proposed approach.
