M2ACS is a new research project, involving 22 senior investigators from 5 institutions. Its central research concept is the one of multi-faceted mathematics -- whereby new mathematics is discovered by sustained investigation of the multiple facets presented by the grand challenge subproblems, such as nonconvexity, stochasticity, integrality, spatio-temporal variability -- from the perspective of all the mathematics discipline area involved. We will discuss the project scope, some of its challenges and how we anticipate it to impact mathematics and complex energy systems practice.