The Electronic Structure Library (ESL) is a new initiative to create an online repository of software for use within electronic structure codes. One of the aims of the ESL is to give members of the community access to a diverse range of Kohn-Sham (KS) eigensolvers, in the form of fully functioning libraries. We focus on the libOMM library implementing the orbital minimization method (OMM), and explore the possibilities for using this method as an exact cubic-scaling solver for the self-consistent KS problem, comparing its performance with that of explicit diagonalization in realistic systems. We discuss its efficiency for codes using a basis of non-orthogonal finite-range atomic orbitals, showing that the OMM can achieve a noticeable speedup with respect to diagonalization even for minimal basis sets for which the number of occupied eigenstates represents a significant fraction of the total basis size. Finally, we discuss the possibility of making use of the natural sparsity of the operator matrices for this type of basis, leading to a method that scales linearly with basis size.