  We consider the variational formulation of the electric field integral
equation (EFIE) on bounded polyhedral open or closed surfaces. We employ a
conforming Galerkin discretization based on div-conforming Raviart-Thomas
boundary elements (BEM) of locally variable polynomial degree on shape-regular
surface meshes. We establish asymptotic quasi-optimality of Galerkin solutions
on sufficiently fine meshes or for sufficiently high polynomial degree.
