As an example for the use of the fully relativistic KKR-Greens function (GF) and fully relativistic KKR-Coherent Potential Approximation (CPA) methods for f-electron systems the electronic structure of delta Pu, of single impurities in delta Pu and of the concentrated alloy Pu90Al10 is discussed. The electronic structures of these systems are discussed in terms of band structures, densities of states and Bloch spectral functions. Particular attention is drawn to the pressure dependence of the Fermi surface for delta Pu.