Starting from the T -Q equations of the open spin-1 XXZ quantum spin chain with general integrable boundary terms, for values of the boundary parameters which satisfy a certain constraint, we derive a set of nonlinear integral equations (NLIEs) for the inhomogeneous open spin-1 XXZ chain. By taking the continuum limit of these NLIEs, and working in analogy with the open spin-1 XXZ chain with diagonal boundary terms, we compute the boundary and the Casimir energies of the corresponding supersymmetric sine-Gordon (SSG) model. We also present an analytical result for the effective central charge in the ultraviolet (UV) limit. 1 email: rmurgan@gustavus.edufor the open spin-1 XXZ spin chain with general integrable boundary terms are reviewed. This is followed by the derivation of a set of NLIEs for the inhomogeneous open spin-1 XXZ chain in section 3. We then give a brief review of the SSG model following [41]. Proceeding by analogy with the SG model with general integrable boundary conditions [14,27] and the SSG model with Dirichlet boundary conditions [46], we consider the continuum limit of the NLIEs in section 4. In section 5, we compute the boundary and Casimir energies for the ground state. We analyze the UV limit of the Casimir energy and give an analytical result for the effective central charge in section 6. Finally, we conclude the paper with a brief discussion of our results and some open problems in section 7.