Multi-criteria decision analysis is used both for location problems and for energy problems. For successful involving of wood-fired cogeneration in Estonia it is important to define the most appropriate region, where the wood-fuel cogeneration plants can be located. The method used for defining the optimal location is based on the multi-criteria decision analysis (MCDA), which includes the Delphi method for criteria selection, the Analytic Hierarchy Process (AHP) method as weighting method and the elementary weighted sum method (WSM) for the final decision defining. In the result the most appropriate county in Estonia for wood-fuel based cogeneration plant installation was defined.