Australia is faced with the need to augment and replace rapidly depleting indigenous petroleum. Because there are many possible solutions and wide ranging impacts associated with this problem, the use of an evaluative technology assessment framework is proposed. The purpose is to provide a means whereby likely technical, socio-economic, legal and regulatory requirements and consequences of policy options can be canvassed and appraised. Factors influencing the credibility, usefulness and efficacy of such technology assessments are examined, and methodologies appropriate to one application, viz petroleum substitution, are explored. The energy sector is used primarily here, therefore, to exemplify the value of the technology assessment approach to policy making. A systems simulation and optimal resources allocation mode is used to illustrate planning procedures and to highlight such matters as innovation needs, resource requirements and societal changes.