The SEEA-2003 provides a categorization of energy resources based on the geological and economic characteristics of the deposits, into proven, probable and possible. This categorization is based on the McKelvey box. More recently, the United Nations Framework Classification for Fossil Energy and Mineral Resources (UNFC) - a new classification for energy and mineral resources - was endorsed by the United Nations Economic and Social Council (ECOSOC) which recommended its application worldwide. The UNFC, in addition to the geological and economic characteristics of the deposits, introduces a third dimension, which is linked to the project feasibility. Should the SEEA develop a categorization of resources in line with the UNFC?