Comparing the use of ODEX indicators with Divisia decomposition analysis to measure true energy efficiency achievements: case study Irish industry

Panel: Panel 5. Energy efficiency in industry

Authors:
Caiman Cahill, Sustainable Energy Research Group, Department of Civil & Environmental Engineering, University College Cork, Ireland
Brian Ó Gallachóir, Sustainable Energy Research Group, Department of Civil & Environmental Engineering, University College Cork, Ireland

Abstract

The European Union Directive for Energy Efficiency and Energy Services (ESD) sets out clear energy efficiency targets for all EU member states for the period up to 2016. The directive states that a harmonised model, combining top-down and bottom-up calculations, shall be used to measure energy efficiency improvements achieved by member states. The ESD mentions that the ODEX energy efficiency indicator is an example of an appropriate top-down calculation method.

Using Irish industry as a case study, this paper examines the effectiveness of ODEX in measuring true energy efficiency improvements in the sector. ODEX is compared to an alternative proxy for energy efficiency, namely an index of energy intensity at constant structure calculated using the Divisia approach. Both methods are subjected to a series of tests to determine their accuracy. The extent to which each can capture energy efficiency improvements achieved in the earlier part of a period under examination is investigated.

The Divisia calculation performs better than ODEX when subjected to the tests. Consequently Divisia gives a better view of energy efficiency improvements in Irish industry. The findings challenge the validity of the method of using an ODEX value to calculate energy savings in terms of energy units.