Actual interaction effects between policy measures for energy efficiency—A qualitative matrix method and quantitative simulation results for households

Starting from the conditions for a successful implementation of saving options, a general framework was developed to investigate possible interaction effects in sets of energy policy measures. Interaction regards the influence of one measure on the energy saving effect of another measure. The method delivers a matrix for all combinations of measures, with each cell containing qualitative information on the strength and type of interaction: overlapping, reinforcing, or independent of each other. Results are presented for the set of policy measures on household energy efficiency in the Netherlands for 1990–2003. The second part regards a quantitative analysis of the interaction effects between three major measures: a regulatory energy tax, investment subsidies and regulation of gas use for space heating. Using a detailed bottom-up model, household energy use in the period 1990–2000 was simulated with and without these measures. The results indicate that combinations of two or three policy measures yield 13–30% less effect than the sum of the effects of the separate measures.