Residential energy efficiency in times – analysis of modelling approaches and impacts on energy policy

The TIMES energy system model has been used for informing energy and climate change policies in several countries and regions around the world. The type and scope of the studies varies, but many works consider (at least briefly) energy efficiency in their findings. However, very few include explicit energy efficiency scenarios and/or direct analysis of energy efficiency improvements. The studies that consider explicitly energy efficiency scenarios (in some cases in combination with other type of scenarios such as emission reduction targets) show significant differences on the modelling approach taken, potentially affecting the results and the impact policy decisions. Moreover, a direct comparison between energy efficiency modelling approaches in TIMES has not been developed yet.
The work developed in this paper aims to provide insight on this issue, analysing the implications of different energy efficiency modelling approaches in TIMES, and discussing best practices on informing energy efficiency policy. Three types of residential energy efficiency scenarios are analysed using the UK TIMES model, all of them with the objective of reducing 10% of energy consumption on residential heating. Results show that these energy efficiency scenarios, which are in theory equivalent, produced different results, suggesting that the modelling approach taken can significantly impact the outcomes of the model. Also, not all energy efficiency scenarios performed as expected. In one of the scenarios, other user constraints (which are common to all the analysed scenarios) limited the amount of conservation technologies available, so the expected energy savings were lower than in other cases. Therefore, the outcomes obtained show the importance of not solely relying on a particular scenario or model for policy analysis, as this might lead to partial views or suboptimal solutions.