Energy efficiency quo vadis? – the role of energy efficiency in a 100% renewable future

Panel: 1. Foundations of future energy policy

This is a peer-reviewed paper.

Authors:
Stefan Lechtenböhmer, Wuppertal Institute for Climate Environment and Energy, Germany
Clemens Schneider, Wuppertal Institut, Germany
Sascha Samadi, Wuppertal Institut, Germany

Abstract

Energy efficiency is typically seen as the cornerstone of future sustainable energy system in almost all of the available scenarios, e.g. those of the IEA Energy Technology perspectives. Following the decisions of the Paris climate conference in 2015 as well as similar proposals e.g. from the G7 in Elmau long term strategies aiming at (almost) full decarbonisation of the energy systems move into the focus of long term targets of energy policy. Deep decarbonisation, however, clearly requires a complete switch of the energy supply towards fossil free, i.e. renewable energy sources.

As desirable such futures are, they might have significant consequences for the role of energy efficiency. Although it seems a basic law that renewable sources are limited and expensive and should thus be used as efficient as possible, there are some inherent characteristics, mainly of renewable electricity generation that might cause problems here. Due to fluctuating production of e.g. wind and solar renewable generation needs overcapacities that at certain times will generate "excess" energy that calls for additional use, e.g. in sectors or appliances so far not supplied with electricity, because it would otherwise not be of use. These characteristics, however, may change the logics of the energy system and may seem energy efficiency much less attractive in such systems.

To elaborate on the relevance of this question very far reaching deep decarbonisation scenarios from the deep decarbonisation pathways project as well as one from the German Environmental Agency will be analysed, on which role energy efficiency plays in these, and what the consequences were, if the expansion of renewable supply would become a significant barrier in further improving energy efficiency. As a result the relevance and robustness of energy efficiency as a strategy for deep decarbonisation is analysed and possible consequences for policies towards long term GHG mitigation strategies are drawn.