Energy Efficiency

Topical Working Group
“Buildings, energy efficiency, heating/cooling”

Duration: November 2018 – July 2020

Efficiency improvement of buildings (stock and new) is expected to play a crucial role in the long-term goals. In Germany it is supposed to contribute about 80% of primary energy savings in 2050, in Japan about 50% of total saving from the reference scenario in 2030. Germany has knowledge of energy-efficient building envelopes and integrated construction of passive houses/plus energy houses; Japan has expertise in the field of building services and control technology, e.g. heat pumps and fuel cells. Mutual leaning may possibly accelerate efficiency improvement in each country.

The Topical working group “Buildings, energy efficiency, heating/cooling” presented its results on the Council meeting in March 2019.

Research questions

  1. Analyzing the energy balance of buildings in Germany and Japan
  2. Qualitative analysis of policy-related questions
  3. Potential overall energy savings targets for the building stock in 2030 and 2050


Toshiharu Ikaga
Manfred Rauschen
Stefan Thomas


Best-Practice: Local Heat Network Randegg (English)

Operated by Solarcomplex AG, based in Singen in the south of Germany, the local heat network in the village of Randegg supplies 150 buildings with heat from renewable energy and is a prime example of a sustainable local supply system. The origin, concept and benefits of this project are presented in the video below.

Study Program
“Energy end-use efficiency potentials and policies and the development of energy service markets”


Duration: May 2016 – November 2017

Energy efficiency measures can lead to considerable energy savings, and hence, to energy cost savings. Various studies show that a high saving potential exists. Furthermore, energy end-use efficiency measures can avoid losses in energy conversion from primary energy into useful energy. Making full use of these potentials, however, requires the removal of barriers and correction of market and state failures.

Title ST4

Both countries – Germany additionally in the context of European energy policy – have been able to gain experience in the development and implementation of new energy end-use efficiency policies and in the development of markets for energy efficiency measures by energy service companies (ESCOs). A German example is the newly introduced competition model. This recently started „STEP up“ competition wants to challenge entities and individuals throughout society to come up with ideas for reducing their electricity consumption and submit them in a competition for subsidies. ESCOs as private providers can realize energy saving potentials and e.g. reduce barriers  in view of different risks and benefits associated with energy savings efforts; in the heating as well as in the electricity sector a high existing potential is considered. Standardization of energy efficiency services as well as improvement of transparency (providers and offers, quality labels) are challenges that exist for enhancing the diffusion of energy services.

Main tasks

  1. What is the size of the cost-effective energy end-use efficiency potential in buildings, appliances, industry, transport and what are the main barriers preventing it from becoming reality?
  2. What is the size of the potential for Demand Response in the different sectors? What synergies and trade-offs exist between energy end-use efficiency and Demand Response?
  3. How will ICT, internet of things, and big data change the potentials for energy efficiency and demand response?
  4. Which policy packages that are supporting energy end-use efficiency and demand response exist in the sectors buildings, heating / cooling, industry, transport, and electricity usage (also sector overlapping) in Japan and Germany? Are there good practice experiences (instruments, models) from which the other country could learn?
  5. Energy efficiency induced rebound effects can reduce the success of energy efficiency measures. What is the estimated size of rebound effect in general? How can and how do the countries deal with unintended energy efficiency induced rebound effects and how can they be differentiated from general growth and comfort effects?
  6. With the Setsuden initiative, Japan was able to realize high energy savings after the Fukushima daiichi NPP accident. What are the experiences with this campaign? Would a transfer of these experiences to Germany be possible?

Key findings

ST4 Bsp  ST4-2 Bsp

Energy efficiency potentials per sector in Germany and Japan, based on a comparison of policy scenarios: Potential = difference between Reference 2030 and Aggressive conservation 2030

  1. Both countries are already world-leading in energy productivity, also due to their existing policies.

  2. Both countries have ambitious energy efficiency targets for the future based on still existing large potentials. Both have to strengthen their packages of energy efficiency policies to overcome barriers, including those hindering demand response.

  3. While Germany could learn from Japan on energy efficiency in the transport sector, Japan could learn from Germany on energy-efficient buildings.

Discussion Papers

“Study on health co-benefits to promote energy-efficient housing retrofit in Japan” (PPT)
Author: T. Ikaga (2018)

“The role of energy efficiency for the energy transition – A brief overview”
Authors: P. Hennicke, S. Thomas (2017)