Revisiting the 2000 Watt Society : An Innovative Tool for Sustainable City Planning

Calendar 3 May 2019
Time 4.00 pm – 5.30 pm. Registration from 3.30pm, seated by 4.00pm 
Location  MND Auditorium, MND Annex A, 5 Maxwell Road Singapore 069110
cpd 1 SILA CPD pts, 2 BOA-SIA CPD pts, 2 SIP CPD pts, 1 PEB PDU pts


Lecture Poster (263 KB)
Lecture Slides by Prof Zehnder (2.39MB)

Lecture Photos



The concept of the 2000 Watt Society has been developed in Switzerland at the ETH domain to inspire more innovations in sustainability and as a yard stick for planning energy and material efficient cities. The concept has been introduced as a planning tool to many central European cities. New districts in various cities have shown the political acceptance and economic viability of the consequences of the concept. In Singapore, the buildings and workplaces at the EcoCampus of NTU are approaching the terms of reference of the 2000 Watt Society for working places. Professor Zehnder delivered a CLC lecture on the 2000 Watt Society in 2011. In this coming lecture, he will review the progress of this idea since then.

Lecture Report

“We always have to think about what can we do, such that actually people want to do it and we don’t have to force them. But it is easier said than done.”


- Prof Alexander Zehnder


In his CLC Lecture on 3 May 2019, Prof Alexander Zehnder, one of the founding fathers of the 2000-watt Society, shared his experiences about creating the planning tool and promoting its use in different countries.


Prof Zehnder began by sharing that this planning tool was created with the consideration that it will be simple to use and easy to understand. In comparison with other forms of measurement such as CO2 emissions and GDP per capita, energy use (measured in kWh) can succinctly represent the cost of all human activities. Alluding to the ease of understanding energy use, he commented that “most people know something about energy because, you have to pay your electricity bill”.


Prof Zehnder pointed out that the 2000-watt Society is not about going back in time, or not doing things we are accustomed to. “Basically, it is allowing us to live our life in a way which is similar, or even better than it is now, by using less resources and energy.”


A 2000-watt Society will not result in significant depreciations in standards of living, he said, referencing a chart comparing GDP with energy use. He pointed out that countries with the highest GDP per capita, such as Switzerland and Singapore, are using lesser energy than expected.


To achieve a 2000-watt Society, Prof Zehnder recommended reducing the use of fossil fuels and embodied energy, while simultaneously improving the efficiency when using non-fossil energy sources. Reducing the reliance on fossil energy and by decreasing the use of embodied energy, humans will become “more efficient in construction with less material, or recycled material”.


He also spoke of “low-hanging fruits” in energy efficiency for governments to target, highlighting that interventions targeting living and working habits as well as infrastructure were well-researched and easy to implement. He provided an example in Forum Chriesbach, a building in Zurich creating a low energy footprint of 500 watts per person, achieved primarily through the recycling of water and a passive heating and cooling system.


“Before people change, they want to see whether it’s possible”, said Prof Zehnder, and he believes the aversion towards the adoption of the 2000-watt Society is best addressed through the creation of “showcases”, such as the Forum Chriesbach building. In his view, information around reducing energy use should be clearly communicated, indicating that people “will move in the right direction” once they realise the importance of sustainability.


In the post-lecture dialogue, Prof Zehnder was asked to clarify how he had arrived at 2000 watts as a realistic target. He said he initially started out with a target of 1000 watts per person in the 1990s, but quickly realised that it was set “too low”. On the other hand, 2000 watts was deemed achievable “with a few innovations”, and sufficient to handle many issues associated with CO2 emissions.


When asked to recommend policies to promote energy efficiency, Prof Zehnder spoke about his dislike for regulations, saying, “I don’t like to be punished and I don’t think anybody likes that”. Instead, he proposed incentives—as opposed to regulations—as a better policy alternative to empower people to adopt energy-efficient behaviours.


Prof Zehnder also emphasised the need for professionals from different disciplines to cooperate in ensuring energy efficiency. He cited building design as one of the platforms for collaboration, saying that “an architect alone does not have all the ideas in the world”. Going back to the example of the Forum Chriesbach, he went on to elaborate that the involvement of engineers within the design process was a key factor in helping it become the world’s most energy-efficient building.


Prof Zehnder’s optimistic outlook on the adoption of the 2000-watt Society was evident pervaded the lecture. Referring to the extensive support received for the 2000-watt Society vision in Zurich, he said that it took a long time coming and that they “needed almost 20 years to get there”.


He said he was heartened by the change in mindsets in Singapore from 2011, when he last gave a speech on the 2000-watt Society. “If you now go to agencies in the government, and talk to ministers and other people working in the different agencies, you see that there is clarity on this idea and this vision: that we want to have smaller footprint, even as we develop,” Prof Zehnder concluded.


This report first appeared in the Jul 2019 Better Cities newsletter.

About the Speakers


Alexander Zehnder

Visiting Professor, Nanyang Technological University
Founder and Director, Triple Z Ltd


Alexander J.B. Zehnder is a Visiting Professor and member of the Board of Trustees of Nanyang Technological University (NTU), Singapore, founder and director of triple Z Ltd., former president of the ETH Board and Professor emeritus of ETH Zurich, Switzerland. He heads NTU’s Sustainable Earth Office which coordinates NTU’s sustainability activities. He has been involved in developing capital market instruments for more sustainable production and use of natural resources. The Dow Jones Sustainability Index is based on some of his contributions. He is one of the “founding fathers” of the concept of the “2000 Watt” Society. He helped to build up the Swiss innovation environment and has reorganized NTU’s innovation system.


Tan Szue Hann

Managing DIrector, Miniwiz SG
Adjunct Professor, SUTD Architecture & Sustainable Design


Tan Szue Hann is Singapore’s 2015 Young Green Architect of the Year, and is the Managing Director for Miniwiz Co. Ltd. He is a Registered Architect with the Board of Architects, Singapore, and a Council Member of the Singapore Institute of Architects. Szue Hann will also serve as Chairman of the Architects’ Regional Council of Asia (ARCAsia) Youth Committee from 2016. Szue Hann graduated with a Master of Architecture and a BA Arch (First Class Honours) from the National University of Singapore, completing his Masters at UCLA. On graduation, he was awarded the Lee Kuan Yew Gold Medal, Board of Architects Medal and ICI Gold Medal.