Skip to main content

Why a Delphi study?

If decision-makers are to shape the future, they need objectives and an idea as to the direction of future trends. As a strategic foresight method, Delphi studies enable us to envisage and analyse alternative development options within complex contexts. The Delphi method is used to take a systematic look 20 to 40 years into the future by bringing together and evaluating a large number of expert assessments and opinions from around the world.

Energy systems are currently undergoing a massive upheaval at global level. Transformation processes affecting society as a whole are on the horizon or are already underway. Sector-specific views and trend updates are not adequate in scope to genuinely examine the future of energy systems and their fast changes. In particular the interaction and interdependencies between the political framework, innovative forces in the private sector, geopolitical transformations and changing consumption patterns predestine the Delphi method for its use in this context.  

The Delphi Energy Future study aims to identify central drivers, actors and dynamics that will have a significant influence on the future of energy systems. Possible future scenarios are to be developed and a cross-sectoral communication process launched, with experts around the world discussing development options and long-term strategies for action.

What exactly is a Delphi study?

A Delphi study is a multi-step, interactive expert survey with built-in provision for feedback. In two or more 'rounds', a fixed panel of professionals and decision-makers provides a written assessment of a list of theses relating to potential future developments. For every thesis, the probability that the trend will actually happen is to be explored, along with the relevant timescale, and the person’s own expert-status. After every round, the results of the previous round are given as feedback. In the subsequent round, experts are asked to reassess the hypotheses and either confirm or revise their own opinion, where it diverges from the majority opinion (giving reasons). The experts thus assess the same theses under the influence of the opinions of their fellow professionals. The results of the assessments are linked to produce various alternative scenarios. Because of their distinctive questionnaire structure, Delphi studies deliver answers with greater differentiation and less ambiguity than conventional interview research techniques.

Delphi Energy Future

The Delphi Energy Future study can be broken down into the following steps:

Interviews with experts and production of theses:
The first step involves about 80 hand-picked national and international experts in their fields. Structured interviews will be conducted focusing on the key factors that will influence future energy systems. The experts, most of whom come from the energy sector, although some are specialists in related fields, represent the public and the private sectors, the academic and research community, and civil society. They have proven credentials as interdisciplinary thinkers. They come from Germany, Europe, non-European industrialised countries, emerging economies and developing countries. Through one-to-one interviews and group discussions, visionary and bold theses will be produced that provide food for thought.

First survey round:
The resulting list of theses will be submitted to an international panel of 500 or so experts from Germany, Europe, other industrialised countries, emerging economies and developing countries for their considered opinions and comments. International organisations like the United Nations, the International Renewable Energy Agency (IRENA) and the Organization of the Petroleum Exporting Countries (OPEC) will also be represented. Although the focus will be on the energy sector, the panel will include professionals from other sectors. The experts will assess the probability of each thesis becoming reality, the timescale involved, and their own expert-status concerning each thematic field.

Second survey round:
The panel of experts will then have another look at the list of theses. They will receive feedback on how the individual theses were seen by the expert panel as a whole during the previous round, as well as the written comments submitted. This will enable them to reflect again on their own assessment. Where their opinion diverged from the majority view, they can either confirm (giving reasons) or revise it. The results will become more precise and focused.

Scenario development:
The results of the theses assessment will be evaluated, linked and combined to produce alternative scenarios and development paths. The various potential scenarios for the future of energy systems will be based on different premises and will illustrate the possible interplay of crucial factors. The scenarios should not be taken as forecasts or normative directions for action. They are intended to raise awareness about the challenges involved, encourage us to reflect on and consider future opportunities, and lay the foundations for the development of positive models for the future.

The results of the Delphi Energy Future study are to be presented in winter 2015.

July – September 2014
Selection of topics, evaluation of benchmark studies, selection of experts

October – December 2014
Interviews with national/international experts from private sector, politics, academic and research community and civil society to identify innovative theses

December 2014 – February 2015
Experts’ workshops to produce theses

from April 2015
Repeated assessment of theses by panel of national/international experts (first and second survey rounds)

October 2015
Evaluation and discussion of results with experts

November 2015 – May 2016
Scenario development and compilation, publication

Thematic spheres

The partners have identified five essential thematic spheres that are to be used to help explore in depth how energy systems will change in Germany, Europe and around the world by 2040 and beyond, as well as to help pinpoint interdependencies between the individual areas affected. The interviews with experts will be conducted on these individual areas, and theses will be established. Although the selected experts have proven credentials as specialists in their own areas, they have also proved their ability to think outside the box. The thematic spheres are:

  • Economics and policies: Comprising future market and business models, public funding and regulation, remunicipalisation and regionalisation of economic cycles, etc.
  • International geopolitics: Comprising long-term impacts of regional crises, changing global raw materials flows with concomitant dependencies, uncertainties and alliances, etc.
  • Technology and infrastructure: Comprising innovation and revolution in electricity generation and storage technologies, the importance of merging the energy and communications sectors and the future mobility of goods and people, etc.
  • Climate change and environment: Comprising the future of emissions trading systems, the importance of climate change as a driver in energy policy and the impacts of the connection between the water and energy sectors, etc.
  • Societies and culture: Comprising future settlement patterns, the impacts of different demographic developments and new consumption patterns geared to sustainability and sufficiency, etc.


We have interviewed 80 experts from politics, private sector and civil society – from industrial countries, emerging economies as well as development countries – and have discussed their expectations and visions concerning the future of our energy systems.

Alberto Acosta, Facultad Latinoamericana de Ciencias Sociales (FLACSO) Ecuador
Dr. Philipp Andrews-Speed, National University of Singapore, Energy Studies Institute
Dr. Jorge Asturias, Latin American Energy Organisation (OLADE)
Dr. Hubertus Bardt, Institut der deutschen Wirtschaft (IW)
Dr. Morgan Bazilian, The World Bank Group
Prof. Dr. Marc Oliver Bettzüge, Energiewirtschaftliches Institut an der Universität zu Köln (EWI)
Dr. David Bresch, Swiss Re
Thomas Breuer, Greenpeace Germany
Dr. Michael Brower, American Council On Renewable Energy (ACORE)
Pablo Carvajal, Ministerio Coordinador de Sectores Estrategicos, Ecuador
Prof. Dr. Paul Collier, University of Oxford, Centre for the Study of African Economies
Stein Dale, E.ON SE
Tomáš David, EP ENERGY, a.s., Czech Republic
Lisa Davis, Siemens AG
Evelyn Dietsche, Dietsche Policy Analysis Limited, UK
Dr. Frank-Detlef Drake, RWE AG
Risa Edelmann, American Council On Renewable Energy (ACORE)
Dr. Christoph Frei, World Energy Council
Dr. Lewis Fulton, University of California, Institute of Transportation Studies
Thomas Fureder, Barclays Capital
Sascha Gabizon, Women in Europe for a Common Future (WECF)
Fabio Garcia, Latin American Energy Organisation (OLADE)
Roland Grebe, SMA AG
Klaus Grewe, Jacobs Engineering
Dr. Alieto Aldo Guadagni, Instituto Di Tella, Argentina
Prof. Dr. Peter Guthrie, University of Cambrigde, Department of Engineering Centre for Sustainable Development
Manfred Haberzettel, EnBW AG
Lex Hartman, Tennet Holding B.V.
Prof. Dr. Peter Hennicke, Wuppertal Institut für Klima, Umwelt, Energie GmbH
Dr. Jörg Hermsmeier, EWE AG
Cornie Huizenga, Partnership on Sustainable Low Carbon Transport (SloCaT)
Dr. Elham Mahmoud Ahmed Ibrahim, African Union Commission
Nikolaus Knebel, German University of Technology, Faculty of Architecture and Urban Planning (GUtech)
Dr. Bernd Kordes, Lahmeyer International GmbH
Dr. Gregor Kumm, ABB
Rachel Kyte, World Bank Group
Alex Laskey, OPower Inc.
Prof. Dr. Uwe Leprich, Institut für Zukunftsenergiesysteme GmbH
Christine Lins, Renewable Energy Policy Network for the 21st Century (REN 21)
Dr. Thorsten Marquardt, E.ON SE
Dr. Ajay Mathur, Government of India, Ministry of Power
Dr. Ritu Mathur, The Energy and Resources Institute (TERI) India
Dr. Felix Christian Matthes, Öko-Institut e.V.
Dr. Urs Meister, Avenir Suisse
Julio Menendez, Cámara Argentina de Energías Renovables (CADER)
Prof. Dr. Christoph Menke, Hochschule Trier
Prof. Dr. Dirk Messner, Deutsches Institut für Entwicklungspolitik (DIE)
Prof. Dr. Eckard Minx, Daimler und Benz Stiftung
Dr. Tatiana Mitrova, Russian Academy of Sciences, Energy Research Institute
Prof. Dr. Wolfram Münch, EnBW AG
Prof. Dr. Nebojsa Nakicenovic, International Institute for Applied Systems Analysis (IIASA)
Reema Nanavati, Self Employed Women's Association (SEWA) India
Eduardo Noboa, Instituto Nacional de Eficiencia Energética y Energías Renovables (INER)
Sheila Oparaocha, ENERGIA – The International Network on Gender & Energy
Dr. Kirit Parikh, Integrated Research and Action for Development, India
Alex Perera, World Resources Institute (WRI)
Prof. Dr. Dr. Franz Josef Radermacher, Forschungsinstitut für anwendungsorientierte Wissensverarbeitung (FAW)
Jairam Ramesh, Member of Parliament, India
Dr. Marina Yesica Recalde, Fundacion Bariloche, Argentina
Lennys Rivera, Latin American Energy Organisation (OLADE)
Alex Rugamba, African Development Bank Group, Energy, Environment and Climate Change Department
Yanina Rullo, Senado de la Nación Argentina
Jamal Saghir, The World Bank Group
Dr. Roberto Schaeffer, Federal University of Rio de Janeiro
Hans-Lothar Schäfer, Techem GmbH
Dr. Michael Schlesinger, Prognos AG
Michael Schmidt, BP Europe SE
Max Schwitalla, Studio Schwitalla
Dr. Fereidoon P. Sioshansi, Menlo Energy Economics
Prof. Albert Speer, AS&P – Albert Speer & Partner GmbH
Dr. Erico Spinadel, Asociación Argentina de Energía Eólica
Prof. Dr. Klaus Töpfer, Institute for Advanced Sustainability Studies e.V.
Clemens Triebel, Younicos AG
Prof. Arturo Villavicencio, Universidad Andina Simón Bolívar, Ecuador
Prof. Dr. Ernst Ulrich von Weizsäcker, The Club of Rome
Prof. Dr. Eicke Weber, Fraunhofer-Institut für Solare Energiesysteme (ISE)
Prof. Dr. Michael Weinhold, Siemens AG
Dr. Kirsten Westphal, Stiftung Wissenschaft und Politik (SWP)
Dr. Marie-Luise Wolff-Hertwig, HSE AG
Jörg Wuttke, BASF (China) Co. Ltd. Beijing
Dr. Hu Zhaoguang, State Grid Energy Research Institut, China
Prof. Wang Zhongying, China National Energy Research Institute, National Development and Reform Commission

More Information about the Delphi Method

  • Häder, Michael (2014): Delphi-Befragungen, 3. Auflage. Springer Verlag, Wiesbaden.
  • Cuhls, Kerstin (2009): Delphi-Befragungen in der Zukunftsforschung. In: Popp, R.; Schüll, E. (Ed.): Zukunftsforschung und Zukunftsgestaltung. Beiträge aus Wissenschaft und Praxis, Springer, Berlin, Heidelberg.
  • Cuhls, Kerstin (2004): Delphi surveys. In: Foresight Methodologies, Seminar Workbook UNIDO, Vienna.

Project partners

The Delphi Energy Future study will be conducted by three partners: the German Association of Energy and Water Industries (BDEW), the Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) GmbH and PricewaterhouseCoopers AG (PwC). All project phases, questionnaire and research results, scenarios and forecasts will be published on this website.

German Association of Energy and Water Industries (BDEW)

The German Association of Energy and Water Industries (BDEW), Berlin, represents over 1,800 companies. The range of members stretches from local and communal through regional and up to national and international businesses. It represents around 90 per cent of the electricity production, over 60 per cent of local and district heating supply, 90 per cent of natural gas as well as 80 per cent of drinking water extraction as well as around a third of wastewater disposal in Germany.

Official Website

Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) GmbH

GIZ is a German federal enterprise offering its clients workable, sustainable and effective solutions in political, economic and social change processes. GIZ works primarily on behalf of the German Federal Ministry for Economic Cooperation and Development (BMZ), but also for other federal ministries and public and private sector clients inside and outside Germany. These include governments of other countries, the European Union and the United Nations. GIZ operates in more than 130 countries worldwide. The energy sector, especially the promotion of renewable energies, energy efficiency and energy policy strategy processes, is a key area of GIZ's work.

Official Website

PriceWaterhouseCoopers (PwC)

PwC helps organisations and individuals create the value they’re looking for. We’re a network of firms in 157 countries with more than 184,000 people who are committed to delivering quality in assurance, tax and advisory services. Tell us what matters to you and find out more by visiting us at

PwC refers to the PwC network and/or one or more of its member firms, each of which is a separate legal entity. Please see for further details.

Official Website