Environmental Science and Pollution Research

, Volume 26, Issue 18, pp 18790–18803 | Cite as

Convergence of clean energy consumption—panel unit root test with sharp and smooth breaks

  • Yifei CaiEmail author
  • Angeliki N. Menegaki
Research Article


This paper first visits the clean energy consumption for 21 OECD countries and 14 Emerging market countries through a panel unit root test with both sharp and smooth breaks covering the period from 1965 to 2016. The time-varying fitted intercepts of the estimation could better fit the path of clean energy consumption for selected countries. The empirical results suggest that not only sharp breaks should be considered, but also smooth breaks. The economic implications are insightful for the convergence of clean energy consumption for 22 of 35 countries. For USA, Canada, Austria, Germany, Greece, Ireland, UK, Australia, New Zealand, South Korea, Hungary, China, Philippines, and Thailand, the clean energy consumption is divergence. Policy encouragement policy would permanently affect not only clean energy consumption path, but also aggregate economic sectors related to consume clean energy.


Clean energy consumption Convergence panel unit root test Sharp breaks Smooth breaks 


Funding information

Yifei Cai acknowledges the work on this paper is supported by the Australian Government Research Training Program (RTP) scholarship and University Postgraduate Award (UPA).


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Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Economics, Business SchoolUniversity of Western AustraliaPerthAustralia
  2. 2.Department of Economics and Management of Tourist UnitsAgricultural University of AthensAmfissaGreece
  3. 3.Hellenic Open UniversityPatrasGreece
  4. 4.Open University of CyprusNicosiaCyprus

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