Revealing the nexus among energy-economy system with Haken model: Evidence from China's Beijing-Tianjin-Hebei region

Economic growth (EG) and energy consumption (EC) are interacting processes critical to regional sustainability. The evolution mechanism and the nexus between them in the development process of Jing-Jin-Ji Region, which is one of the most important agglomerations in China, remain unrevealed systematically. First, the trends in decoupling state between EG and EC during 2001-2016 are checked with the Impact-Gross domestic product-Technology (IGT) model. Then, EG and EC are defined as two subsystems to form a whole system, with EG as the fast variable and EC as the slow one. The evolutional interactions among the two subsystems and the whole system are elaborated through the Haken model based on the synergetic theory. By identifying changes in the decoupling index (D-r) and the control variables (a, b, lambda(1) and lambda(2)) simulated by the Haken model, it can be demonstrated that the development of Beijing reached a relatively good state, with synergetic coordination of EG and EC. The effect of EG on EC and EC on EG reversed in Tianjin (from positive to negative) and Hebei (from negative to positive), respectively. EC kept prompting EG in Tianjin and EG kept inhibiting EC in Hebei. Both regions have not achieved a complete synergy of EG and EC, calling for further ameliorations in economic development and energy consumption patterns in a transitional period. This study is a first attempt to apply Haken model in the field of energy and economy from the perspective of synergetics. The exploration of the evolutional nexus between EG and EC in the Jing-Jin-Ji Region is expected to provide important references for policy formulation both locally and for other regions. (C) 2019 Elsevier Ltd. All rights reserved.