Existing electronic devices will quickly become e-waste when encountering technological iterations, which results in serious environmental and public health problems. Previous circular economy research has mainly focused on the development of new products with long life or recycling discarded products. This study firstly proposes the Green-Extension Design (GED) strategy for developing adaptable accessories that provide existing products with the ability to continue to work in a different context. Competitiveness was selected to evaluate the performance of GED, and three competitiveness components were derived through principal component analysis (PCA). Moreover, AHP (Analytic Hierarchy Process) was applied to define the weights of the three competitiveness components, and a GED model was established on the basis of production function. Furthermore, the calculation method for each competitiveness component was defined. The GED strategy is aimed at extending the life of existing products, as well as reducing resource waste and environmental pollution. The GED model based on competitiveness components can enable enterprises to design products of high competitiveness and obtain market share as a result.

To achieve energy and environmental policy goals, profound social changes have taken place in the Chinese society. Existing relevant research on energy assessment tends to focus on their respective fields, and policy-level support often requires an assessment of predictable effects based on the overall perspective. In response to this problem, this paper carries out an interdisciplinary study. We chose green design as a new perspective to assess this process. Green design has made important contributions to the sustainable development in the fields of building, construction, and urban planning, which deeply affect the energy consumption in the world. By combing through the development concepts and models of green design in various fields, a comprehensive index—green design index (hereafter referred as to GDI)—is first introduced. Further, a multi-level big data structure of GDI has been built and the development of green design in regions of China based on long-term series is quantitatively assessed. The results of this study show that green design in regions of China has been greatly improved during the inspection period, but there are huge regional differences. The required policies and implementation routes also need to be adapted to local conditions. This paper first introduces a credible quantitative analysis framework of green design, and a corresponding research foundation for energy transition research based on green design.