The digital economy development promotes green transformation in China’s economy. Based on provincial-level data from 2011–2019, an ArcGIS spatial analysis is used to explore the spatial and temporal evolution patterns of the digital economy development and green economic efficiency. The digital economy development’s impact on the green economic efficiency is tested through fixed effect, mediation effect, and spatial Durbin models. The digital economy development and green economic efficiency increased during the study period. Spatial patterns of high-level areas spread to form “clusters” with surrounding areas. The digital economy development’s catalytic effect on the green economic efficiency holds after robustness and endogeneity tests. A heterogeneity analysis shows that the digital economy development promotes the green economic efficiency in the eastern and central regions; the impact on the western region is non-significant. Compared with industry digitalization, digital industrialization has a stronger promoting effect on the green economic efficiency. The digital economy development better facilitates the green economic efficiency in regions with high digital economy development levels and Big Data experimental areas. The digital economy development promotes green economic efficiency through human capital, industrial structure upgrading, and technological innovation; industrial structure upgrading has a stronger mediating effect, reaching 40%. The digital economy development facilitates the regional green economic efficiency and significantly promotes green economic efficiency in neighboring regions through spatial spillover effects.

With the increasing severity of environmental threats, the role of governance in environmental protection is particularly important. This paper examines the policy effects of environmental regulation and its implementation and regulatory heterogeneity on green innovation from the perspective of a policy combination formed by demand–pull environmental taxes and supply–push R&D tax incentives, aiming to investigate the targeted effects of green innovation induced by regulatory policies in the tax environments of developing countries. Based on the data on China’s listed manufacturing enterprises from 2013 to 2021, this article uses the DID model to perform a fixed-effect test. The findings show that both environmental taxes and R&D tax incentives can promote the green innovation of enterprises, and their combination has a mutually reinforcing joint effect. Furthermore, an environmental tax can inhibit the strategic innovation problems of R&D tax incentives and improve the quality of green innovation. This paper also reveals that the tax enforcement environment positively affects the induction of green innovation from the perspective of policy implementation and supervision. Finally, the heterogeneity test examines the differences in the effects of policy implementation from the aspects of political association and whether manufacturing firm is a high-tech enterprise. The results of this paper provide a reference for improving the effectiveness of environmental regulatory policy portfolios from the aspects of pre-design optimization and post-implementation and supervision, enriching the evidence for the narrow Porter hypothesis in developing countries.

Renewable energy technology innovation (RETI) is a crucial way to improve energy poverty and combat climate change. However, few studies have examined the impact of RETI on industrial green transformation and upgrading (IGTU) from the perspective of spatial spillover and its regional boundary. Based on the theory of green growth and sustainable development, this paper expands the connotation boundary of IGTU and measures the IGTU levels of 30 provinces in China from 2006 to 2020 using an improved entropy weight method. Kernel density estimation and Moran’s I index are adopted to portray temporal and spatial patterns, the spatial Durbin model is employed to examine the influencing mechanism and spatial spillover effects of RETI on IGTU and its regional boundaries, and the differential impact of its spatial effects on time, region, resource endowment, and environmental regulation are explored further. The results show that (1) RETI and IGTU in China are steadily increasing, indicating a decreasing spatial differentiation pattern of “east–west”; (2) RETI significantly promotes local IGTU but inhibits neighboring IGTU, forming a “beggar-thy-neighbor” situation; (3) the spatial spillover effect of RETI on IGTU has significant regional boundaries—the spatial spillover effect significantly negative and persists up to 800 km, but it is significantly positive from 800 to 1400 km and shows a trend of increasing and then decreasing; and (4) the promoting effect of RETI on IGTU gradually increases over time, presenting spatial differences of promotion in the east and inhibition in the west. Furthermore, RETI has a more substantial promoting effect on IGTU in non-resource-based regions and strong environmental regulation regions. The findings for China provide concrete evidence for formulating targeted policies and seeking a path for IGTU for other developing countries.