Long-Term Cointegration Relationship between China’s Wind Power Development and Carbon Emissions

Towards Carbon Neutrality: The Impact of Renewable Energy Development on Carbon Emission Efficiency

The energy transition and carbon emission efficiency are important thrust and target functions, respectively, for achieving carbon neutrality in the future. Using a sample of 30 Chinese provinces from 2006 to 2018, we measured their carbon efficiency using the game cross-efficiency data envelopment analysis (DEA). Then, a random forest regression model was used to explore the impact of renewable energy development on regional carbon emission efficiency. The results are as follows. First, China’s carbon emission efficiency in the southeast coastal area was better than that in the northwest area. Second, renewable energy development first inhibited and then promoted carbon emission efficiency, and there existed a reasonable range. Third, through a regional heterogeneity analysis, the trend of the influence of renewable energy development on carbon emission efficiency was found to not be significantly different in eastern, central, and western China, but there was a certain gap in the reasonable range. Our study not only helps to promote the study of renewable energy development and the carbon neutral target, but also provides an important reference for Chinese policy-makers to design a reasonable carbon emissions reduction path.

Changes in Energy Supplies in the Countries of the Visegrad Group

The main purpose of the work is to identify and present the current situation and changes in the volume of energy supplies in the countries of the Visegrad Group. The specific objectives of the article are to determine the degree of concentration of energy supply sources in the countries of the Visegrad Group, the directions of their changes, types of energy used and changes in this area, establishing the correlation between the volume of energy supplies and changes in the economic situation in V4 countries. The period of research covers the years 1990–2018. The sources of materials were the literature on the subject, with the data from Eurostat. The following methods were used for the analysis and presentation of materials: descriptive, tabular, graphical, dynamics indicators with a constant basis; Gini concentration coefficient; concentration analysis using the Lorenz curve; coefficient of variation; Pearson’s linear correlation coefficient. It was found that, of a high concentration of energy supplies from one or more sources in all countries of the Visegrad Group, the largest was in Poland and the lowest were in Hungary and the Czech Republic. In each of these countries, the economy was transforming and there was also a gradual diversification of energy sources.

A Comprehensive Review and Technical Guideline for Optimal Design and Operations of Fuel Cell-Based Cogeneration Systems

The need for energy is increasing from year to year and has to be fulfilled by developing innovations in energy generation systems. Cogeneration is one of the matured technologies in energy generation, which has been implemented since the last decade. Cogeneration is defined as energy generation unit that simultaneously produced electricity and heat from a single primary fuel source. Currently, the implementation of this system has been spread over the world for stationary and mobile power generation in residential, industrial and transportation uses. On the other hand, fuel cells as an emerging energy conversion device are potential prime movers for this cogeneration system due to its high heat production and flexibility in its fuel usage. Even though the fuel cell-based cogeneration system has been popularly implemented in research and commercialization sectors, the review regarding this technology is still limited. Focusing on the optimal design of the fuel cell-based cogeneration system, this study attempts to provide a comprehensive review, guideline and future prospects of this technology. With an up-to-date literature list, this review study becomes an important source for researchers who are interested in developing this system for future implementation.