Balkar, Oğuz Emre; Özenoğlu, Yunus Emre; Alkan, Okan

This study examines the determinants of renewable energy efficiency (REE) in a balanced panel of 17 countries (1995–2021), focusing on green technology innovations (GTI), economic growth (EG), and energy taxation (ET). The analysis accounts for heterogeneity, common shocks, and dynamic adjustment by combining two-way fixed effects with dependence-robust and dynamic common correlated effects (CCE) estimators using Driscoll–Kraay inference. The results show strong persistence in REE and a robust positive association between GTI and REE in the preferred common-factor framework, while the average effects of EG and ET are weaker and model-sensitive. Dumitrescu–Hurlin panel causality tests indicate feedback between REE and EG and bidirectional linkages between REE and ET at the level, whereas innovation dynamics are asymmetric. Overall, the evidences support innovation-centered transition strategies and emphasizes evaluating policy instruments over multi-year horizons given strong persistence and cross-country heterogeneity.

Akın, Fatih

This study examines the impact of renewable energy consumption, economic growth, and death rates on healthcare expenditures in G-7 countries over the 1992-2023 period using panel data analysis. Preliminary analyses indicate cross-sectional dependence and heterogeneity across countries. The Fourier LM unit root test reveals that the variables are non-stationary, while the LM Bootstrap cointegration test supports a long-run relationship. Panel-wide AMG estimation results indicate that renewable energy consumption reduces healthcare expenditures, while economic growth and death rates increase healthcare expenditures. Country-based results indicate that renewable energy consumption reduces healthcare expenditures in Germany, Japan, and the United Kingdom. While economic growth increases healthcare expenditures in France, Germany, Italy, and the United Kingdom, death rates increase healthcare expenditures in France, Germany, and the United States, and decrease them in Japan. Furthermore, according to the Dumitrescu & Hurlin causality test, there is a unidirectional causality relationship running from renewable energy consumption and economic growth to healthcare expenditures. The findings show that energy and health policies should be integrated and that renewable energy investments can have positive effects on health systems.

Kilic, Ugur

In this study, a comparison in terms of environmental impact is carried out between regional jet and narrow-body passenger aircraft with different Maximum Take-Off Weights (MTOW) and seating capacities considering the fuel burn and emissions. The flight trajectory is selected from Erzincan Yıldırım Akbulut Airport to Ankara Esenboğa Airport and that trajectory is a frequently performed domestic flight between Erzincan and Ankara. Integrated Aircraft Noise and Emissions Modelling Platform (IMPACT) developed by EUROCONTROL is used for the calculation of fuel burn, CO2, H2O, and other gas emissions (NOx, SOx, CO, HC, soot, and other trace compounds) for the per phase of flight. These emissions have an impact on human health, air quality, and the ecosystem, and cause air pollution, climate change, and global warming worldwide. Commercial air-transport-based simulations are created for regional jet and narrow-body passenger aircraft. According to the results, flying with regional jets which have lower MTOW from/to airports such as Erzincan Yıldırım Akbulut Airport, where the passenger density per aircraft is low, provides advantages in terms of fuel burn and emissions. It is expected that this study will serve as a guide for airline operators for fleet selection based on fuel burn and emission parameters.

Çam, Ömer; Kilic, Ugur

The short-haul flights have higher emission values than medium or long-haul flights when emissions per distance are considered. In this study, the potential to reduce greenhouse gas emissions by replacing short-haul flights which carried out by a narrow-body commercial aircraft from/to Konya City in Turkey with regional jets or high-speed trains (HSRs) has been investigated. The flight trajectory is selected from Konya Airport to İstanbul Sabiha Gökçen Airport, and that trajectory is a frequently performed domestic flight between Konya and İstanbul. The IMPACT platform is used for the calculation of fuel burn and gas emissions. According to the results, traveling with regional jets or high-speed trains from/to Konya City which is the most 15th polluted city in Europe, provides advantages in terms of environmental impact. Traveling with HSR which is the best traveling option in this study, provides approximately 3.3 times more green travel than the currently used narrow-body passenger aircraft between Konya and İstanbul. In addition, this mode of transportation can become more environmentally friendly by using renewable energy sources to produce its electricity needs. It is expected that this study will serve as a guide for airline and high-speed rail operators and regulators to determine the most environmentally efficient travel options based on fuel burn and emission parameters.

Atasoy, Vehbi Emrah

In this study, Gaussian Process Regression (GPR) is utilised to accurately estimate fuel consumption. For this purpose, ten randomly determined flights performed by Boeing B737-800 twin-engine medium-haul narrow-bodied commercial aircraft are selected. In this context, actual flight data obtained from the Flight Data Recorder (FDR) is used to estimate fuel consumption during the climb-out phase. Different statistical tests, namely Root Mean Square Error (RMSE), coefficient of determination (R2), and Mean Absolute Error (MAE), are applied to evaluate the performance of the GPR in this paper. RMSE, R2, and MAE values for GPR is calculated to be 209.41, 0.99, and 111.38, respectively. As can be seen from the results of all statistical tests, the GPR model indicates successful performance.