Yazar "Ozkan, Oktay" seçeneğine göre listele
Listeleniyor 1 - 6 / 6
Sayfa Başına Sonuç
Sıralama seçenekleri
Öğe Analysing the nexus between clean energy expansion, natural resource extraction, and load capacity factor in China: a step towards achieving COP27 targets(Springer Science and Business Media B.V., 2024) Usman, Ojonugwa; Ozkan, Oktay; Adeshola, Ibrahim; Eweade, Babatunde SundayThe excessive use of non-renewable energy in 21st-century economic growth has continued to hurt the environment by accumulating carbon dioxide and other greenhouse gases. However, promoting environmental sustainability requires expanding clean energy utilisation. In this study, we examine the effects of clean energy expansion and natural resource extraction on load capacity factor (LCF) in China from 1970 to 2018. Using the dynamic autoregressive distributed lag simulations approach, we extend the standard load capacity curve (LCC) hypothesis by incorporating clean energy expansion and natural resource extraction as main determinants of the LCF. The empirical outcomes reveal that economic expansion is, although positively associated with the LCF, but its squared term degrades the LCF. This confirms that the LCC hypothesis is not valid for China. Moreover, while clean energy expansion has a positive effect on the LCF, the effect of natural resource extraction is negative. These effects are stronger and statistically significant only in the long run. Therefore, this study highlights the potentials for a sustainable decarbonized economy in China by investing not only in clean energy sources but also efficiently use the available natural resources in the country.Öğe Carbon efficiency in China: Should we be concerned about the shadow economy and urbanization?(John Wiley and Sons Ltd, 2023) Pata, Ugur Korkut; Olasehinde-Williams, Godwin; Ozkan, OktayReducing carbon emissions is critical to achieving a carbon-neutral world according to the Glasgow Climate Pact, but production, and thus carbon emissions, must continue to meet the needs of the world's growing population. Minimizing carbon emis sions per production, that is, increasing carbon efficiency is one way to support the Sustainable Development Goals. Therefore, studying the determinants of carbon efficiency for China, the largest global polluter, is important for zero carbon goals. To this end, this study examines the effects of the shadow economy, globalization, trade openness and urbanization on carbon efficiency using novel dynamic autoregressive distributed lag simulations for China during 1990–2018. The empirical results illustrate that (i) the environmental Kuznets curve (EKC) hypothesis is not valid; (ii) Shadow economy, trade openness and urbanization reduce carbon efficiency and (iii) Globalization enhances carbon efficiency. Based on these results, it is suggested that the Chinese government should combat the shadow economy to increase carbon efficiency, regulate unplanned and polluting urbanization in a green manner, reduce carbon intensity in foreign trade, and benefit from environmental technologies provided by globalizationÖğe Dampening energy security-related uncertainties in the United States: The role of green energy-technology investment and operation of transnational corporations(Elsevier, 2024) Usman, Ojonugwa; Iorember, Paul Terhemba; Ozkan, Oktay; Alola, Andrew AdewaleSeveral studies provide that the green energy transition is critical to attaining environmental sustainability. However, the extent to which investment in green energy technologies influence energy-related uncertainties is not well known. This study set out to investigate the effect of green energy-technology investment and operation of Transnational Corporations (TNCs) on the United States energy security uncertainties over the period 1974–2020. Applying econometric techniques using the Kernel-based regularized least squares (KRLS) and nonparametric multivariate quantile-on-quantile regression (MQQR), we show that green energy-technology investment dampens uncertainties related to energy security. The results also demonstrate that while eco nomic expansion is negatively associated with the United States’ energy security uncertainties, the operational behaviours of TNCs via direct investment by foreigners and trade openness amplify energy security uncertainty matrices. Furthermore, the effects of green energy-technology investment, operational behaviours of TNCs, economic expansion, and trade openness exhibit an inherent heterogeneity, leading to the asymmetric pattern in the distribution of the United States energy security-related uncertainties. Notably, these results are confirmed by the disaggregated models for energy security uncertainties with the exception of the environmental-related risks sub-index which dampens as a result of the operation of TNCs. Given these findings, the study suggests, among others, the need for government and policymakers to increase investment in renewable energy R&D technology to dampen energy security-related uncertainties and achieve a sustainable environment.Öğe Is renewable energy use lowering resource-related uncertainties?(Elsevier, 2023) Olanipekun, Ifedolapo Olabisi; Ozkan, Oktay; Olasehinde-Williams, GodwinInvestment in renewable energy is vital, not just for the climate, but also for energy security. However, most studies on renewable energy focus on its drivers; there is still limited knowledge about how it affects resource related uncertainties. This study is a global analysis of the renewable energy-geopolitical oil price uncertainty nexus. Wavelet coherence analysis, quantile-on-quantile regression and quantile regression are carried out using global time-series data spanning 2004Q1 to 2019Q4. The outcomes show a significant negative relationship between renewable energy use and geopolitical oil price uncertainty in the short and medium term from 2008 to 2010 and in the short to long term from 2012 to 2019. It also reveals that the expansion of renewable energy use minimizes geopolitical oil price uncertainty. The inferences drawn affirm that renewable energy is a means of lowering oil dependence and consequently hedging against global oil price uncertainties induced by geopolitical events. The findings provide an additional rationale, asides the associated environmental benefits, for consid ering renewable energy as an indispensable part of sustainable energy strategy. Thus, it is recommended that international energy institutions’ energy transition efforts should be complemented by increased sponsorship of renewable energy development by other international organizations across the globe.Öğe Reconsidering the environmental Kuznets curve, pollution haven, and pollution halo hypotheses with carbon efficiency in China: A dynamic ARDL simulations approach(Springer, 2023) Ozkan, Oktay; Coban, Mustafa Necati; Iortile, Iormom Bruce; Usman, OjonugwaGiven a new perspective on the environmental hypothesis, this paper systematically investigates the validity of the envi ronmental Kuznets curve (EKC), pollution haven, and pollution halo hypotheses using carbon efciency as the dependent variable. Applying the dynamic autoregressive distributed lag simulations based on the annual time series data over the period 1990–2019, the study found that real GDP per capita has negative efects on China’s environmental quality both in the short and long run, whereas the square of real GDP per capita has positive impacts. This validates the EKC hypothesis for China. Furthermore, foreign direct investment has negative efects on environmental quality in China, implying that the case of China exemplifes the pollution haven hypothesis and not the pollution halo hypothesis. The empirical results also demonstrate that energy efciency and trade openness improve China’s environmental quality both in the short run and long run. These fndings, therefore, provide insights into achieving the ambitious climate goals in China by 2050.Öğe Stock Returns, Crude Oil and Gold Prices in Turkey: Evidence from Rolling Window-Based Nonparametric Quantile Causality Test(Springer, 2023) Pata, Ugur Korkut; Usman, Ojonugwa; Olasehinde-Williams, Godwin; Ozkan, OktayThis study explores the time-varying efects of crude oil prices (OP) and gold prices (GP) on the Turkish stock market using a weekly data series from November 26, 1989 to July 10, 2022. For this purpose, we develop a new hybrid technique, the rolling window-based nonparametric quantile causality test, which allows the inves tigation of time-varying causality at various quantiles. The results reveal that (i) under all market conditions, there is time-varying causality from crude OP and GP to Turkish stock market returns (SMR) and volatility. (ii) The causal efects of both crude OP and GP on stock market volatility are larger than their causal efects on SMR. (iii) The crude OP have a greater impact on SMR than the GP, while the GP has a greater impact on stock market volatility than the crude OP. (iv) Both crude OP and GP have the strongest (least) causal impact on SMR and volatility under normal (bullish) market conditions. (v) Crude OP and GP have a greater impact on stock market volatility than on stock returns under all market conditions. Overall, our results highlight that OP and GP have a strong impact on the Turkish stock mar ket, and this impact varies by returns and volatility. Therefore, fnancial investors should consider the volatility of crude OP and GP in the Turkish stock market.
