basic answer in decreasing contaminant emissions over time. Employing a similar estimation method, Al-Mulali, Solarin and Ozturk (2016) analyzed the influences of real income, conventional and non-conventional energy, trade, financial development and urbanization for Kenya from 1980-2012. The result indicated that renewable energy reduces air pollution. Dogan and Seker (2016) investigated the impact of real output, conventional and non-conventional energy, trade and financial development on CO2secretions in the highest renewable energy nations. Applying Fully Modified Ordinary Least Squares (FMOLS) and Dynamic Ordinary Least Squares (DOLS) techniques revealed that increases in renewable energy, trade openness and financial development decrease CO2emissions. Bildirici and Gökmenoğlu (2017) assessed the link between environmental pollution, hydropower energy and economic growth among the Great Seven (G7) nations in the different business cycle regimes from 1961 to 2013. The Markov Switching-Vector Autoregressive and MS-Granger Causality techniques were adopted. The findings reveal that from the first to the third regimes, CO2emissions Granger cause hydropower energy. Nevertheless, hydropower energy Granger causes CO2secretions for a number of G7 nations. Inglesi-Lotz and Dogan (2018) assessed the impact of renewable and non-renewable energy on CO2emission among the 10 largest electricity generators in SSA from 1980-2011. A panel evaluation method robust to cross sectional dependence was employed. Empirically, result reveals that a rise in renewable energy usage decreases the level pollution in SSA. Furthermore, the causality analysis indicated a unidirectional causality running from emissions, income, trade and non-renewable energies towards renewable energies. Karasoy and Akçay (2018) examined the impacts of renewable energy and trade on environmental pollution in Turkey from 1965-2016 using ARDL and VECM techniques
8 for estimation. The aftermath of the empirical study showed that increase in the consumption of renewable energy reduces environmental pollution from CO2emissions. Employing a panel error correction model on a group of nineteen developed and developing countries, Apergis et al. (2010) examined the underlying changes between emissions, nuclear energy, renewable energy, and economic growth during the period 1984-2007. The finding from the long-run assessments displays a significant positive relationship between emissions and renewable energy. However, the panel Granger causality test outcome suggests that in the short-run renewable energy does not contribute to emission reduction which could be linked to adequate storage technology. Farhani and Shahbaz (2014) examined the underlying link between conventional and non-conventional energy, output and CO2emissions for 10 MENA countries between 1980-2009. Employing the Pedroni cointegration test as well as the FMOLS and DOLS techniques, the findings show that conventional and non-conventional energy enhances CO2emissions. Also, the long-run granger causality test appears to have a bidirectional causality between conventional and non-conventional and CO2emissions.