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Renewable energy sources (RESs) and electricity demand are not evenly distributed geographically across Europe. Thus, harvesting the wind energy from the north and solar energy from the south and delivering them to the demand in central Europe is a more viable solution. However, the present High-voltage alternating current (HVAC) transmission grids have been sometimes congested; thus, High-voltage direct current (HVDC) provides another possibility along the existing HVAC infrastructure. In this paper, we propose a hybrid HVAC-HVDC grid, allowing a large penetration of concentrated RES in Europe and North Africa. More specifically, the HVDC network is constructed to transfer wind and hydro electricity from northwestern Europe and solar electricity from north Africa, while the HVAC network is used to distribute electricity within each country or among adjacent areas. To quantitatively evaluate the feasibility and relevant performances, multiple dimensions of indicators are designed. Employing several European energy scenarios up to 2050, the performances of the proposed HVAC-HVDC infrastructure are analyzed and compared. The calculation results show that compared with the pure HVAC grid, the integrated HVAC-HVDC grid can significantly reduce greenhouse gas emissions and pollutants, leading to a further reduction in the number of deaths from air pollution. In addition, the HVAC-HVDC grids can accommodate a higher penetration of RES without causing infeasible power flows. [ABSTRACT FROM AUTHOR]

This study investigates the relationship between technological innovation, renewable energy, economic growth, and carbon dioxide (CO2) emissions in a group of six specific Middle East and North Africa (MENA) countries from 1990 to 2019. The study utilizes the modified innovation environmental Kuznets curve model (ICC) theory to examine the potential existence of an inverted U-shaped curve between innovation and environmental quality in these selected MENA countries. Various econometric methods are employed to analyse the data. The results show a positive and significant impact of patents for residents on CO2 emissions, affirming the influence of patents on environmental quality. Additionally, the square of patents demonstrates a significant negative relationship with carbon emissions, providing evidence for the inverted U shape of Claudia's theory. These findings imply that the ICC is relevant to the selected countries, with the quadratic patent variable suggesting that the use of innovative technology initially increases emissions but reaches a turning point after a certain threshold. [ABSTRACT FROM AUTHOR]