Fig 3
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Decarbonisation policies adopted worldwide are leading to an increasing deployment of renewable energy sources. In Europe, the growing number of offshore wind farm projects calls for scrutinising merits and opportunities of their interconnection via multi-terminal links rather than conventional point-to-point connections. The semiconductor componen...
Citations
... The interconnection of electricity grids for the transmission of electricity over long distances, even with submarine pipelines at very great depths, from areas with surplus electricity to areas that they need it is intensively being sought today in order to face this destabilization of the grids (Overland 2016;George et al., 2019;Ardelean et al., 2019;Purvins et al., 2018;Ardelean and Minnebo 2017;Bompard et al., 2014;L'abate et al., 2014;Fulli et al., 2011;Purvins et al., 2011;Lazarou et al., 2012;Liu 2016) ( Figure 3). Unfortunately, the most suitable locations for the generation of green electricity are not uniformly 510 LYCOURGHIOTIS distributed. ...
This essay deals with the prospects of supplying humanity with energy in the twenty-first century. The gradual replacement of fossil fuels by green electricity, hydrogen and biofuels is examined in the context of deteriorating climate change and the ongoing depletion of fossil fuels. The production of large amounts of green electricity through the spreading of wind-energy, photovoltaic, concentrated solar power, hydroelectric power and high temperature geothermal plants and its storage through the global interconnection of electricity grids, the spreading of pumped hydro energy storage and melting salts plants and the lithium batteries leads certainly to a future world largely but not exclusively electrical. Hydrogen will be a very important energy carrier. The production of blue and green hydrogen, their transport and usage in cars, industry and trains in the near future as well as in ships and airplanes in the distant future is outlined. Biofuels must be inevitably added to the future energy profile of mankind besides green electricity and hydrogen. The modern trend of producing biofuels from residual fatty raw materials, microalgae and agricultural/forest residual raw materials to overcome the competition with foods production for land and water as well as the residual biomass utility for the production of aircraft fuels and bio-chemicals in the near future is also illustrated. Finally, the increasing contribution of biogas/biomethane to the future energy profile has been presented.
... Contrairement à une ligne de transport AC, symbolisée par des pertes résistives et réactives, dans une ligne de transport DC nous considérons uniquement les pertes résistives. Cela signifie que DC DC Y est une matrice réelle[137][138]. Avec la commande maître/esclave, le convertisseur maître doit garantir que toutes les tensions du système restent dans les limites prédéfinies. ...
... Furthermore, multi-terminal HVDC grids for wind parks integration should be thoroughly studied, applying real wind production energy data derived from the National Centres for Environmental Prediction (NCEP) [18]. As far as the consumption is concerned, the consumption of the potential countries to be connected to a "European super grid" must be taken into account [3]. ...
Transmission system reinforcement is an issue of great importance, in an effort to handle the increasing renewable power generation. Nevertheless, the upgrade of the transmission system (lines, substations, etc.) is not always attainable, due to techno-economical restrictions. To this context, High Voltage Direct Current (HVDC) grids or converting already existing AC lines to DC lines could offer an alternative solution, considering also the interconnection of offshore intermittent renewable generation resources, the connection of remote generation sources to load centers and the inter-continental transfer of large quantities of energy surpassingly an overlay grid. The current work presents a research plan for multi- terminal HVDC grids, in an effort to face technical challenges.
The supply of electrical energy is of importance for the value creation of most industrialized nations. Ultimately, electrical energy is able to provide the appropriate useful energy at the point of need with virtually no emissions. This aspect plays a greater role today than ever before. When using electrical energy as a clean and sustainable energy source, it is important to note that there can be significant losses in the transmission of electrical energy between the point of generation and the point of use. These transmission losses are caused, among other reasons, by line losses due to power quality deviating from the ideal value. In principle, any deviation from the nominal values of the supply voltage listed in EN 50160 (such as voltage level, frequency or harmonic distortion) leads to an increase in transmission losses. Thus, compliance with the power quality parameters is desirable from all perspectives of (economic, ecological, social) sustainability. Especially with reference to SDGs 7, 8 and 12, a supply voltage that complies with the specified parameters is important. Unfortunately, no incentives currently exist for minimizing deviations in power quality parameters and the transmission losses they cause. Goal should be to implement a transition of energy system that provides incentives to increase the transmission efficiency of electricity. One possibility for this is the unbundling of the guarantee of the power quality parameters on a separate market. Regulatory framework conditions must be adapted for sustainable improvements in energy transmission at all levels. Nevertheless, the economic viability of power quality based business models is difficult. A promising solution is to reintroduce a supplementary factor as an extension of the equation of the incentive based regulation. The vision of the business model explained in the paper is to contribute to the efficient operation of the power grid by avoiding the propagation of harmonics through the use of compensation equipment, this is a new approach that has not yet been investigated.
Offshore wind energy is a promising solution to the environment and energy crisis thanks to its excellent performance of production. It would be further developed with the support from low-carbon economy. This paper summarizes the configuration of offshore wind power systems and surveys their optimal planning methods. Methods of offshore wind farm siting, common topologies of collecting systems and different transmission schemes are reviewed, while reliability evaluation is discussed in detail. Based on this, modeling approaches and algorithms for optimal planning of offshore wind power systems are briefly treated. Finally, some suggestions for potential research directions of optimal planning of offshore wind power systems are made.
The emerging Modular Multilevel Converters (MMC) technology is expected to play a key role in the construction of DC grids and integration of renewable energy sources (RESs) at bulk to medium and high voltage. The DC option is also perceived as solution to the steady increase in power demand and the collection of disperse conventional and variable generations. These can be achieved while maintaining the control and operation of the grid into the smart grid playground without affecting the environment. Therefore, this paper presents the characteristics of the MMC along with the modulation techniques as well as control methods for MMC-based high multilevel structures. Also the MMC-HVDC advantages for integrating RES are reviewed. At final section the technical and environmental benefits of using MMC for DC grids are discussed.
