High voltage direct current technology for the integration of renewable energy sources: Potential and relevance for climate change

Abstract

When the monumental Paris Climate Agreement entered into force in 2015, countries pledged to limit global warming to well below 2 °C relative to 1990 levels by 2030 to ensure that planet Earth stays inhabitable to humankind. The near universal ratification of this legal document and the respective Nationally Determined Contributions demonstrated countries’ ambitions to significantly lower greenhouse gas emissions in this pursuit. A fundamental aspect of decarbonization will not only be the increased use of renewable energy sources, but also the infrastructure necessary to integrate these into existing electricity grids. One of the important cornerstones of this integration will be the use of high-voltage direct current (HVDC). However, HVDC has so far not sufficiently been discussed in the context of the energy transition and in what ways specifically it can assist governments in reaching climate targets. Therefore, this thesis aims to find how HVDC can support the integration of renewable energy sources and thereby facilitate the energy transition to mitigate global warming. This will be done by carrying out a technical analysis of HVDC to understand where its benefits and drawbacks lie as well as an examination of the economic feasibility, by relying on secondary literature describing break-even distances. An analysis of the existing legal frameworks based on legal texts as primary literature will allow for the identification of areas that necessitate improvement. In the final section, geopolitical implications of the previous findings will be derived. The variable nature and inflexible sites of renewable energy makes HVDC ideal for their grid integration. HVDC allows for higher use of renewable energy potential because it can be used to transport bulk power over large distances with lower losses and at lower costs than high-voltage alternating current (HVAC) for the same distance. Furthermore, HVDC can be used to connect independent grids to allow for balancing of power in a system based largely on renewables with inherent fluctuations. The contributions towards this field lie in the identification of the reasons that HVDC will significantly contribute to the energy transition, thereby justifying increased consideration and investments, as well as suggestions for further necessary improvements in the field.