Interoperable multi-vendor High-Voltage Direct-Current (HVDC) grids are a key enabler for the integration of renewable energy (in particular offshore wind) and its transmission over longer distances to consumers. However, most HVDC systems today are single-vendor and point-to-point. Various technical and non-technical aspects need to be considered, for example, (real-time) testing, legal aspects (intellectual property and regulation), and the multi-vendor interoperability process. This paper presents findings from the READY4DC project, which is a larger and open European effort involving diverse stakeholders, including HVDC manufacturers, transmission system operators, wind developers, academia, and research institutes. It summarizes key technical recommendations, emphasizing comprehensive interaction studies and the development of a structured legal framework to facilitate the development and operation of a multi-vendor, multi-terminal HVDC grid. The READY4DC project highlights the need for increased harmonization, transparent communication among stakeholders, and future-oriented research to ensure the robustness and interoperability of interconnected grids. Collaborative efforts are key for addressing technical complexities and advancing the deployment of multi-vendor multi-terminal HVDC technology.

Belgium, Denmark and the Netherlands have announced their interest in constructing artificial ‘energy islands’ to enable the integration of large-scale offshore wind energy into the energy system. This raises several legal questions, such as how do these developments fit in the balance of interests required by the United Nations Convention on the Law of the Sea, what European Union law is applicable to artificial islands and how Belgium, Denmark and the Netherlands approach the construction of artificial islands. This article provides a comprehensive overview of the applicable legal framework and shows the variety of approaches and strategic choices States may have when developing energy islands.

The European Commission plans to achieve the decarbonization of dozens of European Union (EU) islands by 2030. This would reduce greenhouse gas emissions, lower the dependency of islands on imported fuels, and potentially reduce local energy prices. At the same time, it may accelerate the mainland’s own energy transition through the import of surplus energy from renewable sources, the provision of aggregated flexibility services, and the testing of both technologies and policies on islands for replication and adaptation on the continent. Although islands are not even a legal category per se in EU energy law, the existing legal framework already allows to harness various concepts to foster the energy transition of EU islands. This article reviews available legal qualifications and regimes such as small systems’ exemptions, energy communities, positive energy districts, and local flexibility markets in the context of the decarbonization of EU islands. Potentially, they could open many different ways to tailor local energy transitions, channelling local actions to accelerate the whole process.

Massive deployment of offshore wind is a core building block of the EU’s climate and energy strategy. So-called ‘hybrid assets’ can be used to connect offshore wind to the onshore grid. A hybrid asset is a connection between at least two countries, to which offshore wind farms are also connected. The connection transports offshore-generated electricity to shore, while facilitating electricity trade through additional interconnection capacity. The current EU Electricity Market Regulation is not fit for this purpose, holding back the development of hybrid assets. This article discusses the legal issues regarding hybrid assets, and a promising solution: offshore bidding zones.

With a growing number of offshore wind farms being constructed increasing distances from the shoreline, different approaches to connecting offshore wind farms must be considered. It is in this context that the development of an offshore electricity grid, connecting offshore wind farms and delivering additional benefits for the system, may be considered – and is the rationale behind such developments being investigated in both Europe and the US. The legal framework for offshore grids depends on the law of the sea and on how states make use of the competences they have at sea. In Europe, EU law provides a general framework for the interoperability of the grids in different countries and sets standards for maritime spatial planning. Other topics are addressed through the national law of the coastal states. In the US, offshore is a federal competence, with an open-door procedure for parties interested in developing offshore transmission.