# Innovative Strategies for Combining Solar and Wind Energy with Green Hydrogen Systems
## 4 Case Studies and Applications
### Case Study 1: Regional Implementation
Novel hybrid interconnectors linkwind farms and permit inter-country transmission. The hybrid systems correspond with the mutual interests of North Sea nations and the European Commission. While not all North Sea nations embrace hybrid interconnectors, the European TSOs' Ten-Year Network Development Plan (TYNDP) 2024 has hybrid projects in consideration [65]. Another expansion of hybrid interconnectors would be the construction of a more meshed offshore grid with terminals connecting different countries. Figure 8 displays various offshore connection types. Concerns regarding legal and regulatory obstacles, such as the ambiguity of project responsibility, have been raised, despite the various advantages of hybrid projects. According to ENTSO-E, a consortium of European TSOs, an interconnected offshore grid can promote energy security, possibilities for trading, standards, and minimize the demand for total assets [66]. The North Sea Wind Power Hub is a prime instance of an offshore facility project. A coalition of TSOs and gas TSOs is driving the initiative, which seeks to build a significant offshore wind hub in the North Sea and link it to the onshore grid using high-voltage direct current (HVDC) cables. In addition to electric interconnectors, the hubs are expected to contain H\({}_{2}\) manufacturing facilities and pipelines linking to them onshore [57]. More closely examining offshore H\({}_{2}\) production, the H\({}_{2}\)Mare project intends to compare the cost-effectiveness of offshore and onshore electrolysis. It investigates a variety of ideas, including manufacturing H\({}_{2}\) offshore and bringing it onshore via pipelines, sending power onshore for electrolysis, or producing and storing H\({}_{2}\) offshore in floating tanks for pickup by ships. The H\({}_{2}\)Mare project is an innovative effort aimed at investigating the feasibility and promise of offshore green H\({}_{2}\) production that is fully independent of grid connections [67]. This significant project, led by a coalition of 33 top industrial and scientific partners and supervised by Siemens Energy, has the potential to transform our understanding of renewable energy and its applications, especially in the setting of offshore wind energy. The H\({}_{2}\)Mare project is focused on manufacturing green H\({}_{2}\) and other power-to-X (PtX) products directly at sea. Unlike traditional approaches that rely on transporting power produced by offshore wind turbines to the mainland grid, the H\({}_{2}\)Mare project envisions a system in which the electricity produced is instantly used to manufacture H\({}_{2}\) by water electrolysis directly at the source [67]. This technique not only eliminates the need for substantial and costly grid infrastructure, but it also provides the possibility of establishing a self-sustaining, emissions-free energy production cycle in the offshore area [68]. The  
Figure 8: A schematic representation of the various types of offshore connections. project's vision goes beyond simply creating H\({}_{2}\). It also intends to manufacture other PtX products, such as synthetic fuels and chemicals, which are required for a variety of industrial operations. This program is in line with worldwide efforts to decarbonize hard-to-abate sectors and transition to a sustainable energy market.