Borkum is an island of about 30 km2 and 5,500 residents, located 20 miles from the north-western coast of Germany. Following concerns of the population regarding air quality due to a new coal fired power plant, Borkum started on a path towards renewable energy many years ago. Following several initiatives in that direction including a citizen dialogue, the island decided to become emission-free and fully decarbonized by 2030. Within this framework, the ISLANDER project will showcase the process of making Borkum a fully autonomous and decarbonised island energy system. Specifically, the project will focus on delivering: a) Distributed RESS systems (Renewable Energy + Small-scale Storage). b) Complementary short-to-seasonal, large-scale electricity storage. c) Seawater district heating coupled with heat storage and sized for 100 residential units, to make use of the heat of the North Sea water as a source of heating and cooling. d) Deployment of an EV charging network. e) A smart IT platform conceived to holistically perform the optimal aggregation of all these components while also implementing Demand Response (DR). f) An optimisation tool to optimally design zero-carbon island energy systems. To achieve such 2030 objectives of financing and maintaining the further roll-out of renewables and storage technologies across the island, the ISLANDER partners will facilitate the kick-start of a Renewable Energy Community in Borkum right during the project following a concrete roadmap. Additionally, and as part of an ambitious plan to replicate the project results, the partners have developed a 3-wave replication strategy including: Wave 1) Replication in the Follower islands, Wave 2) Replication in the related archipelagos. Wave 3) Further replication to the rest of EU islands.