This project is a development of ARC Marine's Reef Cubes and their cement-free, low-carbon concrete. Reef Cubes enhance the marine ecosystem whilst developing offshore renewable energy sites. Our concrete design is an innovative sustainable mixture made of 95% recycled materials, with 10% the carbon footprint of standard concrete. Vast amounts of materials are added to the seafloor during offshore construction to stabilise structures from the effects of current scour, to protect cables from anchors and fishing gear, and to act as moorings for vessels or floating platforms. Our current work is focussed on promoting the use of Reef Cubes as additions or alternatives, to enhance the biodiversity around offshore renewable developments, whilst also meeting the strict technical performance requirements of offshore renewable engineers. Unlike other protection structures, Reef Cubes have a nature-inclusive 3D shape with internal spaces. Deploying Reef Cubes at offshore renewable sites has the benefit of enhancing the surrounding habitat and thus the natural value of biodiversity around renewable developments. The product helps developers to meet their biodiversity licensing requirements and governments to meet UN sustainable development goal 14 of life below water. Reef Cubes are to be deployed in the pioneering Rich North Sea project in the Dutch North Sea later this year. There is a problem with the current use of technology though. Deployment requires the hire of a separate vessel, incurring a significant extra cost to the funders. The additional carbon emissions also balance-out the positive effects of the Reef Cubes on the environment. To overcome this we suggest expanding the capability of Reef Cubes, to be deployable with rock armour by fall pipe vessels. Our aim is to ensure the strength of Reef Cubes is sufficient to survive deployment with rock armour protection by fall pipe vessels, test the innovative low-carbon concrete to ensure compliance with maritime standards and include carbon-storing materials to reach the point of net carbon sequestration. If successful, our product will rapidly convert large offshore renewable energy seabed sites into thriving and healthy marine habitats for the long term benefit of mankind and the planet; while reducing the overall project's carbon footprint! ARC Marine's mission is to create the largest, most comprehensive accelerated reef network in the world and reverse the damage that has been done over centuries of offshore construction and fishing whilst improving renewable energy productivity and aquaculture site efficiency.