An in-depth understanding of the basis of urban sustainability in urbanisation involves tackling a carefully integrated process. By means of a holistic guiding concept pushing the boundaries in the sustainable design of buildings, this article describes the development plan drawn up to reurbanise the seafront “Área de las térmicas del Besós” in Barcelona. This combines residential and tertiary uses, infrastructure and also free areas for museum use in a great industrial building home to a former power station. The current plan will add a kilometre of beach to be used and enjoyed by the citizens of Barcelona. It will also provide the municipality of Sant Adriá de Besòs with access to the sea. The plan’s most original contribution lies in its aim to collaborate towards sustainable urban development. It sets out to do so by incorporating strategies not only on an urban scale, but also on an architectural scale and even introducing landscape and green elements into the design. This methodology will facilitate the generation of urban growth with a minimum environmental impact and with low carbon emissions.