The increase of the world's population leads to an urgent need of radical measures to diminish the energy footprint of humanity. This study considers the realisation of an optimal Masterplan in energy terms for the new EPFL Research Centre in Ras A1 Khaimah. United Arab Emirates (UAE). The methodology makes use of an Urban Energy Modelling tool to define the best urban form considering solar irradiation and buildings' energy needs for cooling. The paper contains the simulation methodology, the simulation results and gives some insights about how to improve sustainability for this specific climate at the concept stage. Keywords: Urban energy modelling, optimal urban form subtropical-arid climate. Copyright © 2011 by IPAC'11/EPS-AG.