Hydrogen-based infrastructures to support the smart cities development

Fifty-one percent of the world's population, approximately 3.5 billion people, reside in urban areas. Cities around the world emit almost 80% of global carbon dioxide as well as significant amounts of other greenhouse gases and this percentage is expected to grow further [1]. Energy use is responsible for approximately 70% of these emissions [2]. Climate change mitigation requirements, globalization of innovation networks and broadband services are the driving forces of new urban development paradigms towards cities which use technology and communication to create more efficient urban areas [3]. Pillars of the EU's overall policy are built upon the current context of climate change issues, increasing energy costs, concerns on security of energy supply and integrated sustainable urban development. The EU Smart Cities Initiative aims to improve energy efficiency and to step up the deployment of renewable energy in large cities going even further than the levels foreseen in the EU energy and climate change policy. It will bring the cities involved to the forefront of the development of the low-carbon economy [4]. Small renewable and non-renewable generators are increasingly becoming important components in the grid at distribution network levels. This creates an opportunity for network operators to balance large power plants, local small generators and demand side management systems with high flexibility, in real time. In this context fuel cells (as efficient power systems in transport), hydrogen (as a clean energy carrier), stationary and portable applications can play an important role within the European Initiative on Smart Cities [5-7]. On the other hand energy infrastructures are becoming co-dependent with information and communication technology (ICT) devices, so that all elements have to be integrated together with the aim to operate with synergy, optimizing efficiency and reducing consumptions [8].