**2. State of art of the smart metering infrastructure**

The implementation of a smart city requires the proper development of a smart metering infrastructure, a system for the intelligent measurement of the energy consumption of each user, through smart meters able to give real-time and remote consumption readings of different services (electricity, water, gas, and district heating), providing advanced services to the users2 .

In order to reach the proper integration of different energy supplies, such as electricity, gas, water, district heating and energy produced by waste3 , and service systems such as the internet, video terminal, and e-cars, it is necessary to promote the use of different electronic meters (e.g. electric, water, heating, and gas meters) and different sensors integrated into a distributed architecture, able to gather and analyses heterogeneous data. So as to achieve this objective, the following subsystems should be implemented:


<sup>2</sup> https://www.endesaeduca.com/Endesa\_educa/recursos-interactivos/smart-city.

<sup>3</sup> http://www.autorita.energia.it/it/com\_stampa/14/140908cs.htm.

*Demand Response Applications for the Operation of Smart Natural Gas Systems DOI: http://dx.doi.org/10.5772/intechopen.101810*

