**4.5 United Kingdom**

The CBA carried on by the UK Department of Energy and Climate Change in 2014 on the smart meters rollout was positive, with an estimation of net benefits equal to £6.2 billion (equivalent to 7.2 billion of euro) [20]. The UK's rollout is the largest project in the gas market, and it involves 30 million customers with a gas consumption equal to 50% of the household energy costs, as investigated by Segalotto [21]. Households can freely choose, if applying or not, for a smart meter of new generation, for the gas and electricity with an in-home display screen that shows in real time the exact amount of the energy consumption8 .

At the end of 2013, there were 295,700 smart meters already installed in domestic properties in the country. However, the British government started officially a smart meter rollout in 2016.

The home area network (HAN) implemented in the UK for the smart meters' remote reading uses a ZigBee Energy network. ZigBee Smart Energy is the network solution for electric meters, gas meters, and in-home displays, due to its maturity and popularity in Smart Energy application profile and its capability of ensuring robust communications architecture of a smart natural gas system [22]. At the end of 2020, there were 98,600 smart meters installed in non-domestic sites and, in spite of the delay due to the COVID-19 pandemic breakdown, smart meters installation showed the highest peak of the rollout (**Figure 5**).

On the other side, the installation in the domestic sites continued increasing in 2020 and reached a total of 3.1 million smart meters installed, as shown in **Figure 6** [23].

<sup>7</sup> http://www.gasnetworks.ie/en-IE/About-Us/Our-commitment/Marketplace/Smart-meters.

<sup>8</sup> https://www.smartenergygb.org/en/about-smart-meters/what-is-a-smart-meter.

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

**Figure 5.**

*Non-domestic smart meter gas installed in Great Britain from 3rd quarter 2012 to 4th quarter 2020 (source: [23]).*

#### **Figure 6.**

*Domestic smart meter gas installed in Britain from 3rd quarter 2012 to 4th quarter 2020 (source: [23]).*
