## Appendix B Detailed Description and Background Data of the Calculation Model and Hourly Simulation  
### Electricity Consumption and Production  
The yellow rectangle in Figure 3 includes the electricity consumption of the services and residential buildings (E\({}_{\text{B}}\)), the HFS compressor and chiller (E\({}_{\text{HFS}}\)), the SHS compressor (E\({}_{\text{SHS}}\)), and the solar electricity production (E\({}_{\text{S}}\)). E\({}_{\text{HFS}}\) and E\({}_{\text{SHS}}\) are calculated by multiplying the hourly hydrogen throughput by the specific energy consumption component values SEC (kWh/kg H\({}_{2}\)) from Table 10.  
The electricity consumption of the services and residential buildings (E\({}_{\text{B}}\)) in the Near Future and the Mid Century scenario is based on the energy consumption at present, called the Present Situation. Therefore, first, the Present annual specific energy consumption of the residential and services buildings SEC\({}_{\text{B}}\) (kWh/m\({}^{2}\)/year) is defined for each location. The method described is applicable to any location within Europe. Building energy consumption is divided into six energy consumption categories:  
1. Space heating
2. Space cooling
3. Water heating
4. Cooking
5. Lighting
6. Electrical appliances  
Space heating and cooling depend on the ambient temperature, which is reflected in the number of annual heating and cooling degree days (HDD and CDD; see Table 11). Hamburg and Murcia differ greatly in this regard. Also, within the respective countries (Spain and Germany), locally, the number of HDDs and CDDs [50; 51; 308] can differ greatly from the national weighted average [118]. Due to a lack of recent and complete studies on building energy demand relations with respect to climatic parameters, a similar method is developed as in [50; 51]. For space heating for both the residential and the services sector, a relation between the specific thermal heating demand and the number of HDDs per country is established using [54; 55; 118]. The specific thermal heating demand is derived from the used fuel mix, useful thermal energy per fuel type, fuel demand, and floor space [54; 55; 118; 127]. The value used as specific thermal demand for space heating in Murcia and Hamburg is taken from countries with a similar number of HDDs as Murcia and Hamburg. For Murcia, the specific thermal demand is based on the specific thermal heating demand of Cyprus, Malta, and Portugal of the available years 2010-2015. For Hamburg, it is based on the specific thermal demand of Germany, Sweden, Finland, and Lithuania. For space cooling, the relations between CDDs, specific thermal cooling demand, and specific electricity demand from [50; 51] are used. For water heating, cooking, lighting, and electrical appliances, it is assumed the local consumption in the Murcia and Hamburg regions does not differ from the national average values [54; 55]. Table 12 shows the specific annual energy consumption for buildings SEC\({}_{\text{B}}\) (kWh/m\({}^{2}\)/year) per energy consumption category, and annual electricity consumption in buildings E\({}_{\text{B}}\) (MWh/year) for the residential and services sector for the Hamburg- and Murcia-based smart city areas in the Present Situation and in the Near Future and Mid Century scenarios. For the Present Situation in Hamburg and Murcia, this is 194 and 173.6 kWh/m\({}^{2}\)/year and 98.6 and 223.5 kWh/m\({}^{2}\)/year for the residential and the services sector, respectively. Combining the SEC\({}_{\text{B}}\) values with the floor areas from Table 12 results in total annual energy consumption of 51,617 MWh and 26,672 MWh for Hamburg and Murcia, respectively. SEC\({}_{\text{B}}\) values in the Near Future and the Mid Century scenario are fully electric in its end-use and are defined by applying specific energy consumption savings (Table 13) to the Present SEC\({}_{\text{B}}\).