**2.3 Calculation of the primary energy factor according to the Standard EN 15603:2008**

The last calculation was carried out by using the default PEFs prescribed by the standard SIST EN 15603 [15]. This methodology evaluates separately the nonrenewable part and the total part of PE. Solar energy (PV) was evaluated in the same way as water and wind energy. Therefore, the default factors are the same in this case. In this method, we used the fractions of individual energies which comprise the mixture of electricity from **Table 1**. The full calculation for 2017 is shown in **Table 6**.


**73**

**Figure 3.**

*Primary Energy Factor for Electricity Mix: The Case of Slovenia*

**Network loss [GWh]**

**Useful energy [GWh]**

Total 16,325 1632.5 14,692 37,500 2.55

*Calculation of PEF by physical energy content method for the electricity production in Slovenia in 2017.*

*PEFs for the electricity mix in Slovenia using the physical energy method for the years 2000–2018.*

**Nonrenewable Total Slovenia (average)**

Nuclear 2.8 2.8 38.5 1.05 1.08 Fossil 4.05 4.05 34.36 1.39 1.39 Hydro 0.5 1.5 25.37 0.13 0.38 Wind 0.5 1.5 0.04 0.00 0.00 Solar 0.5 1.5 1.73 0.01 0.03

*Calculation of the PEF of electricity mix for Slovenia for 2017, using the reference values from the standard* 

*Average PEFs for nonrenewable and total PE calculated in accordance with SIST EN 15603.*

**2017 PEF [/]**

**Primary energy [GWh]**

**Energy share [%] Nonrenewable Total**

Sum 2.61 2.88

**PEF**

*DOI: http://dx.doi.org/10.5772/intechopen.84570*

**Production [GWh]**

**Table 5.**

**Figure 2.**

**Table 6.**

*SIST EN 15603.*

**Table 4.**

*Calculation of PE by physical energy content method for the electricity production in Slovenia in 2017.*

*Primary Energy Factor for Electricity Mix: The Case of Slovenia DOI: http://dx.doi.org/10.5772/intechopen.84570*


**Table 5.**

*Energy Policy*

and ocean).

**2.2 Calculation of primary energy factor by physical energy content method**

The energy content method distinguishes itself in the approach for evaluating renewable sources and nuclear power plants production [19, 20]. PE in this method is considered as the first practically utilizable energy flow. In the case of directly combustible energy carriers (e.g., coal, natural gas, oil, biogas, bio liquids, solid biomass, combustible municipal/industrial waste), PE is defined as the heat generated in the combustion process. For non-directly combustible energy sources, PE can be expressed with the produced heat (e.g., nuclear, geothermal and solar thermal) or produced electricity (e.g., solar photovoltaic, wind, hydro, tide, wave,

A PEF value of 1 is assumed for fuels. For noncombustible renewables a conversion efficiency of 100% is assumed. In contrast, a conversion efficiency of 33% is assumed for nuclear power stations. For combustible renewables such as biomass, the conversion efficiency is calculated from [15]. The resulting PEF for electricity from the various sources are 1 for hydro, wind, and solar PV; 3–4 for biomass; and 3

Just like at the partial substitution method, we took into account 10% losses in

The calculated PEF for the electricity mix using the physical energy method for 2017 is 2.55. For this year, this value is similar to the value assumed for Slovenia, i.e., 2.5. In order to observe the temporal variation of PEF, the same calculations were also carried out for previous years, based on statistical data for Slovenia. The results

**Figure 2** shows that the factor is constantly changing, but we can notice that from 2011 onward the factor has fallen slightly. The likely reason for this is that the share of renewable resources began to increase markedly in the meantime. Since this method assumes 100% conversion efficiency for electricity produced from renewable sources, the primary energy for production is the same as production

The last calculation was carried out by using the default PEFs prescribed by the standard SIST EN 15603 [15]. This methodology evaluates separately the nonrenewable part and the total part of PE. Solar energy (PV) was evaluated in the same way as water and wind energy. Therefore, the default factors are the same in this case. In this method, we used the fractions of individual energies which comprise the mixture of electricity from **Table 1**. The full calculation for 2017 is shown in **Table 6**.

**Production [GWh] Efficiency Primary energy [GWh]**

**2.3 Calculation of the primary energy factor according to the Standard** 

Nuclear 6285 33% 19,045 Fossil 5610 40% 14,025 Hydro 4141 100% 4141 Wind 6 100% 6 Solar (PV) 283 100% 283 Total 16,325 37,500

*Calculation of PE by physical energy content method for the electricity production in Slovenia in 2017.*

for solar thermal and nuclear. The results for 2017 are shown in **Table 4**.

the network to obtain the PE shown in **Table 5**.

are illustrated in **Figure 2**.

**EN 15603:2008**

itself.

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**Table 4.**

*Calculation of PEF by physical energy content method for the electricity production in Slovenia in 2017.*

**Figure 2.**

*PEFs for the electricity mix in Slovenia using the physical energy method for the years 2000–2018.*


#### **Table 6.**

*Calculation of the PEF of electricity mix for Slovenia for 2017, using the reference values from the standard SIST EN 15603.*

**Figure 3.** *Average PEFs for nonrenewable and total PE calculated in accordance with SIST EN 15603.*

In **Table 6**, two PEFs for the electric mixture are calculated through the fractions of individual energies composing the electricity mix in Slovenia for 2017. We can see that the average PEF for nonrenewable is less than the total factor. The reason for this is that the default primary factors that take into account only the nonrenewable part of primary energy are lower than the total or total factor. The difference between the two average factors is almost 0.3, which is not negligible. As with previous methods, here again, the calculation was also performed for previous years, with the same default factors. The results are shown in **Figure 3**.
