# Expected Impacts of the Massive Increase in Electric Vehicles in Slovakia
## 3 Impact of the Increase in Electromobility on Ecology
### The CO\({}_{2}\) Emissions
It is also necessary to indicate the emissions that will be produced by power plants using individual fuels (Table 4) related to the kWh produced. In the case of hydro, solar, wind and nuclear power plants, emissions from the production of these power plants are also included and are therefore not considered to be completely emission-free. For coal-fired power plants, calculations were performed to determine the exact values of carbon dioxide emissions. The CO2 emissions that result from the production of 1 kWh by burning a corresponding amount of brown coal can be quantified by the following calculation, in which the amount of coal needed to \begin{table}
\begin{tabular}{c c} \hline
**Energy Source** & **CO2 Emissions (g/kWh)** \\ \hline Coal & 1180 \\ Brown coal & 958 \\ Oil & 920 \\ Gas & 790 \\ Nuclear & 82 \\ Solar & 37 \\ Wind & 28 \\ Hydropower & 23 \\ \hline \end{tabular}
\end{table} 
Table 4: CO2 emissions depending on fuel and type of power plant [17]. \begin{table}
\begin{tabular}{c c} \hline
**Country** & **Total CO2 Emissions (g CO2 e/km)** \\ \hline Iceland & 70 \\ Sweden & 81 \\ France & 93 \\ Germany & 179 \\ Great Britain & 189 \\ USA & 202 \\ China & 258 \\ Indonesia & 270 \\ Australia & 292 \\ South Africa & 318 \\ India & 370 \\ \hline \end{tabular}
\end{table} 
Table 2: Average emissions of electric vehicles in selected countries [16]. \begin{table}
\begin{tabular}{c c} \hline
**Energy Source** & **Ratio in Electricity Generation (\%)** \\ \hline Other fossils & 0.57 \\ Other renewable & 1.44 \\ Oil & 1.49 \\ Wind power plants & 1.75 \\ Solar power plants & 1.82 \\ Biomass & 5.04 \\ Brown coal & 22.8 \\ Coal & 14.2 \\ Gas & 13.17 \\ Nuclear resources & 53.7 \\ Hydroelectric power plants & 8.08 \\ \hline \end{tabular}
\end{table} 
Table 3: Energy mix in Slovakia [4]. produce 1 kWh is first determined and then the carbon dioxide emission value is calculated for this amount. The first step in the calculation is to determine the output of brown coal power plants:  
\[P_{BCyour}=el_{total/2019\cdot P\%BC}=30000\text{-}0.228\cong 6840\text{ GWh}/\text{year}, \tag{6}\]  
where \(P_{BCyour}\) is electricity produced by brown coal power plants (GWh/year), \(el_{total/2019}\) is total electricity production in 2019 (GWh/year) and \(r_{\%BC}\) is the ratio of brown coal in the energy mix of the Slovakia [10]. The conversion obtains:  
\[P_{BC}=\frac{P_{BCyour}\text{-}1000}{hours_{your}}=\frac{6840\text{-}1000}{365 \text{-}24}\cong 781\text{ MW}, \tag{7}\]  
where \(P_{BC}\) is the average power of brown coal power plants (MW) and \(hours_{your}\) is number of hours per year. It is also necessary to consider the heat value of brown coal, which is commonly used in Slovakia. At present, brown coal in Slovakia has an average heat value of 11 MJ/kg. Furthermore, the thermal efficiency in the production of energy in coal-fired power plants is considered, which is around 38% [18]. \[m_{ph}=\frac{P_{BC}}{\eta\text{-}Q_{r}^{i}}=\frac{781000}{0.38\text{-}11000} \cong 186.84\text{ }\frac{\text{kg}}{\text{s}}=672624\text{ kg}/\text{h}, \tag{8}\]  
where \(m_{ph}\) is amount of brown coal consumed in coal-fired power plants per one hour (kg/h), \(P_{BC}\) is the average power of brown coal power plants (kW), \(\eta\) is thermal efficiency of coal power plants and \(Q_{r}^{i}\) is heat value of brown coal (kJ). In order to determine the amount of brown coal needed to produce 1 kWh, the following calculation is used:  
\[m_{1 kWh}=\frac{m_{ph}}{P_{BC}}=\frac{672624}{781000}\cong 0.861\text{ kg}/\text{kWh}, \tag{9}\]  
where \(m_{1 kWh}\) is amount of brown coal to produce 1 kWh (kg/kWh). From this value, the amount of CO\({}_{2}\) produced by burning a specified number of brown coals is then determined. First, the proportion of carbon in this fuel is determined. The composition of coal is commonly stated as:  
\[C+H+S+O+N+W+A=100\%, \tag{10}\]  
where \(C\), \(H\), \(S\), \(O\), \(N\) corresponds to the percentage of flammable components of each element (%), \(W\) is water content (%) and \(A\) is ash content (%).