# Cumulative Energy Demand and Carbon Footprint of the Greenhouse Cultivation System
## 3 Results and Discussion
### Cumulative Energy Demand and Carbon Footprint during the Use Phase  
The CED was determined on the basis of non-renewable primary energy needed for GH heating. As biomass has a zero-emission factor; hence, the CO\({}_{2}\) emissions in scenario 3 and scenario 4 are fully related to the generation of auxiliary electricity needed for electric propulsion. The analytical work produced the total values of the annual CED during the use phase in GH cultivation (Table 6). The annual exploitation of a GH, for growing flowers in pots, with coal combustion in the heat source (scenario 1), consumes 5592 GJ\(\cdot\)y\({}^{-1}\) of energy, so the specific value referred to in the unit of the cultivated area is 4473.5 MJ\(\cdot\)m\({}^{-2}\cdot\)y\({}^{-1}\). In scenario 2 for natural gas combustion, the annual CED is 4214 GJ\(\cdot\)y\({}^{-1}\) and 3371.3 MJ\(\cdot\)m\({}^{-2}\cdot\)y\({}^{-1}\) of the GH surface, which means that the CED is reduced by 24.6% compared to scenario 1. In the biomass scenarios (scenarios 3 and 4), the combustion of which, irrespective of the source, is described by a factor or non-renewable primary energy 0.2 [31], the annual CED is the lowest at 934.5 GJ\(\cdot\)y\({}^{-1}\), with a specific value referred to the GH are 747.6 MJ\(\cdot\)m\({}^{-2}\cdot\)y\({}^{-1}\). CED specified in a FU MJ\(\cdot\)unit\({}^{-1}\cdot\)y\({}^{-1}\) of a potted flower is, in coal combustion scenario, 15.2 MJ\(\cdot\)unit\({}^{-1}\cdot\)y\({}^{-1}\), and in gas combustion scenario 11.5 MJ\(\cdot\)unit\({}^{-1}\cdot\)y\({}^{-1}\). In the scenarios with biomass combustion, the CED is 2.5 MJ\(\cdot\)unit\({}^{-1}\cdot\)y\({}^{-1}\), which corresponds to a reduction of 83.3%. The CF in scenario 1 is 458,305 kg CO\({}_{2}\)-eq\(\cdot\)y\({}^{-1}\) per unit of cultivated area 366.6 kg CO\({}_{2}\)-eq\(\cdot\)m\({}^{-2}\cdot\)y\({}^{-1}\). Scenario 2 has an absolute value of 212,604 kg CO\({}_{2}\)-eq\(\cdot\)y\({}^{-1}\), target value per unit area is 170.1 kg CO\({}_{2}\)-eq\(\cdot\)m\({}^{-2}\cdot\)y\({}^{-1}\). Combustion of natural gas brings a reduction of 46.4% compared to scenario 1. In scenario 3, the CF in absolute terms is 25,600 kg CO\({}_{2}\)-eq\(\cdot\)y\({}^{-1}\), and the specific value per unit area is 20.5 kg CO\({}_{2}\)-eq\(\cdot\)m\({}^{-2}\cdot\)y\({}^{-1}\), which is only 5.6% CF determined for the coal combustion scenario. In scenario 4 with wood chips burning, the CF is 23,013 kg CO\({}_{2}\)-eq\(\cdot\)y\({}^{-1}\), which converts to the specific value of 18.4 kg CO\({}_{2}\)-eq\(\cdot\)m\({}^{-2}\cdot\)y\({}^{-1}\), which is also 5.0% of the CF of scenario 1. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Scenario/Fuel**} & \multicolumn{5}{c}{**CED**} & \multicolumn{5}{c}{**CF**} \\ \cline{2-9}  & **MJ\(\cdot\)y\({}^{-1}\)** & **MJ\(\cdot\)m\({}^{-2}\cdot\)y\({}^{-1}\)** & **MJ\(\cdot\)unit\({}^{-1}\cdot\)y\({}^{-1}\)** & **\%** & **kg** & **KG\({}_{\text{O}_{2}}\)-** & **kg CO\({}_{2}\)-** & **\%** \\ \hline
1/coal & 5,591,921 & 4473.5 & 15.2 & 100.0 & 458,305 & 366.6 & 1.245 & 100.0 \\
2/natural gas & 4,214,067 & 3371.3 & 11.5 & 75.4 & 212,604 & 170.1 & 0.578 & 46.4 \\
3/wood pellets & 934,523 & 747.6 & 2.5 & 16.7 & 25,600 & 20.5 & 0.070 & 5.6 \\
4/wood chips & 934,523 & 747.6 & 2.5 & 16.7 & 23,013 & 18.4 & 0.063 & 5.0 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: CED and CF for individual scenarios expressed as absolute values, as well as specific values per unit area and per unit of a potted flower.