# Improving the Efficiency of Energy Consumption in Buildings: Simulation of Alternative EnPC Models
## 5 Conclusions  
Given that buildings consume about 40% of total energy consumption in the EU and generate approximately 36% of greenhouse gases in continental Europe, the EU has created various funding programs to support and promote research in the construction \begin{table}
\begin{tabular}{c c c c} \hline \hline  & \multicolumn{3}{c}{**NPV (EUR)**} \\ \hline  & \multicolumn{3}{c}{**First-Out Contract**} \\ \hline
**Annual Energy Savings (\%)** & **Contract Duration (Years)** & **Client** & **Company** \\ \hline
**15** & **9** & 19,317.40 & 614.45 \\ \hline
**20** & **7** & 34,510.30 & 1115.16 \\ \hline
**25** & **6** & 49,373.00 & 4900.40 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Main results of sensitivity analysis—First-Out Contracts. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & \multicolumn{5}{c}{**NPV (EUR)**} \\ \hline  & \multicolumn{5}{c}{**Guaranteed Savings**} & \multicolumn{2}{c}{**Shared Savings**} \\ \hline
**Contract Duration (Years)** &
\begin{tabular}{c} **Annual Energy** \\ **Savings (\%)** \\ \end{tabular} & **Client** & **ESCO** & **Client** & **ESCO** \\ \hline  & **15** & 9814.06 & & 37,346.04 & \(-\)19,168.17 \\ \cline{2-6}
**5** & **20** & 28,706.68 & & 47,664.58 & \(-\)13,557.58 \\ \cline{2-6}  & **25** & 47,599.30 & & 60,946.61 & \(-\)7946.98 \\ \hline  & **15** & 12,201.90 & & 24,310.30 & \(-\)6708.44 \\ \cline{2-6}
**10** & **20** & 31,094.50 & & 33,439.14 & 3055.39 \\ \cline{2-6}  & **25** & 49,987.20 & & 42,597.94 & 12,819.22 \\ \hline  & **15** & 13,969.50 & & 16,854.64 & 2514.82 \\ \cline{2-6}
**15** & **20** & 32,862.10 & & **22,909.02** & **15,353.09** \\ \cline{2-6}  & **25** & 51,754.80 & & **28,963.39** & **28,191.37** \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Main results from sensitivity analysis—Guaranteed Savings and Shared Savings Contracts. area, launching Framework Program 7 (which ended in 2013), Horizon2020 (which ended in 2020), and the Energy-efficient Buildings (EeB) cPPP project. As a consequence, Energy Performance Contracts (EnPCs) emerged; these consist of a contractual agreement between a beneficiary and a supplier of an energy efficiency improvement service, which is supervised and monitored over the contractual period. Alongside these contracts, Energy Service Companies (ESCOs) have also emerged. These are entities that are contracted to implement the energy efficiency improvement measures. Of the EnPCs, Guaranteed Savings Contracts, Shared Savings Contracts, and First-Out Contracts are the most prominent. However, EnPCs still face certain difficulties when it comes to implementation, namely the drafting of contracts and the launching of public tenders. The emergence of these contracts, associated with the new contracting models, has led to the need to adapt and improve the procedures for public tenders, including the possibility of energy audits by ESCOs before the initial bidding stage. In the particular case of energy efficiency, the specifications should attach special importance to the technical quality of the proposal and its value. In addition to tendering and contracting difficulties, EnPCs carry other risks, namely financial and market risks, operational and management risks, technological risks, client risks, and external environmental risks. Through analysis of the positive application of Green Public Procurement (GPP) in European countries, it was possible to perform a sensitivity analysis to verify which contract is the most appropriate for application to a school (Canico Elementary School). After selecting the most appropriate solution (30 kW), several simulations were performed with different values being defined for the critical input parameters. An analysis of the simulations results in the recommendation that a Shared Savings Contract be signed in this case study, as it allows both the client and the company to obtain high and balanced NPVs (EUR 28,963.39 for the company and EUR 28,191.37 for the client) for a 15-year contract.