## 2 Methodology
### Methods for Energy and Environmental Assessment
#### 2.2.2 Energy and Environmental Assessment Methods  
[PERSON] and [PERSON] [23] describe the causalities between society and the environment using the terms driver, pressure, state, impact, and response. This concept is called the \begin{table}
\begin{tabular}{c c c c} \hline
**Abbr.** & **Name** & **Description** & **References** \\ \hline \multicolumn{4}{c}{**Energy and Environmental Assessment Methods**} \\ \hline MIPS & Material Input per Service & Converts the environmental impact to material theoretically used per functional unit, life cycle & [PERSON] [45] \\  & & (t/service) & \\ \hline CExC & Cumulative Exergy Consumption & Upstream resource consumption of a product is considered by its exergy (only materials, energy carriers, and products) & [PERSON] [46] \\ \hline ECEC & Ecological Cumulative Exergy Consumption & Upstream resource consumption of a product is considered by its exergy (exergy of natural resources/ecosystem) & Hau and Bakshi [47] \\ \hline EmA & _Energy_ Analysis & Upstream resource consumption considered by _emergy_, which is work completed by nature or man for the realization of a product or service & [PERSON] [48] \\ \hline ELCA & Exergetic Life Cycle & Life cycle irreversibility as the exergy loss during & \\  & Assessment & the life cycle is the impact category (LCA extension) (kJloss/functional unit) & [PERSON] [49] \\ \hline LCEA & Life Cycle Exergy Analysis & Converts the environmental impact to natural resource consumption measured by exergy (k)/functional unit) & [PERSON] [50] \\ \hline ExA & Exergy Analysis & Second-law analysis, definition of useful output & Second law of thermodynamics \\ \hline PhO & Physical Optimum Method & PhO as ideal reference value, & \\  & & PhO factor = real/limit value (PhO) & VDI 4663-1 [51] \\ \hline \end{tabular}
\end{table} 
Table 3: _Cont._DPSIR framework. Accordingly, some methods or indicators evaluate the environmental impact resulting from environmental pressure. These analysis methods can provide a starting point by focusing on the pressure factor. Based on an energy analysis according to the first law of thermodynamics, exergy analysis also includes the second law. For this purpose, the exergy of the energy and material flows is calculated. The chemical exergy of many substances is tabulated for standard conditions [56]. Subsequently, the overall exergy input and the exergy associated with the product are determined. Exergy loss indicates exergy output that is not part of the product and that remains unused. The difference between the exergy of the output flows and the input flows corresponds to exergy destruction. In some cases, transiting exergy should be considered [57]. This analysis reveals irreversibility due to exergy destruction and the potential for coupling processes based on exergy loss. The physical optimum (PhO) method refers to the theoretical ideal reference process, which requires a minimum amount of energy (and other resources) [58]. The ratio of real resource input to this ideal reference value is called the Pho factor, which is the indicator. LCA can be a useful method for analyzing the environmental impacts of products [59]. According to ISO 14040 [2] and 14044 [38], LCA has four phases. Firstly, the goal and scope are defined. The environmental impact refers to a functional unit. Thus, LCA measures the 'eco efficiency' [60]. Secondly, the life cycle inventory is carried out. The third phase is the life cycle impact assessment, which leads to the last phase: life cycle interpretation. Because of the life cycle impact assessment, LCA is not only an analysis, but goes further towards evaluating the environmental impacts using at least midpoint impact-based aggregation. Different impact categories, category indicators, and characterization models exist for the life cycle impact assessment. For example, it can include the global warming potential, the depletion of natural resources, and other impacts. Inspired by LCA methods, footprint methods serve to represent specific environmental impacts, but usually only in one category.