## 5 Conclusions and Outlook  
Digital twins are a welcome development in the field of digital manufacturing, with many important and useful applications. Since environmentally sustainable requirements are increasing upon manufacturers, it seems fitting that digital twins should also transform to incorporate solutions for companies attempting to become greener in their approaches to products and processes. The work presented above investigates this correlation and the means to transform this potential into concrete solutions to be implemented by software companies that develop twins for real production systems, or firms that create their own local combinations. By relying on such analyses, the results that can be accomplished will have an increased usability and will produce a faster return on the investment. The process of steering the \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Nr. Crt.**} & **Conlicting Attribute 1** & **Conlicting Attribute 2 and** & **TRIZ Contradiction Matrix** & **TRIZ Feature Guiding the** & **Digital Twin** \\  & **Association Feature** & **TRIZ Association Feature** & **Solution Principles** & **Environmental Function** \\ \hline \multirow{3}{*}{**1**} & Data analytics & Visualization options & 1 Segmentation & \\  & 39 Productivity & 33 Ease of operation & 7 Nested dolls & 19 Use of energy by moving 20 Use of energy by stationary 22 Loss of energy \\  & & & 10 Preliminary action & 22 Loss of energy \\ \hline \multirow{3}{*}{**2**} & Process sensors & ML/decision-making & 34 Discarding and recovering & 23 Loss of substance \\  & 37 Difficulty of detecting & 38 Extent of automation & 21 Skipping & \\ \hline \multirow{3}{*}{**3**} & Cyber security protection & Two-way communication & 35 Parameter changes & 27 Reliability \\  & 30 Object-affected harmful & 35 Adaptability or versatility & 11 Beforehand cushioning & 30 Object affected harmful \\  & & 35 Adaptability or versatility & 22 “Blessing in disguise” & 31 Porous materials & \\ \hline \multirow{3}{*}{**4**} & Control mechanisms & Data analytics & 15 Dynamics & 24 Quantity/Quality \\  & 33 Ease of operation & 39 Productivity & 1 Segmentation & 15 Durability of moving object \\  & & 39 Productivity & 28 Mechanics substitution & 16 Durability of \\  & & & & non-moving object \\ \hline \multirow{3}{*}{**5**} & IoT/CPS & VR immersion/AR collocation & 1 Segmentation & 35 Adaptability or versatility \\  & 28 Measurement accuracy & 34 Ease of repair & 13 The other way round & 38 Extent of automation \\  & & & 11 Beforehand cushioning & 39 Productivity \\ \hline \hline \end{tabular}
\end{table} 
Table 2: TRIZ40 Platform [46] solutions for the identified digital twin attributes contradictions (numbers indicate the reference generic feature or inventive principle). development of digital twins in a strategically sound direction that makes use of advanced computing and sensor technologies, while solving important environmental issues, has the possibility to transform the manufacturing sector into one of the champions of the new net-zero carbon economy. The same idea holds true and is implemented on a large scale in smart cities and homes and in precision agriculture, with the production sector being forced to keep up with the new economic and social paradigm that is taking shape in the present. Environmental issues are not yet in the focus of manufacturing, due to the competitive pressures on production companies to deliver quality products at lower and lower costs. Among the guidelines to be revealed by the study, we mention the following functions that can present interest to companies and, therefore, should also be approached by twin solution creators:  
* Analysis and monitoring of material input and outputs. * Real-time tracking of waste, emissions, and discharges. * Product lifecycle management with live cloud database connections. * Assessment of the circularity potential and achievements. * Quantification of greenhouse-gas emissions, effects, and synergies. * Reporting based on mandatory and voluntary schemes.