Weighted eco-efficiency for energy systems: What can we learn from different stakeholder groups?

Nowadays energy systems are expected to comply with a great range of technical, economical, environmental and social criteria. Due to the pressuring climate targets launched by the European Union, more attention and effort is paid to decarbonize the current energy systems, e.g. by integrating more renewable energy carriers into the electricity grid.
Next to economic evaluations of energy systems, more environmental assessments were established over the last decade. However, decision-makers and stakeholders are left with a wide range of indicators to find consensus amongst the evaluated energy systems. Additionally, stakeholders might express different preferences for the single indicators.
Therefore, a new method is proposed to reflect the stakehoder preference for economic and environmental evaluation of energy systems. To examplify this new method and the results of different stakeholders, a case study of a residential energy system is presented.
First, the energy system is simmulated by a design and optimization tool using mixed-integer linear programming. Second, the carbon footprint (CF) and the levelized cost of electricity (LCOE) are calculated and integrated into the model. Third, the CF and LCOE are then weighted according to the preferences of different stakeholders. Consumption and generation data of the residential energy system originate from primary sources. Weighting data herefore are obtained from stakeholder workshops. Forth, the weighted CF and LCOE are used to calculate the eco-efficiency of the energy system for various stakeholders. Fifth, in the same manner, the eco-efficiency of the national grid is determined and used as a benchmark.
Overall, a higher eco-efficiency will represent higher emissions and costs. Therefore, the eco-efficiency of energy systems integrating more renewable energy sources will be, expected to be lower, compared to the benchmark.
In general, this study examplifies the linkage of CF and LCOE methodology with energy system programs, which can be adapted to other sites. Besides, the variance of the eco-efficiency of different stakeholders is presented.
In the context of the European energy crisis, the proposed method provides a valuable assessment for further accommodating renewable energy carriers.