Environmental and Economic Prioritization of Building Energy Refurbishment Strategies with Life-Cycle Approach

Abstract

An increasing number of studies apply life-cycle assessment methodology to assess the impact of a new building or to prioritize between different building refurbishment strategies. Among the different hypotheses to consider during the application of this methodology, the selection of the impact indicator is critical, as this choice will completely change the interpretation of the results. This article proposes applying four indicators that allow analysing the results of a refurbishment project of a residential building with the life-cycle approach: non-renewable primary energy use reduction (NRPER), net energy ratio (NER), internal rate of return (IRR), and life-cycle payback (LC-PB). The combination of environmental and economic indicators when evaluating the results has allowed to prioritize among the different strategies defined for this case study. Furthermore, an extensive sensitivity assessment reflects the high uncertainty of some of the parameters and their high influence on the final results. To this end, new hypotheses related to the following parameters have been considered: reference service life of the building, estimated service life of material, operational energy use, conversion factor, energy price, and inflation rate. The results show that the NRPE use reduction value could vary up to −44%. The variation of the other indicators is also very relevant, reaching variation rates such as 100% in the NER, 450% in the IRR, and 300% in the LC-PB. Finally, the results allow to define the type of input or hypothesis that influences each indicator the most, which is relevant when calibrating the prioritization process for the refurbishment strategy.

Analysis of Energy Retrofit Assessment Methodologies in Buildings by European Research Projects

“…The Economical scope has a specific evaluation in all the projects, but by different indicators and calculation methods. As a complete economic assessment, ALDREN [10], REVALUE [15], OptEEmAL [25] and EASEE [26] have used life cycle thinking methods, the Life Cycle Cost method (LCC) [42], for their economic calculations. With a similar treatment, ENERPAT and EFFESUS use the Circular Economy (CE) [9] bases, in this case also evaluating the whole life cycle in terms of economy [9]; further, they are focused on the local economy, enhancing the use of local material and techniques to boost local business and logistic easiness [9].…”

Environmental assessment of four Basque University campuses using the NEST tool

“…Qualitative tools are related to Multi Criteria Sustainability Evaluation systems, such as DGNB (German Sustainable Building Council), BREEAM (Building Research Establishment Environmental Assessment Method) or LEED (Leadership in Energy and Environment Design), which are of great significance at international levels, and play a key role in the whole development of sustainability [33]. Based on different calculation systems, these evaluation systems determine a score range for each assessed parameter and once that score has been attained, the end user obtains the final score or rating [34].…”

Energy Effectiveness or Economic Profitability? A Case Study of Thermal Modernization of a School Building

“…On the other hand, also many authors have presented more complex methods that require complicated calculations or dedicated computer programs. Among different indicators and assessment methods there were used Net Present Value (NPV) [39], global cost [40], macroeconomic and a financial cost [41], multi-objective optimization [40], or life cycle assessment (LCA) [42][43][44]. These comprehensive approaches differ from those adopted in Polish regulations [45], but the general direction is the same-selection of the measure with the lowest SPBT to choose optimal variant of investment.…”