Business Models in the context of carbon mitigation: New Questions and Approaches illustrated by the Example of Energy Performance Contracting in Germany

The German government has set ambitious climate protection targets to limit global warming. The goal is to achieve an energy efficient and almost climate-neutral building stock by 2050. This will require, among other actions, a reduction of the primary energy demand of buildings by up to 95% by the end of 2050. In order to achieve an almost climate-neutral building stock, measures for deep energy retrofit are required. In addition to an existing financial demand, there are additional barriers to the expansion of activities to improve the energy performance and to reduce greenhouse gas (GHG) emissions of the existing building stock. One way to overcome these barriers are novel business models such as Energy Performance Contracting (EPC). The question arises as to whether and how the reduction of GHG emissions can be taken into account in the savings guarantees as they are typical for EPCs. This and other questions are addressed in the paper using conjoint analysis. Among other results, it is pointed out that specific approaches are required for different target groups such as the public sector and private homeowners. Finally, recommendations for further action are given. The presented partial results are drawn from the research work "Analysis of business models with regard to their potential for GHG reduction and energy efficiency of buildings"

IEA EBC Annex 72 - Assessing life cycle related environmental impacts caused by buildings - Targets and tasks

Investment decisions for buildings made today largely determine their environmental impacts over many future decades due to their long lifetimes. Such decisions involve a trade-off between additional investments today and potential savings during use and at end of life - in terms of economic costs, primary energy consumption, greenhouse gas emissions and other environmental impacts. Life cycle assessment (LCA) is suited to identify measures and action to increase the resource efficiency and the environmental performance of buildings and construction. This paper gives an overview of an ongoing international research project within the IEA EBC with the overall aim to harmonise LCA approaches on buildings and foster life cycle thinking in the real estate and construction sectors. The objectives of the project are i) to establish a common methodology guideline to assess the life cycle based environmental impacts caused by buildings, ii) to establish methods for the development of specific environmental benchmarks for different types of buildings, iii) to derive regionally differentiated guidelines and tools for the use of LCA in building design and tools such as BIM, and iv) to improve data availability by developing national or regional databases with regionally differentiated LCA data tailored to the construction sector. To ensure practical solutions a number of case studies will be used to test and illustrate the consensus approaches and research issues

To weigh or not to weigh. Recommendations for communicating aggregated results of buildings LCA

Interpreting contradictory results of multiple midpoint environmental indicators is challenging task. Hence, partial or full aggregation into building single scores has gained ground for the clear message they convey. This paper helps to improve understanding of the possibilities and limitations of such practice. Partial aggregated scores of five buildings were explored, limited to the environmental indicators shared by the methods examined and inventoried for the case studies. In general, the buildings’ single score ranking was maintained regardless of the aggregation approach, but rank reversal is possible if e.g., ecotoxicity impact indicators are considered. Such indicators are directly influenced by the mass of metals used in a building. Furthermore, uncertainties on their results, in LCI data and in impact and damage assessment are high, and experience with them is still limited. No single best aggregation stands out per se. All of them can play their part if officially supported to ensure that coherent weights/factors are built upon solid, up-to-date data and fair intergenerational and income equity valuation procedures. In such cases, LCA practitioners are encouraged to use single scores in addition to environmental profiles or selected indicators. Overall aggregation procedures shall be transparently described, and zero pure time preference rate and equity weighting applied and explicitly declared. Sensitivity/uncertainty analysis shall be performed to assess results robustness, potential ranking reversal risks, and the effect of different discount rates. When partial aggregation is alternatively pursued, it shall be based on endpoint categories

Interaktionen zwischen Anbaubedingungen, Pilzbefall, Backqualität und Mykotoxinbelastung in der ökologischen Weizenproduktion

1. Feldversuche Die Winterweizensorten Arina und Capo wurden im Versuchsjahr 2002/2003 auf insgesamt 12 Standorten im Ökologischen Anbau als Reinbestände und als Sortenmischung angebaut. Das Versuchsjahr war extrem trocken, weshalb kein relevanter Krankheitsbefall zu verzeichnen war. Die Erträge variierten je nach Standort von 26 bis 53 dt/ha wobei Capo deutlich ertragsstärker war als Arina. Die Mischung brachte im Schnitt 3% mehr Ertrag als erwartet und war im Ertrag deutlich stabiler. Dies war auf die stärkere Konkurrenzkraft der Sorte Capo an fast allen Standorten zurückzuführen. Arina übertraf Capo signifikant im Rohprotein (RP) (12.9 versus 12.2%) und Feuchtklebergehalt (FK) (29.8 versus 25.3%), was auch im Backvolumen reflektiert wurde. Während bei Arina RP und FK mit dem Backvolumen mittelmäßig korrelierten (R2=0.45), bestand keinerlei Zusammenhang zwischen diesen Parametern bei Capo. Im Gegensatz dazu war der Zusammenhang in der Mischung so stark wie bei Arina. Die Mischung verhielt sich insgesamt wie erwartet, konnte aber stärker von verbesserten Standortbedingungen profitieren als die beiden Einzelsorten. In einem Exaktversuch wurden 8 Sorten und 12 Mischungen auf Ertrag und Backqualität nach zwei Vorfrüchten getestet. Wie in den Praxisversuchen entsprachen die Mischungen den Erwartungen oder übertrafen sie leicht, aber nicht signifikant. Die Ergebnisse legen nahe, dass Sortenmischungen mindestens so gut, wenn nicht besser zur Erzeugung von Qualitätsweizen geeignet sind. . 2. Serologischer Fusarien- und Mykotoxinnachweis Serologische Testmethoden, die bereits erfolgreich für die Bewertung der Resistenz von Getreidegenotypen nach künstlicher Inokulation mit Fusarium-Isolaten eingesetzt werden konnten, wurden für die Prüfung von insgesamt 164 Weizenproben aus dem Ökoanbau angewandt. Die Untersuchungen ergaben einen insgesamt sehr geringen Fusarium-Befall. Der Gehalt an Fusarium-Exoantigenen (ExoAg) sowie die Kontamination mit den Mykotoxinen DON und ZEA lagen bei den untersuchten Proben in der Regel unterhalb der Nachweisgrenzen der jeweiligen Testsysteme. Eine Analyse der in Weizenkörner nachweisbaren Antigene ergab, dass es sich hierbei hauptsächlich um glykosilierte Proteine handelt, die infolge eines Befalls mit Fusarium-Arten gebildet werden. Für den Nachweis von Mykotoxinen können die Testsysteme „Ridascreen DON“ und "Ridascreen Zearalenon“ empfohlen werden

Embodied GHG emissions of buildings – The hidden challenge for effective climate change mitigation

Buildings are major sources of greenhouse gas (GHG) emissions and contributors to the climate crisis. To meet climate-change mitigation needs, one must go beyond operational energy consumption and related GHG emissions of buildings and address their full life cycle. This study investigates the global trends of GHG emissions arising across the life cycle of buildings by systematically compiling and analysing more than 650 life cycle assessment (LCA) case studies. The results, presented for different energy performance classes based on a final sample of 238 cases, show a clear reduction trend in life cycle GHG emissions due to improved operational energy performance. However, the analysis reveals an increase in relative and absolute contributions of so‐called ‘embodied’ GHG emissions, i.e., emissions arising from manufacturing and processing of building materials. While the average share of embodied GHG emissions from buildings following current energy performance regulations is approximately 20–25% of life cycle GHG emissions, this figure escalates to 45–50% for highly energy-efficient buildings and surpasses 90% in extreme cases. Furthermore, this study analyses GHG emissions at time of occurrence, highlighting the ‘carbon spike’ from building production. Relating the results to existing benchmarks for buildings’ GHG emissions in the Swiss SIA energy efficiency path shows that most cases exceed the target of 11.0 kgCO$^{2}$eq/m$^{2}$a. Considering global GHG reduction targets, these results emphasize the urgent need to reduce GHG emissions of buildings by optimizing both operational and embodied impacts. The analysis further confirmed a need for improving transparency and comparability of LCA studies

Embodied GHG emissions of buildings - Critical reflection of benchmark comparison and in-depth analysis of drivers

In the face of the unfolding climate crisis, the role and importance of reducing Greenhouse gas (GHG) emissions from the building sector is increasing. This study investigates the global trends of GHG emissions occurring across the life cycle of buildings by systematically compiling life cycle assessment (LCA) studies and analysing more than 650 building cases. Based on the data extracted from these LCA studies, the influence of features related to LCA methodology and building design is analysed. Results show that embodied GHG emissions, which mainly arise from manufacturing and processing of building materials, are dominating life cycle emissions of new, advanced buildings. Analysis of GHG emissions at the time of occurrence, shows the upfront \u27carbon spike\u27 and emphasises the need to address and reduce the GHG \u27investment\u27 for new buildings. Comparing the results with existing life cycle-related benchmarks, we find only a small number of cases meeting the benchmark. Critically reflecting on the benchmark comparison, an in-depth analysis reveals different reasons for cases achieving the benchmark. While one would expect that different building design strategies and material choices lead to high or low embodied GHG emissions, the results mainly correlate with decisions related to LCA methodology, i.e. the scope of the assessments. The results emphasize the strong need for transparency in the reporting of LCA studies as well as need for consistency when applying environmental benchmarks. Furthermore, the paper opens up the discussion on the potential of utilizing big data and machine learning for analysis and prediction of environmental performance of buildings

Existing benchmark systems for assessing global warming potential of buildings – Analysis of IEA EBC Annex 72 cases

Life cycle assessment (LCA) is increasingly being used as a tool by the building industry and actors to assess the global warming potential (GWP) of building activities. In several countries, life cycle based requirements on GWP are currently being incorporated into building regulations. After the establishment of general calculation rules for building LCA, a crucial next step is to evaluate the performance of the specific building design. For this, reference values or benchmarks are needed, but there are several approaches to defining these. This study presents an overview of existing benchmark systems documented in seventeen cases from the IEA EBC Annex 72 project on LCA of buildings. The study characterizes their different types of methodological background and displays the reported values. Full life cycle target values for residential and non-residential buildings are found around 10-20 kg CO$_2$e/m$^2$/y, whereas reference values are found between 20-80 kg CO$_2$e/m$^2$/y. Possible embodied target- and reference values are found between 1-12 kg CO$_2$e/m$^2$/y for both residential and non-residential buildings. Benchmark stakeholders can use the insights from this study to understand the justifications of the background methodological choices and to gain an overview of the level of GWP performance across benchmark systems

Towards a life cycle sustainability assessment method for the quantification and reduction of impacts of buildings life cycle

The construction and building sectorsare one of the highestconsumersof resourcesand energy. Literature evidences the potentialities of the design phase towardsthe improvement of environmental, economic and social performance of buildings. Thus, the Life Cycle Sustainability Assessment (LCSA) approach is recognized as suitable method. It isbased on the “triple bottom line”principle, to calculate environmental, economic, social impacts produced by buildings during itslife cycle. The present paper aims to present a methodological framework based on anLCSA, used during design stages of buildings and integrated into a building’s design technology such as Building Information Modeling (BIM). A conceptual approach to conduct the data integration and a possible workflow to integrate the LCSA into BIMis proposed. The value of the present approach is the possibility to conductquantitative environmental, economic and social assessment of buildings to guide designers to measure and predict the building’s performanc