Energy storage systems for family dwellings such as thermal and battery energy storage systems are of significant interest for several reasons, particularly in the context of increasing renewable energy adoption, ensuring grid resilience, and reducing environmental impact. This study examines the potential life cycle energy savings and environmental impacts related to the addition of the two energy storage technologies namely thermal such as a domestic hot water tank (DHW) and electrical which is a battery bank and attempts to evaluate the contribution of each component to the whole life cycle impacts. Moreover, the use of a second life electric vehicle Li-on NMC battery bank is examined as an optional replacement of a stationary battery bank LiFePO4. For a reference case is used a detached single-family house with a roof top photovoltaic system which has a compact exhaust air heat pump system to provide the hot water and space heating annual demand for the Swedish climate conditions. High resolution weather data and historic price data for the same year as well as stochastic occupancy profiles that include the domestic hot water load are used as boundary for a parametric simulation study for the system modelled in detail in TRNSYS 17. Main results show as far as the life cycle cost comparison that thermal storage has the least life-cycle cost among the three examined energy storage options. Examining the global warming potential of the first life of the electrical storage is found to be approximately more than 5 times the impact of the domestic hot water tank comparing the specific products from the two storage types. 

To assess the progress towards a circular economy, numerous circularity metrics have been developed in recent years. However, there is a lack of alignment between circularity metric results and greenhouse gas emissions, as circularity metrics are mainly geared towards capturing material efficiency of circularity strategies and mostly disregard energy use. We target this gap by developing a new mass-based circularity metric that considers both material and energy resources (i.e., fuel and electricity). The circularity metric results are compared to the midpoint impact category Global Warming Potential in two case studies, where circularity strategies are applied to energy consuming products in several different scenarios. The results show that by including energy resources, the new metric is more aligned with GWP than purely material-based metrics. We discuss how this alignment changes in different systems and in which situations the circularity metric is a suitable proxy for GWP. 

Increased self-sufficiency and circularity are often presented as means to decrease the environmental impact from urban resource management, but more knowledge is needed about how this approach in fact compares with conventional systems from a life-cycle perspective when resource consumption and emissions from both the production and for running the processes are included. This paper presents the results from a life-cycle assessment for energy, water, and wastewater systems in a Swedish, urban neighbourhood where local, more self-sufficient and circular systems, including solar power, rainwater harvesting, and resource recovery from wastewater, were compared to conventional, centralized systems. The analysis revealed that the cases with local systems had a lower marine eutrophication and land use impact, but they did not decrease the environmental impact in terms of global warming, mineral resource depletion, and freshwater eutrophication in this site with well developed, efficient conventional systems. There were however differences between the subsystems, such as a lower global warming potential for local wastewater management due to avoided impacts from resource recovery. Local systems also had advantages under certain conditions, such as in neighbourhoods with large infrastructure networks per person and long distances to connect to the existing infrastructure grids. For planners and decision-makers, this study indicates that self-sufficiency is currently rather motivated by other benefits than decreased environmental impact in places with similar conditions to this study. It also highlights that these systems are more worthwhile from an environmental perspective in the above-mentioned conditions or in sites with larger environmental impact from the conventional systems. For producers, some key areas for improvement to decrease the environmental impact include production of photovoltaic modules and batteries for electricity, leakage of refrigerant from heat pumps for the heat supply, production of the storage tank for rainwater collection, production of expanded clay as filter material for the greywater treatment, production of sodium hydroxide for blackwater treatment, and emissions in operation for both greywater and blackwater treatment.

The development of new urban areas offers a unique opportunity to improve urban resource management, where a more local resource provisioning, through decentralized and integrated infrastructure systems, can be put forward as an alternative approach for potentially reducing the environmental impact and increasing the resilience of vital functions. This study is based on a transdisciplinary workshop series with local stakeholders in the Swedish municipality of Knivsta, where a conceptual model illustrating a future decentralized and integrated infrastructure system was iteratively developed, resulting in a possible design with high societal relevance and feasibility due to this transdisciplinary process. The performance of selected solutions, in terms of the annual level of self-sufficiency in energy, water, and nutrients, was quantified, where the potential for a local provisioning of resources in a typical multifamily building neighborhood in Knivsta was up to 66% for heat, 24% for transportation, and 38% for vegetable supply. For a neighborhood with the same population, but with single-family houses requiring a larger area for both the buildings and private gardens per person, the potential was 31% for heat, 10% for transportation, and 210% for vegetable supply. Electricity, water, and graywater management could be fully supplied in all studied cases. Our findings demonstrate that decentralization and integration can provide important opportunities for utilizing resources in the urban environment, contributing to the desired functions of energy, water, and nutrients, even in countries with relatively cold and dark climates, although these are not enough for urban areas to be fully self-sufficient with their current levels of resource consumption.

Previous research has shown a lack of studies with comparisons between primary (virgin) and secondary (re-used) building materials, and their embodied emissions. The creation of different scenarios comparing the environmental impact of virgin vs. re-used materials is also motivated by the scarcity of raw materials in the world and the emergency of mitigating greenhouse gas (GHG) emissions from buildings. The aim of this study was to investigate scenarios, including new vs. re-used building products, applying the LCA method for a wooden single-family building. The findings showed a 23% reduction potential for total released (positive) CO2e when comparing the Reference scenario with Scenario I, using re-used wooden-based materials. Further, Scenario II, using all re-used building materials except for installations, showed a 59% CO2e reduction potential compared to the Reference scenario. Finally, Scenario III, which assumes all re-used building products, showed a 92% decreased global warming potential (GWP) impact compared to the Reference scenario. However, when including biogenic carbon and benefits (A5 and D module), the Reference scenario, based on newly produced wooden building materials, has the largest negative GHG emissions. It can be concluded that the re-use of building products leads to significant carbon savings compared to using new building products.

Greenhouse Gas (GHG) emissions significantly impact the environment and human health, but many people are unaware of how their daily choices affect climate change. Carbon calculators estimate emissions in sectors like construction, digital health, transportation, and food production. However, they are still developing and face challenges that require attention from both industry and academia. Researchers highlight the absence of a unified framework for assessing these tools, leading to simplistic binary evaluations, which result in inaccuracies in household tool evaluations. In the current study, an assessment framework has been created by integrating existing binary frameworks and incorporating the MCDA method for weighted multi-criteria evaluation, offering a quantitative scoring system for qualitative criteria. This dual-criteria framework addresses both practical and academic aspects of the evaluated tools. The framework was used to evaluate 15 tools chosen for their prominence in search engine results and their impact on scientific publications. Findings revealed that tools such as Svalna, WWF calculator, and Carbon Savvy produce comparable results, while others, like the UN CF calculator, show deviations up to 136 tons. The study highlights challenges related to feasibility, availability of resources, and user engagement, noting that the criterion for accessibility for special groups received a score of zero across all CF tools. The work is expected to yield enhanced understanding that will aid in the selection of appropriate CF tools, foster sustainable practices, and offer developers direction to ensure their designs conform to established standards.

The aim of this study was to investigate how the carbon accounting of a wooden single-family house is affected by (1) decreasing the carbon footprint by changes in building design, (2) differentiating biogenic carbon from fossil carbon and (3) including external benefits beyond the state-of-the-art system boundaries. The motivation of exploring different system boundaries, improved building design and investigating benefits aside of system boundaries rely on the fact of having the “full” picture of GHG emissions of building products. Changes in building design were analyzed by life cycle assessment (LCA) focusing on greenhouse gas (GHG) emissions, while the costs were assessed by using lice cycle cost (LCC). The findings showed that by including positive and negative emissions from the production phase for an improved building design within scenario 4 ‘Cradle to Gate + Biogenic Carbon + D module’ has the lowest embodied GHG emissions when compared to other approaches with −3.5 kg CO2e/m2/y50. Considering the impacts of the whole building, the lowest GHG emissions are within the scenario 8 ‘Cradle to Grave + Biogenic Carbon + D module‘ for the improved building design with −0.7 kg CO2e/m2/y50. The results suggest that a change to sustainable alternatives for building components that makes the whole building to be constructed by wood, could lead to significant reduction of GHG emissions compared to conventional material choices. Economically, testing sustainable solutions, the highlighted results are the construction costs that are almost double higher for CLT elements for the foundation compared to concrete.

In this study, an environmental and economic assessment of hydrogen production from biowaste and biomass is performed from a life cycle perspective, with a high degree of primary life cycle inventory data on materials, energy, and investment flows. Using SimaPro LCA software and CML-IA, 2001 impact assessment method, ten environmental impact categories are analyzed for environmental analysis. Economic analysis includes capital and operational expenditures and monetization cost of life cycle environmental impacts. The hydrogen production from biowaste has a high climate impact, photochemical oxidant, and freshwater eutrophication than biomass while it performs far better in ozone depletion, terrestrial ecotoxicity, abiotic depletion-fossil, abiotic depletion, human toxicity, and freshwater ecotoxicity. The sensitivity analysis of LCA results indicates that feedstock to biogas/pyrolysis-oil yields ratio and the type of energy source for the reforming process can significantly influence the results, particularly climate change, abiotic depletion, and human toxicity. The life cycle cost (LCC) of 1 kg hydrogen production has been accounted as 0.45–2.76 € with biowaste and 0.54–3.31 € with biomass over the plant's lifetime of 20 years. From the environmental impacts of climate change, photochemical oxidant, and freshwater eutrophication hydrogen production from biomass is a better option than biowaste while from other included impact categories and LCC perspectives it’s biowaste. This research contributes to bioresources to hydrogen literature with some new findings that can be generalized in Europe and even globally as it is in line with and endorse existing theoretical and simulation software-based studies.

The food supply chain is responsible for a large share of the anthropogenic contribution to global warming, as well as being a major contributor to several other impact categories such as acidification and eutrophication. Therefore, it is necessary to find ways of limiting the impact from food production and the food supply chain. Many crops are not adapted to growing in regions with cold climate, which creates the need to either import them or to use production methods such as greenhouses to artificially create good conditions for the crops. Sweden is currently reliant on imports for many different crops, including tomatoes where most of the consumption is covered by import from the Netherlands. This study uses life cycle assessment to analyze the potential environmental impact of Swedish tomato consumption, by comparing several year-round domestic production scenarios with scenarios representing import from the Netherlands. This is done by using a greenhouse simulation software to simulate a theoretical greenhouse placed in both countries, and then using the simulation results in combination with data from the database EcoInvent to perform a life cycle assessment. The results showed that Swedish domestic production has the potential to decrease the environmental impact of tomatoes consumed in Sweden, when compared to import from the Netherlands. There were a couple of combinations of production scenarios and impact categories where the Dutch production performed better, but the Swedish production scenarios performed better in general. The results also clearly showed that scenarios using LED lighting systems consistently had a lower impact than similar production scenarios using high-pressure sodium lighting systems. The choice of energy sources was identified as a crucial factor when it comes to the environmental impact of the studied systems.

The concept of Circular Economy is a principle aiming to improve sustainable development by reducing resource use and impact on ecological systems. An increasing number of companies are applying this theory on design strategies and business models in order to close, slow and narrow material loops. To highlight the importance, guide practitioners, and evaluate the progress of circular economy, a high number of circularity metrics (C-metrics) have been developed. However, little attention has been given to creating a connection between quantification of circularity and environmental performance. Existing metrics also do not highlight the interplay between micro (product), meso (industrial symbiosis), and macro (regional) level circularity. Moreover, existing metrics do not capture all material loops and do not adopt a value chain perspective on material flows. To improve the connection between C-metrics and environmental performance, a framework connecting circular economy strategies and material flows was developed. Based on this framework, a material flow-based C-metric was designed aimed at converting mechanisms of closing, narrowing and slowing material loops into a single-point value. To evaluate its feasibility, the metric was tested on three circular business models that represent all three mechanisms in a value chain perspective. The results showed that the metric is feasible in more situations than existing metrics and that the circularity value is highly dependent on assumptions. In future studies, the metric should be tested and compared to Life Cycle Assessments on multiple system levels to ensure that it generates valid results. Furthermore, user input assumptions should be standardized to ensure metric reliability.