Time-dependent climate impact of short rotation coppice willow–based systems for electricity and heat production

Fossil fuel use and man-made land use change has increased carbon dioxide (CO₂) levels in the atmosphere, contributing to climate impacts such as global warming. Perennial crops such as short rotation coppice (SRC) willow have received attention because of their potential to sequester carbon (C) from the atmosphere and build up soil organic carbon stocks while producing biomass which can be used to generate energy services. The aim of this thesis was to assess the climate impact of bioenergy systems and develop the methodology used to evaluate these systems. The biomass from a SRC willow plantation can be used in a number of different ways to produce energy services. Specific objectives of this thesis were to investigate the energy efficiency and time-dependent climate impact of SRC willow–based bioenergy systems using different ways of converting the biomass into electricity and heat. Life cycle assessment (LCA) methodology was used to enable the assessment of time-dependent climate impacts using a time-distributed inventory and a time-dependent indicator, i.e. the global mean surface temperature change (∆Ts). Several different ways of generating electricity and/or heat from the biomass produced at a SRC willow plantation were compared, taking biogenic C stock changes into account. The main conclusions were that SRC willow–based bioenergy systems can be truly C negative and help contribute to counteract the current trend in global warming while delivering renewable energy at the same time. The choice of energy conversion technology affects both the energy efficiency and the potential climate impact mitigation potential of the system. Biogenic C pools can have a very large influence on the climate impact in bioenergy systems. It is therefore important to take these pools into account whenever land use or management changes take place, in order to counteract global warming more effectively

Biogas plant management decision support – a temperature and time-dependent dynamic methane emission model for digestate storages

The aim was to develop a temperature and time-dependent model that can calculate the methane production in an anaerobic digester and its subsequent digestate storage tank under realistic and variable conditions. With a daily resolution, the model was applied to a Swedish dairy farm under two different climatic conditions. The most influential parameters were hydraulic retention time and the substrate specific first order reaction rates in the digester, which have a big influence on the residual biogas potential, and hence the potential methane production in the digestate storage. The management of the storage can have a large impact on the emissions from the storage due to its temperature dependence. The model can be used to support plant design and operation of anaerobic digesters and storages, but further research is needed to determine first-order reaction rates and the relationship between the ambient and digestate temperatures at different times of the year

Climate impact of willow grown for bioenergy in Sweden

Short-rotation coppice willow (SRCW) is a fast-growing and potentially high-yielding energy crop. Transition to bioenergy has been identified in Sweden as one strategy to mitigate climate change and decrease the current dependency on fossil fuel. In this study, life cycle assessment was used to evaluate and compare the climate impacts of SRCW systems, for the purpose of evaluating key factors influencing the climate change mitigation potential of SRCW grown on agricultural land in Sweden. Seven different scenarios were defined and analysed to identify the factors with the most influence on the climate. A carbon balance model was used to model carbon fluxes between soil, biomass and atmosphere under Swedish growing conditions. The results indicated that SRCW can act as a temporary carbon sink and therefore has a mitigating effect on climate change. The most important factor in obtaining a high climate change-mitigating effect was shown to be high yield. Low yield gave the worst mitigating effect of the seven scenarios, but it was still better than the effect of the reference systems, district heating produced from coal or natural gas

Albedo on cropland: Field-scale effects of current agricultural practices in Northern Europe

Agricultural land use and management affect land surface albedo and thus the climate. Increasing the albedo of cropland could enhance reflection of solar radiation, counteracting the radiative forcing (RF) of greenhouse gases (GHGs) and local warming. However, knowledge is lacking on how agricultural practices affect albedo under local conditions, and on the benefits of individual practices. In this study, field measurements were made in 15 paired plots at a site in Northern Europe to determine albedo, net shortwave irradiance and RF impacts under various common crops, cultivation intensities and tillage practices. Field data for 2019-2020 were compared with satellite-based albedo for the surrounding region in 2010-2020. At regional level, different combinations of soil type, yearly weather and agricultural practices led to great variability in the albedo of individual crops, despite similar pedo-climatic conditions. At field level within years, albedo differences were determined mainly by crop type, species-specific phenology and post-harvest management. Annual albedo was higher with perennial ley (0.20-0.22) and winter-sown crops (0.18-0.22) than with spring-sown crops (0.16-0.18) and bare soil (0.13). Barley had the highest albedo among winter and spring cereals. In summer, when increased albedo could alleviate local heat stress, oats reduced net shortwave irradiance at the surface by 0.8-5.8 Wm(-2) compared with other cereals, ley, peas or rapeseed. Delayed or reduced tillage gave high local cooling potential (up to-13.6 Wm(-2)) in late summer. Potential benefits for global mean climate as GWP(100 )per hectare and year reached-980 kg CO(2)e for avoiding black fallow,-578 kg CO(2)e for growing a winter-sown variety and-288 kg CO(2)e for delayed tillage. Thus realistic albedo increases on cropland could have important effects on local temperatures and offset a substantial proportion of the RF deriving from field-scale GHG emissions on short time-scales

Albedo impacts of current agricultural land use: Crop-specific albedo from MODIS data and inclusion in LCA of crop production

Agricultural land use and management practices affect the global climate due to greenhouse gas (GHG) fluxes and changes in land surface properties. Increased albedo has the potential to counteract the radiative forcing and warming effect of emitted GHGs. Thus considering albedo could be important to evaluate and improve agricultural systems in light of climate change, but the albedo of individual practices is usually not known. This study quantified the albedo of individual crops under regional conditions, and evaluated the importance of albedo change for the climate impact of current crop production using life cycle assessment (LCA). Seven major crops in southern Sweden were assessed relative to a land reference without cultivation, represented by semi-natural grassland. Crop-specific albedo data were obtained from a MODIS product (MCD43A1 v6), by combining its spatial response pattern with geodata on agricultural land use 2011–2020. Fluxes of GHGs were estimated using regional data and models, including production of inputs, field operations, and soil nitrogen and carbon balances. Ten-year mean albedo was 6–11% higher under the different crops than under the reference. Crop-specific albedo varied between years due to weather fluctuations, but differences between crops were largely consistent. Increased albedo countered the GHG impact from production of inputs and field operations by 17–47% measured in GWP100, and the total climate impact was warming. Using a time-dependent metric, all crops had a net cooling impact on global mean surface temperature on shorter timescales due to albedo (3–12 years under different crops), but a net warming impact on longer timescales due to GHG emissions. The methods and data presented in this study could support increasingly comprehensive assessments of agricultural systems. Further research is needed to integrate climatic effects of land use on different spatial and temporal scales, and direct and indirect consequences from a systems perspective

Climate impact and energy efficiency from electricity generation through anaerobic digestion or direct combustion of short rotation coppice willow

Short rotation coppice willow is an energy crop used in Sweden to produce electricity and heat in combined heat and power plants. Recent laboratory-scale experiments have shown that SRC willow can also be used for biogas production in anaerobic digestion processes. Here, life cycle assessment is used to compare the climate impact and energy efficiency of electricity and heat generated by these measures. All energy inputs and greenhouse gas emissions, including soil organic carbon fluxes were included in the life cycle assessment. The climate impact was determined using time-dependent life cycle assessment methodology. Both systems showed a positive net energy balance, but the direct combustion system delivered ninefold more energy than the biogas system. Both systems had a cooling effect on the global mean surface temperature change. The cooling impact per hectare from the biogas system was ninefold higher due to the carbon returned to soil with the digestate. Compensating the lower energy production of the biogas system with external energy sources had a large impact on the result, effectively determining whether the biogas scenario had a net warming or cooling contribution to the global mean temperature change per kWh of electricity. In all cases, the contribution to global warming was lowered by the inclusion of willow in the energy system. The use of time-dependent climate impact methodology shows that extended use of short rotation coppice willow can contribute to counteract global warming

Life cycle assessment of an all-organic battery: Hotspots and opportunities for improvement

Organic batteries are emerging as a potential sustainable power source for future flexible devices. Using life cycle assessment, this study analyzed the environmental impacts from the synthesis process for an all-organic battery with conducting redox polymers as active materials for electrodes. Synthesis steps were modeled and analyzed in detail, based on actual laboratory processes data for electrodes, and industrial data for other battery components. Complete and transparent inventory data are presented and can be used in future environmental assessments. The organic battery studied is still at an early development stage, so environmental hotspots and potential improvements in the synthesis processes were examined. For selected environmental impact categories, the life cycle assessment results showed that synthesis of cathode backbone was the major contributor (47-63%) to the environmental impacts of the all-organic battery cell among different synthesis stages, because of a long synthesis route associated with high solvent usage. Solvents (e.g., dichloromethane), catalysts (e.g., copper oxide, Pd (PPh3)4), zinc, and waste treatment processes were important single contributors to the total impacts. The results reveal significant potential for improvement by optimizing the amount of solvents needed to synthesize battery electrodes. Changing treatment methods for laboratory waste solvents can also strongly influence the results

Prospective life cycle assessment of a flexible all-organic battery

Strong interest from researchers and industry is accelerating development of flexible energy storage technologies for future flexible devices. It is critical to consider the environmental perspective in early development of new emerging technologies. In this study, cradle-to-factory gate prospective life cycle assessment (LCA) was performed on production of an all-organic battery with conductive redox polymers as electrode material. To gain a better understanding of the environmental performance of the all-organic battery, a flexible lithium-ion (Li-ion) battery with lithium titanate oxide and lithium cobalt oxide as electrode active materials was modeled as reference. Main environmental impacts of the all-organic battery were attributable to anode and cathode production, with electrode backbones being the main contributors. Solvents, catalysts, waste treatment, energy, and bromine were key individual contributors. Comparison with the flexible Li-ion battery indicated inferior environmental performance of the all-organic battery due to its relatively low specific energy (Wh/kg) and large amount of materials needed for production of its electrode backbones. Sensitivity analysis showed that changing scaling-up parameters and the production route of 3,4-ethylenedioxythiophene (a precursor of electrode backbones) strongly influenced the results. In order to lower the environmental impacts of the all-organic battery, future research should focus on designing a short production chain with lower material inputs of electrode backbones, increasing battery cycle life, and improving the specific energy of the battery. In addition, relevant recommendations were provided for prospective LCAs of upscaled systems

A Swedish comment on ‘review: the availability of life-cycle studies in Sweden’

The article entitled ‘Review: the availability of life-cycle studies in Sweden’ by Croft and colleagues (January 2019, volume 24, issue 1, pages 6–11) has puzzled many researchers in Sweden. The stated purpose of the article is to review the availability of water and carbon footprinting studies and life-cycle assessment (LCA) studies in Sweden. Despite its title and purpose suggesting otherwise, the article appears to be about the accessibility of life-cycle case studies from Sweden in South Africa. It is problematic that the article claims to be a review in the title and text, but is presented by the journal as a commentary. We believe that the article’s method is unclear and that its title and results are misleading. The authors of the article found only 12 academic papers, 10 academic theses, 8 company reports, and 1 presentation. This result significantly underestimates the actual production and availability of Swedish LCA case studies

User-centered design and evaluation of a children's book app through social interaction

Med dagens teknik kan traditionella bilderböcker för barn återskapas i form av interaktiva applikationer. Detta gör att digitala element som animationer och ljudeffekter kan implementeras för att förstärka berättelsens budskap. Detta öppnar också upp för intressanta forskningsfrågor kring hur sådana applikationer, och deras interaktiva funktioner, bör utformas i den givna kontexten. I den här studien undersöks hur utformningen av en barnbokapplikation, med fokus på inlärning av känslor och empati, kan påverka den sociala interaktionen mellan den vuxna läsaren och barnet. För att förstå hur utformning av barnböcker och barnbokappar påverkar den sociala interaktionen under högläsning utfördes en omfattande teori- och litteraturstudie inom dessa områden. En state-of-the-art-analys utfördes även för att studera den nuvarande marknaden av barnbokappar. Detta ledde fram till studiens frågeställning: Vilka interaktiva element i en barnbokapplikation bidrar till ökad relevant social interaktion, och därmed uppmuntrar till inlärning av känslor och empati, mellan barn och vuxen? Frågeställningen undersöktes genom att en barnbokapp, baserad på barnboken ”Sammy hjälper till”, utvecklades och testades i en användarstudie där tre användartest utfördes; två test på förskolor i Stockholm och ett test där ett antal småbarnsfamiljer fick testa appen i hemmet under en veckas tid. Den utvecklade barnbokappen bestod av tre huvudsakliga interaktiva funktioner; diskussionsfrågor, interaktiva karaktärer och interaktiva områden. Resultaten visade att diskussionsfrågorna var de som bidrog mest till ökad social interaktion mellan barnet och den vuxne läsaren. De andra funktionerna varierade mer i hur de påverkade den sociala interaktionen och behöver därför utforskas vidare. En tydlig slutsats från studien är att det finns många viktiga faktorer att tänka på vid design och utformning av en barnbokapp med fokus på känslor och empati. Den sociala kontexten är viktig att tänka vid utformning av en app, liksom det åldersspann som appen är tänkt att riktas mot. Slutligen presenteras förslag på fortsatt forskning inom området.With modern technology, traditional picture books for children can be recreated in the form of interactive applications. This opens up the possibility of implementing digital elements like animations and sound effects to reinforce the message of the story. This also opens up interesting research questions about how these applications, and their interactive features, should be designed in the given context. This study examines how the design of a children's book app (short for application), focusing on teaching and understanding emotions and empathy, can affect the social interaction between the adult reader and the child. A comprehensive literature study was conducted in order to understand how the design of picture books and book apps affects the social interaction during reading sessions. A state-of-the-art analysis was also conducted to study the current state of children’s book apps. This led to the main research question of the study: Which interactive elements in a children's book app help increase the relevant social interaction between child and adult? A children’s book app based on the Swedish picture book “Sammy helps out” was developed and tested in a user study where three user tests were conducted; two tests in preschool facilities in Stockholm and one test where a number of families with small children were asked to test the app in their homes for a week. The developed app consisted of three main interactive features called “discussion questions”, “interactive characters” and “interactive areas”. The results showed that the discussion questions were the largest contributors to increased social interaction between the child and the adult reader. The other functions were more varied in how they affected the social interaction and therefore need to be explored further. A conclusion from the study is that there are many important factors to consider in the design of a children’s book app focusing on emotions and empathy. The social context is important to keep in mind while designing an app, as well as the age range that the app is supposed to be marketed towards. Finally, suggestions for further research in the area are presented