Net-zero Target Research Articles

Evaluating environmental impacts of bio-based insulation materials through scenario-based and dynamic life cycle assessment

Abstract Purpose Bio-based insulation materials can have a significant impact in achieving net zero target in the construction sector. However, they face challenges due to lack of data on environmental performances and professional perception, hindering their proliferation. This study aims to combine scenario-based and dynamic analyses of environmental performances to provide comprehensive environmental information on bio-based thermal insulation materials. The goal is to empower professionals with robust information, facilitating informed decisions and promoting the selection of bio-based materials. Methods Data on manufacturing, use, recyclability, and technical performance of eleven commercially available natural insulation materials were collected from the literature to create a Life Cycle Inventory (LCI). For each material, a scenario-based life cycle assessment (LCA) was conducted by modelling variation in manufacturing, transportation, end-of-life and material properties, using the UK as the primary case study. Materials were compared to three non-bio-based insulation materials by ranking the thirteen environmental impact categories in EN 15804(2013) + A2(2019) to give an exhaustive overview of their potential benefits and burdens. Additionally, a dynamic LCIA was performed to implement in the analysis both short-and long-term emissions, exploring the impact of biogenic carbon. Results The scenario analysis highlighted that recycled cotton and hemp fibre insulation have the lowest impact across all impact categories, attributed to their sustainable manufacturing processes and minimal impacts at the end-of-life stage. The dynamic LCIA demonstrated that recycled textile insulation has the lowest impact both in the short-term (prior to waste disposal) and the long-term (post-waste disposal), regardless of the chosen end-of-life scenario. Furthermore, it indicated that cotton and hemp fibre have a negligible impact on global temperature changes, achieving a net-zero effect in the short-term and close-to-zero impact in the long-term. Conclusion The novelty of this paper lies in its comprehensive investigation of the environmental impacts of bio-based thermal insulation materials, employing multiple tools to enhance generalizability. These results will support decision-making by providing data ranges to help practitioners identify the most environmentally friendly insulation materials. Additionally, they offer insights into how similar products compare within that range, driving progress in the built environment towards net-zero emissions. Whilst the full dataset and evaluation methods are illustrated through a UK-based case study, this method can be adapted for specific scenarios and projects, due to the transparency of data and methods. This research significantly influences the built environment and promotes net-zero targets within the sector.

Role of Solar Energy in Achieving Global Net-Zero Targets: Policy and Technological Perspective

Solar Energy Essential in Global Drive for Net Zero Emissions This paper sets out to address the complex role of solar power as an enabler for decarbonization, highlighting both policy and technology-related matters. We assess the effectiveness of different policy instruments in fostering solar energy uptake: financial incentives and regulatory frameworks that level the playing field with other technologies or curtail them by limiting, e.g., fossil fuel use, carbon pricing mechanisms, and international cooperation. We also review key technological advancements in photovoltaics, energy storage, and grid integration that are essential for solar energy to play an optimized role in a sustainable energy future. For these intents and purposes, we explore how new technologies such as perovskite solar cells (PSCs), concentrated solar power (CSP), or building-integrated photovoltaics (BIPV) could offer a significant enhancement of efficiency and dynamism in converting sunlight into electricity. Case We explore the dos and don’ts of being a perfect project through stories from successful solar energy integration projects. We assess the challenges and opportunities associated with solar powering in the future, underscoring the provision of cohesive policy as well as technology road-maps to achieve global net-zero targets. Our study underscores the potential of solar energy as a transformative resource. It provides direction to policy-makers, scholars, and industry actors regarding pathways that may accelerate the deployment of this increasingly vital renewable technology.

Diversity of biomass usage pathways to achieve emissions targets in the European energy system

Abstract Biomass is a versatile renewable energy source with applications across the energy system, but it is a limited resource and its usage needs prioritization. We use a sector-coupled European energy system model to explore near-optimal solutions for achieving emissions targets. We find that provision of biogenic carbon has higher value than bioenergy provision. Energy system costs increase by 20% if biomass is excluded at a net-negative (−110%) emissions target and by 14% at a net-zero target. Dispatchable bioelectricity covering ~1% of total electricity generation strengthens supply reliability. Otherwise, it is not crucial in which sector biomass is used, if combined with carbon capture to enable negative emissions and feedstock for e-fuel production. A shortage of renewable electricity or hydrogen supply primarily increases the value of using biomass for fuel production. Results are sensitive to upstream emissions of biomass, carbon sequestration capacity and costs of direct air capture.

Uncertainties around net-zero climate targets have major impact on greenhouse gas emissions projections.

Globally, more than 100 countries have adopted net-zero targets. Most studies agree on how this increases the chance of keeping end-of-century global warming below 2°C. However, they typically make assumptions about net-zero targets that do not capture uncertainties related to gas coverage, sector coverage, sinks, and removals. This study aims to analyze the impact of many uncertainty factors on the projected greenhouse gas (GHG) emissions by 2050 for major emitting countries following their net-zero pathways, and their aggregate impact on global GHG emissions. Global emission projections range from 23 to 40 gigatons of CO2 equivalent (GtCO2eq), with a median of 31GtCO2eq. Our full range corresponds to about 40-75% of 2015 emission levels, which is much wider than the range of 30-45% reported by various integrated assessment models. The main factors contributing to this divergence are the uncertainty in the gas coverage of net-zero targets and uncertainty in the socioeconomic baseline. Countries with net-zero GHG targets by 2050 have a small range of 2050 emissions, while countries with net-zero targets beyond 2050 and unclear coverage, such as China, India, and Indonesia, have a large range of emissions by 2050.

Life cycle assessment of drinking water and wastewater treatment works in mainland Scotland.

Assessing the global warming potential (GWP) of water treatment systems is vital for reducing the carbon footprint of the water industry and aiding the net zero target. The approach of life cycle assessment (LCA) was used to determine the GWPs of four drinking water treatment works (DWTW) and one wastewater treatment works (WWTW) on the Scottish mainland. The results were compared with a previous study on the DWTWs and WWTWs of five Scottish islands which used the same method (LCA), modelling and context as the mainland work. The GWPs for the DWTW ranged from 0.09 to 0.27 kg CO2-eq/m3 and for the WWTW was 0.44 kg CO2-eq/m3 which were generally much smaller than that for island systems whose GWPs ranged from 0.18 to 0.79 kg CO2-eq/m3 for DWTWs and 0.51 to 1.14 kg CO2-eq/m3 for WWTWs. The largest contributor is the electricity consumption for all the mainland systems and asssociated footprints are smaller than that for island systems. By comparing Scottish mainland and island systems, the suitability of mainland systems for rural island systems is discussed. In terms of carbon abatement in the water industry, post treatment processes such as sludge reduction or resource recovery as well as the use of increased renewable energy sources would benefit both mainland and island water treatment works.

Agro-Forestry & Natural Farming for Bioeconomy, Speedy Net Zero Carbon and Climate Change Resilience in India

Boosting agroforestry and low emission farming on 85 million ha i.e. 25% of India’s landmass can offset about additional 750 Million ton CO2 Equivalent green house gas (GHG) emissions i.e. nearly 50% % of Indian GHG emissions by 2050. This is over 2 times the to the tune of 522 MtCO2E i.e. 22% of India’s total GHG emission of nearly 2,959 million ton CO2 equivalent/ year in 2023. This can help India meet its net zero target to be carbon neutral close to 2050 as per the global target, ahead of its declared plan to be next zero by 2070 at COP26 at Glasgow in 2021.

Different technology packages for aluminium smelters worldwide to deliver the 1.5 °C target

Production of aluminium, one of the most energy-intensive metals, is challenging for mitigation efforts. Regional mitigation strategies often neglect the emissions patterns of individual smelters and fail to guide aluminium producers’ efforts to reduce GHG emissions. Here we build a global aluminium GHG emissions inventory (CEADs-AGE), which includes 249 aluminium smelters, representing 98% of global primary aluminium production and 280 associated fossil fuel-based captive power units. We find, despite the installation of more efficient and higher amperage cells, that the share of aluminium production powered by fossil fuel-based captive power units increased from 37% to 49% between 2012 and 2021. Retiring fossil fuel-based captive power plants 10 years ahead of schedule could reduce emissions intensity by 5.0–10.5 tCO2e per tonne of aluminium for dependent smelters. At least 18% of smelting capacity by 2040 and 67% by 2050 must be retrofitted with inert anode technology to achieve net-zero targets.

Towards carbon neutrality: mapping mass retrofit opportunities in Cambridge, UK.

This study proposes a methodology and a proof of concept to target and prioritize mass retrofitting of residential buildings in the UK using open building datasets that combine fabric energy efficiency and fuel poverty to meet the net-zero targets. The methodological framework uses a series of multi-variate statistical and geospatial methods that consider urban, socio-economic and physical attributes. In addition, thermal imaging is implemented to provide insights at the building scale. We define a hard-to-decarbonize (HtD) metric to enable the clustering of different residential types to establish retrofitting priorities. Using Cambridge, UK, as a case study, five neighbourhoods were identified and characterized to help determine decarbonization intervention priorities. We found that one of five clusters of neighbourhoods is HtD and requires more policy support from government for the implementation of retrofit strategies. The achieved framework has the potential to inform policy and decision making. Of relevance, it is applicable to different urban contexts.

Life cycle engineering and sustainable manufacturing for net-zero targets and environmental sustainability

Life cycle engineering and sustainable manufacturing for net-zero targets and environmental sustainability

Carbon reduction and nuclear energy policy U-turn: the necessity for an international treaty on small modular reactors (SMR) new nuclear technology

Pressure to reduce carbon emission and meet Net-zero targets is forcing countries to re-introduce nuclear energy in their energy-mix. As a result, many countries have re-classified nuclear energy as a green energy to encourage investments and developments in this sector. Further, advances in nuclear energy technology have led to the development of Small Modular Reactors (SMR), which has continued to stimulate increasing interests from both developed and developing countries. Hence, it is expected that in the coming years, there would be increased deployment of SMR across the globe. This renewed interest in nuclear energy and expected global deployment of the novel SMR, would encounter some legal issues. Therefore, this paper analysed the nuclear energy international legal and regulatory frameworks (relevant nuclear energy conventions and treaties) currently used for the conventional large nuclear power plants (NPPs) to understand how adequate they are for SMR deployment. Various critical gaps were found in the extant laws that could make them not to fully cater for all the peculiarities of the new SMR nuclear technology. This may affect the effective regulation and smooth deployment of SMRs across countries. Therefore, this paper argues that a single specific international treaty on SMR that will cover the regulation of all aspects of SMR deployment, and their peculiarities is highly needed to support countries to justly transition into a Net-zero era.

Effects of Retrofit Strategies on Thermal Comfort and Energy Performance in Social Housing for Current and Future Weather Scenarios

With growing concerns over energy and heat-related mortality/morbidity rates, enhancing building performances is key to improving the health and well-being of building occupants while reducing CO2 emissions, in line with the UK Government’s Net-Zero targets. This study investigates the impacts of different retrofitting scenarios on overheating risk and energy performance in social housing for current and future climate conditions. Dynamic thermal simulations were carried out using Design Summer Year (DSY) weather files in DesignBuilder software for selected case study buildings. Winter performance was analysed using the Predicted Mean Vote (PMV) index, while summer results were assessed according to the Chartered Institution of Building Services Engineers Technical Memorandum 59 (CIBSE TM59) guidelines. The findings revealed that bedrooms, especially those facing south, were at high risk of overheating. Factors such as building construction, the number of exposed surfaces, and window area influenced the risks. External wall insulation outperformed internal wall insulation in improving summer comfort. In the winter, Passivhaus standards with natural ventilation ensured thermal comfort across all zones, with a 41–53% reduction in heating energy consumption under current weather conditions. The risk of overheating and associated health issues significantly increased for the future weather scenarios. Further investigation into ventilation strategies, occupant behaviour, and passive design is required to mitigate overheating risks while reducing energy consumption in buildings.

Near-term carbon dioxide removal deployment can minimize disruptive pace of decarbonization and economic risks towards United States’ net-zero goal

Deep decarbonization is essential for achieving the Paris Agreement goals, and carbon dioxide removal is required to address residual emissions and achieve net-zero targets. However, the implications of delaying the deployment of removal technologies remain unclear. We quantify how different carbon removal methods and their deployment timing affect achieving net zero emissions by 2050 in the United States. Our findings show that postponing novel technologies until mid-century forces accelerated decarbonization of energy-intensive sectors, reducing residual emissions by at least 12% compared with near-term deployment of carbon dioxide removal. This delay increases transition costs, requiring carbon prices 59–79% higher than with near-term deployment. It also heightens the risk of premature fossil fuel retirement in the electricity sector, leading to 128–220 billion USD losses compared to gradual scale up starting now. A balanced, near-term co-deployment of novel removal methods mitigates risks associated with relying on a single approach and addresses sustainability and scalability concerns.

Scales of governance, polycentricity and the case of active travel infrastructure in West London

In the context of net zero targets, the Bloomington School raises vital questions for public administration about the suitability and inter-relationships between different scales of governance for addressing this complex challenge. The extant empirically orientated literature exploring different examples of polycentric climate governance can gain from a closer focus on Elinor Ostrom’s conjecture that large scale externality problems can be most effectively addressed through decentralised governance processes. There is significant need and scope for applying Ostrom’s Institutional Analysis and Development (IAD) framework to urban governance contexts. This paper applies the IAD framework to a case study of urban governance in London, focusing on sustainable transport targets and the task of delivering active travel infrastructure. The case confirms the pertinence of Bloomington insights into the importance of local knowledge and collaborative and entrepreneurial approaches to governance. The study also demonstrates that the Bloomington case for decentralised processes of institutional adaptation needs to be qualified where externalities cut across multiple jurisdictions, and in the case of reducing CO2 emissions are global in scale. Enabling active travel is found to require national and city-level governance initiating policy coordination across multiple local jurisdictions.

Local, place-based governance for net zero: a review and research agenda

Net zero is widely perceived to be a societal challenge that cannot be addressed through business as usual but requires active governance aimed at societal transformation. In the UK, three quarters of all local authorities have declared climate emergencies, yet local action on net zero remains slow and uneven. Transforming local governance so that it is capable of organising to deliver change at a speed and scale commensurate with net zero targets is proving problematic. In this commentary the reasons why are explored. Using a narrative review method, informed by contemporary thinking on Transformative Innovation Policy, the commentary critically examines a growing body of knowledge on local, place-based governance of net zero, which has emerged at the interface of policy and practice in the UK since 2019. The review synthesises this evidence into seven place-based governance challenges and identifies extant obstacles and opportunities in navigating towards more effective governance arrangements. Collectively these challenges highlight the importance of organising to deliver change, not just organising the delivery of change, and the guiding role of the state in the process. The commentary concludes by setting out future research avenues.

Attention and positive sentiments towards carbon dioxide removal have grown on social media over the past decade

Scaling up CO2 removal is crucial to achieve net-zero targets and limit global warming. To engage with publics and ensure a social licence to deploy large-scale carbon dioxide removal (CDR), better understanding of public perceptions of these technologies is necessary. Here, we analyse attention and sentiments towards ten CDR methods using Twitter data from 2010 to 2022. Attention towards CDR has grown exponentially, particularly in recent years. Overall, the discourse on CDR has become more positive, except for BECCS. Conventional CDR methods are the most discussed and receive more positive sentiments. Various types of users engage with CDR on Twitter to different degrees: While users posting little about CDR pay more attention to methods with biological sinks, frequently engaged users focus more on novel CDR methods. Our results complement survey studies by showing how awareness grows and perceptions change over time.

Greenhouse Gas Footprints of Nations Significantly Reshaped by Sink Changes.

In addition to greenhouse gas (GHG) emissions by sources, GHG removal by sinks is essential in achieving the net zero target by 2050. Both the GHG sources and sinks are influenced by local and remote socioeconomic activities through international trade. However, the impacts of international trade on global net GHG emissions remain unknown. This study estimates net GHG emissions of nations from the consumption perspective, considering both GHG sources and sinks influenced by human activities. Results show that 26% of global net GHG emissions were embodied in international trade. GHG footprints in tropical nations would be significantly underestimated if only sources are considered and sink changes are neglected, especially in Indonesia (counting 65% of its GHG footprints) and Africa (44%). After considering sink changes, the consumption of processed foods and animal products exerted larger impacts on GHG footprints of tropical nations, which is mainly attributed to emissions from forest conversion; and the GHG leakage through international trade from tropical nations (e.g., Indonesia) to other nations (e.g., India and the United States) was more prominent. These results highlight the importance of sink changes in assessing GHG footprints. They can offer new insights into expediting the achievement of the net zero target.

Chasing net zero: critical uncertainties in coffee emissions calculations

Summary Net zero as a policy for reducing atmospheric carbon emissions is relatively straightforward; however, the implementation of that policy is not, particularly in difficult-to-measure sectors such as agriculture. As strategies to reduce emissions are explored, multiple uncertainties in measuring these emissions are confronted. In this paper, we use the example of a coffee supply chain in Peru to illustrate the magnitude of potential variability in emissions accounting results, which represent a necessary first step in moving towards net zero. We show that scope boundaries and emissions factors chosen for carbon calculations significantly alter emissions outcomes and can result in discrepancies of over 77 million kg CO2e when scaled to a medium-size coffee trader. Net zero targets and efforts to reduce emissions may be over- or understated depending on subjective decisions that cause significant differences in emissions results. Although framework guidance exists, it is apparent that a greater set of micro-level agreements is needed for calculating the emissions of lesser-studied sectors, such as agricultural supply chains. This process is imperative to focus efforts on reducing emissions and on moving from net zero as a mere policy to action and implementation.

City–company collaboration towards aligned science-based target setting

Cities and companies have great potential to reduce pressures on Earth system boundaries. Science-based target setting has emerged as a powerful tool to help achieve the potential, but its uptake has been limited. Moreover, cities and companies usually develop their targets separately, even though many are co-located. Focusing on the top 200 cities and 500 companies by greenhouse gas emissions, we analyse the current state and potential of adopting science-based targets for climate. Of these key actors, 110 cities with existing net-zero targets and 22 companies with existing science-based targets could together eliminate up to 3.41 GtCO2e of annual emissions. We argue that this reduction potential could increase by as much as 67% (to 5.70 GtCO2e) if the cities and companies that already have targets bring their co-located counterparts on board to keep abreast of their ambitions. Using freshwater as another example, we discuss entry points for addressing interrelated Earth system boundaries through city–company collaborations. Our findings elucidate previously untapped potentials that could accelerate transformations for operating within Earth system boundaries.

H2-powered aviation – Optimized aircraft and green LH2 supply in air transport networks

The final financial decisions on starting the commercialization of the next single-aisle aircraft programs for entry-into-service in the 2030s are due in less than 5 years. These programs will shape the future climate impact over the following 20–30 years of this aircraft segment and will determine if the sector can achieve its 2050 net-zero target. And so far, there are only limited holistic research perspectives available evaluating the best decarbonization options for such a crucial next product.This study provides a first-of-its-kind holistic evaluation approach for the business case of single-aisle hydrogen-(H2)-powered aircraft to enable true-zero CO2 flying. It combines the optimization of green liquid hydrogen (LH2) supply and aircraft designs as well as the investigation of operational strategies with such aircraft in one specific air traffic network.It is found that LH2 could cost around 2 to 3 USD/kg at main European airports in a 2050 scenario. Even though the aircraft with H2 direct combustion would be less efficient, average total operating costs would be 3% lower than flying with synthetic kerosene in the given network in 2050. As an operational strategy to save fuel costs, tankering might play an essential role in reducing operating costs for H2-powered aircraft in the early adoption phase with high differences in LH2 supply costs.Finally, it is derived that usage of LH2 as a fuel would lead to lower installation requirements of renewable energy generation capacity compared to the synthetic kerosene option. Since green electricity will be a constrained resource in the next decades, this is another important aspect for choosing future decarbonization options in air travel.All in all, the study proves the importance of the derived methodology leading to a broader techno-economic assessment for two decarbonization options in aviation. Such novel approaches might be further developed and applied to other related research topics in this field.

SA91 Aligning Health Technology Assessment With Healthcare Net Zero Targets: A Parallel Evaluation of Single Use Versus Reusable Devices

SA91 Aligning Health Technology Assessment With Healthcare Net Zero Targets: A Parallel Evaluation of Single Use Versus Reusable Devices