Operational Greenhouse Gas Emissions Research Articles

Mitigating operational greenhouse gas emissions in ageing residential buildings using an Urban Digital Twin dashboard

With the increasing stock of ageing infrastructure and resource constraints in Singapore, related risks and carbon emissions can be mitigated through long-term resilience planning, automated building inspection, and effective maintenance. Sustainable actions are needed to maintain Singapore's ageing infrastructure. Hence, a state-of-the-art control and management system is required in the form of smart city digital tools. We introduce an Urban Digital Twin (UDT)—GHG App for decision-makers in Singapore's operational building greenhouse gas (GHG) emission mitigation and decarbonisation initiatives. Based on multiple-criteria decision analysis (MCDA), a Potential for Intervention (PFI) map was created to rejuvenate the building system. Decision-makers can use this map to prioritise the rejuvenation of low-carbon building systems in the built environment. A heat map of the PFI results highlights which buildings need urgent rejuvenation based on critical parameters. The GHG App utilises this method to generate maps and enables users to modify parameter weights based on their priorities, automatically updating the map. Users can plan an intervention for buildings with higher PFI values once the map is generated. The GHG App provides interactive data visualisation of 119,872 features representing Singapore's built environment, including the context size of 6,785 existing residential buildings modelled and used to demonstrate the analysis results. Our research findings can contribute to the development of standards for accounting for operational GHG emissions, setting emission limits, and planning decarbonisation in the built environment sector.

Seasonal variation in electricity demand of solar-powered net-zero energy housing in temperate climates

Net-zero energy buildings produce enough renewable energy to meet their own annual energy requirements and have been proposed as an important method of reducing operational greenhouse gas emissions in the building sector. However, self-generation via building-integrated solar PV in cold and temperate climates is anti-correlated with increasingly-electrified heating demand and could increase seasonal variability in net electricity demand to the point that it poses challenges for future electricity systems. In this paper we explore scenarios of future large-scale uptake of electrically-heated, solar-PV net-zero energy residential buildings in New Zealand and quantify the seasonal variation of the resulting net electricity demand. A scenario of large-scale uptake of very high efficiency buildings leads to reductions in annual demand of −30% and seasonal variation of −50% in 2050 compared to a base case of current building standards. In comparison, a scenario with self-generation via solar PV without changes to the building standard reduces annual demand by −30% but increases seasonal variation by +40%. In a scenario where very high building standards are combined with solar PV, annual demand decreases by −65% and seasonal variation by only −4%. From a policy perspective, whether large-scale solar PV self-generation should be supported (in addition to very-high efficiency buildings) depends on an economic trade-off between the value of distributed solar generation (including any carbon emission reductions) vs the electricity system cost of seasonal variation. For New Zealand, given the low cost of renewable electricity from a variety of alternative sources, scenarios of large-scale uptake of solar-powered net-zero energy buildings are not favourable from an electricity system perspective.

A perspective on tools for assessing the building sector’s greenhouse gas emissions and beyond

Increasing impacts from anthropogenic climate change, coupled with the rising need to provide safe and healthy buildings in which people can live, work, and play, necessitates methods and tools for decarbonizing the building sector. Governments, industry, and others are interested in assessing both the embodied and operational greenhouse gas (GHG) emissions of buildings. Stakeholders have embraced whole building life-cycle assessment (WBLCA) as a framework for quantifying the life-cycle impacts of buildings, from raw material extraction to the building’s end of life. The purpose of this perspective is to offer an analysis on prominently used WBLCA tools, focusing on how well the tools are suited for assessing the embodied and operational GHG emissions from all phases of a building’s life cycle, and to suggest recommendations for improving the tools. Existing WBLCA tools can provide a detailed assessment of most materials used in the building’s core and shell but lack the capability to quantify impacts accurately and comprehensively from all building systems as well as from the construction, transportation, operation, and end-of-life phases. Suggested short term improvements for the tools include: (1) increased standardization among tools and environmental product declarations (EPDs) to allow for detailed comparison among different material options earlier in the design process; (2) incorporation of verified, local-manufacturer EPDs for all building materials, components, and systems and of specific on-site conditions; and (3) integration of tradeoffs between embodied and operational design decisions. We need to move beyond the prevailing approach of using WBLCA tools to select building materials that have the lowest embodied footprint. Future WBLCA tools need to be able to assess, in detail, how different design, construction, transportation, operation, and end-of-life decisions for a building not only affect GHG emissions, but other key sustainability goals including resilience to climate change, environmental justice, and human health of local communities.

Optimum Design, Socioenvironmental Impact, and Exergy Analysis of a Solar and Rice Husk-Based Off-Grid Hybrid Renewable Energy System

This study examines the optimal sizing of an off-grid hybrid system comprising solar photovoltaic (PV), rice husk-based biomass, and lead-acid battery for meeting the electric demand of a rural community. Considering a selected remote village in Bangladesh as a case study, the proposed optimized system is primarily compared with the diesel generator and the micro gas turbine (MGT)-based options in techno-economic and environmental terms. The potential social benefits, such as the employment creation and the improvement in the human development index in the locality, have been investigated in this study. Moreover, the impacts of operational greenhouse gas emissions on the human health damage and the surrounding ecosystem have been examined. Additionally, an exergy analysis of the hybrid system and the components has been carried out. Results indicate that in addition to being the environmentally preferable option, the proposed PV/biomass/battery system offers a lower cost of energy of 0.314 $/kWh compared to the MGT-based system (0.377 $/kWh). Although the diesel-based system offers a marginally better economy (9.55% less energy cost), it comes with the expense of probable damages to human health and the ecosystem worth of $15,211 and $6,608, respectively, making biomass the best option with no such damages. Exergy analysis reveals higher loss from PV than biomass and 13.09% system exergy efficiency. The assessment of the social indicators testifies to the potential of promoting the human development index from its current value and the formation of 1.41 jobs to as high as 15.15 full-time permanent jobs with the installation of hybrid systems in the community.

Does cost of debt reflect the value of quality greenhouse gas emissions reduction efforts and disclosure?

Using a sample of North American companies reporting to the CDP (formerly Carbon Disclosure Project), we investigate whether details of companies’ carbon management practices reduce the cost of debt associated with greenhouse gas (GHG) emissions, with credit risk ratings as a proxy for cost of debt. Specifically, employing structural equation modeling (SEM) for the main analysis and three-stage least squares (3SLS) regression for further in-depth analysis, we simultaneously, yet separately, study the effect of detailed GHG emissions performance and assured GHG emissions disclosure on the cost of debt. Based on the theory of voluntary disclosure, our findings suggest that providing details about the implementation of many diverse GHG emissions reduction projects and assuring GHG emissions disclosure provides integrity to carbon management practices and, therefore, decreases cost of debt. Furthermore, we find that a reduced cost of debt assists companies to invest more in GHG reduction related projects. We recommend that further research considers aspects of voluntary disclosure that add to its integrity.

Assessing Efficiency and Environmental Performance of a Nearly Zero-Energy University Building’s Energy System in Norway

Increasing awareness of climate issues in recent decades has led to new policies on buildings’ energy consumption and energy performance. The European Union (EU) directive 2010/31/EC, i.e., the energy performance of buildings directive (EPBD), is one of the measures initiated to achieve climate and energy goals by reducing energy use and greenhouse gas emissions in the building sector. The EPBD required all new buildings to be nearly zero-energy buildings (nZEBs) by 2021. Nearly zero-energy buildings (nZEBs) are buildings with a very-high-energy performance and nearly zero or low-energy requirements covered to a very significant extent by energy from renewable sources produced on-site or nearby. The utilisation of solar photovoltaic (PV) panels is a common approach for achieving the nZEB standard. The carbon footprint of PV panels is often not discussed as a parameter. This paper aimed to analyse the environmental performance of an existing nearly zero-energy university building in a Norwegian use case scenario. This analysis is performed by assessing annual electricity and heat consumption from both energetic and environmental perspectives. The energy required for the building during the studied period is then used to analyse the environmental and energy performance of the building. When it comes to the environmental assessment, the commercial software SimaPro was used. The proposed revision EPBD and nZEB definition from 2021 suggests that nZEBs should also consider operational greenhouse gas emissions and life-cycle global warming potential from 2027. The life cycle assessment (LCA) of the building’s energy sources looks at the global warming potential (GWP) and greenhouse gas (GHG) emissions, and how they compare to Norwegian grid electricity. The results of the analysis highlights potential challenges to justifying the use of alternative energy sources to fulfil the criteria of nZEBs. When installing solar PV, it is important to consider the energy mix of the country where the solar PVs are produced. To solely consider the energy performance of the building, the installation of solar PV panels in countries with a high share of renewable energy may result in a reduced impact in terms of emission reduction from a life cycle perspective.

Comparative life cycle assessment of a reinforced concrete residential building with equivalent cross laminated timber alternatives in China

With the development of mass timber, cross laminated timber (CLT) has gradually become a sustainable alternative to conventional building materials to alleviate the increasing energy consumption and carbon emissions by the building sector. This study aims to explore the life cycle greenhouse gas emissions (LCGHGE) and life cycle primary energy (LCPE) of three high-rise residential buildings in the cold region of China through a life cycle assessment approach. The three buildings are conventional reinforced concrete (RC), CLT and hybrid CLT buildings. The results show that CLT and hybrid CLT buildings produce 15.00% and 10.77% lower LCGHGE, respectively, compared to the RC building within a 50-year service life. A clear difference in greenhouse gas (GHG) emissions and primary energy (PE) in the product and construction stages is visible, with 46.52% and 37.24% of embodied GHG emissions reduced in CLT and hybrid CLT buildings, respectively, compared to the RC building. In the operational stage, RC building has lower PE and GHG emissions to CLT alternatives. The thermal mass effect has led to a 2.25% and 2.12% PE increase for space heating and cooling in CLT and hybrid CLT buildings, respectively, compared to the RC building. For the End-of-Life (EoL) stage, CLT demonstrates great recycling potential and biomass residues. The sensitivity analysis shows that the design of the low U-value of the building envelope and high-efficiency energy systems has a significant relationship with energy reduction during the operational phase of the three buildings, magnifying the impacts of the initial and EoL stages. • CLT and hybrid CLT buildings produce 15.00% and 10.77% less LCGHGE than RC buildings in Tianjin, China, respectively. • Mass timber construction shows great advantages over RC buildings in the P&C/EoL stage. • The operational GHG emissions and PE of CLT and hybrid CLT buildings were 12–13% higher than those of the RC building. • Energy-efficient methods can enhance the LCA performance of hybrid CLT building.

Development of comprehensive carbon footprint and environmental impact indicators for building transportation assessment

PurposeThe purpose of the study is to consolidate a set of indicators for assessing design and construction phase strategies for reducing operational greenhouse gas (GHG) emission. They will also estimate the quantity of operational GHG emission and its associated reduction over assessment period.Design/methodology/approachFive steps framework adopted include defining the purpose of the indicators and selection of candidate indicators. Others are defining the criteria for indicator selection, selecting and defining the proposed indicators. Relevancy, measurability, prevalence, preference, feasibility and adaptability of the indicator were the criteria used for selecting the indicators.FindingsThe study consolidated public transport accessibility, sustainable parking space, green vehicle priority, proximity to amenities and alternative modes as indicators for design and construction phase strategies. Transportation accounting and carbon footprint (CFP) and their associated reduction are indicators for operational GHG emission while plan and policy is an indicator for policymakers and stakeholders.Practical implicationsThe study shows that providing correct indicators for assessing direct and indirect GHG emission with easy to obtain data is essential for assessment of built environment. Stakeholder can use the indicators in developing new rating systems and researchers as an additional knowledge. Policy makers and stakeholders can use the study in monitoring and rewarding the sustainability and activities of building related industries and organisations.Originality/valueThe study was conducted at the Center for Energy and Industrial Environmental Studies (CEIES) Universiti Tun Hussein Onn Malaysia and utilises existing rating systems and tools, Intergovernmental Panel on Climate Change (IPCC) and GHG protocol reports and guides and several other standards, which are open for research.

Information infrastructure and greenhouse gas emission performance in urban China: A difference-in-differences analysis

Owing to its network spillover effect, information infrastructure performs outstandingly in promoting economic growth and technological innovation, and has received widespread attention. However, the ecological performance of information infrastructure, especially its impact on greenhouse gas (GHG) emission performance, has been less studied. To investigate this issue, using panel data for 281 prefecture-level cities in China from 2003 to 2018, we treat the Broadband China policy as a quasi-natural experiment in information infrastructure, and conduct a difference-in-differences (DID) analysis. The results show that: (1) Information infrastructure significantly improves urban GHG emission performance. This conclusion holds even after controlling for pilot selection endogeneity, sampling bias, and other policy interference. (2) Technological innovation, industrial structure upgrading, factor allocation enhancement, and tertiary agglomeration are effective channels for information infrastructure to improve GHG emission performance. (3) The treatment effect varies with city size, digital economy level, and economic status. Specifically, information infrastructure exhibits significant emission reduction performance in cities with large size, advanced digital economy, and leading economic status, while the emission reduction effect drops in other cities. This study provides insights into the transition to a carbon-neutral manner for infrastructure in China and other developing countries.

Whole-building life-cycle analysis with a new GREET® tool: Embodied greenhouse gas emissions and payback period of a LEED-Certified library

Embodied greenhouse gas (GHG) emissions of building components and buildings operations need to be quantified to holistically address building sustainability. To evaluate embodied GHG emissions of buildings and to provide insights on building materials and building design decisions toward decarbonization, we have recently created a building life-cycle assessment (LCA) module in the widely used Greenhouse gases, Regulated Emissions, and Energy use in Technologies (GREET®) LCA model. We applied the GREET building LCA module to examine embodied GHG impacts and the payback period of a LEED (Leadership in Energy and Environmental Design)-certified public library in Chicago, USA. We developed localized, detailed life-cycle inventories to address individual building materials used in the library. We expanded the LCA system boundary to include the mechanical, electrical, and plumbing system, as well as refrigerant impacts, which are often ignored in previous studies. Results show that the total embodied GHG emissions are approximately 817 metric tons, or approximately 538 kg/m2. Sensitivity analysis highlights the positive role of increasing the use of recycled materials for reducing embodied GHG emissions. Sensitivity analysis on embodied GHG emissions payback periods shows the need to benchmark the embodied and operational carbon performance of buildings for comparison to alternative building designs and sustainability practices. This analysis demonstrates that building LCA models, such as the GREET building LCA module, which addresses embodied and operational GHG emission impacts of whole buildings holistically, could empower building architects, technology developers, manufacturers, and general contractors to address embodied and operational impacts holistically for building sustainability.

Dynamic Life Cycle Assessment of Energy Technologies under Different Greenhouse Gas Concentration Pathways.

Global warming potential (GWP) has been widely used in the life cycle assessment (LCA) to quantify the climate impacts of energy technologies. Most LCAs are static analyses without considering the dynamics of greenhouse gas (GHG) emissions and changes in background GHG concentrations. This study presents a dynamic approach to analyze the life-cycle GWP of energy technologies in different timeframes and representative GHG concentration pathways. Results show that higher atmospheric GHG concentrations lead to higher life-cycle GWP for long-term analysis. The impacts of background GHG concentrations are more significant for technologies with large operational emissions or CH4 emissions than technologies with low operational emissions. The case study for the U.S. electricity sector in 2020-2050 shows the impacts of background GHG concentrations and different LCA methods on estimating national climate impacts of different energy technology scenarios. Based on the results, it is recommended for future LCAs to incorporate temporal effects of GHG emissions when (1) the technology has large operational GHG emissions or CH4 emissions; (2) the analysis time frame is longer than 50 years; (3) when LCA results are used for policymaking or technology comparisons for mitigating climate change.

Detecting Patterns in Energy Use and Greenhouse Gas Emissions of Cities Using Machine Learning

Cities are expected to play a major role in managing climate change in the coming decades. The actual environmental performance of urban centres is difficult to predict due to the complex interplay of technologies and infrastructure with social, economic, and political factors. Machine learning (ML) techniques can be used to detect patterns in high-level city data to determine factors that influence favourable climate performance. In this work, rough set-based ML (RSML) is used to identify such patterns in the Sustainable Cities Index (SCI), which ranks 100 of the world’s major urban centres based on three broad criteria that cover social, environmental, and economic dimensions. These main criteria are further broken down into 18 detailed criteria that are used to calculate the aggregate SCI scores of the listed cities. Two of the environmental criteria measure energy intensity and greenhouse gas (GHG) emissions. RSML is used to generate interpretable rule-based (if/then) models that predict energy utilisation and GHG emissions performance of cities based on the other criteria in the database. Attribute reduction techniques are used to identify a set of 7 non-redundant criteria for energy use and 9 non-redundant criteria for GHG emissions; 6 criteria are common to these two sets. Then, RSML is used to generate rule-based models. A 10-rule model is determined for energy intensity, while an 11-rule model is found for GHG emissions. Both models were reduced further by eliminating rules with weak generalisation capability. A key insight from the rule-based models is that social, environmental, and economic attributes are associated with energy intensity and GHG emissions due to indirect effects.

Greenhouse gas mitigation potential from waste heat recovery for power generation in cement industry: The case of Thailand

The cement industry has the highest proportion of energy consumption and greenhouse gas (GHG) emitted in the Thai demand-side industry sector. Therefore, the potential GHG emission from energy efficiency is necessary to achieve the NDC target. Due to vast thermal energy consumption for cement production, especially clinker production, waste heat recovery utilization for power generation which partially replaced the on-grid electricity for cement production, has been estimated the GHG emission performance tracking in this study. We found that there are 12 waste heat power plants with a total 263.5 MW installed capacity in the Thai cement industry. With a potential of 1,663,674.21 MWh electricity production annually and GHG mitigation potential of 793,572.60 tons CO2eq per year in 2019. This GHG mitigation figure accounts for 7.21% of GHG mitigation targets for the NDC roadmap.

Biomimetic building facades demonstrate potential to reduce energy consumption for different building typologies in different climate zones.

Greenhouse gas (GHG) emissions leading to anthropogenic global warming continue to be a major issue for societies worldwide. A major opportunity to reduce emissions is to improve building construction, and in particular the effectiveness of building envelope, which leads to a decrease in operational energy consumption. Improving the performance of a building's thermal envelope can substantially reduce energy consumption from heating, ventilation, and air conditioning while maintaining occupant comfort. In previous work, a computational model of a biomimetic building façade design was found to be effective in temperate climates in an office context. Through a case study example based on animal fur and blood perfusion, this paper tests the hypothesis that biomimetic building facades have a broader application in different building typologies across a range of climate zones. Using bioinspiration for innovation opens new ideas and pathways for technological development that traditional engineering design does not provide. This study exemplifies the process in a building façade, integrating a new form of insulation, heating and cooling. Methods of mathematical modelling and digital simulation methods were used to test the energy reduction potential of the biomimetic façade was tested in a set of operational applications (office, school, and aged care) and across different climate zones (tropical, desert, temperate, and cool continental). Results indicated that the biomimetic façade has potential to reduce energy consumption for all building applications, with the greatest benefit shown in residential aged care (67.1% reduction). Similarly, the biomimetic building façade showed potential to reduce operational services energy consumption in all climate zones, with the greatest energy reductions achieved in the tropical (55.4% reduction) and humid continental climates (55.1% reduction). Through these results the hypothesis was confirmed suggesting that facades engineered to mimic biological functions and processes can improve substantially decrease building operational energy consumption and can be applied in different building classifications and different climate zones. These results would significantly decrease operational greenhouse gas emissions over the lifetime of a building and provide substantial savings in energy bills. Such facades can contribute to the further reduction in greenhouse gas emissions in a broad range of contexts in the built environment and other areas of technology and design. The flexibility and adaptability of biomimetic facades exemplify how biological strategies and characteristics can augment and improve performance in different environments, since the organisms that inspire innovation are already well-adapted to the conditions on earth. This study also exemplified a method by which other biomimetic building envelope features may be assessed. Further work is suggested to assess economic viability and constructability of the proposed facades.Graphic abstract

Supply potential of lignocellulosic energy crops grown on marginal land and greenhouse gas footprint of advanced biofuels—A spatially explicit assessment under the sustainability criteria of the Renewable Energy Directive Recast

AbstractAdvanced biofuels produced from lignocellulosic crops grown on marginal lands can become an important part of the European Union (EU) climate change mitigation strategy to reduce CO2 emissions and meet biofuel demand. This study quantifies spatially explicit the availability of marginal land in the EU, its production biomass potentials for eight different crops, and the greenhouse gas (GHG) performance of advanced biofuel supply chains. Available land is mapped based on land marginality and Renewable Energy Directive Recast (REDII) land‐related sustainability criteria. Biomass potentials are assessed with a water‐use‐to‐biomass‐production approach while considering the available land, location‐specific biophysical conditions and crop‐specific phenological characteristics. The GHG balance of advanced biofuels from energy crops produced on marginal lands is assessed considering both land‐related carbon stock changes and supply chain emissions with the carbon footprint approach from the REDII. Available marginal land that meets REDII criteria is projected at 20.5–21 Mha 2030 and 2050, respectively. Due to biophysical limitations, not all available land is suitable for energy crop production. The maximum biomass potential of lignocellulosic energy crops (optimal crop choice with maximum yield for each available location) varies between 1951 PJ year−1 in 2030 and 2265 PJ year−1 in 2050. The GHG emission performance (net emissions) of different advanced biofuel supply chains varies on average between −32 g CO2‐eq MJfuel−1 for poplar/willow diesel to 38 g CO2‐eq for reed canary grass renewable jet fuel. The large variability in GHG performance is strongly determined by the spatial heterogeneity, which dictates the type of feedstock produced under specific local biophysical conditions, the crop characteristics, and the best conversion pathway. Negative GHG emissions are related to increased carbon stocks for the biomass and soil organic carbon pools compared to the land prior to conversion. When for each location, the advanced biofuel supply chain with the highest GHG performance (lowest net GHG emissions) is selected, 618 PJ year−1 of advanced biofuels can be produced by 2030. Under REDII GHG emission criteria, slightly less (552 PJ year−1) is viable. Smart choices on location, crop type and supply chain design are paramount to achieve maximum benefits of bioenergy systems.

Techno-economic and life cycle analysis of biofuel production via hydrothermal liquefaction of microalgae in a methanol-water system and catalytic hydrotreatment using hydrochar as a catalyst support

The hydrochar, a by-product of hydrothermal liquefaction (HTL) of algal biomass, was utilized through two methods; combustion and activation, for its usage as a source of heat and a catalyst support for hydrodeoxygenation (HDO) process in the production of algal biofuels. In this study, techno-economic analysis (TEA) and life cycle assessment (LCA) of algal biofuels production in a two-stage process (HTL and HDO) were investigated. Aspen plus simulation and SimaPro software were used to analyze process economics and greenhouse gas (GHG) emissions. Microalgae at 200 dry metric tonnes day−1 was the basis for its conversion to biocrude oil through HTL in the methanol-water system followed by catalytic upgrading to produce biofuels. According to HTL experimental results, maximum biocrude oil yield of 57.8 wt% was obtained using microalgae-solvent mass ratio and methanol-water mass ratio of 1:5 and 3:1, respectively. Produced biocrude oil contained 14.5 wt% of oxygen and HHV of 33.4 MJ kgbiocrude oil−1 which required upgrading to be utilized as a transportation fuel. HDO was employed to enhance the quality of biocrude oil with decrease in oxygen content (3.1 wt%) and increase in HHV (42 MJ kgbiofuel−1). The minimum fuel selling price (MFSP) for using method #2 (activation) was 2.2 $ L−1 to breakeven the cost of operation, which was about 10% lower than that from method #1 (combustion). The GHG emissions performance was estimated at −1.13 gCO2-eq MJ−1 indicating the significant GHG emissions reduction compared to petroleum-based fuels production.

Life Cycle GHG Emissions of Residential Buildings in Humid Subtropical and Tropical Climates: Systematic Review and Analysis

Improving the environmental life cycle performance of buildings by focusing on the reduction of greenhouse gas (GHG) emissions along the building life cycle is considered a crucial step in achieving global climate targets. This paper provides a systematic review and analysis of 75 residential case studies in humid subtropical and tropical climates. The study investigates GHG emissions across the building life cycle, i.e., it analyses both embodied and operational GHG emissions. Furthermore, the influence of various parameters, such as building location, typology, construction materials and energy performance, as well as methodological aspects are investigated. Through comparative analysis, the study identifies promising design strategies for reducing life cycle-related GHG emissions of buildings operating in subtropical and tropical climate zones. The results show that life cycle GHG emissions in the analysed studies are mostly dominated by operational emissions and are the highest for energy-intensive multi-family buildings. Buildings following low or net-zero energy performance targets show potential reductions of 50–80% for total life cycle GHG emissions, compared to buildings with conventional energy performance. Implementation of on-site photovoltaic (PV) systems provides the highest reduction potential for both operational and total life cycle GHG emissions, with potential reductions of 92% to 100% and 48% to 66%, respectively. Strategies related to increased use of timber and other bio-based materials present the highest potential for reduction of embodied GHG emissions, with reductions of 9% to 73%.

Towards zero life cycle GHG emissions apartment buildings in Lebanon

Buildings are one of the main drivers of greenhouse gas (GHG) emissions and their life cycle emissions need to be significantly reduced in order to address the unprecedented climate emergency. While there are numerous studies on zero operational energy and GHG emissions buildings, very few studies exist on buildings that aim to reach zero life cycle GHG emissions buildings. The apartment building typology is particularly challenging due to the very small roof area per apartment and the limited capacity for renewable energy generation. This study investigates a four-storey apartment building in Sehaileh, Lebanon and modifies it to reach zero life cycle GHG emissions through a series of measures targeting embodied and/or operational GHG emissions. Both a life cycle GHG emissions analysis and a life cycle cost analysis are conducted on all measures their combination, including the installation of a 50kWp photovoltaic array for the building. Results demonstrate that it is possible to achieve zero life cycle GHG emissions for that building typology and number of storeys, in a Lebanese Mediterranean climate, but at a net life cycle cost of ∼43 kUSD2020 over 50 years, compared to the base case guilding. Implications in terms of policy and further research are discussed.

Mitigating Curtailment and Carbon Emissions through Load Migration between Data Centers

Summary As the share of variable renewable energy (VRE) grows in the electric grid, so does the risk of curtailment. While energy storage and hydrogen production have been proposed as solutions to the curtailment problem, they often pose technological and economic challenges. Here, we analyze the potential of data center load migration for mitigating curtailment and greenhouse gas (GHG) emissions. Using historical hourly electricity generation, curtailment, and typical data center server utilization data, we simulate the effect of migrating data center workloads from the fossil-fuel-heavy PJM to the renewable-heavy CAISO. The results show that load migration within the existing data center capacity during the curtailment hours in CAISO has the potential to reduce 113–239 KtCO2e per year of GHG emissions and absorb up to 62% of the total curtailment with negative abatement costs in 2019. Our study demonstrates the overlooked role that data centers can play for VRE integration and GHG emissions mitigation.

Board interlocks and greenhouse gas emissions

AbstractUsing resource dependence theory, we analyze board interlocks, their industry origin, and their relationship to firms' greenhouse gas (GHG) emissions. Interlocks create connections by having board members from one firm sit on other firms' boards, providing an avenue for sharing information and resources to aid in knowledge transfer and capability development. As firms face challenges for improved GHG emissions performance, they may look to their board members' connections to other firms to acquire needed resources. Using a sample of US Standard & Poor's (S&P) 1500 firms for years 2009 to 2018, we find that firms with a greater number of board interlocks achieve lower GHG emissions intensity. We also find that boards for the best performing companies have interlocks in the same industry, in other industries, and with firms leading in GHG emissions intensity, especially for firms in higher environmentally impacting industries, as they face greater emissions challenges.