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The current geopolitical landscape of the European Union has made it clear that the energy sector must be a top priority in EU policy, especially in light of the sudden escalation of Russian–Ukrainian conflicts. Energy efficiency has been used as the first tool of EU policy to tackle energy and climate crises, given the issues surrounding energy vulnerability and the need to limit gas emissions that contribute to climate change. The white certificate mechanism in Italy has played a pivotal role in encouraging measures to achieve the country's energy-saving goals. Given the high energy requirements of Wastewater Treatment Plants (WWTPs), especially for aeration in the biological section, this paper examines the replacement of the air distribution system for a large WWTP as a viable intervention. In order to provide economic perspective for the plant, both the discounted Payback Period (dPBP) and the Net Present Value (NPV) were calculated for the investment. When viewed through an economic lens, the dPBP metric exhibits values that span from less than 1 year to nearly 4.5 years. Additionally, the investment's cost-effectiveness was emphasized by the NPV, which, depending on the factors considered, can exceed 17.5 million euros. Finally, given the centrality of the theme of climate change, the avoided greenhouse gas emissions generated by the efficiency intervention were calculated, according to the GHG Protocol, resulting in a quantity of avoided emissions equivalent to over 57,770 tonnes of CO2e. These results highlight important achievements in terms of both the cost-effectiveness of the plant and the reduction of greenhouse gas emissions. [ABSTRACT FROM AUTHOR]

The increasing concentration of CO2 in the atmosphere is related to global climate change. Carbon capture, utilization, and storage (CCUS) is an important technology to reduce CO2 emissions and to deal with global climate change. The development of new materials and technologies for efficient CO2 capture has received increasing attention among global researchers. Ionic liquids (ILs), especially functionalized ILs, with such unique properties as almost no vapor pressure, thermal- and chemical-stability, non-flammability, and tunable properties, have been used in CCUS with great interest. This paper focuses on the development of functionalized ILs for CO2 capture in the past decade (2012~2022). Functionalized ILs, or task-specific ILs, are ILs with active sites on cations or/and anions. The main contents include three parts: cation-functionalized ILs, anion-functionalized ILs, and cation-anion dual-functionalized ILs for CO2 capture. In addition, classification, structures, and synthesis of functionalized ILs are also summarized. Finally, future directions, concerns, and prospects for functionalized ILs in CCUS are discussed. This review is beneficial for researchers to obtain an overall understanding of CO2-philic ILs. This work will open a door to develop novel IL-based solvents and materials for the capture and separation of other gases, such as SO2, H2S, NOx, NH3, and so on. [ABSTRACT FROM AUTHOR]

Global warming, climate change, and resource depletion have forced us to reconsider energy usage and efficiencies over the last few decades. Residential and commercial buildings are both large energy consumers, so improving energy and material usage efficiency in this sector is a common research topic. According to a recent study, the Building Sector (BS) accounts for 40% of greenhouse gas emissions. The primary objective of this paper is to examine and assess the potential of Renewable Energy Systems (RES) and their combinations for enhancing energy efficiency in the BS. Specifically, the focus will be on converting low energy-efficient buildings into highly efficient ones. The potential of the RES and their combinations for the BS is evaluated based on payback durations, energy generation, and reduction of CO 2 emissions. The optimization flow charts for the RES, feasibility studies, commercialization road maps of energy storage systems and the necessity of control mechanisms for enhancing RES efficiency were discussed. Additionally, the technology drawbacks are discussed, along with various innovative techniques recommended to direct future study in this area. Finally, this article assists the audience clear idea in the selection of the right combination of potential RES based on different conditions to achieve deep decarbonization in BSs. • Buildings sector (BS) responsible for 40% of GHG emissions. • Study assesses potential of Renewable Energy System (RES) in BS. • RES evaluated on payback, energy generation, and CO 2 reduction. • Optimization, feasibility and commercialization studies were discussed. • Article recommends right RES combinations for deep decarbonization in BS. [ABSTRACT FROM AUTHOR]

[Display omitted] Dynamic modeling of building performance is essential for understanding how current buildings will respond to projected changes in environmental conditions, and how these responses will in turn affect building occupants. Additionally, expected shifts in background energy systems will change the carbon intensity of energy delivered to buildings, while shifts in atmospheric composition will alter the global warming potential of each greenhouse gas. This paper models these three dynamic systems simultaneously to determine which projected shifts will have the largest influence on global warming impacts and occupant satisfaction metrics throughout the use phase of an office building prototype model in different climate zones of the United States. The median of RCP8.5 and RCP4.5 climate scenarios were used to morph local weather files to simulate the electricity and natural gas needed to meet heating and cooling loads in each location, as well as thermal comfort and daylighting metrics. These RCPs were also used to estimate shifts in the global warming potential factors for CO 2 , CH 4 , and N 2 O. Projected shifts in the electricity generation mix and upgrades to transmissions and distribution infrastructure in each region were used to estimate future carbon intensity factors for building site energy use. Compared to the baseline results, decarbonization of the electricity grid results in the largest shift in building operational GHG emissions, far outweighing emissions increases due to higher cooling loads. Shifts in ambient temperatures and direct and diffuse radiation had heterogeneous effects on occupant comfort, particularly in Boston across different seasons and orientations. Understanding how building performance is expected to respond to complex future trends will assist in designing adaptive buildings that take advantage of projected changes. [ABSTRACT FROM AUTHOR]

Buildings contribute to greenhouse gas emissions that cause environmental impacts on climate change. Net Zero Energy (NZ) buildings would reduce greenhouse gases. The current definition of NZ lacks consensus and has created uncertainties, which cause delays in the adoption of NZ. This paper proposes a Process for Clarification to Accelerate the Net Zero (PC-A-NZ) through three integrated steps: variations, strategies, and requirements. We expand on the results in published NZ literature to clarify the differences in definition and strategy. The objective of this review is to (1) distinguish current variable parameters that are slowing the acceptance of NZ, and (2) focus the discussion internationally on moving faster toward applying NZ to a larger common agreement. The publications of global NZ target assessment and energy efficient strategies will be reviewed to address the main requirements in expediting NZ's successful progress. Our NZ review analysis highlights (1) how the existing NZ definitions and criteria differ, (2) how calculation strategies vary, and (3) how standards and requirements are often localized. The proposed PC-A-NZ will help policymakers and stakeholders to re-evaluate the existing definitions, standards, and requirements to optimize the use of renewable technologies, improved energy efficiency and electrification to speed up achieving the NZ targets. Definition: There are multiple NZ definitions that vary in source and supply requirement, timescale, emission source, and grid connection. [ABSTRACT FROM AUTHOR]

Decarbonization by the mid-21st century requires strong commitment to greenhouse emission abatement measures, but national emission reduction pledges are made for the medium term. Achieving medium term targets without taking into account the long term can lead to a lock-in effect, binding countries in pathways that cannot lead to strong decarbonization. This paper sheds light in this issue by combining a theoretical approach with real-world engineering and cost data. We develop a constrained optimization model to examine least-cost greenhouse gas emission abatement pathways, taking into account (a) emission reduction objectives for two years: 2030 and 2050; and (b) the potential speed of implementation of each measure, which expresses technical and behavioural inertia in the deployment of a measure. We focus on European countries and economic sectors that are not subject to the EU Emissions Trading System. We derive relationships between 2030 abatement targets of varying ambition and the possibility for a country to achieve a strong 2050 target. We find that more ambitious EU-wide targets have to be set by 2030 so that Europe delivers deep decarbonization by 2050. Moreover, if air pollution costs are taken into account, strong decarbonization by 2050 has lower social costs than less ambitious policies. [ABSTRACT FROM AUTHOR]