Related Emissions Research Articles

A comparative evaluation of the sustainability of alternative aeration strategies in biological wastewater treatment to support net-zero future

In the plight for sustainable development and to support net zero ambitions for climate change mitigation, a broad range of aeration strategies have been developed with the hope of improving efficiency to minimize environmental and economic costs associated with the wastewater treatment processes. However, a balance is levied between reducing oxygen availability and hindering aerobic processes thus compromising performance. In the present work, we evaluate and compare the sustainability of a range of investigated strategies including continuous aeration (CA) at different dissolved oxygen (DO) setpoints (0.5 mg/L, 2.5 mg/L, 4.5 mg/L) and intermittent aeration (IA) at different oxic-anoxic portions (2.5 h on/0.5 h off, 2.0 h on/1.0 h off, 1.5 h on/1.0 h off). To achieve this, an eco-efficiency assessment is performed based on the results of previous life cycle impact and costing analyses for each strategy, while also incorporating a third factor to account for their respective treatment performance. The results demonstrate a clear pattern of increased sustainability for the IA strategies (0.54–0.56 Pt/m3), compared to the CA strategies (0.76–0.77 Pt/m3). While only negligible difference was observed within each aeration type, the trade-off between environmental and economic efficiency and treatment performance was distinct in CA strategies. At the individual pollutant level, IA strategies demonstrated decreasing sustainability for total phosphorous (TP) removal as the anoxic cycle portion increased, while CA at 0.5 mg/L was shown to be the most sustainable strategy for the removal of this pollutant (0.61 Pt/m3). Further work is suggested to incorporate the relative N2O emissions generated by each strategy and to investigate other strategies based on automated control.

Modeling and forecasting of CO2 emissions resulting from air transport with genetic algorithms: the United Kingdom case.

The increase in the air transportation density affects global warming negatively by increasing the CO2 emitted to the environment. The issue becomes even more important when the agricultural lands and drinking water resources on the flight routes are considered. This situation leads to the development of certain environmental concerns in the society and makes it necessary for the countries to forecast in the correct direction to develop some preventive strategies. To make a contribution to this issue, emission modeling and forecasts regarding emissions originating from air transportation were made in this study through genetic algorithms, a popular artificial intelligence technique. Using the flight information of 32 European countries, the degree of relationship between the number of flights and passengers and CO2 emission from air transportation was calculated. Based on the highly correlating results obtained, time series models were developed for the UK’s domestic and international airline transportation in which the highest number of flights takes place and passengers are carried. Using these models, the forecasts based on the UK’s flight numbers until 2029, the number of passengers to be transported, and air transportation–related emissions were made. Results with high correlation values ranging from 0.99 to 0.87 were obtained in the implementations.

Life cycle impact of winter heating in rural China from the perspective of environment, economy, and user experience

Winter heating related carbon emissions is a significant contributor to climate change. Coupled with the soaring energy price, low-carbon transformation of residential heating is being carried out worldwide. China recently introduced a clean heating policy that could impact more than 100 million people living in the countryside. However, a series of issues, such as high economic cost, insufficient fuel supply, and poor heating effect, have seriously hindered its implementation. To help address these issues, this study employs life cycle assessment, equivalent annual cost, and multiple attribute decision-making to evaluate the environmental impact, economic cost, and user experience of the following eight typical rural heating methods: soft coal, hard coal, clean briquette, biomass pellet, natural gas, air conditioner, air source heat pump, and electric boiler. As a result of field tests, three optimal methods are recommended, i.e. biomass pellet, air source heat pump, and air conditioner, depending on the resources, climate, economy, and living habitat in different regions. Although using any one of the optimal heating methods will increase residents’ heating costs by 30%-80%, the total environmental impact of rural winter heating will be reduced by 80% by 2030. And annual carbon dioxide emissions will be cut by 260 million tons in 2030 at 2020 levels. This is of great significance for China in its effort to control air pollution and fight climate change. Findings from the study will provide a useful reference for residential heating problems in other regions of China and the world.

Life cycle GHG emissions of the Austrian building stock: A combined bottom-up and top-down approach

Construction and operation of buildings are responsible for 37% of global greenhouse gas (GHG) emissions. In contrast, the Austria’s National Inventory Report attributes a mere 10% of national emissions to buildings – including only direct operational emissions of residential and service sector buildings. This narrow definition of the buildings sector neglects important environmental hotspots attributable to building-related life cycle emissions and calls for a comprehensive analysis of GHG emissions of Austrian buildings. In this study, we assess annual building related GHG emissions for the Austrian building stock from a full life cycle perspective (i.e. including operational and embodied emissions). For embodied emissions, we model emissions using both a process-based and an input-output based life cycle assessment (LCA) approach. Building LCA case studies and statistical building stock data are used to estimate embodied emissions from a bottom-up perspective, which are complemented by estimated emissions from the input-output based LCA approach. Our work illustrates the importance of adopting a life-cycle perspective on building-related emissions to inform the different stakeholders and advance climate action in the built environment. While both the chosen system boundaries and methods significantly determine the results, we argue that emission reduction measures should be based on a comprehensive system boundary of building-related emissions to contribute towards the achievement of a climate-neutral built environment and the stringent climate targets. By adding indirect emissions and non-residential buildings to the officially reported building emissions, the operational emissions alone increase by a factor of 2.4. As expected, the process-based LCA yields lower embodied emissions than the input-output based approach. Depending on the method, they can be responsible for up to 40% of total buildings related emissions. Summing up, total buildings related emissions rise by a factor of 3 to 4 when extending the system boundaries to comprise the whole area of action buildings, and go from 7 Mt CO2-eq/a (direct operational emissions, 10% of national emissions), to 22-31 Mt CO2-eq/a for the case of Austria.

Spatially resolved inventory and emissions modelling for pea and lentil life cycle assessment

Pulses are an increasingly popular source of plant-based protein among food manufacturers, food service providers, and retailers globally. Canada is currently a global leader in pulse production and exports. Given the large geographical scope of their production within Canada, pulses are produced under a variety of conditions reflecting differences in soil, climate, and characteristic management practices. In order to understand the influence of regional factors on the impacts of pulse production, high-resolution, regionalized life cycle assessments (LCAs) were carried out using both region-specific input/output data and emissions modelling. Six hundred Canadian pea and lentil farmers were surveyed to collect detailed data regarding characteristic farm inputs, yields and management practices at the reconciliation unit level of spatial resolution, which reconciles Canadian provincial borders with terrestrial ecozones based on soil and climate factors. The process-based model DeNitrification DeComposition (DNDC) was used to estimate regionally specific N emissions. This was compared to emissions estimates generated using the IPCC Tier II empirical models, which are typically used to estimate greenhouse gas emissions for national inventory reports. The main contributors to the life cycle environmental impacts of pea and lentil production were fertilizer and fuel use. This was consistent across all levels of regional aggregation including the total Prairie province average, as well as ecozone and provincial levels. There was variation in the magnitude of the impacts in each region assessed, which was mainly attributable to differences in yield, as well as reported fertilizer application rates and related emissions and fuel use for field operations. Significant differences were found in N emissions estimates between the DNDC and IPCC models, the magnitude of which varied by region and by the N emissions model employed. DNDC was found to provide better-resolved emissions estimates at the ecozone scale. This demonstrates the relevance of regionally specific emissions modelling since local soil and climate conditions had a large impact on the emissions estimates. In addition, the levels of uncertainty in the models were generally higher at the provincial and prairie province scale than at the ecozone scale. This may indicate that farming practices and associated resource/environmental impacts are more strongly influenced by soil and climate conditions than by provincial standards and guidelines. These results underscore the necessity of spatially resolved data collection and modelling to provide accurate estimates of the environmental impacts of crop production and to support more sustainable management of arable crop production.

Increasing building`s self-sufficiency rates through PV plus storage hybrids

Decarbonizing the building stock is of utmost importance for achieving sustainability as buildings are holding an important role for the clean energy transition. In this paper, the impact on the electrical consumption and building related CO2 emissions are analysed through real measurements by taking the effect from the implementation PV plus battery energy storage hybrids within 5 residential buildings in Plovdiv area. Increased self-sufficiency rates are quantified for a period of 3 years under pure self-consumption mode, where no power sells are taking place. Indicators such as monthly and yearly self-sufficiency rates with and without storage are compared. Building`s related CO2 avoidance are also compared in two scenarios-with and without battery energy storage system.

Carbon sequestration and storage potential of urban residential environment – A review

• Residential vegetation, soil and housing can store substantial amounts of carbon. • Biochar and biogenic construction materials offer novel opportunities in the field. • Underlying background variables are extremely complex and related to urban form. • Residential carbon sink potential can be utilised to mitigate related emissions. • More research is needed, especially in the developing countries. Cities are hotspots of anthropogenic activity and consumption. Thus, the consumption-based carbon footprints of their residents are pronounced. However, the beneficial climate impacts attributable to individual residents, such as carbon sequestration and storage (CSS) provided by residential green spaces and housing, have received less attention in the scientific literature. This review article presents an overview of the current research on the urban residential environment's CSS potential and argues for its inclusion in the so-called carbon handprint potential of individual consumers. The focus of existing research is on developed countries, and in empirical studies the absence of compiling literature presents a clear research gap. Most current potential is estimated to lie within the carbon pools of residential vegetation, soils and wooden construction, with biochar and other biogenic construction materials presenting key future development pathways. The underlying background variables guiding the formation of a residential carbon pool were identified as extremely complex and interconnected, broadly classified into spatial, temporal and socioeconomic factor categories. Our findings suggest that there is significant potential for growth in the residential CSS capacity, but substantial efforts from the scientific community, urban planners and policy-makers, and individual residents themselves are needed to realise this.

What can the Glasgow Declaration on Forests bring to global emission reduction?

What can the Glasgow Declaration on Forests bring to global emission reduction?

The Impact of Energy Renovation on Continuously and Intermittently Heated Residential Buildings in Southern Europe

To achieve carbon neutrality in the EU, it is important to renovate the existing EU residential buildings for a higher building energy efficiency. This study examines the impacts of several novel renovation technologies on energy consumption, CO2 emissions and indoor climates in southern European residential buildings through building-level simulations. Three typical residential buildings in South Europe were chosen as the demo buildings to implement the novel technologies. The technologies were classified into passive, ventilation and generation packages, and then simulated independently under the intermittent and continuous heating schedules. Additionally, two final combinations of renovation technologies were also simulated to demonstrate the maximum energy and CO2 emissions reduction potential of the demo buildings. All novel retrofit technologies manifested obvious effects on the energy consumption and CO2 emissions. Nevertheless, the effects were significantly affected by the heating schedule. When the intermittent heating schedule was switched to the continuous heating schedule, the relative energy conservation and CO2 emissions reduction potential of the thermal insulation improvement measures (e.g., bio-aerogel thermal insulation) increased, while those of the generation measures (e.g., solar assisted heat pump) diminished. Renovation with the final combinations reduced the primary energy consumption by up to 66%, 74% and 65% in the continuously heated Greek, Portuguese and Spanish demo buildings, the corresponding CO2 emissions reductions of which were 65%, 75% and 74%, respectively.

Volatile organic compounds in urban Lhasa: variations, sources, and potential risks

Lhasa is a typical high-altitude city with strong solar radiation and high background ozone levels. With the rapid development and urbanization, the emission of volatile organic compounds (VOCs) in Tibet has been increasing annually. However, VOCs activity and the impact on air quality and human health have scarcely been investigated. We conducted online measurement of VOCs in urban Lhasa during May 2019. The mean mixing ratio (with one standard deviation) of the total VOCs was 21.5 ± 18.6 ppb. Of the total VOCs, alkanes, alkenes, and aromatic hydrocarbons accounted for 57.7%, 20.9%, and 21.4%, respectively. On the basis of VOC atmospheric reactivity, the ozone formation potential (OFP) and hydroxyl radical loss rate (LOH) were 91.7 ppb and 3.1 s−1, respectively. Alkenes accounted for the largest proportion of the OFP and LOH, followed by aromatic hydrocarbons. The results of correlation analysis on the benzene series (BTEX), and the similarity of the diurnal changes in CO, NOy, BTEX, and TVOC mixing ratios indicated that Lhasa city strongly affected by motor vehicle emissions. Source apportionments using positive matrix factorization (PMF) model further confirmed that traffic related emissions, including gasoline automobiles, diesel vehicles, and public transportation vehicles fueled with liquid natural gas contributed the most in total VOCs concentration (44.5%–50.2%), LOH (41.6%–46.8%) and OFP (47.4%–52.3%). Biomass combustion, mainly from the traditional biomass fuel in the plateau, was the second contributor to ambient VOCs (41.3%), LOH (26.4%), and OFP (29.7%), and existed a less variation in diurnal changes with a feature of regional background. Plants contributed only about 1.5% to the VOCs concentration but a relatively high (approximately 14.6%) LOH. The noncarcinogenic risk of BTEX did not exceed the hazard quotient value, but the carcinogenic risk of benzene was 4.47 × 10–6, indicating a potential risk.

H2-rich syngas production from pyrolysis of agricultural waste digestate coupled with the hydrothermal carbonization process

A novel process to produce a H2-rich syngas from a high moisture-containing agricultural waste digestate is proposed. This process combines the use of hydrothermal carbonization (HTC), dewatering, pyrolysis, and catalytic reforming. Due to the feature of the high moisture content in the digestate, the effect of the HTC and dewatering on the process performance is of interest, and four scenarios were considered. Furthermore, three pyrolytic temperatures were chosen to understand the effect of pyrolysis conditions on the produced H2-rich syngas. A life cycle assessment was conducted to investigate the environmental impact of the proposed process. Results show that the application of HTC technology, increases the process efficiency, produces less syngas from one ton of digestate, lowers the cumulative energy demand and the negative carbon emissions. When the dewatering technology is used, the syngas yield is promoted but the H2 concentration in the syngas is reduced. The H2 to CO molar ratio reaches the maximum value of 9.2 when using a 450 ˚C pyrolysis temperature, by only using HTC. When the combining process of HTC and dewatering is used, it results in the highest process efficiency, but the smallest relative negative CO2 equivalent emissions by treating one ton of dry digestate.

The impacts from cold start and road grade on real-world emissions and fuel consumption of gasoline, diesel and hybrid-electric light-duty passenger vehicles

Progressively stringent regulations regarding vehicle emissions and fuel economy have spurred technology diversification in light-duty passenger vehicles (LDPVs). To assess the real-world emissions and fuel economy performances of hybrid electric vehicles (HEVs) compared to conventional internal combustion engine (ICE) vehicles, on-road measurements of ten gasoline, four diesel and six full hybrid LDPVs were performed using portable emissions measurement systems (PEMS) in Macao, China. The hot-running emission results indicate that the high emission risks of gasoline vehicles are associated with high mileage and old model years. Diesel vehicles are found to be the highest pollutant emitters in this study due to the intentional removal of aftertreatment systems. Under hot-running conditions, HEVs, as expected, could achieve carbon-reduction benefits of approximately 30 % (i.e., lower CO2 emissions and fuel consumption) compared to their conventional gasoline counterparts, while no measurable reduction in pollutant emissions was observed except in NOX (~70 % reduction). In contrast, the cold-start extra emissions (CSEEs) of CO2 reached 120–364 g/start for these HEVs, even exceeding the maximum values of conventional gasoline vehicles. However, the higher CO2 CSEEs of HEVs can be far offset by their hot-running emission reduction benefits. For tailpipe pollutants, the CSEEs of the HEVs were reduced by 21 %–68 % on average in comparison to those of conventional gasoline vehicles. Furthermore, strong correlations (R2 values of 0.69–0.89) between the road grades and relative emissions were observed. These results can provide necessary information regarding the improvement of future LDPV emission models and inventories.

Synthesis of GaN nanowires by ammoniating Ga2O3/BN

GaN nanowires were successfully prepared on Si (111) substrate through ammoniating Ga2O3/BN films deposited by radio frequency magnetron sputtering system. The synthesized nanowires were confirmed as hexagonal wurtzite GaN by X-ray diffraction, selected-area electron diffraction and Fourier transform infrared spectra. Scanning electron microscopy and transmission electron microscopy revealed that the grown GaN nanowires have a smooth and clean surface with diameters ranging from 40 to 160 nm and lengths typically up to several tens of micrometers. The representative photoluminescence spectrum at room temperature exhibited a strong UV light emission band centered at 363 nm and a relative weak purple light emission peak at 422 nm. The growth mechanism is discussed briefly.

The growth and luminescence mechanism of novel near-infrared Cs4Eu(Br,I)6:Sm crystal

A novel NIR emitting scintillator with 825 nm was developed by doping Sm2+ in Cs4Eu(Br,I)6 crystal. The single crystals of Cs4Eu(Br,I)6:Sm were successfully grown by the Bridgman method. The crystal structure and valence state was approved by XRD and XPS methods. The luminescence properties and energy transfer were systematically investigated. The energy transfer mechanism is variable for different Sm2+ concentration. The PL decay profiles show that the Sm2+-related emission has fast decay of nanosecond. The proportion of fast decay can be tunable by adjusting Sm2+ doped concentration. The Sm2+ doped europium -host material will have a potential application for unclear detection as near-infrared (NIR) scintillators.

Quantitative analysis of impact factors and scenario prediction of energy related carbon emissions at county level

ABSTRACT The key to coping with climate change is to control carbon emissions from energy consumption. Scientific prediction of energy consumption carbon emissions based on influencing factors is of great significance to the determination of carbon control aim and emission reduction strategies. Given the lack of previous studies on county-level carbon emissions, this paper proposed a systematic approach to study the influencing factors of county-level energy consumption carbon emissions and to predict future emissions. Firstly, the annual energy consumption carbon emissions were calculated based on the method proposed by the Intergovernmental Panel on Climate Change (IPCC). Then the expanded Kaya equation and existing research were combined to select influencing factors for the establishment of the optimal Stochastic Impacts by Regression on Population, Affluence, and Technology (STIRPAT) model, which was used to quantitatively analyze the influencing factors of carbon emissions from energy consumption at the county level. Finally, the emission reduction aims and low-carbon strategies were determined based on scenario analysis. The method was applied to Changxing, a typical county with large energy consumption and carbon emissions. Based on 16 years of data, the STIRPAT carbon emission prediction model was established and the forecast results of future emissions under three different scenarios were obtained. The results indicated that population size, industrial structure, and affluence degree were the three most influential factors, and the influence degree of each factor was quantified to support targeted low-carbon strategies for county-level cities.

Dairy Trade Helps to Alleviate Global Carbon Emission Pressure.

Global dairy production, consumption, and trade are growing rapidly, driven by population and per capita income growth and increasing health concerns mainly from developing countries, which has aroused concerns about the related carbon emission (mostly in the form of methane) increase. If all of the dairy products consumed were produced locally/domestically in the developing countries/economies (a counterfactual scenario), the carbon emissions in 2018 would be 28 Mt CO2-equiv higher than its status quo (a factual scenario). The present study indicates that unlike in many global trade cases in which carbon leakages are from developed to developing countries, global dairy trade is characterized by net embodied carbon flows from developed to developing countries/economies due to the fact that there is an overwhelming one-way-flow of dairy products from developed to developing countries/economies. The differences in the carbon emission factors between the developed and developing countries/economies provide an opportunity that global dairy trade and production specialization can help to reduce carbon emissions from increasing dairy product demand, and the total reduction potential is estimated to be about 414 Mt CO2-equiv from 2018 to 2030. Free trade agreements such as the Regional Comprehensive Economic Partnership will incentivize larger carbon emission reduction benefits through promoting dairy trade.

Extended methane mitigation capacity of a mid-season drainage beyond the rice growing season: a case in Spain.

Rice cultivation is a major source of methane (CH4) emissions. Intermittent irrigation systems in rice cultivation, such as the mid-season drainage (MSD), are effective strategies to mitigate CH4 emissions during the growing season, though the reduction rates are variable and dependent on the crop context. Aeration periods induce alteration of soil CH4 dynamics that can be prolonged after flooding recovery. However, whether these changes persist beyond the growing season remains underexplored. A field experiment was conducted in Spain to study the effect of MSD implemented during the rice growing season on greenhouse gas (GHG) emissions in relation to the standard permanently flooded water management (PFL). Specifically, the study aimed at (1) assessing the CH4 mitigation capacity of MSD in the studied area and (2) testing the hypothesis that the mitigating effect of MSD can be extended into the following winter flooded fallow season. Year-round GHG sampling was conducted, seasonal and annual cumulative emissions of CH4 and N2O as well as the global warming potential were calculated, and grain yield was measured. MSD reduced growing season CH4 emissions by ca. 80% without yield penalties. During the flooded fallow season, MSD reduced CH4 emissions by ca. 60%, despite both fields being permanently flooded. The novelty of our observations lies in the amplified mitigation capacity of MSD by extending the CH4 mitigation effect to the following flooded winter fallow season. This finding becomes especially relevant in rice systems with flooded winter fallow season given the large contribution of this season to the annual CH4 emissions.

Simulations of aerosol pH in China using WRF-Chem (v4.0): sensitivities of aerosol pH and its temporal variations during haze episodes

Abstract. Aerosol pH is a fundamental property of aerosols in terms of atmospheric chemistry and its impact on air quality, climate, and health. Precise estimation of aerosol pH in chemical transport models (CTMs) is critical for aerosol modeling and thus influences policy development that partially relies on results from model simulations. We report the Weather Research and Forecasting Model coupled with Chemistry (WRF-Chem) simulated PM2.5 pH over China during a period with heavy haze episodes in Beijing, and explore the sensitivity of the modeled aerosol pH to factors including emissions of nonvolatile cations (NVCs) and NH3, aerosol phase state assumption, and heterogeneous production of sulfate. We find that default WRF-Chem could predict spatial patterns of PM2.5 pH over China similar to other CTMs, but with generally lower pH values, largely due to the underestimation of alkaline species (NVCs and NH3) and the difference in thermodynamic treatments between different models. Increasing NH3 emissions in the model would improve the modeled pH in comparison with offline thermodynamic model calculations of pH constrained by observations. In addition, we find that the aerosol phase state assumption and heterogeneous sulfate production are important in aerosol pH predictions for regions with low relative humidity (RH) and high anthropogenic SO2 emissions, respectively. These factors should be better constrained in model simulations of aerosol pH in the future. Analysis of the modeled temporal trend of PM2.5 pH in Beijing over a haze episode reveals a clear decrease in pH from 5.2 ± 0.9 in a clean period to 3.6 ± 0.5 in a heavily polluted period. The increased acidity under more polluted conditions is largely due to the formation and accumulation of secondary species including sulfuric acid and nitric acid, even though being modified by alkaline species (NVCs, NH3). Our result suggests that NO2 oxidation is unlikely to be important for heterogeneous sulfate production during the Beijing haze as the effective pH for NO2 oxidation of S(IV) is at a higher pH of ∼ 6.

Demonstration of feasible waste plastic pyrolysis through decentralized biomass heating business model

As the global recycling industry has collapsed since the China import ban of 2017, the amount of plastic waste has been rapidly increasing with little to no economic incentives for its utilization as a feedstock. For the first time, this work demonstrates a proof of concept, pilot-scale cogeneration system for biomass heating and plastic-derived pyrolytic oil production (MacroConverter ®). Furthermore, a disruptive techno-economic business model for decentralized plastic pyrolysis is assessed and compared with a traditional centralized industrial system through superstructure supply-chain optimization. Results of this initial assessment indicate that using a decentralized plastic pyrolysis model, combined with seasonal heating demand, profitability can be increased (1.3–2.4 x) and the process is unlikely to show a loss of profit whereas the centralized process may show losses. Furthermore, compared to centralized pyrolysis, transportation costs, and related CO2 emissions were significantly decreased by 3–10 x and 1.4–7 x respectively.

Dynamic modelling and thermoeconomic analysis for the energy refurbishment of the Italian building sector: Case study for the “Superbonus 110 %” funding strategy

• Development of a dynamic model simulating the thermal load for space heating of a building located in different weather zones. • Analysis of the thermostatic valve control applied to the emitters of the heating system. • Analysis of the refurbishment solutions applied in several combinations to the buildings considered. • The dynamic analysis of the CO2 heat pump reveals interesting perspective for the energy transition scenarios. • The thermoeconomic analysis shows a great economic profitability when the “Superbonus 110%” incentive is considered. The refurbishment of the building sector is a relevant issue in several Countries, such as Italy, where the poor energy performance of residential buildings dramatically affects the overall primary energy consumption and the related emissions of CO 2 . Such buildings are featured by a significantly poor efficiency of the conventional centralized boilers and by a scarce thermal insulation of the envelope. Therefore, the use of renewable technologies, as the solar ones, may significantly reduce the environmental impact of such residential buildings. Moreover, the use of modern and highly efficient boilers is crucial to reduce the primary energy consumption. The combination of these solutions along with the improvement of thermal insulation of the building envelope seems very promising to enhance the energy performance of existing residential buildings. In particular, this work proposes the integration of a CO 2 heat pump to replace a conventional gas-fired boiler. This solution aims to be suitable for the Italian economic funding policy, known as “ Superbonus 110%”, where some specific energy refurbishment actions are fully funded by the Government. In the layout presented in this paper, the existing radiators are supplied by a new CO 2 heat pump, since its high outlet temperature is very close to the boiler one. Furthermore, the thermal insulation of the building envelope and the use of photovoltaic panels are also considered in combination with the CO 2 heat pump. In this work, the dynamic, monthly, and annual results of the carried out dynamic simulations are then presented and discussed. The optimal solution of the proposed layout is detected by means of a detailed sensitivity analysis which considers different weather zones. The energy and environmental analyses show that the CO 2 heat pump coupled with all the other solutions leads to a reduction of the primary energy consumption by 52% and a total CO 2 emission savings of 49%. The Italian incentive is considered in the economic analysis and results show a Net Present Value of the investment of roughly 27 k€, considering a lifespan of 25 years.