CO2eq Emissions Research Articles

The Inestimable Challenge

As those across both the industry and border community know, concrete is one of the most essential and versatile materials of modern society, and its importance is beyond doubt. Present in countless infrastructure projects of the ages, and into the future, its durability, strength, and versatility as a modern building material—and its indispensability—are unquestioned. Concrete structures can last for decades or even, under the right conditions and designs, centuries! Resistant to weathering, erosion, and fire makes concrete a remarkable material for structures that need to withstand extreme conditions. A versatile material that can be used for a wide range of applications, from pavements, buildings, and infrastructure to decorative elements. However, this widely used material of ours also has its darker side, and that is in its sustainable usage. The importance of understanding the implications of this material to ensure that concrete production and usage do not cause harm to the environment, and society, is a paramount discussion and debate for experts across conferences, public debates, and journals such as this journal, which informs and influences policy makers. According to the United Nations Climate Action, G20 countries are responsible for about 75 per cent of the world's CO2-eq emissions. To keep global warming below 1.5 degrees Celsius, we need to reduce greenhouse emissions to −45 per cent of 2010 levels by 2030; however, we are currently tracking to +10 per cent. The use of concrete has significant implications for sustainability, primarily due to its environmental impact. It is widely quoted that concrete is second only to water as the most consumed material, with about four tonnes per year used for every woman, man, and child on the planet. It is also widely cited that cement production accounts for around 8 per cent of global greenhouse gas emissions, which was a figure first presented in the 2000s, before accurate emissions data were available, and repeatedly requoted since and leading to dramatized headlines such as “Concrete: the most destructive material on Earth.” It is time that was corrected. According to IPCC AR6 WPIII report, with process improvements, cement production accounts for 2.6% of global greenhouse gas emissions (1.5 Gt CO2-eq of a global total of 59 Gt CO2-eq) and if these make up 40% of total cement-related emissions, this figure goes to about 4%. This is not by any means to understate the challenges ahead, just to best reflect where cement and concrete production, more broadly, sit in the hierarchical challenges. According to the September 2022 tracking report by the International Energy Agency, the cement subsector is currently not on course to achieve a net zero emissions scenario by 2050, and significant efforts and investments are required if progress is to be made. This involves investing in all aspects of abatement, including dematerialization, substitution, capture, and storage, as well as natural and industrial sequestration. Furthermore, it necessitates the critical development of design codes and standards to facilitate these efforts. This requires significant commitment and investment in research and low-carbon industries and products, clear policy direction by governments, and speedy rollouts of new codes and standards—and starts with all of us!

Winter wheat responses to enhanced efficiency granular nitrogen fertilizer in the Canadian Prairies

Optimizing the timing of nitrogen (N) enhanced efficiency fertilizers (EEFs) may maximize winter wheat ( Triticum aestivum L.) grain yield, protein content, and N-use efficiency (NUE). From 2013 to 2018, experiments were conducted at two irrigated and six rain-fed sites across the Canadian Prairies (24 site-years) to evaluate winter wheat responses to N source and timing/placement effects of EEFs. Nitrogen sources included untreated urea, nitrification inhibitor nitrapyrin treated urea, urease inhibitor N-( n-butyl) thiophosphoric triamide (NBPT) plus nitrification inhibitor dicyandiamide (DCD)-treated urea (NBPT + DCD), and polymer-coated urea (PCU). The N sources were all side-banded at planting, 30% side-banded at planting plus 70% broadcast in-crop late-fall (averaged 38 days after planting; split-applied late-fall), or 30% side-banded at planting plus 70% broadcast in-crop early-spring (averaged 224 days after planting; split-applied early-spring). Nitrous oxide and methane emissions were measured at one rain-fed site to test whether N source and timing/placement influenced CO2-equivalents (CO2-eq; nitrous oxide + methane). Under irrigation, NBPT + DCD consistently produced the highest yields regardless of timing/placement; however, the 80% of the recommended rate caused suboptimal protein responses (≤11%) unless split-application of N was adopted. Untreated urea produced the highest net CO2-eq and yield-scaled CO2-eq emissions, with the highest emissions when urea was split-applied early-spring. To optimize winter wheat production and NUE, we conclude that NBPT + DCD all-banded during seeding operations or split-applied early-spring provided similar and often superior results to other sources, including a more typical system of urea side-banded at the time of seeding.

Application of leached iron ore tailings to produce sustainable cements

The use of iron ore tailings (IOT) is a trend for the future of mining. The adoption of alternatives that minimise the disposal of natural resources and add value to production processes strongly supports this effort. Hydrometallurgy, by means of acid leaching, has been investigated as a processing route for iron recovery from IOT. After the separation of the liquor, a solid fraction of insoluble quartz and kaolinite remains (the main mineralogical phases). In the same way, the cement industry is an intensive consumer of raw materials and a major emitter of greenhouse gases. As one of the main alternatives for reducing these impacts, clinker substitution by wastes from other industries is being extensively considered. Thus, this work aims to evaluate the properties of the solid product of IOT leaching (L-IOT) and its potential to produce sustainable cements. L-IOT main composition is based on silicon (≈35%), aluminium (≈8%) and iron (2%). After thermal activation, the L-IOT was incorporated into pastes, replacing the cement by up to 20 wt%. The rheological parameters, hydration kinetics, compressive strength, mineralogy through X-ray diffraction (XRD) and thermogravimetric analysis (TGA) of cement pastes were assessed. L-IOT increased cement pastes' dynamic yield stress and viscosity and anticipated its main heat flow peak by up to three hours. Replacement contents of up to 20 wt% showed an equivalent 28-d compressive strength in the control sample, associated with carboaluminates formation. Finally, a simplified carbon dioxide equivalent emission (CO2-eq) analysis was conducted to evaluate the L-IOT’s environmental feasibility. Reductions of up to 21% CO2-eq emissions were observed for an L-IOT content of 20 wt%, compared to plain cement. The hydrometallurgical route allowed the recovery of 95% of the iron content in IOT, and its by-product presented technical and environmental feasibility for cement replacement in cementitious matrices.

Full-cycle greenhouse gas balance of a Sphagnum paludiculture site on former bog grassland in Germany

Growing Sphagnum on rewetted bogs (=Sphagnum paludiculture) is an alternative to drainage-based land use because it retains its value as productive land while mitigating greenhouse gas (GHG) emissions. However, studies on GHG exchange covering the full production system and cycle are missing. Here, we combined data of the establishment phase with newly recorded data of a 7-year old Sphagnum paludiculture site in Germany including partial Sphagnum harvest. GHGs were measured with closed chambers at all elements of the system (production fields, ditches, causeways).Over the full production cycle, the production fields were GHG sinks with −3.2 ± 4.2 t ha−1 a−1 (in CO2-eq), while ditches represented sources emitting 13.8 ± 11.5 t ha−1 a−1. New measurements on the causeway indicated that it was a stronger GHG source with 29.3 ± 9.8 t ha−1 a−1 than previously assumed from literature values. Corrected for the area share of its elements and including the partial Sphagnum harvest (in dry mass) of ~13.8 ± 0.6 t ha−1 (=average 7-year CO2 emissions of 3.3 ± 0.1 t ha−1 a−1), the site was a GHG source of 10.7 ± 4.6 t ha−1 a−1, thus reducing emissions by ~20 t ha−1 a−1 compared to the German emission factor for grassland on drained organic soils. Per ton harvested dry biomass, the paludiculture site emitted 9.9 ± 4.6 t of CO2-eq. The causeways were the major contributor to the warming, calling for reducing causeway area in Sphagnum paludicultures. Future ‘best-practice’ could realistically comprise areal shares of 80 % production fields, 5 % ditches, 15 % causeways and a full Sphagnum harvest with the uppermost 5 cm remaining on site for recovery. In this scenario the site would emit CO2-eq emissions of 4.3 ± 1.9 t ha−1 a−1 or 0.9 ± 2.1 t per ton harvested dry mass.

Spatial patterns of diffusive greenhouse gas emissions from cascade hydropower reservoirs

Greenhouse gas (GHG) emissions from reservoirs have received increasing attention in recent years. Despite extensive studies in single reservoirs, GHG emission patterns in cascades of multiple reservoirs, which are becoming increasingly common worldwide, remain unknown. This study investigated the spatial patterns of diffusive carbon dioxide (CO2), methane (CH4) and nitrous oxide (N2O) emissions, as well as their total CO2-equivalent (CO2-eq), for a cascade hydropower system in the heavily dammed upper Mekong River, China. Results demonstrated that GHG emissions in cascade reservoirs were higher than that in the upstream channel since the accumulated sediments fueled microbes for GHG production. In cascade reservoirs, CO2 made the largest contribution (58.6%–84.8%) to total CO2-eq, while the contribution of N2O was marginal. Deep reservoirs emitted less CO2, which was attributed to higher CO2 consumption by phytoplankton. Reservoirs formerly occupying the most upstream position for the longest period of time in the cascade emitted the most CH4, perhaps due to accumulations of river borne sediments. The total CO2-eq generally increased with distance downstream except within deep reservoirs. These findings indicate that, with respect to mitigating GHG emissions, the deepest, most upstream reservoir should be constructed first in the configuration of cascade hydropower reservoirs, and less sediment will enter downstream reservoirs, which have higher CO2-eq emissions.

Conservation tillage and diversified cropping enhance system productivity and eco-efficiency and reduce greenhouse gas intensity in organic farming

Environmental pollution, resource dwindling, and soil degradation questioned the sustainability of contemporary agricultural production systems. Organic farming is advocated as a sustainable solution for ensuring food security without compromising environmental sustainability. However, poor farm productivity quizzed the sustainability of organic production systems. Hence, a field study was carried out in the Sikkim region of the Indian Himalayas to assess the efficacy of conservation-effective tilling and diversified cropping on system productivity, profitability, environmental quality, and soil nutrient balance in organic farming. Three tillage systems, namely, (i) conventional tillage (CT), (ii) reduced tillage (RT), and (iii) zero tillage (ZT), and four maize based diversified cropping systems (maize–black gram–toria, maize–black gram–buckwheat, maize–rajmash–toria, and maize–rajmash–buckwheat) were tested using a three times replicated split-plot design. The ZT system recorded 13.5 and 3.5% higher system productivity over CT and RT, respectively. Of the four diversified cropping systems, the maize–rajmash–buckwheat system recorded the maximum system productivity (13.99 Mg ha−1) and net returns (3,141 US$ ha−1) followed by the maize–black gram–buckwheat system. Among the tillage practices, ZT recorded the significantly high eco-efficiency index (EEI; 1.55 US$ per kg CO2-eq emission) and the lowest greenhouse gas intensity (GHGI; 0.15 kg CO2-eq per kg production). Of the diversified cropping systems, the maize-rajmash-buckwheat registered the lowest GHGI (0.14 CO2-eq per kg production) and the highest EEI (1.47 US$ per kg CO2-eq emission). Concerning soil nutrient balance, after three cropping cycles, the soil under ZT recorded significantly higher available N (340.0 kg ha−1), P (16.6 kg ha−1), and K (337.3 kg ha−1) over the CT system at 0–10 cm soil depth. Similarly, the soil under the maize–black gram–buckwheat system had the maximum bio-available NPK. Thus, the study suggests that the cultivation of the maize–black gram/rajmash–buckwheat systems under ZT and/or RT would increase farm productivity, profitability, and soil fertility with minimum GHGI in organic farming under the Eastern Himalayan region of India.

Fossil-fuel consumption and CO2eq emissions of cut-to-length industrial roundwood logging operations in Finland

The aim of this study was to measure and model the fuel consumption of cut-to-length (CTL) logging machinery in cutting and forwarding under Nordic harvesting conditions, and to clarify which factors had the greatest effect on the fuel consumption. In addition, the total annual fuel consumption and CO2eq emissions were calculated for CTL logging operations in Finland in 2020. The data were collected during a long-term follow-up study on the fuel consumption of harvesters and forwarders conducted between March 2018 and April 2019. The fuel consumption data were obtained from a total of 16 harvesters and 13 forwarders equipped with digital flow metres featuring an accuracy of ± 1% of the fuel volume measured. The engine power of the forest machines explained most of the hour-based fuel consumption. Correspondingly, the harvesting conditions of the forest stand best explained the cubic-metre-based fuel consumption. The fuel consumption of CTL logging operations (cutting and forwarding) averaged 1.4 L m−3 in final felling, and 3.1 and 2.2 L m−3 in first and later thinning, respectively. There was a large variation in the cubic-metre-based fuel consumption between individual machines, both for harvesters and forwarders. The total calculated fuel consumption in Finnish CTL operations in 2020 was 126.6 million L, with the calculated CO2eq emissions totalling 334,209 t (i.e. 5.7 kg m−3). Several measures to accelerate fuel and energy efficiency and reduce CO2eq emissions in CTL logging operations are discussed in the paper.

Optimisation of multi-period renewable energy systems with hydrogen and battery energy storage: A P-graph approach

Renewable energy systems play an important role in alleviating environmental pollution, and their characteristics, including low emissions and recyclability, are highly favourable. At present renewable energy can be costly and renewable energy systems have room for optimization, particularly systems which cater to remote and island areas. This paper develops a P-graph-based multi-period energy model, using hydrogen for energy storage to satisfy the fluctuating electrical and thermal energy demand of an island. Hydrogen can be generated from renewable energy sources during off-peak periods and can be used to serve as an energy carrier. An economic and carbon footprint analysis of the system is performed, which compares a pure renewable energy system, with hydrogen storage, and with battery storage. Within the same scenario, the results show that the renewable energy systems with hydrogen storage and battery storage are 21.5 % and 5.3 % cheaper than the renewable energy system without energy storage, with CO2eq emissions of 1,717 t/y and 1,680 t/y. These findings show that the inclusion of energy storage systems has great potential to reduce costs within renewable energy systems. Changes in the supply of biomass were investigated (which had the greatest impact in the study area), as well as changes in the cost of hydrogen storage. In addition to the optimal solution, near-optimal solutions were also suggested to provide well-rounded guidance for implementation.

Carbon-neutral hydrogen production from natural gas via electrified steam reforming: Techno-economic-environmental perspective

This study proposes and evaluates a novel carbon-neutral hydrogen (H2) production process from natural gas through electrified steam methane reforming (e-SMR) with renewable electricity. The process model consists of different unit technologies such as reforming, water–gas shift, hydrogen pressure swing adsorption, and CO2 capture, along with heat recovery. Then, we evaluated the techno-economic-environmental performance of the proposed e-SMR process by comparing it with the conventional fired-heating steam methane reforming (f-SMR). By employing an electrically driven reformer using renewable energy, e-SMR outperforms f-SMR with less natural gas consumption, higher energy efficiency of 78.7%, and lower net CO2eq emission of 5.28 kg CO2eq/kg H2 and captured 5.58 kg CO2/kg H2; however, it has a drawback, i.e., higher H2 unit production cost (UPC) of 3.49 $/kg with a capacity of 7.06 ton/day. Sensitivity and uncertainty analyses identified the major cost drivers of UPC, such as the prices of natural gas, renewable electricity, and interest rates, as well as economic risks and uncertainties. The economic viability of e-SMR was determined by investigating multiple plant capacities, natural gas markets, renewable energy prices, and possible future CO2 selling prices. According to the investigation, currently, the US and India show promise for e-SMR, with abundant and affordable natural gas and renewable energy resources, both priced at around 3.49 $/kg of H2, respectively. Furthermore, the global 2030's scenario with 45 $/MWh of renewable electricity, and capture CO2 credit of 35 $/ton is observed at 3.40 $/kg H2, compared with that of 2050 at 2.91 $/kg H2. e-SMR is well adaptable to many countries' energy mix because it is flexible to utilize hybrid primary energy input, conventional natural gas as feedstock, and conventional/renewable energy for utilities.

Αn integrated life cycle assessment and life cycle costing approach towards sustainable building renovation via a dynamic online tool

Building stock retrofitting is essential to achieve the ambitious sustainability goals of the building sector due to its high energy consumption rates. The evaluation of the various building interventions shall be holistically assessed in terms of environmental and costing impact. The aim of this paper is twofold: First, it presents the innovative characteristics of a developed online tool (Virtual intEgrated platfoRm on LIfe cycle AnalYsis - VERIFY) able to perform dynamic life cycle analysis and global warming impact assessments by capitalizing on the well-known LCA and LCC methodologies, applicable in the case of building renovation. VERIFY is able to analyse dynamic life cycle inventories that consider the temporal profiles of energy consumption, and the time-dependent temperature changes, while being also interoperable in terms of exchanging data with other available energy simulation engines, or even using real-time monitoring data from sensors, processing any data time granulation. Second, the paper evaluates, from a life cycle perspective, the impact of specific energy retrofitting measures, meeting the Passive House Standard, for the case of a multi-family residential building in Athens, Greece. The proposed energy-retrofitting scenario examines actions related to the deep retrofitting of the building envelope and the upgrade of the thermal components as well as to the incorporation of clean electricity generation based on renewable energy systems; all aiming to drastically reduce the environmental impact of the building, rendering it almost near zero energy. Through the planned infrastructure installations, the primary energy needs and CO2eq emissions were reduced by 91 % and by 95 % respectively, while for a building operational lifespan of 25 years, savings up to 515 k€ compared to the baseline scenario, can be achieved.

A new methodological approach to the establishment of sustainable agricultural ecology in drought vulnerable areas of eastern India

Rice (Oryza sativa L.), the staple food for much of the world, requires gallons of water during its growth phase from tillage to harvest through conventional farming and emits significant greenhouse gases. Hence, modified cultivation techniques are felt to be needed to increase rice productivity, minimize water and fertilizer consumption effectively, and mitigate greenhouse gas emissions to a certain extent. The present experiment was based on the Purulia district, identified as a drought-prone zone through the RS-GIS technique. Two methods, the conventional method (CVN) and the system of rice intensification (SRI), were studied with four varieties of rice, viz. var. MTU 1010, var. IET 4786, var. IET 17430 and var. IET 9947 on water resource vulnerability, associated greenhouse gas emissions (CH4, N2O) and global warming potential (GWP). The results indicated that SRI cultivation is the smart method compared to CVN in the drought-prone Purulia District due to its lower water requirements and greenhouse gas (GHG) emissions. There was higher CH4 flux among the CVN plots than in the SRI plots (p < 0.05). The N2O flux in the rice field plots of CVN (Rabi-1.54 ± 0.04 kg ha−1, Kharif 1.51 ± 0.10 kg ha−1) was lower than the SRI (Rabi-2.08 ± 0.07, Kharif- 1.83 ± 0.02 kg ha−1) during Rabi season. The CH4 flux for CVN (Rabi-94.32 ± 2.71 kg ha−1; Kharif 110.33 ± 3.90 kg ha−1) was higher than the SRI (Rabi-68.16 ± 2.37, Kharif- 61.72 ± 2.41 kg ha−1) during Rabi season. The CO2-eq emission (pGWP) and yield-scaled CO2-eq emission (YpGWP) from the SRI were significantly lower when compared with CVN (p < 0.05). The result shows that the SRI technique is an effective agricultural method that farmers should be encouraged to follow in the drought-prone region to ensure less water consumption and a sustainable future for generations.

Carbon footprint of the globe artichoke supply chain in Southern Italy: From agricultural production to industrial processing

The globe artichoke represents one of the leading vegetables worldwide, accounting for a global production of 1.52 Mt in 2020, and Italy is ranked as the top producer with over 0.37 Mt. Under the environmental perspective, it is considered as a large greenhouse gases emitter, and its environmental sustainability, from agricultural production to industrial transformation, should be enhanced. The present research assesses the global warming potential of the globe artichoke crop in the Apulia region (Southern Italy) through the carbon footprint (CF) method (ISO/TS 14067:2018), and it evaluates the CO2eq emissions associated with input acquisition, artichoke cultivation and industrial processing. It also discusses strategies to reduce GHG emissions by optimizing the artichoke supply chain, according to a circular economy perspective. The main functional unit is 1 High-Density-Polyethylene (HDPE) drum of 229 kg, composed of 150 kg of drained finished “rustic artichoke” 70 kg of preserving liquid, and 9 kg of HDPE drum. Results reveal that the CF is 335.84 kg CO2eq, of which 276.86 kg CO2eq are generated during the agricultural production and 58.97 kg CO2eq during the industrial processing. CO2eq emissions could be reduced by increasing crop yield per ha, or by substituting chemical fertilizers with manure, PK3 fertilizer and bio stimulants. Under the circular economy lens, artichoke waste biomass could be used to produce: (a) bioenergy; (b) bio-stimulants and biomaterials; and (c) inulin. The research represents the first article, which assesses the CF of either the agricultural production or the industrial processing in the artichoke supply chain.

Energy comparison based on experimental results of a cascade refrigeration system pairing R744 with R134a, R1234ze(E) and the natural refrigerants R290, R1270, R600a

Refrigeration architectures for low-temperature applications are gaining interest in the Industrial, Commercial and Health fields. One of the most classical architectures is cascade systems, where two mechanical single vapor compression cycles are thermally paired by the cascade heat exchanger (HXcc). The HXcc, acts as condenser for the low temperature cycle and as evaporator for the high temperature cycle. Each cycle is charged with a different refrigerant adapted to the operating conditions. New environmental rules make necessary to find proper refrigerant pairs to get refrigeration plants with high energy efficiency together with environmentally friendly fluids. This experimental work compares the energy performance of a cascade refrigeration system working with the pair R134a/R744 against four alternative refrigerant pairs: R290/R744, R1270/R744, R600a/R744CO2 and R1234ze(E). Laboratory tests were conducted at three heat rejection temperatures: 20, 30 and 40°C, maintaining a fixed low-temperature heat source level (−20°C). The energy analysis shows that R290/R744 and R1270/R744 improve the cooling capacity at low heat sink temperatures, and the pair R290/R744 improves the energy performance at low temperatures. The environmental analysis shows that all the refrigerant pairs achieve a reduction in CO2eq emissions.

A reduced order model for triethylene glycol natural gas dehydration system

In natural gas processing plants, glycol dehydration is commonly used to remove water from the gas streams, to avoid pipeline blockage and equipment breakdown due to hydrates formation. This paper proposed a reduced order model developed based on integrated simulation-optimization approach for the glycol dehydration system, with the aim to minimize its operating cost while satisfying pipeline quality specifications. Steady-state process simulation software was used to identify important operating parameters for the glycol dehydration process; these include reboiler temperature and flow ratio of the regeneration column, and solvent flowrate. The identified parameters are built into a non-linear programming model, which was developed as a reduced order model for ease of implementation in the plant. The studied parameters are reboiler duties, hot oil, condenser, and pump, as well as TEG make-up flow rate and CO2 equivalent (CO2-eq) emissions. The Pareto Front is developed to identify the minimum operating cost at different levels of water dew point specification. The work has resulted in the annual savings of more than 34.6%.

Is reusable packaging an environmentally friendly alternative to the single-use plastic bag? A case study of express delivery packaging in China

The rapid growth of employing single-use plastic delivery bags (SPDBs) as express delivery packaging has led to serious resource depletion and environmental pollution. To mitigate these environmental threats, reusable plastic delivery boxes (RPDBs) were developed as an alternative option. This study utilized the life cycle assessment method to compare the environmental impacts of RPDBs and SPDBs. The results indicated that RPDBs cause fewer environmental impacts than SPDBs during intra-city delivery but higher impacts during inter-city delivery. Greenhouse gas emissions from plastic production were found to be the largest impact contributor, mainly from fossil energy generation during primary plastic pelleting. Increasing the average number of reuse cycles of RPDBs to 50, by 2025, would generate 6.24 million kg CO2-eq but could reduce CO2-eq emissions by 309.3 million kg and tons of plastic wastes by 0.96 million, compared to using SPDBs.

Environmental-cost framework to investigate impacts of carbon tax policy on material selection for building structures

ABSTRACT Building materials, mainly steel and concrete used in residential buildings, significantly impact CO2-eq emissions. Nowadays, carbon tax policy is used in some countries to reduce carbon emission effects. However, few comprehensive studies have been conducted to investigate the overall impact of such a carbon tax policy on minimizing building CO2-eq emissions. Stakeholders in the building industry often focus on cost criteria to select construction materials, neglecting environmental factors. Providing a cost-emission framework can be beneficial in choosing appropriate materials based on financial and environmental factors. This study proposes a comprehensive framework to analyze the embodied CO2 equivalent emission, carbon taxation, and cost of steel and Reinforced Concrete (RC) structures employing Life Cycle Assessment (LCA) methodology. The framework is implemented on an actual residential building case study to validate its potency. The case study’s results show that the embodied CO2-eq emission of the RC structure is 36% higher than the emission in a similar steel structure leading to 36% more carbon taxation. However, the total material cost of the steel structure is around 65% higher than the RC structure. Thus, carbon taxation policy does not necessarily reduce embodied CO2-eq emissions because stakeholders may prioritize the cost criteria to select building materials.

A Telemedicine Center Reduces the Comprehensive Carbon Footprint in Primary Care: A Monocenter, Retrospective Study.

Telemedicine reduces greenhouse gas emissions (CO2eq); however, results of studies vary extremely in dependence of the setting. This is the first study to focus on effects of telemedicine on CO2 imprint of primary care. We conducted a comprehensive retrospective study to analyze total CO2eq emissions of kilometers (km) saved by telemedical consultations. We categorized prevented and provoked patient journeys, including pharmacy visits. We calculated CO2eq emission savings through primary care telemedical consultations in comparison to those that would have occurred without telemedicine. We used the comprehensive footprint approach, including all telemedical cases and the CO2eq emissions by the telemedicine center infrastructure. In order to determine the net ratio of CO2eq emissions avoided by the telemedical center, we calculated the emissions associated with the provision of telemedical consultations (including also the total consumption of physicians' workstations) and subtracted them from the total of avoided CO2eq emissions. Furthermore, we also considered patient cases in our calculation that needed to have an in-person visit after the telemedical consultation. We calculated the savings taking into account the source of the consumed energy (renewable or not). 433 890 telemedical consultations overall helped save 1 800 391 km in travel. On average, 1 telemedical consultation saved 4.15 km of individual transport and consumed 0.15 kWh. We detected savings in almost every cluster of patients. After subtracting the CO2eq emissions caused by the telemedical center, the data reveal savings of 247.1 net tons of CO2eq emissions in total and of 0.57 kg CO2eq per telemedical consultation. The comprehensive footprint approach thus indicated a reduced footprint due to telemedicine in primary care. Integrating a telemedical center into the health care system reduces the CO2 footprint of primary care medicine; this is true even in a densely populated country with little use of cars like Switzerland. The insight of this study complements previous studies that focused on narrower aspects of telemedical consultations.

Comparative Study on Heating and Cooling Systems Integrated with Energy Storage

Taking a commercial building in Shanghai as an example, a list of cooling and heating systems are established and operation strategies are formulated. Based on the precondition that the excess electricity can be sold to the grid, the primary energy utilization rate and economices of the energy supply schemes are analyzed. The results show that compared with the traditional heating and cooling supply method, the combined cooling, heating, and power systems have better energy-saving and economic benefits. Additionally, the inclusion of the thermal energy storage yields additional economic benefits (up to 36% reduction in the CO2eq emissions and up to the 21% reduction in the total annual cost). Under the following-electric-load operation mode, the role of the thermal energy storage is to alleviate the temporal mismatch between the electric demand and the heating or cooling demand. To be specific, in the combined cooling, heating, and power systems, the total annual cost is reduced by up to 5.8% and the annual carbon dioxide equivalent emissions are reduced by up to 2.4% when the thermal energy storage is used. While under the following-electric-price operation mode, the performance of the CCHP system is largely subject to the natural gas price. Last, although heat pump systems are often regarded as efficient systems owing to the relatively high coefficient of performance of the heat pump, the energy supply through the heat pump systems may be carbon-emission-intensive currently.

Characterization of Municipal Solid Waste and Assessment of Its Potential for Refuse-Derived Fuel (RDF) Valorization

Reuse and recycling are preferred strategies in waste management to ensure the high position of waste resources in the waste management hierarchy. However, challenges are still pronounced in many developing countries, where disposal as a final solution is prevalent, particularly for municipal solid waste. On the other hand, refuse-derived fuel as a means of energy recovery provides a sustainable option for managing mixed, contaminated and residual municipal solid waste (MSW). This study provides one of the earliest assessments of refuse-derived fuel (RDF) from MSW in Ghana through a case study in the cities of Accra and Kumasi. The residual/reject fractions (RFs) of MSW material recovery were characterized for thermochemical energy purposes. The studied materials had the potential to be used as RDF. The combustible portions from the residual fractions formed good alternative fuel, RDF, under the class I, II-III classification of the EN 15359:2011 standards. The RDF from only combustible mixed materials such as plastics, paper and wood recorded a significant increase in the lower heating value (28.66–30.24 MJ/kg) to the mass RF, with the presence of organics (19.73 to 23.75 MJ/kg). The chlorine and heavy metal content met the limits set by various standards. An annual RDF production of 12 to 57 kilotons is possible from the two cities. This can offset 10–30% of the present industrial coal consumption, to about 180 kiloton/yr CO2 eq emissions and a net cost saving of USD 8.7 million per year. The market for RDF as an industrial alternative fuel is developing in Ghana and similar jurisdictions in this context. Therefore, this study provides insights into the potential for RDF in integrated waste management system implementation for socioeconomic and environmental benefits. This supports efforts towards achieving the Sustainable Development Goals (SDGs) and a circular economy.

A prospective study on the environmental feasibility of supplying electricity to the Brazilian Amazon through biogas power generation

This study supports a renewable way to generate electricity for Amazonian people living in isolated areas by determining the environmental impacts of a biogas power plant (BGPP) operated with agricultural residues. The study's novelty lies in measuring the environmental effects of projects based on residual biomass to reduce the high dependence on fossil fuels in a very impoverished region of Brazil. The localities under analysis lie in the country's lowest social indices zones, where severe development obstacles are noted, with the local electricity supply based on diesel engines. We constructed a model of BGPP based on data collected from the literature and adapted it to the conditions of the Brazilian Amazon. Then, the Life Cycle Assessment (LCA) method evaluated the system's environmental performance. The system was favorable in terms of Global Warming Potential and Primary Energy Demand for all scenarios, which represented up to 7.7-fold less CO2eq emissions, and 71-fold less energy consumption compared to the production of electricity from diesel. Conversely, Ecotoxicity's impacts must still be reduced to make this alternative attractive. Biogas unit seems to be up to 8.8-fold more toxic to the environment than the counterpart, although this effect is drastically reduced by adequate digestate destination.