Greenhouse Gas Emission Reduction Potential Research Articles

Greenhouse Gas Emission Reduction Potentials in Europe by Sector: A Bootstrap-Based Nonparametric Efficiency Analysis

The reduction of greenhouse gas emissions is the key action to limit global warming. An important source of greenhouse gas emissions and pollution is the inefficiency of production processes. We report results from a stochastic nonparametric efficiency analysis using directional distance functions to take account of undesirable outputs like greenhouse gases. With this approach, we are able to provide estimates of the potential emission reductions for 7 main sectors in 16 European countries. A specially adapted bootstrapping approach allows to implement a bias correction of the estimates and to compute confidence intervals. The results show that static efficiency improvements are a quantitatively important element of the emission reductions which are required to achieve the reduction targets of the European Union.

Liquefied natural gas exports from Canada to China: An analysis of internationally transferred mitigation outcomes (ITMO)

The ever-increasing anthropogenic greenhouse gas (GHG) emissions worldwide make it quite challenging to meet country-specific Nationally Determined Contributions (NDC) targets. Therefore, it is evident that the existing emissions abatement measures need to be taken a step further. Internationally Transferred Mitigation Outcomes (ITMOs) are allowed in Article 6.2 of the Paris Agreement as a cooperative approach to achieving NDC goals. There is a potential to create ITMOs between Canada and China by replacing coal use in China with British Columbia (BC)'s liquefied natural gas (LNG) supply. Replacing coal with LNG in energy generation applications is a promising approach to mitigate emissions. With global and national pressures to reduce emissions, China has created a market for LNG imports to cater to its rising natural gas (NG) consumption due to the coal-to-gas source switching strategy. However, the terms under Article 6.2 requires generated ITMOs to ensure environmental integrity, support sustainable development goals, and have a robust accounting system. Therefore, the current study aims to quantify the life cycle environmental outcomes of generating ITMOs by exporting LNG from BC to Chinese end-users while integrating uncertainties and to provide policy recommendations in adherence with the requirements of Article 6.2. Different LNG export scenarios were generated in the study and environmental impacts of each scenario were assessed and compared using a life cycle assessment (LCA) framework developed by the authors. Sensitivity and uncertainty analyses were conducted to understand the impacts created by the data uncertainties in the final result. By replacing conventional coal with NG, approximately 40–45% and 26%–32% emissions reductions can be obtainable for Chinese textile and chemical industries, respectively. The highest emissions reduction of approximately 60% was observed when coal is replaced with NG for district heating. The life cycle emissions (LCE) quantification framework provided in the study provides stakeholders with a systematic approach to determine the total GHG emissions and emissions reduction potential of different LNG export scenarios.

Urban mining potential to reduce primary material use and carbon emissions in the Dutch residential building sector

Urban mining is regarded as an important strategy to replace primary raw materials in the building sector. This study presents a bottom-up dynamic building stock model to explore the potential of urban mining to reduce primary material consumption and greenhouse gas (GHG) emissions in the residential building sector of the Netherlands. The model builds upon geo-referenced individual buildings, making it possible to analyze the spatiotemporal pattern of material supply from demolition and material demand for construction and renovation. The main results can be summarized as three points. (1) Urban mining cannot meet future material demand due to the new construction caused by population increase and its limited ability to supply the required kinds and amounts of materials. Therefore, large amounts of primary materials still have to be consumed in the future. (2) The generation of demolition wastes and the requirement for materials will be mainly concentrated in the big cities (e.g. Amsterdam, Rotterdam, and The Hague). (3) The GHG emission reduction potential of urban mining is very small and is not as large as the transition to a greener electricity mix. Recycling together with a greener electricity mix would reduce annual GHG emissions by about 40% in 2050 compared to 2020. This study provides a tool to link future material inflows and outflows in space and time. It further helps to assess the performance of strategies aimed at closing the material loops and reducing GHG emissions in the building sector.

Assessing the efficiency and sustainability of three eco-campus systems in Northwestern China using a comprehensive evaluation framework

Efforts have been made to alleviate plenty of various environmental issues and economic backwardness of elementary and secondary schools in rural China. In this paper, a multiple-perspective assessment framework was applied to evaluate the performance of three eco-campus systems. A set of emergy analysis, life cycle assessment, economic and social analysis indicators of the integrated framework were quantified and analyzed in detail. The results showed that the “Toilet-Biogas-Vegetables” mode (ESI=3.23) had the best sustainability in terms of comprehensive performance, followed by the “Grass-Goats&Toilet-Biogas-Fruits” mode (ESI=1.62) and the “Pigs&Toilet-Biogas-Vegetables” mode (ESI=0.82). In terms of environmental impact, the XDZS has the highest greenhouse gas emission reduction potential, reaching 26.44 ton in total. However, compared to common biogas integrated ecosystems, the three systems have some similarities in many aspects, such as appreciable resource recycling, net carbon sink, energy conservation, and economic feasibility. In this case, the combination of emergy synthesis, life cycle assessment, economic and social analysis provided a better insight into the comprehensive properties of rural campuses and thus could help us make a better environment for all the students and faculty.

Integrated approach for the estimation of regional low carbon potential: Application for Ho Chi Minh City, Viet Nam

Currently, multidisciplinary integrated and quantitative methodologies are necessary for policymakers in deciding a reasonable and acceptable target of greenhouse gas (GHG) reduction as well as realization of mitigation actions. Therefore, this study aims to develop an integrated methodology to harmonize the top-down and bottom-up approaches to support the development of low carbon actions at the regional or city level based on their energy-saving programs and technology status. This integrated approach is necessary to bridge the theoretical and empirical frontiers of modeling in quantifying and analyzing the feasibility of the local police framework and international cooperation in terms of climate mitigation projects. The top-down approach uses the Extended Snapshot (ExSS) tool to estimate GHG emissions and reduction potential based on macro socioeconomic information. Meanwhile, the technology-based bottom-up approach is a method to estimate the reduction potential of GHG emissions by accumulating specific energy-saving projects. Parameters related to energy service demand, energy efficiency, energy share, and dispersed power generation are harmonized in the integration process via a set of equations. Under the assumption of socioeconomic growth of Ho Chi Minh City (HCMC), which is a 1.37 times increase for population and a 4.41 times increase for GDP growth in 2030 compared to 2013, the total energy consumption will increase 3.73 times compared to 2013, which is nearly 26 million toe (Mtoe) in 2030. The total GHG emissions will also increase 4.02 times, reaching nearly 117.2 MtCO2eq if HCMC does not consider any climate change mitigation actions. However, if HCMC successfully implements the mitigation projects discussed and quantified in this study, the total GHG emissions might be lower, approximately 85.6 MtCO2eq. Analysis of the results from the two scenarios (BaU and CCAP) shows that the energy saving potential is approximately 15.0% and that the total GHG emissions reduction potential of HCMC (excluding the potential from grid power, which is outside the effort of HCMC) is 20.7% of BaU’s emissions, which is between the 8-25% reduction target of Vietnam intended nationally determined contribution. By looking at the disaggregation of reduction potential by each sector and project, policymakers can prioritize mitigation measures to meet the GHG emissions reduction target or to maximize GHG emissions reduction potential. The integrated approach requires the consistency between classifications in top-down (driving force based) and bottom-up (technology based) approaches as well as the modification and bridging of the top-down sectors and the bottom-up categories with detailed data. This method is very applicable for cities or regions that are developing climate change action plans with precise technological information.

Analysis of Agricultural Biomass Energy Use and Greenhouse Gas Reduction Evidence from China.

China is a large agricultural country, where agricultural activities and rural life cause a large amount of greenhouse gas (GHG) emissions. In the process of crop growth, production, and processing, a large number of crop straws and agricultural wasted products are produced, which become one of the important sources of biomass resources. However, few detailed studies focused on the potential of China's agricultural biomass energy conversion and carbon emission reduction, and fewer studies proposed GHG emission reduction strategies from the perspective of making full use of China's agricultural waste resources. In this study, the quantity calculation index of agricultural biomass energy was given, and the GHG emission reduction potential calculation index of agricultural biomass energy was constructed, with which the amount of GHG emissions caused by agricultural waste use in China was measured and the potential of GHG emission reduction caused by agricultural waste use would be easily speculated. Based on the statistical data of China, the quantity and GHG emission reduction potential of agricultural biomass resources in China in the recent 10 years (2009∼2018) were clarified. According to the research, the amount of agricultural waste equivalent to standard coal in China from 2009 to 2018 reached 280,0711 million tons. If all these resources were used to replace coal, a total of 4,474,483 million tons of carbon dioxide emissions could be saved. Assuming that these wastes are anaerobic, carbonized, or fully burned as fuel, CH4 emissions could be reduced by up to 12.024 million tons and N2O emissions by up to 185,000 tons. It can be seen that the effective utilization of agricultural biomass resources can replace coal, reduce backwardness such as land burning, and then reduce CO2, CH4, N2O, and other greenhouse gas emissions, and promote the realization of carbon peak and carbon neutrality.

Low carbon potential of urban symbiosis under different municipal solid waste sorting modes based on a system dynamic method

Urban symbiosis (UrS) is an innovative application of circular economy focusing on municipal solid waste (MSW). However, few studies have been conducted to forecast the impact of UrS on climate change under different MSW sorting policies such as four-category/two-category MSW separation standards and high/low sorting rates from a long-term and dynamic perspective. This study develops a system dynamics model to simulate the greenhouse gas (GHG) emission reduction potential and the energy saving potential of UrS under different MSW sorting modes in Shanghai for the period of 2020–2050. The results show that UrS with four-category MSW separation and a high sorting rate (scenario S1) has the highest energy saving and GHG reduction potential at both annual level and accumulative level, approximately 10.75 times the energy saving and 146.30% of the GHG emission reduction compared with the Business-As-Usual (BAU) scenario in 2050. Meanwhile, the scenario of two-category MSW sorting and a high sorting rate (S3) can further help reduce 12.84% GHG emissions than the scenario of four-category MSW sorting and low sorting rates (S2) in 2050. Among all the UrS measures, waste plastic recovery can contribute the most GHG emission and energy consumption reductions, with figures of approximately 2.15 Mt and 17.28 Mtce, respectively. Finally, policy recommendations on strengthening implementation of four-category MSW separation, making efficient two-category MSW separation as a backup plan, and promoting reutilization of waste plastic and Refuse Plastic & Paper Fuel technology are proposed.

Abatement cost for selectivity negative emissions technology in power plant Indonesia with aim/end-use model

The Indonesian government has followed up the Paris Agreement with Law No. 16 of 2016 by setting an ambitious emission reduction target of 29% by 2030, and this figure could even increase to 41% if supported by international assistance. In line with this, mitigation efforts are carried out in the energy sector. Especially in the energy sector, it can have a significant impact when compared to other sectors due to an increase in energy demand, rapid economic growth, and an increase in living standards that will push the rate of emission growth in the energy sector up to 6. 7% per year. The bottom-up AIM/end-use energy model can select the technologies in the energy sector that are optimal in reducing emissions and costs as a long-term strategy in developing national low-carbon technology. This model can use the Marginal Abatement Cost (MAC) approach to evaluate the potential for GHG emission reductions by adding a certain amount of costs for each selected technology in the target year compared to the reference technology in the baseline scenario. In this study, three scenarios were used as mitigation actions, namely CM1, CM2, CM3. The Abatement Cost Curve tools with an assumed optimum tax value of 100 USD/ton CO2eq, in the highest GHG emission reduction potential, are in the CM3 scenario, which has the most significant reduction potential, and the mitigation costs are not much different from other scenarios. For example, PLTU – supercritical, which can reduce a significant GHG of 37.39 Mtoe CO2eq with an emission reduction cost of -23.66 $/Mtoe CO2eq.

Local Climate Action Planning as a Tool to Harness Greenhouse Gas Emissions Mitigation and the Equity Potential of Autonomous Vehicles and On-Demand Mobility

This paper focuses on how cities can use climate action plans (CAPs) to ensure that on-demand mobility and autonomous vehicles (AVs) help reduce, rather than increase, greenhouse gas (GHG) emissions and inequitable impacts from the transportation system. We employed a three-pronged research strategy involving: (1) an analysis of the current literature on on-demand mobility and AVs; (2) a systematic content analysis of 23 CAPs and general plans (GPs) developed by municipalities in California; and (3) a comparison of findings from the literature and content analysis of plans to identify opportunities for GHG emissions reduction and mobility equity. Findings indicate that policy and planning discussions should consider the synergies between AVs and on-demand mobility as two closely related emerging mobility trends, as well as the key factors (e.g., vehicle electrification, fuel efficiency, use and ownership, access, and distribution, etc.) that determine whether the deployment of AVs would help reduce GHG emissions from transportation. Additionally, AVs and on-demand mobility have the potential to contribute to a more equitable transportation system by improving independence and quality of life for individuals with disabilities and the elderly, enhancing access to transit, and helping alleviate the geographic gap in public transportation services. Although many municipal CAPs and GPs in California have adopted several strategies and programs relevant to AVs and on-demand mobility, several untapped opportunities exist to harness the GHG emissions reduction and social benefits potential of AVs and on-demand mobility.

Estimation of the sustainable production of gaseous biofuels, generation of electricity, and reduction of greenhouse gas emissions using food waste in anaerobic digesters

Food waste is a type of organic waste generated by restaurants, food processing plants, households, and commercial and institutions. This study aims to assess the sustainable biofuel, electricity production and greenhouse gas emission reduction potential of food waste using anaerobic digestion technology. Food waste data was collected from the Australian government database to estimate the biomethane and biogas yield and to evaluate the opportunities to convert the biomethane into electricity and heat. This study found that food waste can yield 47% biomethane and hence for Australia, an estimated total of 0.07 million m3 to 1.54 million m3 of biogas can be produced and up to 414,898 tonnes of greenhouse gas emissions reduced annually. The study also estimated that the generated biogas can replace fossil fuel-based electricity generation of up to 52.36 GW and 554.4 TJ heat per year. The environmental assessment indicated that the complete conversion of food waste can lower greenhouse gas emissions (GHG) by up to 5,07,434 tonnes per year and Australia can earn about $52.38 M revenue from electricity production. Therefore, conversion of food waste into biofuel through the anaerobic digestion process can play a significant role in generating electricity from non-fossil-based sources, reducing GHG emissions and earning revenue.

Policy communication for health and sustainability: comparison of food-based dietary guidelines

Abstract Background Food-based dietary guidelines (FBDGs) provide advice on what constitutes a healthy diet, influencing both decision-making at the policy level, and educational programs addressed to consumers. There is a growing body of literature that allows to estimate the health and environmental impacts of the wide adoption of FBDG at the country and global levels. This unlocks the possibility of evaluating the most sustainable dietary guidelines from a communication perspective. This study aims at answering what are the key converging messages and main differences in the communication of FBDG that have a high environmental potential, and what of those FBDG do communicate a sustainability purpose in an explicit way. Methods A mixed-method comparative review of FBDGs with a two-stage sampling process was developed. Building on Springmann et al (2020) we identified the countries where the wide population adoption of dietary guidelines would have the highest potential of reducing food-related greenhouse gas emissions (GHGe) while delivering positive health outcomes. In a second stage, a purposeful sample of FBDGs was designed to cover countries from different WHO regions, income levels, and languages. Results This study is in progress and results are preliminary. Out of the initial sample of identified FBDG with a GHGe reduction potential of more than 25 percent, a few of them, Germany, Brazil, Sweden, Netherlands, and France had been previously identified in the literature as having sustainability-based recommendations. Other guidelines with similar GHGe reduction potential, such as those of Switzerland and Italy also address sustainability in an explicit way. Conclusions FBDGs have been traditionally focused on health and nutrition messages. Several countries have updated recommendations considering the environmental impacts of food consumption. Not all the FBDG with a high environmental potential explicitly communicate sustainability concerns. Key messages Several countries can improve their health and climate change outcomes by promoting a wider adoption of their official dietary guidelines. Communication is a key aspect of this process.

The emission reduction potential of electric transport modes in Finland

The transportation sector has become the fastest growing source of greenhouse gas (GHG) emissions. One solution to mitigate the impacts is a shift towards electric modes. Where previous studies have only focused on the replacement of individual modes, our study presents a more holistic approach by comparing land-based, water-based and airborne transportation modes. We study the GHG emission reduction potentials of electric cars, buses, trains, ferries and aircraft in comparison to existing modes on 34 routes within Finland and across the Baltic Sea to Sweden and Estonia. By comparing the GHG emissions in carbon dioxide equivalents (CO2-eq) per passenger kilometer for each mode, we also consider the emissions generated from battery production as well as the differences in the energy mix from electricity production of the three studied countries. In addition to CO2-eq emissions per passenger kilometer, we also take real door-to-door travel times into account. Our study found that electric transportation modes possess great potential for emissions reduction. Nevertheless, depending on the energy mix used for electricity production, the emissions of electric transportation modes can exceed those of existing modes significantly. In addition, the emissions generated by battery production can have a significant share of the total emissions and should therefore always be considered. Finally, while also taking into account the door-to-door travel times, our study identified the great potential of electric aircraft to provide a less carbon intensive transportation option paired with short travel times starting on routes beyond 300 km where no high-speed rail exists as well as on routes across the water.

Energy and environmental impact assessment of Indian rice straw for the production of second-generation bioethanol

This study assessed the energy and environmental impacts in terms of second-generation (2G) bioethanol production, renewable electricity generation and greenhouse gas (GHG) emissions reduction potential of surplus rice straw (SRS) in India. National rice production database, and standard procedures for life cycle assessment of rice straw to 2G bioethanol production using two different pretreatment technologies namely, dilute acid (DA) and steam explosion (SE) pretreatments were explored for the analysis. Two scenarios (benchmark and resource-efficient) were constructed to evaluate the availability of SRS and to determine the potential from 2020 to 21 to 2030–31. Under benchmark for the year 2030–31, the potential from SRS using DA and SE pretreatment methods for the production of 2G bioethanol and the surplus renewable electricity generation were estimated to be 10,547 and 11,165 million L; and 5295 and 6928 GWh, respectively, and the corresponding GHG emissions reduction potential were assessed to be 11,954 and 14,375 kt CO2eq., respectively while generated renewable electricity replaces crude oil-driven grid electricity, and 11,498 and 14,498 kt CO2eq., respectively while generated renewable electricity replaces coal-driven grid electricity. The study revealed that both the availability of SRS and the choice of pretreatment method play decisive roles in the determination of its potential.

Assessment of site-specific greenhouse gas emissions of chemical producers: Case studies of propylene and toluene diisocyanate

The chemical industry accounts for 20% of global industrial greenhouse gas (GHG) emissions and the plastics production is increasing worldwide by approx. 4% annually. To reduce GHG emissions and increase GHG transparency in chemical value chains despite industrial secrets, we developed an approach to estimate the product carbon footprint of chemicals site-specifically without using classified production data. The new approach, is applied to two comparative case studies: propylene and toluene diisocyanate (TDI) production in Germany. The case study analyses 23 crackers on 17 production sites and four TDI production sites in Germany. The results indicate significant GHG emissions variations between productions sites (Cradle-to-Gate) that could not be quantified before. Among the production sites, product-specific GHG emissions range between 0.95 and 1.51 kgCO2e/kg propylene (reduction potential of GHG emissions of 37.1%) and between 3.17 and 3.62 kgCO2e/kg TDI (reduction potential of GHG emissions of 12.4%). This indicates massive differences in GHG efficiency in the production of propylene and TDI and an immense GHG emission reduction potential in the manufacture of plastic-intensive products (e.g. in the automotive sector) by increased transparency and informed supplier selection and procurement decision making. The method is transferable to chemical sites worldwide and indicates an even higher GHG reduction potential worldwide.

Assessment and Modeling of Household-Scale Solar Water Heater Application in Zambia: Technical, Environmental, and Energy Analysis

Solar water heaters (SWHs) are one of the most effective plans for general and easy use of solar energy to supply hot water in domestic and industrial sectors. This paper gives the first-ever attempts to assess the optimal localization of SWHs across 22 major cities in Zambia, as well as determine the possibility of hot water generation and model the greenhouse gas (GHG) emission saving. The climate data used is extracted by using the MeteoSyn software which is modeled in TSOL™. Results show the high potential of GHG emission reduction due to nonconsumption of fossil fuels owing to the deployment of SWHs, and three cities Kabwe, Chipata, and Mbala had the highest GHG mitigation by 1552.97 kg/y, 1394.8 kg/y, and 1321.39 kg/y, respectively. On average, SWHs provide 62.47% of space heating and 96.05% of the sanitary hot water requirement of consumers. The findings have shown the potential for the deployment of SWHs in Zambia. The techno-enviro study in this paper can be used by the policymakers of Zambia and countries with similar climates.

Agroecological public policies to mitigate climate change: public food procurement for school canteens in the municipality of Ames (Galicia, Spain)

ABSTRACT This work evaluates and discusses the greenhouse gas (GHG) emissions reduction potential of agroecological policies implemented in public food procurement for school canteens. Using a life cycle analysis (LCA) methodology (cradle-to-grave approach) and the information gathered from the Red Municipal de Comedores Escolares (Local Network of School Canteens) in the municipality of Ames (A Coruña, Galicia, Spain), the results show how organic production, dietary change (less animal protein), seasonal consumption, and packaging reduction, among other measures, can mitigate the climate impact of school meals. The food policies implemented in Ames have allowed mitigating the GHG emissions of local school canteens by 13.4%. Under realistic conditions, this reduction could rise to 40.6% should the agroecological transformation of the food system continue to advance.

China’s Tea Industry: Net Greenhouse Gas Emissions and Mitigation Potential

Tea is an important cash crop and a beverage that is widely consumed across the world. In China (the largest producer of tea), the industry is growing, and there is a need to understand current greenhouse gas (GHG) emissions and sequestrations and the potential for mitigation so that climate action can be strategically undertaken. Life cycle assessment and carbon footprint methods were used to quantify emissions in tea cultivation and processing in the 16 major producing regions for the year 2017. The system boundary was from cradle to factory gate, which was divided into three subsystems, namely agricultural materials production, tea production and tea processing. Several units of analysis were chosen: the production region (province), the production area (ha) and the product (kg loose tea), etc. Total GHG emissions were 28.75 Mt CO2eq, which were mainly attributable to energy use in tea processing (41%), fertilizer production (31.6%) and soil emissions (26.7%). This equated to 12.0 t CO2eq per ha and 10.8 kg CO2eq per kg processed tea. Production in Hubei, Yunan, Guizhou, Sichuan and Fujian provinces contributed almost two thirds of industry emissions, representing priority areas for strategic action to reduce GHG emissions. At the same time, the total carbon sink amounted to 21.37 MtCO2, representing 74.3% of total GHG emissions. The proportions stored in soil, biomass, and tea production were 49.3%, 30.0%, and 20.7%, respectively. If best recommended management practices for fertilizer application were adopted and biomass was used as a source of energy for tea processing, the GHG emissions reduction potential was 16.66 Mt CO2eq, or 58% of total emissions. The GHG emissions associated with tea production and processing in China appeared high by comparison to other regions of the world. However, considering the carbon sink and emissions reduction potential, the tea industry should be viewed as an important sector for climate action. Moreover, the potential for substantial GHG emissions reduction through the adoption of improved practices seems very realistic. There may also be additional opportunities for GHG emissions reduction through the development of organic tea cultivation systems.

The decarbonisation of Europe powered by lifestyle changes

Decision makers increasingly recognise the importance of lifestyle changes in reaching low emission targets. How the mitigation potential of changes in mobility, dietary, housing or consumption behaviour compare to those of ambitious technological changes in terms of decarbonisation remains a key question. To evaluate the interplay of behaviour and technological changes, we make use of the European Calculator model and show that changes in behaviour may contribute more than 20% of the overall greenhouse gas (GHG) emission reductions required for net-zero by 2050. Behaviour and technology-oriented scenarios are tested individually and in combination for the EU plus the UK and Switzerland. The impacts of behavioural change vary across sectors, with significant GHG emission reduction potential and broader benefits. Changes in travel behaviour limit the rising demand for electricity, natural resources and infrastructure costs from the electrification of passenger transport. Adopting a healthy diet reduces emissions substantially compared to intensifying agricultural practices, while at the same time making cropland available for conservation or bioenergy crops. The trade-offs between energy and food may be substantially alleviated when deploying technological and behavioural changes simultaneously. The results suggest that without behavioural change, the dependency of Europe on carbon removal technologies for its net-zero ambitions increases. Structural changes will be necessary to achieve full decarbonisation by 2050, yet changes in lifestyles are crucial, contributing to achieving climate targets sooner.

Renewable Energy Generation and GHG Emission Reduction Potential of a Satellite Water Reuse Plant by Using Solar Photovoltaics and Anaerobic Digestion

Wastewater treatment is a very energy-intensive process. The growing population, increased demands for energy and water, and rising pollution levels caused by fossil-fuel-based energy generation, warrants the transition from fossil fuels to renewable energy. This research explored the energy consumption offset of a satellite water reuse plant (WRP) by using solar photovoltaics (PVs) and anaerobic digestion. The analysis was performed for two types of WRPs: conventional (conventional activated sludge system (CAS) bioreactor with secondary clarifiers and dual media filtration) and advanced (bioreactor with membrane filtration (MBR)) treatment satellite WRPs. The associated greenhouse gas (GHG) emissions were also evaluated. For conventional treatment, it was found that 28% and 31.1% of the WRP’s total energy consumption and for advanced treatment, 14.7% and 5.9% of the WRP’s total energy consumption could be generated by anaerobic digestion and solar PVs, respectively. When both energy-generating units are incorporated in the satellite WRPs, MBR WRPs were on average 1.86 times more energy intensive than CAS WRPs, translating to a cost savings in electricity of $7.4/1000 m3 and $13.3/1000 m3 treated, at MBR and CAS facilities, respectively. Further, it was found that solar PVs require on average 30% longer to pay back compared to anaerobic digestion. For GHG emissions, MBR WRPs without incorporating energy generating units were found to be 1.9 times more intensive than CAS WRPs and 2.9 times more intensive with energy generating units. This study successfully showed that the addition of renewable energy generating units reduced the energy consumption and carbon emissions of the WRP.

Greenhouse gas emissions reduction potential by using antifouling coatings in a maritime transport industry

There are many measures for decarbonisation of maritime transport, however only a few of such measures have been applied in practice. The method for the assessment of the potential energy savings due to the application of antifouling coatings with lower roughness in terms of decrease in fuel consumption and consequently greenhouse emission is proposed within this paper. Using the proposed method, detailed analysis of the potential benefits of the application of antifouling coatings with lower roughness in terms of fuel savings and greenhouse emission reduction is performed for the first time. In addition, an economic analysis related to the implementation of this technical energy-saving measure is carried out. This study quantifies the fuel savings and carbon dioxide emission reduction that can be attained by applying antifouling coatings with lower roughness on the example of crude oil and bulk carriers. The results have shown that 138 t of fuel can be saved per route with a decrease in carbon dioxide emission up to 430 t for the investigated crude oil carrier. Furthermore, 20.4 t of fuel can be saved per route with a decrease in carbon dioxide emission up to 63.6 t for the investigated bulk carrier. In addition, the return on investment related to the application of antifouling coatings with lower roughness varied approximately from 1.5 to 3 years, which is lower than the usual dry-dock period. Based on these findings, it has been shown that antifouling coatings with lower roughness can be applied even for ships sailing at a lower speed, and that notable savings in fuel consumption and carbon dioxide emission can be attained.