Avoided Greenhouse Gas Emissions Research Articles

Upgrading low-concentration oxygen-bearing coal bed methane by dual-reflux vacuum swing adsorption

AbstractFugitive methane (CH4) is a typical by-product of mining processes, which is commonly known as coal bed methane (CBM) or coal mine gas (CMG). The capture of these CH4 gases can simultaneously avoid greenhouse gas emissions and provide extra energy benefits. However, the explosion risk of low-concentration CBM (CH4 molar fraction ≤ 30%) requires strictly safe operating protocols to conduct the capture process. Dual reflux vacuum swing adsorption (DR-VSA) is a promising candidate with a vacuum operating condition which can lower the explosion risk and simultaneously reach CH4 enrichment and O2 removal targets in product and effluent streams. Herein, a low-concentration oxygen-bearing CBM (20% CH4, 16% O2 and 64% N2) can be upgraded to 69.7 mol% in the product gas while ensuring an effluent concentration of 2.5 mol% by the DR-VSA cycle using ionic liquidic zeolites (ILZ) as the adsorbents. A rigorous safety analysis has been conducted to investigate the explosion risk in the adsorption column and product tank, suggesting that the DR-VSA process is a safe technology for upgrading low-concentration oxygen-bearing methane.

Climate mitigation potential and economic costs of natural climate solutions for main cropping systems across China

CONTEXTNatural climate solutions (NCS) offer immediate and cost-effective ways to tackle the climate crisis by transforming atmospheric carbon to soil carbon or avoiding greenhouse gas emissions. However, the climate mitigation potential and economic costs of NCS for cropping systems in China remain inconclusive. OBJECTIVEThe major objectives of this study are (i) to estimate the NGHG reduction potential across Chinese main cropping systems caused by NCS, (ii) to quantify the economic costs of adopting optimal management with different abatement potentials. METHODSThe Denitrification-Decomposition (DNDC) model was used to estimate the NGHG, including SOC sequestration, N2O emissions, and CH4 emissions. After calibration, we ran the DNDC model with derived data at municipality-level. We estimated the NGHG under current management, adopting optimal management individually, and integrated optimal management to project the maximum NGHG reduction potential caused by NCS. We used the marginal abatement cost method to estimate the economic cost. RESULTS AND CONCLUSIONSThe four natural climate solutions, N fertilization management (NFM), straw returning management (SRM), tillage management (TM), and rice irrigation management (RIM) can reduce national NGHG in main cropping systems by approximately 118.8 Tg CO2-eq, 116.3 Tg CO2-eq, 35.2 Tg CO2-eq, and 74.4 Tg CO2-eq, respectively. The integrated optimal management may potentially reduce NGHG by 256.9 Tg CO2-eq, equivalent to 90.2% of current NGHG, and 80% of which can be realized at the price of CN¥ 285 (Mg CO2-eq)−1. We further identify the priority NCS for different crops and regions and conclude that nitrogen fertilization management should be the priority NCS at the national level. SIGNIFICANCEOur findings highlight the great potential of NGHG reduction by adopting NCS precisely and the importance of optimizing agricultural management as a whole, and they will help policy makers to develop smart-agriculture in China.

Application of untreated versus pyrolysed sewage sludge in agriculture: A life cycle assessment

Recycling of phosphorus (P) from waste streams such as sewage sludge to agriculture is essential in order to ensure future food security. Land application of sewage sludge is controversial due to its content of pollutants, such as heavy metals and toxic organic compounds. Pyrolysis is a technology that can eliminate harmful contaminants while enabling the recycling of P in the sludge. Organic pollutants are degraded during pyrolysis, while most of the P remains and approximately 40 % of the carbon is retained in a stable form in the biochar. When performing pyrolysis at a temperature of around 800 °C or more, cadmium is evaporated and can be separated from the biochar. Electricity-driven pyrolysis facilitates this by means of easier temperature control. The aim of the present study was to undertake a Life Cycle Assessment (LCA) to evaluate the environmental impacts of high-temperature electricity-driven pyrolysis of sewage sludge, including the separation of cadmium, and field application of sludge biochar as compared with sewage sludge storage and field application. The results showed that pyrolysis can offer a more climate-friendly solution due to avoided greenhouse gas emissions from the sludge and to carbon sequestration of the biochar. However, field application of untreated sludge resulted in a higher application of nitrogen (N) and more plant-available P. Agricultural modelling tools indicated that this produces higher crop yields than biochar application. In the LCA model, higher crop yields lead to savings in land use and water consumption as the higher yields can replace other crop production. The lower plant availability of biochar P implies a possible risk of lower yields when the P application is restricted based on total P, and a risk of greater P loss with soil erosion to the environment. Overall, the present study stresses the importance of including the long-term agronomic impacts of sludge and biochar field application in LCAs, and highlights the trade-offs that need to be considered in decision-making regarding the implementation of pyrolysis technology.

Regional economic aspects of carbon markets and anaerobic digesters in the USA: the case of swine production

AbstractThe USA has significant potential to produce energy from anaerobic digesters (AD) due to the size of its agricultural sector. The use of ADs reduces greenhouse gas (GHG) emissions from manure management. The financial benefits to farmers come from the on‐farm use, or off‐farm sales, of biogas and its end products, namely renewable natural gas (RNG) or electricity. Current energy prices and policies in the USA are insufficient to trigger large‐scale construction of ADs; however, payments to avoid GHG emissions and sequester carbon could become sufficiently high to prompt investment. This analysis quantifies the economic incentives necessary for the construction of ADs for swine producers and can easily be expanded to include other feedstocks. Various end‐use pathways to produce RNG and electricity are considered to account for location, herd size, and other parameters to deliver a comprehensive analysis for the USA. The analysis and results are composed of a generic part to illustrate the effects of carbon payment on profitability in general as well as a specific analysis for states representing 83.6% of the US hog inventory. Our results indicate that carbon payments would be a stronger determinant than energy prices in farm‐level decisions to install ADs, but that energy prices would be influential in determining the optimal biogas end use. The potential need for long‐term contracts – both for energy and carbon payments – to reduce investment uncertainty and increase investment in ADs is also discussed.

Climate-smart agricultural practices for enhanced farm productivity, income, resilience, and greenhouse gas mitigation: a comprehensive review

This study reviews the literature published between 2013 and 2023 to comprehensively understand the consequences of adopting climate-smart agricultural (CSA) practices. We categorize the literature into three categories based on the scopes of climate-smart agriculture: (a) sustainably increase agricultural productivity and incomes; (b) adapt and build the resilience of people and agrifood systems to climate change; and (c) reduce or where possible, avoid greenhouse gas emissions. The review demonstrates that adopting CSA practices, in many instances, improves farm productivity and incomes. This increase manifests in increasing crop yields and productivity, income and profitability, and technical and resource use efficiency. Moreover, adopting CSA practices reinforces the resilience of farmers and agrifood systems by promoting food consumption, dietary diversity, and food security and mitigating production risks and vulnerabilities. Adopting CSA practices is environmentally feasible as it reduces greenhouse gas emissions and improves soil quality. An integrative strategy encompassing diverse CSA practices portends an optimized avenue to chart a trajectory towards agrifood systems fortified against climatic change.

Collected knowledge on the impacts of agricultural soil management practices in Europe

AbstractSoil plays a central role in most aspects of human societies, and there is a large body of literature about sustainable soil management. Nevertheless, soil is currently facing degradation arising from different threats, which undermines sustainable development globally. In order to design effective research and policy strategies, it is necessary to identify the current knowledge level about sustainable soil management. This study summarises the key findings from a systematic stocktake of available knowledge about agricultural soil management practices in 23 European countries, which included the identification of soil management practices in use, the associated impacts and the soil challenges addressed. The aim of the study was to understand the current state of knowledge about the impacts of soil management practices, investigated and/or implemented across Europe. The results were analysed at the European level and were also grouped into European Regions and Environmental Zones. Key findings from this study were the identification of knowledge gaps that are key to climate mitigation and adaptation. There is a knowledge gap about soil management practices to avoid greenhouse gas emissions from agricultural soils, as the few reported studies evidence the complexity of the processes governing these emissions. Further knowledge is needed on the impact of tillage practices on long‐term carbon storage and distribution along the soil profile, as the reported knowledge was not consensual about carbon storage in deeper soil layers.

Tackling climate change through wastewater reuse in agriculture: A prioritization methodology

Water shortages, exacerbated by climate change, are posing a major global challenge, particularly impacting the agricultural sector. A growing interest is raised towards reclaimed wastewater (RWW) as an alternative irrigation source, capable of exploiting also the nutrient content through the fertigation practice. However, a prioritization methodology for selecting the most appropriate wastewater treatment plants (WWTPs) for implementing direct RWW reuse is currently missing. Such prioritization would benefit water utilities, often managing several WWTPs, and policymakers in optimizing economic asset allocation. In this work, a prioritization framework is proposed to evaluate WWTPs' suitability for implementing direct RWW reuse considering both WWTP and surrounding territory characteristics. This procedure consists of four key steps. Firstly, a techno-economic model was developed, in which monthly mass balances on water and nutrients are solved by matching crop requirements, rainfall conditions, and effluent characteristics. Economic suitability was quantified considering economic benefits due to savings in freshwater resource, mineral fertilizers and avoided greenhouse gases emissions, but also losses in crop yield due to RWW salinity content. Secondly, a classification procedure was coded to select representative WWTPs among a set of WWTPs, based on their size, presence of nutrient removal processes, and type of crops in their surroundings. The techno-economic model was then applied to these selected WWTPs. Thirdly, input parameters' relevance in determining WWTP suitability for RWW reuse was ranked. Finally, scenario analyses were conducted to study the influence of rainfall patterns and nutrient treatment removal on the RWW reuse feasibility. The type of crops surrounding the WWTPs and RWW salinity content resulted to be crucial elements in determining WWTPs suitability for RWW reuse implementation. The proposed methodology proved to be an effective support tool for policymakers and water utilities to assess the techno-economic feasibility of direct RWW reuse, generalizing results to several combinations of WWTPs and crops.

Life cycle analysis of anaerobic digestion processes of poultry litter

This article presents results of life-cycle assessment of anaerobic digestion processes of poultry litter (PL) preceded or not by thermal pretreatment (autohydrolysis). For this, the environmental impact categories, greenhouse gas (GHG) emissions, eutrophication, and soil acidification were evaluated using the ReCiPe Midpoint (H) method. Based on primary data provided by a partner company, life-cycle inventories were constructed for three forms of poultry waste management: i. disposal of in natura PL into the soil, which is the commonly used management technique; ii. anaerobic digestion of in natura PL; and iii. thermal pre-treatment by autohydrolysis of PL before its anaerobic digestion. It is concluded that anaerobic digestion of PL reduces GHG emissions compared to the “business as usual” scenario of soil disposal. The use of digestate (liquid fraction generated by PL anaerobic digestion) as soil fertilizer would result in avoided GHG emissions of 34%, while thermal pre-treatment by autohydrolysis of PL prior to its anaerobic digestion would result in a slightly lower reduction (27%) in GHG. Anaerobic digestion of in natura PL would also reduce the eutrophication potential by 98.2% (kg eq PO4-3/t litter) and the acidification potential by 98.4% (kg eq SO2/t litter) compared to its soil disposal. These results show that anaerobic digestion is a more sustainable way to manage PL than its environmental discharge.

Vulnerability of multi-designated landscape and its connectivity toward conservation: A case study in Kampar Kerumutan, Riau, Indonesia

Indonesia is declared by the United Nations as a country that meets its conservation targets. However, Indonesia has not maximized the potential conservation of its territory, and the ecosystem is still threatened by anthropogenic activity, particularly due to small and large scales cultivation. Besides, the Government of Indonesia (GoI) built taskforces at the national level to avoid greenhouse gas emissions through FOLU Net Sink 2030 that could tackle climate and biodiversity crises. Therefore, identifying OECMs and creating a sustainable management framework by elaborating on the carbon pool and its dynamics across the Indonesian landscape is crucial to meet the targets of the global conservation agenda. Kampar Kerumutan Landscape (KKL) is one of the critical landscapes in Indonesia with high potential conservation for biodiversity and high intervention from various concessions. Our result showed that most KKLs were categorized as potential restoration areas. Industrial forest plantations (IFP) had the highest threat for conservation. To connect the potential highly conserved areas within KKL for species mobility, restoration projects (particularly in IFP, Protected Areas, and Non-managed areas) should be conducted to achieve human and nature balance in the KKL.

Electricity generation potential from natural gas pressure reduction turbines in Brazil

This paper addresses the urgent need to meet increasing energy demand while avoiding greenhouse gas emissions by improving energy efficiency. One significant challenge is the energy losses that occur during gas pressure reduction at city gates in natural gas distribution systems. To tackle this issue, this study proposes installing pressure reduction turbines (PRTs) parallel to existing reduction valves, which can generate electricity and enhance system efficiency. This research mainly focuses on Brazil’s natural gas supply, where the potential for installing PRTs is evaluated. The methodology analyzes the country’s distribution network and estimates the electricity generation capacity achievable from PRTs. The results indicate a potential power generation of 66 MW, capable of avoiding the emission of 235,800 tons of CO2 annually and generating 333 GWh/year of electricity, all at a LCOE of $27/MW. These contribute to the environment using the energy efficiency achieved through the installation of PRTs, consequently, Brazil can help to a cleaner and more sustainable energy future.

Seaweed as climate mitigation solution: Categorizing and reflecting on four climate mitigation pathways

AbstractGlobal concerns about climate change were once again expressed at the COP27 in Sharm El‐Sheikh. Seaweed is frequently presented as a solution for climate mitigation. For a proper appraisal of its contribution to mitigating climate change, it is necessary to distinguish between, and critically scrutinize, the various pathways seaweed‐based climate mitigations can take. This article identifies four different climate mitigation pathways and critically reflects on each. First, carbon sequestration, occurring when grown seaweed is left in the seas or, second, purposefully sunk. Third, carbon emission reduction, resulting when seaweed‐based products replace products with a higher carbon footprint, either fossil based products or other organic material. Fourth, carbon emission avoidance, taking place when seaweed products are used to avoid greenhouse gas emissions in other production processes. Each of these pathways requires specific methods to quantify their magnitude and comes with critical questions to ask. The sequestration pathway requires monitoring of net carbon production and the amount of carbon that is eventually exported to the deep sea. Pathways 3 and 4 require Life Cycle Assessment and/or Carbon Footprint with system boundaries set to include the production system itself and installation thereof. We propose an unequivocal categorization in a belief that confusion on the benefits of seaweed will eventually impede development of seaweed‐based solutions.This article is categorized under: The Carbon Economy and Climate Mitigation > Benefits of Mitigation

Corn ethanol production with thin stillage anaerobic digestion for bioenergy recovery: A technical and economic evaluation

The generation of bioenergy from thin stillage in a corn ethanol mill provides a new perspective for the use of by-products in a circular economy concept. Alternative technological routes for the corn ethanol by-products energy and nutrients recovery must be investigated to assess present and future decision-making toward economic and environmental indicators. The theoretical biogas production from an up-flow anaerobic sludge blanket (UASB) reactor in a corn-ethanol mill and the potential thermal and electrical power generation along with the avoided greenhouse gas (GHG) emissions were estimated for a large-scale industrial facility. This work aimed to assess the anaerobic digestion (AD) contribution to techno-economic indicators of a corn ethanol mill in three scenarios: 1) Standard corn-to-ethanol mill; 2) AD-CHP - thin stillage AD to produce biogas and its burning in a combined heat and power (CHP) system; 3) AD-BU - biogas purification to obtain and commercialize biomethane. The existent Brazilian market and fuels and biofuel policies place the system without AD in a slightly better position when analyzing financial indicators related to investment return. In contrast, the global energy and mass balances considering thin stillage AD showed that in the AD-CHP scenario, processing 1 ton of thin stillage would produce 10.37 m³ of biogas, which could generate 119.9 MJ of heat and 24.7 kWh of electricity in a CHP system, favoring a greener energy scenario. The energy recovered from biogas returns to the industry, supplying 7.15% of the heat required for steam production and 52.74% of the electricity requirement for industrial processing. As a renewable energy source, biogas would replace fossil sources for energy generation avoiding GHG emissions. Extrapolating the results of the present work to the Brazilian national scale, the biogas yield from the corn-to-ethanol industry would be 179.68 million m³ , the thermal energy generation from biogas could mitigate 125,574.42 ton CO2eq, and the electricity replacement could mitigate 58,193.02 ton CO2eq. Besides the mentioned energy generation and environmental benefits, the financial indicators for the examined scenarios showed that the Brazilian market and public policies related to biogas/biomethane are constraints to overcoming to larger adoption of AD by the corn-to-ethanol industry.

Meeting Lofty Aspirations? English National Planning Policy, International Law, and Climate Change

Abstract The National Planning Policy Framework (nppf) is the primary expression of central government planning policy for England. Given the importance of the planning system for a transition to a more sustainable future, including seeking to reduce and avoid greenhouse gas emissions, the nppf is a highly significant document. The nppf refers to the ideas of sustainable development and intergenerational equity, important in international environmental law. However, intergenerational equity has scarcely featured in the many legal challenges regarding the interpretation of the nppf. Having considered the extent to which the nppf achieves the aspirations set out in the instruments to which it refers, this article suggests potential changes to policy so as to provide greater support to the aim of reducing greenhouse gas emissions.

Modelling of Amino Acid Fermentations and Stabilization of Anaerobic Digestates by Extracting Ammonium Bicarbonate

With the current increase in demand for animal and agricultural products, management of agrowaste has become critical to avoid greenhouse gas emissions. The present article investigates the applicability of ammonium bicarbonate synthesis via flash distillation to valorize and stabilize several types of anaerobic digestates which are produced from individual fermentations of amino acids. The content of CO2 in the digestate was found to be responsible for the OH alkalinity (0.4 equivalents of acid/kg digestate), while the partial and total alkalinities (0.8 eq/kg digestate) were essentially derived from the content of NH3. The most suitable conditions for the flash distillation were 95 °C and 1 bar with the condensation occurring at 25 °C. However, in order to attain the precipitation of NH4HCO3 in the distillate, it was necessary to consider digestates with a moisture content of 50 wt.%, since saturation levels of inorganic nitrogen and inorganic carbon were not attained otherwise. Even under these conditions, few amino acids (i.e., arginine, glycine, and histidine) were able to provide an anaerobic digestate upon fermentation that would be suitable for NH4HCO3 stabilization. The process of stabilization with a capacity of a t of digestate per h was improved by adding hydrochloric acid or sodium hydroxide at a rate of 44 kg/h, leading to production of 34 kg NH4HCO3/h. Given the role of the volatile elements of the biogas as endogenous stripping agents, it is recommended to use a fresh and saturated digestate as feed for the flash distillation.

The Influence of Photovoltaic Self-Consumption on Water Treatment Energy Costs: The Case of the Region of Valencia

Energy consumption is one of the principal components of the operative costs incurred by providers of water services, both financial and environmental. Fortunately, in recent years solar panel technology has improved substantially, and photovoltaic self-consumption has become a tool that can reduce the costs of water reuse and other water services. Regions with a scarcity of water resources make a considerable use of non-conventional sources, consuming a significant amount of energy, which has a high financial and environmental cost and compromises the sustainability of the water supply. This research analyses the possibility of replacing part of this energy with self-consumption through photovoltaic panels based on data obtained for the Region of Valencia in order to analyse the impact of energy substitution on energy costs. Performing a Cost–Benefit Analysis, self-consumption projects require an electricity market price of between 0.14 and 0.18 EUR/kWh, so in financial terms it is not a particularly attractive alternative. However, the avoided greenhouse gas emissions have a high value, and including them in the calculations, the price needed to be in feasible amounts of 0.04–0.10 EUR/kWh for a small installation and 0.02–0.08 EUR/kWh for a large one. In other words, photovoltaic self-consumption is still today an alternative with financial difficulties, but the associated environmental benefit justifies public intervention as it is a beneficial energy alternative in a context of high greenhouse gas emissions.

Application of Anaerobic Co-digestion of Brewery by-Products for Biomethane and Bioenergy Production in a Biorefinery Concept

This study investigated the anaerobic co-digestion (AcoD) of brewery by-products for biomethane and bioenergy recovery, focusing on operational performance evaluation, kinetic analysis, microbial metataxonomic, and metabolic function prediction. The biochemical methane potential was conducted under mesophilic (35 °C) and methanogenic conditions (pH 7.5) by mixing brewery wastewater and sludge from the brewery wastewater treatment plant (1:1, v/v), following the addition (2.5 – 12.5 %, w/v) of brewer’s spent grains (BSG). The results demonstrate that the highest methane yield (88.02 mL CH4/g TVS) was obtained with 12.5 % BSG, which was 20.66-fold higher than the control reactor operated with wastewater and sludge (4.26 mL CH4/g TVS). The bioenergy recovery from biomethane could generate electricity (0.348 kWh/kg TVS) and heat (1556 MJ/kg TVS), avoiding greenhouse gas emissions (0.114 kg CO2-eq/kg TVS). The microbial community dynamics revealed a predominance of Halobacterota, Chloroflexi, and Euryarchaeota phylum. The genera Methanosaeta and Methanobacterium, and the Anaerolineaceae family predominated in the AcoD process. The metabolic function prediction showed the presence of genes (K01895, K00193, K00625, and K00925) associated with the direct activation of acetate in the acetoclastic pathway and methane production. Finally, the data obtained provide a perspective on using brewery by-products for bioenergy production in a biorefinery concept, reducing the environmental impacts and contributing to the circular bioeconomy transition of the beer industry.Graphical abstract

Enhancing the Energy Efficiency of Wastewater Treatment Plants through the Optimization of the Aeration Systems

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

Controlling feral ruminants to reduce greenhouse gas emissions: a case study of buffalo in northern Australia

Context The bourgeoning carbon economy is creating novel ways to incentivise conservation management activities that have the co-benefits of reducing greenhouse gas (GHG) emissions and social inequality. Aim To estimate the monetary value of carbon credits that landowners could generate by reducing ecologically destructive feral populations of the Asian water buffalo (Bubalus bubalis) in northern Australia. Methods First, we estimated buffalo enteric emissions based on the population structure of feral buffalo in northern Australia, and discounted the reduction of fire emissions due to the consumption of grassy fuel by feral buffalo. We then predicted the change in buffalo population size across the South Alligator River region of Kakadu National Park under four buffalo management scenarios: (1) no buffalo control; (2) low-intensity buffalo control; (3) moderate-intensity buffalo control; and (4) high-intensity buffalo control. We quantified the reduction of GHG emissions under the three buffalo control scenarios, relative to the scenario of no buffalo control, while discounting the GHG emissions that directly result from buffalo control actions (e.g. helicopter emissions). Key results All three buffalo control scenarios substantially reduced the estimated GHG emissions that would otherwise have been produced. The low-intensity buffalo control scenario was predicted to abate 790 513 t CO2-e over the 20-year simulation, worth USD15 076 085 (or USD753 804 year−1). Our high-intensity buffalo control scenario had the greatest reduction in GHG emissions, with a total net abatement of 913 231 t CO2-e, worth USD17 176 437 (or USD858 822 year−1). Conclusions The potential value of carbon credits generated by controlling feral buffalo populations in northern Australian savannas far exceeds the management costs. Implications The management of feral ruminants could be incentivised by the generation of carbon credits. Such management could simultaneously avoid GHG emissions, generate income for landowners and offer significant ecological benefits.

Estimation of biogas production potential and greenhouse gas emissions reduction for sustainable energy management using intelligent computing technique

This paper presents estimation of Biogas Production Potential and Greenhouse Gas Emissions Reduction for sustainable energy management using intelligent computing technique. Slaughterhouse wastes present a promising opportunity to partially reduce reliance on fossil-based energy. Biogas technology is regarded as one of the methods used in Ghana and can be used to combat climate change, while meeting demand for energy in the country. The objective of the research seeks to theoretically estimate biogas production potential from livestock and slaughterhouse wastes in Ghana, in order for policymakers to consider biogas technology as a potential source of renewable energy to meet the country's energy demand, while contributing to the SDG goals. This study obtained livestock population data from the Ministry of Food & Agriculture and the Ministry of Fisheries & Livestock from 2010 to 2020, and estimated the livestock waste production from slaughterhouses, biogas generation capacity, electricity production potential, greenhouse gas (GHG) reduction potential and biofertilizer generation capacity of Ghana in the fiscal year 2020. The findings indicated that, in the year 2020, slaughterhouses in Ghana generated 4.205 × 1010 kg of waste which can be used to produce 6.792 × 109 m3 of biogas, electricity generation rate of 7.110 × 109 kwh/year which represents about 43.01% of the total electricity consumed in the country that year. Also, the amount of GHG (CO2) emissions by using methane from the AD is 3.631 × 109 kgCO2. The avoided GHG emissions estimated is 1.075 × 1010 kg and biofertilizer of 4.514 × 108 kg can be produced.

Optimization of a diabatic compressed air energy storage coupled with photovoltaics for buildings: CO2-eq emissions vs payback time

The necessary path towards sustainable development makes increasingly crucial the role of energy storage systems because the most affordable renewable energy sources (RES) are typically intermittent In this perspective compressed air energy storage (CAES) is one of the main alternatives to batteries and pumped hydro energy storage. This study shows how an integrated system coupling RES and CAES may significantly reduce greenhouse gas emissions with acceptable payback times. The electrical load is provided by a representative building sample (RBS) located in Naples (Southern Italy), generated using the simulation-based large-scale uncertainty/sensitivity analysis of building energy performance (SLABE) methodology. A Pareto multi-objective optimization is performed via a brute-force search to minimize CO2-eq emissions and payback time. The design variables refer to a photovoltaic system design and to size and operation of an associated diabatic CAES. Two different application scenarios are envisaged: 1000 buildings and 2000 buildings. The avoided greenhouse gas emissions are about 55% and 51% with simple payback times of 14.3 years and 12.4 years, respectively. The results show that the proposed integrated framework, with the right mix of renewables, may lead to the complete satisfaction of the electrical load at reasonable costs.