Global Energy Matrix Research Articles

Effects of Offshore Wind Farms: Environmental and Social Perspectives from Uruguay

The installation of offshore wind farms is rising, driven by the goal of changing the global energy matrix. However, many of their possible impacts are still unknown. Increased noise levels, disruptions to food chains, pollution due to traffic, and impacts on fishing communities and tourism are all potential effects to consider. Marine habitats are essential carbon dioxide sinks. Therefore, losing marine biodiversity due to offshore wind farms can be counterproductive in mitigating climate change. Balancing biodiversity conservation, wind potential, and political interests is challenging. Today, Uruguay has significantly decreased the fossil share in its electricity generation, incorporating electricity generation from wind, solar, and biomass energy alongside hydroelectricity. In line with this, the country’s Hydrogen Roadmap highlights green hydrogen as relevant, potentially serving as a fuel for both domestic and export transportation. Combining the country’s strong base of wind energy production experience with its sustainable policy, it plans to implement offshore wind farms to produce green hydrogen, making studies of its impacts crucial. This paper reviews the current social and environmental information on the Uruguayan coastal habitat, analyzes onshore wind farms’ ecological studies, and examines offshore wind farms’ global environmental and social impacts. Finally, it proposes studies for environmental approval of offshore wind farms.

Energy recovery of residual yeast via hydrothermal liquefaction with multi-cycle reuse of the post-HTL wastewater and subsequent anaerobic digestion

Coupling hydrothermal liquefaction (HTL) with anaerobic digestion (AD) could be an interesting alternative for the energetic reuse of residual yeast derived from ethanol production, generating two valuable biofuels to diversify the global energy matrix. A central composite rotational design 23 optimized residual yeast HTL. The independent variables were temperature (300–400 °C), retention time (30–60 min), and solid content (5–12 wt%). The principal response variable was bio-oil yield. Three recirculation cycles of post-HTL wastewater (PHW) into the HTL reaction were investigated to enhance the energy recovery. The methanogenic potential of PHWs from recirculation cycles was then determined at mesophilic temperatures. During HTL, the bio-oil yield remained constant, while the volume of PHW decreased with recirculation cycles. The organic matter and total nitrogen present in the PHW were reduced until Cycle 2. The highest energy recovery in HTL was achieved at Cycle 0. However, the highest energy recovery in AD was attained at AD-Cycle 2, showing an approximately ∼14 % increase compared to AD-Cycle 0 (no recirculation). The total energy recovery for HTL-AD was higher in both Cycle 0 and Cycle 2, with Cycle 0 being more advantageous regarding net energy recovery from the products. In contrast, Cycle 2 offered more significant energy recovery and sustainability benefits.

Thermodynamic Analysis of Low-Emission Offshore Gas-to-Wire Firing CO2-Rich Natural Gas: Aspects of Carbon Capture and Separation Systems

Despite the growth of renewable energy, fossil fuels dominate the global energy matrix. Due to expanding proved reserves and energy demand, an increase in natural gas power generation is predicted for future decades. Oil reserves from the Brazilian offshore Pre-Salt basin have a high gas-to-oil ratio of CO2-rich associated gas. To deliver this gas to market, high-depth long-distance subsea pipelines are required, making Gas-to-Pipe costly. Since it is easier to transport electricity through long subsea distances, Gas-to-Wire instead of Gas-to-Pipe is a more convenient alternative. Aiming at making offshore Gas-to-Wire thermodynamically efficient without impacting CO2 emissions, this work explores a new concept of an environmentally friendly and thermodynamically efficient Gas-to-Wire process firing CO2-rich natural gas (CO2 > 40%mol) from high-depth offshore oil and gas fields. The proposed process prescribes a natural gas combined cycle, exhaust gas recycling (lowering flue gas flowrate and increasing flue gas CO2 content), CO2 post-combustion capture with aqueous monoethanolamine, and CO2 dehydration with triethylene glycol for enhanced oil recovery. The two main separation processes (post-combustion carbon capture and CO2 dehydration) have peculiarities that were addressed at the light shed by thermodynamic analysis. The overall process provides 534.4 MW of low-emission net power. Second law analysis shows that the thermodynamic efficiency of Gas-to-Wire with carbon capture attains 33.35%. Lost-Work analysis reveals that the natural gas combined cycle sub-system is the main power destruction sink (80.7% Lost-Work), followed by the post-combustion capture sub-system (14% Lost-Work). These units are identified as the ones that deserve to be upgraded to rapidly raise the thermodynamic efficiency of the low-emission Gas-to-Wire process.

A smart parametrisation for robust adaptive PI controller applied on renewable energy power generation systems under weak and uttermost weak grid conditions

The increasing penetration of renewable energy systems into the global energy matrix is a necessity for sustainable development. The benefits impact the well-being of humanity and the environment directly. However, these power generation systems demand reliable controllers to regulate the current injection into the electrical grid. Therefore, this paper presents a smart parametrisation for a robust adaptive proportional integral controller applied to grid-injected current control of a voltage inverter source with an LCL filter. Controller parameter optimisation and the initialisation of their gains are performed using the particle swarm optimisation algorithm. Three cost functions are assessed on controller parametrisation, considering the current tracking error minimisation and control action limitations: integral of absolute error (IAE) + integral of absolute control action (IAU), integral of square error (ISE) + IAU, and integral of the time-weighted absolute error (ITAE) + IAU. A framework for performance analysis and an in-depth discussion are presented, providing a systematic decision-support methodology for controller configuration. The function determined as the best one is implemented experimentally and compared with a designer’s experience-based robust adaptive proportional integral controller using a hardware-in-the-loop test bench, where the improvements in controller performance are corroborated, contributing to the enhancement of energy quality in renewable energy systems. In addition, the controller’s robustness is evaluated on a weak grid and an uttermost weak grid, where it presents high robustness and global stability.

Performance of Ni/Si‐MCM‐41 catalysts in CO2 methanation

AbstractThe production of methane from the methanation reaction between H2 and CO2, also known as the Sabatier reaction, is one way to diversify the global energy matrix, providing a use for CO2. This work evaluates the performance in this reaction of Ni catalysts supported on type MCM‐41 silica, synthesized y a wet impregnation method. Catalytic tests were performed for 2.5 h under atmospheric pressure. The reaction variables considered were the catalyst nickel mass content (5% and 10%), temperature (T = 400 and 550°C), reactant ratio (H2/CO2 = 4 and 2.5), and space velocity (VHSV = 5 and 10 L g−1 h−1). The catalysts were characterized by Brunauer–Emmett–Teller (BET), X‐ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive x‐ray spectroscopy (EDS) analyses before the reactions, and by thermogravimetric analysis (TGA), SEM, and EDS analyses after the reactions. The reaction variables were evaluated using an experimental design with 2 factors and 4 variables, in order to determine the effects of the reaction conditions on catalyst selectivity, reactant conversion, and reaction yields in terms of CH4 and CO. The best result was obtained using a reactant ratio of 2.5, space velocity of 5 L g−1 h−1, and reaction temperature of 550°C, resulting in 93.7% selectivity for methane, 69.4% CO2 conversion, 74% H2 conversion, and methane yield of 20.69%. Findings show Ni/Si‐MCM‐41 catalyst's applicability in methanation, advancing CH4 production technology, and addressing local demand while reducing CO2 emissions.

Ethanol and electricity: Fueling or fooling the future of road passenger transport?

The vast majority of countries arguably agree that the planet is reaching a point of no return regarding global warming and climate change. Proof of that is the 2030 Agenda and the Paris Agreement, ratified by almost every nation worldwide. However, despite signing both great commitments, the states have made too little to meet the sustainability plans. Among the targets, renewable energy sources stand out to mitigate greenhouse gas emissions, but still, petrol wells continue to be drilled, and vehicle assemblers keep investing in new technologies for running their cars with fossil fuels. At the same time, government policies seem to be betting all their chips on electric engines, as if electricity were the best substitute for oil. This critical review analyses the pros and cons of such alternative fuel for road passenger transport, also taking into account another potential substitute for gasoline: bioethanol. In the following pages, we address the challenges and avenues of both alternatives and demonstrate that diversification of the global energy matrix and the biomass feedstocks should be our guiding principles.

Reserves, well drilling and production: Assessing the optimal trajectory of oil extraction for Brazil

The global energy matrix is in transition, leading to expectations of a reduction in fossil sources in the coming years. Brazil has substantial oil reserves but has not yet considered optimization strategies for extracting these resources. The research proposed the calibration of a Hotelling model adapted for Brazil, with a focus on maximizing the economic return from extracting reserves. We employed optimization methods to calculate the ideal annual rates of oil drilling and production in Brazil. We also assess the sensitivity of these rates to changes in oil prices, well drilling costs, discount rates, and technical progress, according to the characteristics of the reserves. The results indicate that optimal onshore production would continue to decrease in the coming years, while offshore production may be nearing its peak. Assuming higher oil prices, offshore production is expected to increase over the next five years and decline thereafter.

Thermodynamic analysis and optimization of a biogas-powered trigeneration system to produce power, cooling and freshwater

Despite all the efforts to reduce the consumption of fossil fuels worldwide, the majority of the global energy matrix continues to depend on them, leading to serious environmental impacts such as droughts, that heavily affect rural areas in arid and semi-arid regions. In this work, aiming to reduce environmental impacts, losses and instability associated with power lines and water scarcity, a computational model of a decentralized small-scale trigeneration system to produce power, cooling and freshwater was developed and operating conditions were optimized to maximize both Energy Utilization Factor (EUF) and exergetic efficiency. The trigeneration system consists of biogas-powered microturbines, an LiBr/H2O absorption refrigeration system and a humidification-dehumidification desalination system. The results obtained have shown that the system was able to produce 104.4 kW, 12 kW and 0.1231 kg·s−1 of power, refrigeration and freshwater mass flow rate, respectively, with an EUF of 1.024 and exergetic efficiency of 25.39%. The analysis of exergy destruction has revealed that the microturbines, particularly their combustion chambers, accounted for 78.23% of the total exergy destruction rate in the system which was 295.92 kW for the base case. Using Genetic Algorithm to maximize the EUF, it was possible to achieve a 12.12% increase in the EUF and a 16.25% increase in freshwater production when compared to the base case considered.

Towards renewable energy projects under sustainable watersheds principles for forest biomass supply

The transition in the global energy matrix to sources of renewable electric generation has been the main demand of countries in the face of a state of climatic emergency. Forest biomass is a potential alternative to meet the growing demand. The expansion of thermoelectric projects based on forest residues highlights the need to assess raw materials' availability and land suitability. This is usually a problem of spatial decision and geographic intelligence under a holistic perspective since, in planning these projects, it is essential to understand the economic, environmental, and social feasibility. In this article, we propose a decision support system based on multi-criteria modeling on a GIS structure associated with a mathematical optimization model for zoning the suitability and availability of land for constructing thermoelectric power plants. The geospatial model for determining priority sites integrated various environmental, social, and economic criteria and constraints. The AHP method was used to weigh and estimate the relative importance weights of the criteria for modeling territorial aptitude. The results of the GIS stage formed the basis of a mixed-integer linear programming model that incorporated technical and economic aspects for a better allocation of financial resources. The minimized cost function included transport costs, harvesting, forestry, purchasing land/leasing land/forest outgrower schemes, and purchasing wood from the market to supply the biomass. We used a sizeable hydrographic basin in southeastern Brazil as a case study for the demonstration. The mapping of suitability and constrained zones identified the classes of preference and availability of land. The proposed mathematical model recognized sets of supply locations (new plantations or existing areas) and minimized the project's final cost to supply biomass to meet the demand of potential thermoelectric plants that are candidates for implementation. Despite the problem's large scale and the large data set, our findings indicated that we could provide a broad and multidimensional view of the potential of developing electrical generation systems based on forest biomass. The methodology and the model proposed in this study can be replicated in other global regions and modified to assess other resources from different biomasses and bioenergy systems. Our study promotes the UN's sustainable development goals, particularly SDG 7 (Affordable and clean energy) and SDG 13 (Climate Action).

Institutional and macroeconomic stability mediate the effect of auctions on renewable energy capacity

Renewable energy (RE) auctions have become an increasingly popular policy instrument for decarbonizing the global energy matrix, and have been rapidly adopted by several countries worldwide. Previous research has used data from higher-income countries and two-way fixed effects models to estimate the impact of auctions on RE capacity, mostly with favorable results. However, these studies did not account for heterogeneous treatment effects across units to explore whether auctions are also effective in countries with unstable business environments. We analyze whether auctions also foster RE in countries experiencing macroeconomic instability or poor institutional quality. For this purpose, this study has drawn from multiple publicly available databases to build a dataset comprising 98 countries from 2000 to 2020. Our definition of RE includes solar, wind, and biomass sources. We first cluster countries by the quality of their business environment and then perform a differences-in-differences analysis considering staggered treatment adoption. We find that auctions positively affect RE capacity, yet the average treatment effects are higher for countries with better business environments. Thus, governments should exercise caution in adopting this instrument, especially in countries that experience macroeconomic or institutional instability. At the same time, dynamic treatment effects suggest that the policy needs time to show results.

The expansion of renewable energy in Brazil: opportunities and barriers within the context of energy transition and climate change mitigation

Due to the intense emission of greenhouse gases (GHG) in the production and consumption of energy related to the global energy matrix, analyzing climate change mitigation measures, such as using renewable energy sources, becomes essential in combating such changes. In the specific case of Brazil, this is very relevant given the growing participation of fossil sources (to generate electricity in thermoelectric plants), in the country, in the last decade. In this context, this work aims to establish, characterize and analyze the relationships between the likely impacts of climate change in the context of renewable energy sources vis-à-vis the country’s NDCs under the Paris Agreement. The methodology was based on a systematic literature review, analysis of primary data on the Brazilian energy system, and interviews with stakeholders. It was possible to conclude that hydroelectric plants and those based on solar and wind energy tend to register a reduction in their electricity generation potential in Brazil; however, the last two can still be used on a large scale until at least the end of the current 21st century. In contrast, electricity generation based on biofuels should be the renewable source potentially least affected by climate change.

The Contribution of Nuclear Technology to the Sustainability of the Global Energy Matrix and the Mitigation of Climate Change

The Contribution of Nuclear Technology to the Sustainability of the Global Energy Matrix and the Mitigation of Climate Change

Thermoeconomic and life cycle assessments for a trigeneration system: A case study

ABSTRACT The current need to diversify the global energy matrix implies introducing renewable energy sources and evaluating commercially available solutions. This study assesses a trigeneration system from thermoeconomic and environmental viewpoints, employing the Theory of Exergy Cost and Life Cycle Assessment. The location of the theoretical study case is the state of Pernambuco, Northeast Brazil. The trigeneration system operates on biogas and is comprised of four subsystems: biogas purification, molted carbon fuel cell, combined cycle, and absorption refrigeration system. The energy services produced are electricity, heat (hot water), and cooling. The results of the thermoeconomic analysis revealed that the energy system requires an electricity tariff of at least US$ 106.76/MWh to generate revenue due to the high costs associated with the purchase of biogas and capital costs of the equipment for biogas purification and fuel cell. The life cycle assessment identified that the biogas purification step presented the highest environmental impacts due to the material composition of the absorption and regeneration columns, which is interesting as this is the most critical step of the process. LCA results indicate that although methane is a vital energy vector for energy transition, further studies are required on the technical and environmental aspects of its use in energy systems.

Increasing Recovery Factor in Heavy Oil Fields Using Alternating Steam and Surfactant Injection

Fossil fuels, particularly oil, currently dominate the global energy matrix. With a projected 30% increase in demand by 2040 compared to 2010, it is crucial to maintain current oil production levels. To achieve this, it is necessary to increase the oil recovery factor through alternative methodologies that will improve oil extraction from reservoirs and exploration viability in mature fields. While previous studies have investigated thermal and chemical methods to increase the recovery factor, this study aims to explore the synergy between steam and non-ionic surfactants varying the surfactant degrees of ethoxylation and injection configurations. The experimental study investigated the application of solutions of ethoxylated nonylphenol surfactants (NP-10EO and NP-100EO) combined with steam injection into banks at different concentrations and injection configurations. The results showed that combining the NP-100EO surfactant (0.5% m/m) with steam demonstrated the highest oil recovery (64.88%) compared to conventional steam (45.19%). The most effective configurations were surfactant + steam + surfactant (65.06%) and surfactant + steam + water (65.88%). These findings suggest that the proposed technique of steam injection and surfactant solution could be a promising alternative. By revitalizing marginal fields, this technique could help extend production and stimulate local and regional development.

Economic Analysis: Green Hydrogen Production Systems

The continued use of energy sources based on fossil fuels has various repercussions for the environment. These repercussions are being minimized through the use of renewable energy supplies and new techniques to decarbonize the global energy matrix. For many years, hydrogen has been one of the most used gases in all kinds of industry, and now it is possible to produce it efficiently, on a large scale, and in a non-polluting way. This gas is mainly used in the chemical industry and in the oil refining industry, but the constant growth of its applications has generated the interest of all the countries of the world. Its use in transportation, petrochemical industries, heating equipment, etc., will result in a decrease in the production of greenhouse gases, which are harmful to the environment. This means hydrogen is widely used and needed by countries, creating great opportunities for hydrogen export business. This paper details concepts about the production of green hydrogen, its associated technologies, and demand projections. In addition, the current situation of several countries regarding the use of this new fuel, their national strategy, and advances in research carried out in different parts of the world for various hydrogen generation projects are discussed. Additionally, the great opportunities that Chile has for this new hydrogen export business, thanks to the renewable energy production capacities in the north and south of the country, are discussed. The latter is key for countries that require large amounts of hydrogen to meet the demand from various industrial, energy, and transportation sectors. Therefore, it is of global importance to determine the real capacities that this country has in the face of this new green fuel. For this, modeling was carried out through mathematical representations, showing the behavior of the technologies involved in the production of hydrogen for a system composed of an on-grid photovoltaic plant, an electrolyser, and compressor, together with a storage system. The program optimized the capacities of the equipment in such a way as to reduce the costs of hydrogen production and thereby demonstrate Chile’s capacity for the production of this fuel. From this, it was found that the LCOH for the case study was equivalent to 3.5 USD/kg, which is not yet considered a profitable value for the long term. Due to this, five case studies were analyzed, to see what factors influence the LCOH, and thereby reduce it as much as possible.

Latest Oligocene to middle Miocene low-latitude calcareous nannofossil biostratigraphy and paleoenvironmental interpretations of stratigraphic well 4, Sinú-San Jacinto onshore basin, northwest Colombia

Calcareous nannofossils are one of the main fossil groups used in the petroleum industry to determine the relative age and correlation of lithofacies identified in gas and oil wells. A limited number of biostratigraphic zonation schemes based on nanoplankton and paleoceanographic reconstructions have been suggested to onshore Colombian Caribbean. Most of them are compiled in several publications for the northern Colombian units (Mejía-Molina et al., 2008, 2010). In this study, a medium to high-resolution biostratigraphy study was carried out on one of the best-known Neogene sedimentary successions in the Sinú-San Jacinto onshore Basin, where the Stratigraphic Well 4 (SW4) was drilled by Ecopetrol, the Colombian state-run oil company. The nannoplankton biostratigraphic zonation proposed here constitutes the first calcareous nanoplankton research to construct a biochronologic scheme for the Neogene of northern Colombia, which has direct applications for oil exploration, global energy matrix and the transition to clean energy in the onshore areas of the Sinú-San Jacinto domain. The section studied has a thickness of ∼269 m and comprises mainly a very thick succession of claystone and mudstone with occasional intercalations of silty sandstones corresponding to the El Carmen Formation. The studied interval is assigned to the nannofossils Zones NP25 (CP19) to NN4 (CN3) of Martini (1971) and Okada and Bukry (1980), spanning from the latest Oligocene (latest Chattian) to middle Miocene (early Langhian), approximately 24 Ma to 15 Ma. Intervals without fossil content were identified in the record and could constitute hiatuses, but the nannofloral events, which define the limits of the biozones, can be identified. Global and regional climatic changes which occurred in the Caribbean region at those times are reflected in important changes in the fossil assemblages and abundance pattern of nanoplankton. These could indicate variability in environmental conditions linked to temperature and increased nutrients within the nannofossil communities in this part of the San Jacinto folded belt (SJFB), northwest Colombia. Middle Miocene Climate Optimum (MMCO) episodes of “blooming” intervals of Sphenolithus were identified, accompanied with a drastic reduction in total nannofossil abundance and CaCO3 content. Since the Caribbean geology is framed in a very complex scenario, the data acquired and presented in this research has a potential application to improve the current stratigraphy in the area, targeted to hydrocarbon exploration and studies related to the global energy matrix and the transition to clean energy. It also strengthens the paleoceanographic reconstructions based on these organisms at low latitudes.

The global energy matrix and use of agricultural residues for bioenergy production: A review with inspiring insights that aim to contribute to deliver solutions for society and industrial sectors through suggestions for future research.

Promoting the use of renewable energy sources has become an important policy strategy for mitigating climate change and for providing better energy security and financial sustainability. To overcome the problems generated by non-renewable energy sources, it is essential to use new energy sources. A literature review was conducted to investigate and understand the opportunities for implementing new renewable energy sources. Agricultural residues have great potential to receive significant consideration worldwide as an alternative, sustainable, and green energy source. The use of agricultural residues for bioenergy generation is a broad and favourable scenario for exploration. This review identified potential and almost unexplored research approaches with the aim of contributing and promoting researchers to deliver technological solutions for the society and industrial sectors. For example, a potentially promising technological solution would be for industries that produce machinery and agricultural implements to adapt their harvesters for different grain crops, to collect these agricultural residues simultaneously during harvest and readily perform granulation, compaction (pressing), pelletizing or briquetting directly on the property. Further studies are required to investigate the use of agricultural residues for bioenergy generation, which can contribute to the diversification of the energy matrix. Accordingly, in this review, several challenges and future research perspectives have been presented, such as suggestions for future research on how to collect, transport, process, market and use these agricultural residues to generate bioenergy, aiming at reducing the dependence on fossil fuels.

Global bioenergy potentials projections for 2050

This paper makes projections of the theoretical and technical potentials of bioenergy supply for 2050. The projections consider changes in available land for bioenergy and food for the global demand and advancements in yield, productivity, expansion of bio-waste recovery, and energy conversion. We present a literature review on projections. We introduced a novel logical and transparent forecasting model. Three future scenarios were established: business as usual (BUS), optimistic trends (OPT), and full adaptation response (FAR). The projection is carried out based on four adjusting factors. An uncertainty analysis was carry-out based on a Monte-Carlo method. Projections of bioenergy production in 2050 were compared with other projections in the literature. The FAR scenario showed that it would be possible to produce twenty-one times the current primary bioenergy supply and to even supply all global primary energy demand in 2050, mostly by energy crops. The assumptions adopted for the BUS and OPT scenarios make their projections more likely. Therefore, the contribution of bioenergy in the global energy matrix is expected to be between 64 and 313 EJ (7.5%–37%) in 2050. There would be a significant change in the composition of the bioenergy supply from today's mostly firewood to energy crops and biowastes. The technical potential for fuel and electric power mostly follow the supply trends for primary bioenergy (theoretical). The potential avoided greenhouse emissions are estimated. The heuristics and the level of transparency of the novel model will allow adjustments and exploration of other scenarios as time passes.

Energy and Covid 19


 
 
 
 Pandemics reverberated their times, changing social and economic contexts, prompting, and redirecting changes in social ties, business, and education, restructuring the world that generated them. In this context, this study aims to assess the impact of the COVID-19 pandemic on the global energy matrix, supported by an analysis of consumption, demand, and GDP from January 2019 to June 2021. The energy balance showed variations in this period, with impacts on the environment. We will assess whether the changes will be lasting.
 
 
 
 

Nanoengineering of Catalysts for Enhanced Hydrogen Production

Hydrogen (H2) has emerged as a sustainable energy carrier capable of replacing/complementing the global carbon-based energy matrix. Although studies in this area have often focused on the fundamental understanding of catalytic processes and the demonstration of their activities towards different strategies, much effort is still needed to develop high-performance technologies and advanced materials to accomplish widespread utilization. The main goal of this review is to discuss the recent contributions in the H2 production field by employing nanomaterials with well-defined and controllable physicochemical features. Nanoengineering approaches at the sub-nano or atomic scale are especially interesting, as they allow us to unravel how activity varies as a function of these parameters (shape, size, composition, structure, electronic, and support interaction) and obtain insights into structure–performance relationships in the field of H2 production, allowing not only the optimization of performances but also enabling the rational design of nanocatalysts with desired activities and selectivity for H2 production. Herein, we start with a brief description of preparing such materials, emphasizing the importance of accomplishing the physicochemical control of nanostructures. The review finally culminates in the leading technologies for H2 production, identifying the promising applications of controlled nanomaterials.