Hasil untuk "Energy industries. Energy policy. Fuel trade"

Aaron Malone, Alannah Brett, Elisheba Spiller et al.

The global scramble for critical minerals and the US push to increase domestic production have generated interest around the potential for direct lithium extraction from oilfield brines (OB-DLE) in Arkansas. This paper provides an interdisciplinary scoping review to analyze the knowns and unknowns around resource potential, socio-economic, and environmental dynamics. An initial three OB-DLE projects could contribute an estimated 53 100 tons per year lithium carbonate equivalent beginning as soon as 2028, around one-fifth of estimated US consumption at 2024 levels, while additional proposed projects could expand that figure later. However, uncertainties remain around the resource, technology, and economic dimensions, all of which have implications for the eventual impacts for local communities and the environment. The paper reviews geology and reservoir characteristics and unknowns, and summarizes the legal and regulatory advantages that have brought Arkansas to the forefront of a resource that extends across multiple states. However, at 2025 lithium prices, none of the proposed projects would be profitable; viability depends on projected price increases materializing. Impacts to communities would include employment, royalties, and tax revenues, the distribution of which will determine whether existing uneven development in the region is reinforced or disrupted. Finally, we compare OB-DLE’s environmental profile to that of other lithium production methods. The first round of OB-DLE projects will be greenfield, rather than reusing oil and gas infrastructure or produced waters. Freshwater consumption is projected to be higher than in brine evaporation but similar or lower than mining lithium from rock. The paper concludes by identifying areas for future research.

L. Evangelisti, R. Vollaro, F. Asdrubali

Abstract The need to put in place alternative energy policies stems from the awareness that fossil fuels are exhaustible and harmful to the environment. For this reason, during the last decades the scientific world has focused on systems able to use and convert renewable energy sources, particularly solar radiation. Nowadays, solar thermal collectors use solar energy to distribute low-cost domestic and industrial heating. In this review a comprehensive analysis of peer-reviewed journals and relevant papers on solar thermal collectors is provided. Descriptions of the different types of solar collectors are provided. Theoretical analyses, latest developments related to the functional elements, and hybrid systems have been considered throughout this analysis. Performance test methods for solar thermal collectors and standards are discussed. This cross-review aims to assist researchers, engineers and manufacturers in keeping them abreast of latest developments in the field of solar thermal collectors.

Yuliya Lovcha, Alejandro Pérez-Laborda, I. Sikora

Abstract In 2005, the European Union launched its Emissions Trading System (ETS), the first and one of the largest international carbon markets aimed at reducing member states' CO2 emissions. Policymakers tend to use the carbon price as an indicator of the “health” and effectiveness of the ETS mechanism, although this measure is influenced by many other energy and climate policies, energy market fundamentals, and speculative shocks. This paper develops a model that links the energy sector (oil, natural gas, coal, electricity prices, and the share of fossil fuels in electricity generation), economic activity, and the carbon price. The model can be used as a monitoring tool for carbon price dynamics. We represent the model empirically through a Structural Vector Autoregression and use frequency-domain analysis to distinguish the effects of changes in fundamental factors from shocks to market microstructure. Our empirical results show that up to 90% (65% on average) of the fluctuations in the carbon price, adjusted for supply effects, are explained by fluctuations in fundamental market variables; however, the individual contributions are not stable. Overall, our results suggest that the ETS has started to work well.

Claudie‐Maude Canuel, Evelyne Thiffault, Nelson Thiffault

ABSTRACT Many jurisdictions within the boreal and temperate biomes have adopted targets to increase the contribution of forest bioenergy for climate change mitigation. Using residual forest biomass as feedstock is considered, but the carbon emission reductions associated with this practice remain controversial. Our study evaluated how intensifying wood procurement for bioenergy production, alongside supplying fiber for conventional wood industries, can support low‐carbon forest management. We used six sites established in eastern Canada as a case study. We compared the carbon balance of four harvesting scenarios with increasing wood procurement intensity (from procuring sawtimber only to procuring sawtimber, pulpwood and biomass) to three scenarios of unharvested forests, two of which experienced natural disturbances. We modeled carbon fluxes over a 100‐year simulation period, considering biogenic and fossil emissions from aboveground forest ecosystems, harvested wood products, and wood supply and manufacturing. We assessed the mitigation potential of procuring biomass to produce bioenergy in the form of stemwood, treetops (including branches) or pulpwood. We found that forest harvesting, regardless of the wood procurement intensity, offered limited carbon benefits compared to the referenced undisturbed mature stands in most cases. However, increasing wood procurement can reduce the carbon footprint of wood supply chains, with pulpwood identified as a key feedstock. Compared with harvesting roundwood for conventional industries only, procuring biomass for bioenergy is likely to increase carbon emissions unless it substitutes high‐emission energy sources on markets or enhances the next‐rotation stand yield, which seems achievable in the context we studied. Bioenergy displacement factors should range from 0.072 to 0.701 tonne of carbon emission reduction per tonne of carbon in the bioenergy product, depending on stand characteristics, biomass feedstock, and cutting cycle length. Our findings provide a foundation for assessing the GHG reduction potential of harvesting activities at a broader scale, considering varying feedstock recovery intensities.

Jieyang Xu, Sebastian Mosbach, Jethro Akroyd et al.

The adoption of heat pumps to displace the use of gas for domestic heating is a major component of the strategy to reduce emissions in the UK. This study examines the impact of adopting heat pumps on regional inequalities in the UK. An index is used to assess how variations in household fuel costs could affect regional disparities across different future price scenarios. The findings reveal that, at 2019 prices, most households would face higher heating costs with heat pumps. However, following the 2022 energy price shock, heat pump adoption would lead to lower heating costs for most households compared to gas heating. The effect is sensitive to the electricity-to-gas price ratio, with regions experiencing high fuel poverty being most vulnerable to negative impacts. By mapping these geospatial effects, the study enables the forecasting of future inequality trends, providing insights for informed policy development. The results suggest that, under appropriate price structures, heat pump adoption could contribute to both decarbonisation and reduced social inequality. An example mechanism for financial support to mitigate the impact of adopting heat pumps on inequality is demonstrated. This study highlights the novel capability of The World Avatar (TWA) approach to integrate cross-domain data sets, combining energy policy with social equity goals. By forecasting future inequality trends based on energy price scenarios, the study provides a route to valuable insights to support informed policy development, highlighting how the adoption of heat pumps can influence regional inequalities and emphasising the need for targeted interventions to support vulnerable regions.

J. Jayamuthunagai, R. Mary Nancy Flora, K. Senthilkumar et al.

Lithium-ion batteries (LIBs) are essential to today's energy storage technology, powering from handheld devices to electric vehicles and grid-scale renewable energy installations. With demand for LIBs rising ever more strongly—fuelled by the global clean energy shift—the demand for sustainable lithium recovery has accelerated. Extraction of lithium using traditional mining is energy-wasting, environmentally disruptive, and not viable given dwindling natural reserves. Thus, recycling lithium from retired LIBs is critical not just for resource security but also for environmental minimization. Herein is an overview of existing technologies applied for lithium extraction from spent LIBs, with emphasis on four dominant methods: pyrometallurgy, hydrometallurgy, electrochemical extraction, and bioleaching. The technologies are compared based on commercialization stage, efficiency in lithium extraction, cost, environmental impact, and applicability. Although pyrometallurgy and hydrometallurgy are more conventional, they may require high energy expenditure and toxic chemical utilization. For comparison, new technologies such as bioleaching and electrochemical extraction provide less polluting and more selective processes but are yet to be developed for large-scale use. Newly developed innovations in deep eutectic solvent-aided leaching, mechanochemical treatment, and bio-electrochemical systems have exhibited potential in enhancing lithium extraction efficiency while reducing environmental footprint. In spite of advances in technology, < 1 % of lithium is recycled world-wide, and there is an urgent need for optimizing and integrating the available technologies. This review paper contrasts these technologies and presents directions for the enhancement of lithium recycling techniques with the aims of realizing higher recovery rates, cost-effectiveness, and eco-friendliness. Eventually, designing effective recycling schemes will be important for underpinning a circular economy of lithium and in delivering long-term energy security.

Harriet Thomson, Carolyn Snell

Mohd Zaidi Mohd Tumari, Mohd Ashraf Ahmad, Mohd Riduwan Ghazali et al.

Automatic voltage regulators (AVR) are designed to manipulate a synchronous generator’s voltage level automatically. Proportional integral derivative (PID) controllers are typically used in AVR systems to regulate voltage. Although advanced PID tuning methods have been proposed, the actual voltage response differs from the theoretical predictions due to modeling errors and system uncertainties. This requires continuous fine tuning of the PID parameters. However, manual adjustment of these parameters can compromise the stability and robustness of the AVR system. This study focuses on the online self-tuning of PID controllers called indirect design approach-2 (IDA-2) in AVR systems while preserving robustness. In particular, we indirectly tune the PID controller by shifting the frequency response. The new PID parameters depend on the frequency-shifting constant and the previously optimized PID parameters. Adjusting the frequency-shifting constant modifies all the PID parameters simultaneously, thereby improving the control performance and robustness. We evaluate the robustness of the proposed online PID tuning method by comparing the gain margins (GMs) and phase margins (PMs) with previously optimized PID parameters during parameter uncertainties. The proposed method is further evaluated in terms of disturbance rejection, measurement noise, and frequency response analysis during parameter uncertainty calculations against existing methods. Simulations show that the proposed method significantly improves the robustness of the controller in the AVR system. In summary, online self-tuning enables automated PID parameter adjustment in an AVR system, while maintaining stability and robustness.

Junming He, Romanus Osabohien, Wenyu Yin et al.

This study examines the impact of green economic growth and renewable energy on food security in Sub-Saharan Africa (SSA). The rationale for the study comes from the background that with a fast rate of growing population, there is a high pressure on natural resources, which often leads to resource depletion, being experienced across the globe. This study utilises panel data analysis consisting of 37 SSA countries that are members of the Official Development Assistance (ODA). Data was obtained from the Food and Agriculture Organisation (FAO) and World Development Indicators (WDI) for the period 2005–2022. To control for endogeneity, the study applies the system Generalised Method of Moments (GMM). The result shows that renewable energy and green economic growth have a positive significant impact on food security, though this impact is asymmetric across SSA sub-regions. On the other hand, industrialisation through its emissions, contributes negatively to food security. The implication is that SSA countries should focus on policies aimed at improving green economic growth and renewable energy consumption; while policies aimed at reducing the inefficient adoption of renewable electricity and discouraging industrialisation aimed at suppressing agricultural practices should be adopted.

J. Mugisha, Mike Arasa Ratemo, Bienvenu Christian Bunani Keza et al.

Abstract With the world's lowest electrification rate, Africa is repositioning to offer its citizens a brighter future. Global renewable energy agencies and international financing to expedite rural electrification fueled by off-grid solar systems are attracting worldwide attention. Currently, 770 million people lack access to electricity on the continent, and more than 60% live in poor rural areas where the national power grid is non-existent. The challenge herein is how to supply electricity to rural population, living on $1.5 a day, at a reasonable power tariff. Although there are opportunities for off-grid solar energy to keep growing in sub-Saharan countries, it is impossible to ignore particular challenges in these countries. This paper focuses on three sub-Saharan counties: Kenya, Ethiopia, and Rwanda. Rwanda, Kenya, and Ethiopia foster off-grid solar systems as the primary solution through rural electrification programs. This paper provides a comparative analysis of the electrification experiences of these countries in terms of sources of funding, the challenges and opportunities they have been experiencing as well as an analysis of policy implications. The results show that off-grid solar systems improve health, ICT, and micro-enterprises in rural areas. However, governments should generate more robust developmental schemes that provide income to rural people that pushes them above the poverty line and enables them to afford off-grid solar products.

Da Huo, Qian Zhang, Yujie Dong et al.

Beijing's power system has experienced a significant transition by eliminating coal-fired power generation and increasing the extent of electrification over the past two decades. This study uses a plant-level dataset, pair-wise energy flow, and customized index decomposition analysis to investigate the driving forces behind Beijing's rapid electrification and carbon mitigation effects. Our assessment approaches can reveal the role of electrification in driving city-level emissions and identify a reasonable timeline to accelerate electrification for cities. We find that electrification-related factors are responsible for 21.8% of carbon emission changes in Beijing between 1995 and 2019. The extent of electrification in Beijing has doubled from 9.5% in 1995 to 19% in 2019, while the carbon intensity of electricity consumption has reduced by 26%. Particularly, the average emission intensity of Beijing's local power generation has dropped from 860 tCO2e/GWh in 2000 to 370 tCO2e/GWh in 2018, which is far below a critical level at which the high penetration of electricity in transportation and housing should be prioritized for decarbonization. Our results confirm that Beijing is in the best position to accelerate electrification to meet its carbon neutrality goals; however, this will increasingly rely on regionally collaborative decarbonization efforts with surrounding regions.

Peter Asigri, Francis Boafo Effah, Daniel Opoku et al.

This paper presents a comprehensive analysis of the technical performance of grid-connected rooftop solar photovoltaic (PV) systems deployed in five locations along the solar belt of Ghana, namely Sakumono, Wa, Bolgatanga, Kumasi, and Kintampo. These locations were selected based on their diverse environmental conditions, offering a representative sample for the study. The study utilized PVSyst software version 7.3 to simulate the performance of the PV systems for each location, using south orientation, which gives the best results in the tilted global irradiation across all locations. According to the simulation results, the average performance ratio for the five locations was 79.7%, indicating the PV systems' highly efficient utilization of the available solar energy. The average final yield, representing the actual energy output, was also measured to be 4.38 kWh/kWp/day for the studied locations.  This study demonstrates the technical feasibility of Ghana's grid-connected rooftop solar PV installations. The results underscore the significance of optimal system design and orientation, emphasizing the potential for substantial renewable energy generation. The insights obtained from this study can aid policymakers, investors, and solar energy stakeholders in making informed decisions to promote the widespread adoption of rooftop solar PV systems in the region.

K. Handayani, Y. Krozer, T. Filatova

This study analyses a diffusion of renewable energy in an electricity system accounting for technological learning. We explore long-term scenarios for capacity expansion of the Java-Bali electricity system in Indonesia, considering the country’s renewable energy targets. We apply the Long-range Energy Alternative Planning (LEAP) model with an integration of technological learning. Our results reveal that, at the medium and high pace of technological learning, the total costs of electricity production to achieve the long-term renewable energy target are 4–10% lower than the scenario without considering technological learning. With respect to technology, solar PV and wind become competitive with other types of renewables and nuclear. Moreover, the fulfilment of the renewable energy targets decreases CO2 emissions by 25% compared to the reference scenario. Implications of our results indicate that energy policies should focus on the early deployment of renewables, upgrading the grid capacity to accommodate variable renewable energy, and enabling faster local learning.

Shuming Zhang, Shuzhuang Sun, Ningbo Gao et al.

Ash sintering is an essential factor for the competitiveness of biomass gasification. Compared to conventional air biomass gasification, the gasification temperature is reduced in the auto thermal biomass gasification, as the utilisation of thermal compensation for the CaO carbonation reaction, which ultimately could suppress the extent of ash sintering. This work firstly investigated the inhibition effect of this process on the sintering of simulated ashes (silica, potassium oxide and alumina) in a lab-scale fixed bed reactor. The results indicate that the alumina particles are present under different CO2 concentrations, gasification temperature and CaO/ biomass ratios. However, silica and potassium oxides react with CaO and disappear at high temperatures. Among the three simulated ashes, alumina particles are relatively stable in the auto thermal biomass gasification. The average particle size decreases from 116.9 µm to 64.9 µm and 93.8 µm when CaO/alumina ratio is 2 and 5, respectively, indicating the increase of CaO addition under the flue gas atmosphere could inhibit the sintering degree of simulated ash. Meanwhile, the reaction between CaO and CO2 in the carrier gas can reduce the formation of calcium silicate. Therefore, compared with conventional biomass gasification, auto thermal biomass gasification is favourable to restrain the degree of ash sintering because of the relatively low gasification temperature.

Milica Mladenović, Dragoljub Dakić, Nevena Petrov

U kontekstu savremene geopolitičke situacije i energetske neizvesnosti, cilj rada je da jače afirmiše upotrebu biomase kao domaćeg energenta i da ukaže na smernice za njeno pravilno i efikasno iskorišćenje. Prema zvaničnim podacima Ministarstva rudarstva i energetike Republike Srbije, biomasa predstavlja ubedljivo najveći potencijal obnovljive energije u zemlji. Preko 60% procenjenog potencijala obnovljive energije u Republici Srbiji pripada biomasi (ne računajući velika hidroenergetska postrojenja). Mogućnost energetskog iskorišćenja biomase, pri tome, ne zavisi od vremenskih prilika, doba dana ili godišnjeg doba, za razliku od drugih izvora obnovljive energije poput energije vetra i sunca. Pored ove i drugih prednosti koje biomasa kao jedino ugljenično – CO2 – neutralno obnovljivo gorivo ima, potrebno je istaći i to da su postrojenja za konverziju energije iz biomase putem sagorevanja relativno jednostavna i u celosti se mogu proizvoditi u našoj zemlji. Ukoliko bi se ova postrojenja koristila u sistemima daljinskog grejanja uz mogućnost korišćenja toplotne energije i za tehnološke procese u uzgoju i preradi poljoprivrednih proizvoda i van grejne sezone, potencijali se šire. Postrojenja za preradu i doradu poljoprivrednih proizvoda (poput sušara) takođe se u velikoj meri mogu proizvoditi u Republici Srbiji. Prednosti i stepen iskorišćenja biomase kao obnovljivog energenta još više dolaze do izražaja pri njenoj upotrebi u kogenerativnim postrojenjima. Kad se sve navedeno uzme u obzir može se zaključiti da primena biomase može zauzeti značajno mesto u sveobuhvatnoj reindustrijalizaciji naše zemlje, o čemu će više reči biti u ovom radu. U radu je, takođe, ukazano na neke od prepreka za realizaciju ovih napora kao i primeri dobre prakse.

Mohammad S. Roni, Thomas Mosier, Tzvi D. Feinberg et al.

Resiliency has been studied in the power and water systems separately. Often the resiliency study is not so comprehensive as to understand interdependent, integrated water and power systems. This research outlines the relevant factors necessary to understand and advance quantification of such integrated systems. It also presents a review of integrated water-power systems resiliency. Based on literature survey and identification of challenges, the authors present quantification and computational steps needed to understand integrated water-power systems resiliency. A conceptual framework is proposed to quantify integrated water-power system resiliency. Finally, the authors presented an opportunity for improved water and power system resilience.

Kai-Hua Wang, Chi-Wei Su, Oana-Ramona Lobonţ et al.

Bijon Brown, Richard Schoney, James Nolan

J. Kabayo, P. Marques, Rita Garcia et al.

This article presents a life-cycle sustainability assessment of electricity generation systems in Portugal, namely coal, natural gas, hydro (large and small), wind, and photovoltaic systems, and evaluates their environmental and socioeconomic impacts. The environmental life-cycle assessment methodology was used to quantify impacts in metal depletion, fossil fuel depletion, global warming, ozone depletion, terrestrial acidification, freshwater eutrophication, aquatic acidification, water scarcity footprint, and toxicity (towards freshwater ecosystems and humans). Socioeconomic impacts were estimated for employment provision, dependence on fossil fuels, capacity factor, and levelised cost of electricity. The results show that electricity based on coal has the highest environmental impacts in all categories except: metal depletion (wind had the highest impacts), ozone depletion (natural gas), water scarcity footprint (large hydro), and freshwater ecotoxicity and human toxicity, non-cancer (photovoltaic). For socioeconomic categories, there was a greater variability. Photovoltaic generated the most employment and wind-based generation was estimated to have the lowest levelised cost, while coal generated the second-highest total employment and the third-lowest levelised cost. Overall, the life-cycle sustainability assessment shows small hydro as the most environmentally and socioeconomically sustainable system. By exposing the trade-offs amongst technologies and sustainability dimensions, this work provides an informed basis for future energy policy in Portugal.

史谢虹, 周鹏超, 张锐 et al.

碳中和背景下，世界多国对气候变化问题形成共识，俄罗斯等欧亚地区国家与时俱进，在战略层面明确表态发展可再生能源，提出明确的清洁电力目标，在实践层面加快技术引进、推进重大项目落地、拓展氢能开发和能源通道建设。欧亚国家具备转型的显著动能，包括可再生能源的资源禀赋、全球能源技术发展、自身较强的能源产业基础、邻近区域的示范与带动作用等。同时，区域国家仍面临一系列突出阻碍，包括对化石能源资源的路径依赖、部分国家的动荡政局、区域国际关系波动及全球能源博弈等。在新时期，中国与欧亚国家能源转型合作的着力点应放在清洁能源产业和跨国电力互联互通建设，建议采取贸易先导—技术跟进—共同开发的顺序，持续推动以中俄为中心的地区多边合作。