Aggregate Resources Research Articles

Modeling the distributed energy resource aggregator services in a macroeconomic framework: The application to Japan

Distributed energy resources (DER) are highly interconnected with public and private entities in one economy, thus often modeled in the long-term decarbonization transition pathways. However, at the initial stage of the DER integration scaling-up, barriers such as consumer behavior and market dynamics can impede progress, which has not yet been thoroughly considered and accurately represented even in models. Therefore, we proposed an approach to integrated DER aggregator services in the macroeconomic framework. It can reveal how industrial and household DER providers participate in demand response requests, as well as how thermal power can be substituted by distributed renewables. We applied the framework to the benchmark year in Japan. The results show that the DER aggregator services at a full scale may have occupied 33.2 % of all grid aggregator services in electricity transmission and distribution. Faster-pace implementation of policy supports related to DER aggregator services is required to match such a potential market size.

National-Scale Geospatial Modelling of Pyrrhotite in Bedrock Across Canada: A Pilot Study

The most abundant iron sulphide minerals in igneous, metamorphic, and some sedimentary rocks are FeS2 (pyrite/marcasite) and Fe1-xS (pyrrhotite). The oxidation of pyrite and pyrrhotite in bedrock aggregates and mine tailings is undesirable to infrastructure and the environment because such chemical reactions are linked with concrete deterioration and acid mine drainage, respectively. The oxidation rate of pyrrhotite is up to one hundred times greater than that of pyrite; thus, pyrrhotite oxidation is of particular concern to society. Pyrrhotite-bearing concrete aggregates may lead to rapid expansion cracking and failure of critical concrete infrastructure including bridges, buildings, and houses, posing a significant safety concern. Additionally, premature disintegration of concrete requires replacement of concrete, leading to excessive aggregate resource extraction and associated increases in CO2 emissions. Considering the widespread concrete infrastructure across Canada, the distribution of pyrrhotite in bedrock used for aggregate is of fundamental importance to the short- and long-term safety of Canadians at the national, regional, and local scales. This pilot study details the initial steps taken to generate national-scale geospatial models of pyrrhotite occurrences in bedrock across Canada and illustrates the associated map products. In total, 12,577 known pyrrhotite occurrences were identified from publicly available provincial and territorial mineral occurrence datasets. The overall modelling strategy involved normalizing the number of pyrrhotite occurrences with respect to the total surface area of major bedrock types and characterizing three different classes of pyrrhotite occurrence density (< 1, 1–4, and 4–10 occurrences/1000 km2). The maps illustrate that pyrrhotite occurrence density is highest in volcanic rocks and undifferentiated sedimentary and volcanic rocks, moderate in intrusive and unknown rocks, and lowest in sedimentary and metamorphic rocks. Sedimentary rocks with no pyrrhotite occurrences span large surface areas across central-western Canada thus resulting in an overall low pyrrhotite occurrence density (< 1 occurrence/1000 km2) for this rock type, despite the fact that numerous pyrrhotite occurrences are identified in sedimentary rocks and may be abundant locally or regionally. Volcanic, undifferentiated sedimentary and volcanic, intrusive, and unknown rocks occur throughout the Canadian Shield of central and northern Canada, the Cordillera of western Canada, and the Appalachians of eastern Canada, but bedrock type and associated occurrence density are highly variable within these geological domains. Comparison of pyrrhotite occurrence density maps for Canada with pyrrhotite permissive geology maps for the United States of America illustrates that rocks with a high pyrrhotite occurrence density in Canada (volcanic rocks and undifferentiated sedimentary and volcanic rocks), are contiguous overall with areas of pyrrhotite potential in the United States. Inconsistencies across the international border reflect the differing methodologies and assumptions consisting of a statistically based approach for Canada and a qualitative approach for the United States. In the Cordillera and Appalachians, such discontinuities across the international border may reflect the underestimation of pyrrhotite occurrences in sedimentary rocks of Canada because of the impact of high surface area on the pyrrhotite occurrence density calculations. The maps presented herein are a first step in illustrating the distribution of pyrrhotite-bearing bedrock across Canada and greater North America. These national-scale map products are useful first-order references for selecting regions for follow-up studies on bedrock pyrrhotite occurrences. Regional and local geospatial analysis combined with field work for ground truthing will be important aspects of future research, especially in the vicinity of population centres where bedrock is utilized for concrete aggregate. Detailed regional and local studies of pyrrhotite occurrences in bedrock will help guide the extraction of safe concrete aggregate and contribute to the long-term sustainability of bedrock resources, safe infrastructure, and a habitable climate.

Stochastic Risk-driven Bidding of a Solar and Storage Aggregator in Primary Frequency and Energy Markets: A Performance-based Capacity Allocation Approach

The ever-increasing impact of deploying renewable energy resources reducing power system inertia, requires distributed energy resource (DER) aggregators to secure high-performance, fast-responding primary frequency reserve (PFR) in ancillary service markets. However, enabling immediate and local regulation of the operating point upon detecting frequency deviations imposes the necessity of allocating specific headroom for DERs. The individual headroom susceptibility to uncertainty and response speed of a certain DER not only compromises aggregated headroom performance in the PFR market but also leads to incurring unnecessary opportunity costs in the energy market and inadequate frequency control in the power system. To address this challenge, this paper introduces an integrated probabilistic performance index for DERs that considers their individual interactive heterogeneous response speed and uncertainty. Using this index, aggregators overseeing photovoltaic and smart buildings equipped with energy storage can evaluate, allocate, and remunerate optimal headroom capacity for individual DERs based on their performance. This approach ensures maximum aggregated profits and minimum opportunity costs in the PFR and energy markets while improving the performance of the provided PFR capacity, respectively. These tasks are aimed by a novel optimal capacity allocation strategy for an aggregator in both markets. This strategy employs a mixed-integer linear programming model to find the optimal solution and the conditional value-at-risk measure to tackle the uncertainties faced with the problem. The efficiency of the proposed model is assessed within a system reflecting the ERCOT market structure, demonstrating improved aggregated headroom performance, reduced energy opportunity costs, diminished risk of capacity shortage, and improved load frequency control (LFC) from the power system perspective.

Innovation and Practice of Diversified Business Model of New Energy Power Generation Enterprises

With the growing global demand for clean energy, new energy power generation enterprises are facing new opportunities and challenges. This paper explores the diversified business model of new energy power generation enterprises. Firstly, the theoretical basis of the business model of new energy power generation enterprises is analyzed, including the characteristics and income sources of single and multiple industrial chain models. The advantages and applications of different business models are analyzed through the study of cases at home and abroad, such as the European aggregated generation side resource model, the United States focused on controllable load demand response model, and the domestic cases of Shanghai and Shenzhen virtual power plant projects and distributed photovoltaic power generation. Then it puts forward the diversified business model innovation strategy of new energy power generation enterprises, covering the innovation of comprehensive energy services, the development of power side energy storage business, and the expansion of key businesses and profit models. Finally, the research conclusions are summarized and the future research directions are prospected. In short, the exploration of diversified business models of new energy power generation enterprises is of great significance to promote the development of clean energy and improve the competitiveness of enterprises.

Co-optimization of virtual power plants and distribution grids: Emphasizing flexible resource aggregation and battery capacity degradation

Coordination between virtual power plants and active distribution networks is crucial as these plants increasingly aggregate distributed resources within the power system. This study introduces a bilevel optimization framework to coordinate the scheduling of multiple virtual power plants and an active distribution network using pricing strategies for energy and reserves. The upper-level optimization minimizes total operating costs by incorporating bidding plans of the active distribution network in various markets, its interactions with multiple virtual power plants, and operational costs. The lower-level optimization maximizes revenue for each virtual power plant, considering both battery capacity degradation costs and operational costs of various resources. To facilitate solutions, this research developed a nonlinear transformation method for modeling capacity degradation. Based on the dispatching strategy from the virtual power plant, this study uses the squared difference between energy consumption of equipment for controllable loads and the strategy as the optimization target to derive control strategies for two equipment types. Results show that the framework effectively integrates dispatch and control strategies without oversimplifying the system model, proving its applicability in various scenarios with diverse resource compositions.

Multiscale spatial analysis of two plant–insect interactions: effects of landscape, resource distribution, and other insects

ContextBiotic resource exploitation is a critical determinant of species’ distributions. However, quantifying resource exploitation patterns through space and time can be difficult, complicating their incorporation in spatial ecology studies. Therefore, understanding the local drivers of spatial patterns of resource exploitation may contribute to better large-scale species distribution models.ObjectivesWe investigated (1) how the resource exploitation patterns of two trophic interactions (plant–insect) are explained by insect behaviour, resource aggregation, and potential insect-insect interactions. We also analyzed how (2) resource patch size and (3) resource accessibility in a heterogeneous landscape affected host exploitation patterns.MethodsWe quantified nectar robbing by insects in the genus Bombus (bumblebees) and seed predation by Brachypterolus vestitus larvae (Antirrhinum beetle) on Antirrhinum majus L. (wild snapdragons) in the Pyrenees Mountains, Catalonia, Spain. We tested hypotheses about resource exploitation by integrating spatial analyses at multiple scales.ResultsBoth trophic interactions were aggregated, explained by the aggregation of their resource. At some scales, nectar robbing is more aggregated than the resource. Trophic interaction abundance is proportional to resource patch size, following the ideal free distribution model. Landscape features do not explain the locations exploited. Nectar robbing and seed predation occur together more often than expected.ConclusionsOur findings suggest that multiple biotic and ecological spatial factors may simultaneously affect resource exploitation at a local scale. These findings should be considered when developing agricultural projects, management plans and conservation policies.

Optimal two-stage arbitraging and scheduling strategy for distributed energy resource aggregators

Given the rapid development of the distributed energy resources (DER), involving DERs into the wholesale market under the market and renewable uncertainties to achieve economic benefits is necessary but challenging. In this work, an arbitraging strategy is proposed for DER aggregators that bridge DERs with the wholesale market through energy trading. Besides, a novel self-adaptive minimax regret (MMR)-based optimal offering model is proposed for the DER aggregator to handle the uncertainties in both renewable generations and market prices. Additionally, an exact and communication-free solution methodology is proposed to resolve the formulated optimization problem with high computational efficiency. In the numerical results, the proposed methods can achieve near-to-optimal profits. Moreover, the performance of the proposed approach remains satisfactory even if the environment becomes very volatile.

A dispatch model coordinated power and heating system in electricity market considering resource aggregation and decomposition

Abstract With the high proportion of installed capacity of renewable energy, the stability and robustness of the new power system need to be improved. The integration of the power system and heating system is an orientation to promote the ability of wind power accommodation. This thesis first introduces the integrated model considering power and heating systems. However, the integrated model requires the topology in the heat network and the parameters of heat devices, which is difficult to access and complicated to solve. Under this situation, the heat devices are aggregated into an equivalent generation unit in the power network. A coordinated dispatched model based on resource aggregation and decomposition is then proposed. In simulation, the economy, flexibility, and security of a given formulation are investigated through marginal price and units’ behavior.

Resource Aggregates, Acquisition Decisions, and Resource-Rich Environments: An Inductive Study

Resource Aggregates, Acquisition Decisions, and Resource-Rich Environments: An Inductive Study

Dynamic simulation of policy-driven green technology innovation networks: Digital empowerment and collaborative efficiency

To delve into the intricate dynamics of green innovation, it is imperative to establish a policy-driven green innovation network and optimize its multi-entity collaborative mechanism. Given the dynamic complexity of a technological innovation network composed of multiple entities, this paper examines the interactions among four subsystems based on system dynamics (SD) simulation: resource input, innovation performance, policy-driven, and digital empowerment subsystem. Furthermore, we analyze the combined effects of policy-driven initiatives and the role of digital platforms in facilitating innovation efficiency based on empirical evidence. The results indicate that: (1) Government can effectively promote green development by enforcing stronger environmental regulations, such as increasing carbon trading price, while enhancing the emission reduction efficiency of innovative products. (2) Increased per capita R&D investment, along with financial, tax, fiscal incentives for innovation investment, will increase the rate of innovation achievements. (3) Government should strengthen talent policy during anticipated increases in talent numbers and reduce the intensity of introductions during expected declines. (4) By implementing incentive policies to develop S&T platforms, government can broaden innovation network cooperation, promotes resource aggregation, and leverages multi-entity cohort effects.

Eco-friendly concrete: Combining treated wastewater and recycled aggregates.

The concrete industry is a significant consumer of drinking water and natural aggregates, such as sand and gravel. However, the scarcity of water and aggregate resources and the challenges associated with the disposal of construction and demolition waste prompted the exploration of alternative materials. This study investigates the feasibility of incorporating secondary treated wastewater from UASB reactors followed by trickling filters and mixed recycled aggregates as potential alternatives. To assess the viability of these alternatives, the study considered the replacement of 100% potable water with treated wastewater, as well as varying proportions of recycled gravel (20, 40, 60, 80, and 100%) and recycled sand (10, 20, 30, 40, and 100%). Physical and mechanical properties were negatively affected, but it was possible to reach compressive results over 40 MPa and splitting tensile strength over 4 MPa for almost all mixes. Regarding physical properties, the use of alternative materials caused poorer outcomes for density, water absorption, and air-void ratio. The limited magnitude of these detrimental effects indicates the potential of manufacturing concrete with the addition of combined treated wastewater and recycled aggregate as a viable strategy while enhancing reuse practices.

Mechanical properties and repairing mechanism of recycled cement stabilized macadam for road base based on microbial induced carbonate precipitation technology

The utilization of recycled coarse aggregate derived from construction and demolition waste (CDW) in the construction of road cement stabilized macadam base could effectively alleviate the shortage of natural sand and aggregate resources. To explore the repairing effect of microbial induced carbonate precipitation (MICP) on recycled cement stabilized macadam (RCSM), the physical, mechanical, and microscopic properties of recycled concrete aggregate under different precipitation precursor concentrations were researched in this paper. The mechanical properties of RCSM with varying contents of recycled concrete aggregate were analyzed before and after repairing. Based on scanning electron microscopy (SEM) and mercury intrusion porosimeter (MIP) tests, the microstructure and pore structure parameters of recycled concrete aggregate were explored, and the repair mechanism of MICP on RCSM was revealed via the performance analysis of recycled concrete aggregate and RCSM. The results show that MICP could effectively reduce the water absorption of recycled concrete aggregates, while simultaneously enhancing its apparent density and crushing resistance. In a certain range, the higher the concentration of the precipitation precursor, the better the repairing effect on the performances of recycled concrete aggregates. However, while the concentration of urea or calcium source concentration exceeding 1.0 mol/L, the activity of urease would start to be inhibited. The unconfined compressive strength of RCSM after MICP repairing could be increased by 22.7 % with a maximum extent compared with that before repair, while the maximum increase of indirect tension strength and flexural tensile strength was 15 % and 8.2 %, respectively. The biological CaCO3 generated by MICP reaction could fill the micro-cracks and pores of the recycled concrete aggregate efficaciously. Besides, it could also optimize the pore parameters and pore size distribution parameters, and enhance the adhesive strength of interfacial transition zone (ITZ) between cement and recycled concrete aggregates, which could improve the mechanical properties of RCSM.

Virtual Power Plant Response Strategy Considering Dynamic Aggregation of Different Flexible Resources

Abstract Aggregate and adjust distributed resources, the virtual power plant realizes the collaborative optimization of different forms of electric energy, which greatly improves the flexibility of the power system. Considering the flexibility of distributed resources, this paper designs the active power and frequency regulation modes of virtual power plants, and proposes a response strategy for dynamic resource aggregation of virtual power plants. Firstly, the distributed energy resources of virtual power plants are classified, and their dynamic characteristics are fully considered for dynamic aggregation, and the active power and based on these characteristics, a frequency regulation model is established. Secondly, according to the real-time operation status of sampled distributed resources, a response prediction model of virtual power plant based on dynamic resource aggregation was proposed. Finally, taking the 35kV substation workbench as an example, the response effect of the virtual power plant at different times of a typical day is verified.

Assessing the ecological effects of low-intensity marine aggregate extraction in a strong-hydrodynamic, coarse environment context: A case study of the GIE GMO site (English channel)

Marine aggregate extraction represents an opportunity to face the depletion of terrestrial aggregate resources. The environmental effects of this activity have been assessed in several studies, leading to the formulation of recommendations to mitigate its effects. This study investigates its environmental impacts in a coarse, high-current environment with low-intensity extraction, a unique scenario not extensively studied before. Employing multivariate analyses and a trophic group approach, it examines complex responses at both species and community levels. Results indicate a decline in biodiversity, promoting the establishment of r-selected species, particularly filter feeders. Although site restoration timelines remain uncertain, initial indications suggest rapid recovery (2–3 years) for this site. The study also discusses methodological challenges in sampling these low-intensity dredged sites and emphasizes the need for new indices tailored to this pressure and coarse sediments under strong hydrodynamics. These insights offer valuable directions for future research.

Experimental Study of Mechanical Properties and Theoretical Models for Recycled Fine and Coarse Aggregate Concrete with Steel Fibers.

With diminishing natural aggregate resources and increasing environmental protection efforts, the use of recycled fine aggregate is a more sustainable approach, although challenges persist in achieving comparable mechanical properties. Exploration into the incorporation of steel fibers with recycled aggregate has led to the development of steel-fiber-reinforced recycled aggregate concrete. This study investigates the shrinkage performance and compressive constitutive relationship of steel fiber recycled concrete with different steel fibers and recycled aggregate dosages. Initially, based on different replacement rates of recycled coarse aggregate and different volume contents of steel fiber, experimental results demonstrate that as the replacement rate of recycled coarse aggregate increases, shrinkage also increases, while the addition of steel fiber can mitigate this effect. An empirical shrinkage model for steel fiber recycled concrete under natural curing conditions is also proposed. Subsequently, based on the uniaxial compression test, findings indicate that with an increasing replacement rate of recycled fine aggregate, the peak stress and elastic modulus of concrete decrease, accompanied by an increase in peak strain, and the addition of steel fiber limits concrete crack development and enhances its brittleness while the peak stress and strain of recycled fine aggregate concrete are enhanced. However, the steel fiber volume percentage has a negligible effect on the elastic modulus. A constitutive relationship for concrete considering the effects of recycled fine aggregate and steel fiber is also proposed. This finding provides foundational support for the influence patterns of steel fiber dosage and recycled aggregate ratio on the mechanical properties of steel fiber recycled concrete.

Assessing the viability of using BOF steel slag treated with tartaric acid as coarse aggregate in concrete

This study investigated the effectiveness of tartaric acid treatment in inhibiting the expansive behaviour of basic oxygen furnace (BOF) steel slag, aiming to optimize its utilization as a sustainable replacement for natural coarse aggregate in concrete. Tartaric acid-treated steel slag (TTSS) and non-tartaric acid-treated steel slag (NTSS) were comprehensively characterized for particle size and shape properties, physical and mechanical behaviour, and durability aspects including MgO stability factor and iron unsoundness. Chemical, morphological, mineralogical, and microstructural analyses were conducted using XRF, SEM-EDS, XRD, FT-IR, and optical microscopy, elucidating the impact of tartaric acid treatment. Compressive strength tests were then performed with TTSS incorporation levels of 30 %, 40 %, 50 %, and 0 % as reference batch (RB). As a result, TTSS showed 7.44 % and 10.92 % better physical and mechanical properties than NTSS respectively. Whereas on durability aspects, TTSS depicts 40 % better results on iron unsoundness and 36.43 % higher water absorption over NTSS. Furthermore, a maximum compressive strength of 44 MPa was achieved with a significant improvement of 15.80 % from RB. Additionally, TTSS aggregate-based cement concrete exhibited a denser microstructure and improved performance. This work highlights the potential of BOF steel slag as an aggregate resource, contributing to a circular economy and mitigating the environmental burdens associated with traditional aggregate production.

Dynamic hierarchical partitioning method of flexible resource for virtual power plant based on event triggering

Abstract With the advantage of efficient aggregation of flexible resources on the demand side, virtual power plants have been widely considered as one of the effective solutions to solve the lack of large-scale access systems and regulation capacity of new energy. Aiming at the problem of how the flexible resources of the virtual power plant can effectively participate in the optimal operation of hierarchical zoning of the power grid, this paper takes the aggregation of flexible resources of the virtual power plant to alleviate multiple line overload as an example. By deducing the transfer factor matrix under the linearized AC power flow model, an event-triggered hierarchical zoning method of flexible resources of virtual power plants considering resource effectiveness is proposed. The effectiveness of the algorithm is verified in several network examples, which provides a new idea for the virtual power plant to participate in the optimal operation of various levels and regions of the power grid.

Distributed Energy Resources Aggregation and Optimization Scheduling Model and Algorithm for Virtual Power Plants

With the ongoing energy transition and power system reform, Distributed Energy Resources (DERs) are playing an increasingly important role in modern power systems. DERs mainly include distributed photovoltaics, distributed wind power, small hydropower, biomass energy, fuel cells, and controllable loads, characterized by decentralized deployment and local consumption. The large-scale integration of these resources presents new opportunities and challenges for power systems. Effectively coordinating and managing these distributed energy resources has become a hot research topic.

Knowledge Element Relationship and Value Co-Creation in the Innovation Ecosystem

In the era of Innovation 3.0, more and more enterprises are working together to build an innovation ecosystem to achieve value creation. The various participants in the innovation ecosystem promote resource aggregation and integration through cross boundary collaboration, jointly creating the value of the ecosystem. Value co-creation has become the core goal pursued by the participants in the innovation ecosystem. As an innovative participant in the innovation ecosystem, it is particularly necessary for enterprises to explore the formation mechanism of value co-creation from the perspective of enterprise knowledge characteristics. This article analyzes the value co-creation mechanism of innovation ecosystems from the perspective of including internal knowledge bases and external relationships. Based on the dimension of knowledge element relationships, a theoretical model is constructed to investigate the impact of enterprise knowledge element relationships on value co-creation in innovation ecosystems and explore the mediating role of knowledge synergy and the moderating role of innovation ecosystem normativity. The relationships are modeled based on survey data collected from 427 Chinese companies, and multiple regression analysis and bootstrap methods are used to empirically test the hypotheses. The research results show that different dimensions of knowledge element relationships have different impacts on value co-creation. Knowledge element substitution negatively affects value co-creation, while knowledge combination diversity positively affects value co-creation. However, there is an inverted U-shaped relationship between knowledge element complementarity and value co-creation. Knowledge synergy partially mediates the relationship between knowledge element relationships and value co-creation, and innovation ecosystem normativity has a two-stage moderating effect on the path from knowledge element relationships to knowledge synergy to value co-creation. This article enriches the research content of knowledge management in innovation ecosystems, guides enterprises in the innovation ecosystem to reasonably construct their own knowledge systems, and promotes the formation of innovation ecosystem norms, thus promoting the development of value co-creation activities.

Distribution Characteristics of Land and River Aggregate Resources in Yeongam Area by Deposition Period

Distribution Characteristics of Land and River Aggregate Resources in Yeongam Area by Deposition Period