Distributed Grid Infrastructure Research Articles

Mitigating impacts associated with a high-penetration of plug-in electric vehicles on local residential smart grid infrastructure

The transition to plug-in battery and fuel cell electric vehicles (PEVs) is emerging as a principal strategy to mitigate greenhouse gas (GHG) and criteria pollutant emissions. For PEVs, this paradigm shift requires attention to the impact of home charging on the grid in an era where distributed energy resources (DERs), such as solar panels and batteries, are being commercially deployed. To understand the integration of light-duty PEVs with residential DERs, a model is developed to simulate PEV charging demand profiles in combination with field data from three different home groups of varying DER configurations. A valley-filling smart charging algorithm is explored to optimize vehicle charging, more effectively utilize solar PV, reduce emissions, and reduce peak demand. The results show that (1) the impact on transformer hot spot temperature and loss of life is acceptable for all cases, (2) smart charging can increase transformer life, (3) while PEV deployment reduces GHG emissions, additional reduction can be achieved through the integration of DERs and smart charging, and (4) the addition of DERs and implementation of smart charging virtually eliminate the negative impacts of PEVs on distribution grid infrastructure, increases PV penetration, and reduces emissions and peak demand.

Geographical Modeling of Charging Infrastructure Requirements for Heavy-Duty Electric Autonomous Truck Operations

This study presents an analysis of the charging infrastructure requirements for autonomous electric trucks (AETs) in a specified geographical region, focusing on the state of Texas as a case study. A discrete-time, agent-based model is used to simulate the AET fleet and consider various model parameters such as trip distance/duration, the number of trips, and charging speeds. The framework incorporates unique properties of the Texas road network to assess the sensitivity of charging infrastructure needs. By synergizing electrification and automation, AETs offer benefits such as reduced carbon emissions, enhanced transportation safety, decreased congestion, and improved operational costs for fleets. By simulating daily trips and energy consumption patterns, an analysis of the charging infrastructure needs for cities along the Texas highway triangle formed by I-35, I-45 and I-10 revealed that the total charging energy and average charging power for these major cities ranges between 443~533 MWh/day and 18.5~22 MW, with costs in the range of USD $7.74~$15.93 million for each city, depending on charging infrastructure design and exclusive of any enhancements to the distribution grid infrastructure needed to support the charging infrastructure. This data-driven approach may be replicated for other regions by adapting the simulation parameters to allow policymakers and stakeholders to assess the charging infrastructure requirements and related investments needed to support the transition to electric and autonomous heavy-duty trucking.

Maximising Distribution Grid Utilisation by Optimising E-Car Charging Using Smart Meter Gateway Data

The transition towards climate neutrality will result in an increase in electrical vehicles, as well as other electric loads, leading to higher loads on electrical distribution grids. This paper presents an optimisation algorithm that enables the integration of more loads into distribution grid infrastructure using information from smart meters and/or smart meter gateways. To achieve this, a mathematical programming formulation was developed and implemented. The algorithm determines the optimal charging schedule for all electric vehicles connected to the distribution grid, taking into account various criteria to avoid violating physical grid limitations and ensuring non-discriminatory charging of all electric vehicles on the grid while also optimising grid operation. Additionally, the expandability of the infrastructure and fail-safe operation are considered through the decentralisation of all components. Various scenarios are modelled and evaluated in a simulation environment. The results demonstrate that the developed optimisation algorithm allows for higher transformer loads compared to a P(U) control approach, without causing grid overload as observed in scenarios without optimisation or P(U) control.

Assessment of using hydrogen in gas distribution grids

Substantial changes in the energy system are necessary to achieve greenhouse gas neutrality. Green hydrogen is a key to defossilisation. Politicians frequently mention the use of hydrogen in the building sector to supply decentrally produced heat as a potential field of application. An advantage repeatedly mentioned is that the existing gas distribution network infrastructure is an important asset that could still be used in the future. However, there is a lack of analyses of the conversion of gas distribution networks to hydrogen focussing on the economic implications on the costs of the distribution network infrastructure. The paper provides insights using a techno-economic model network analysis (MNA) tool called gas Distribution grId modelliNg tOol (DINO). The analysis is carried out for Germany and considers hydrogen use in all counties. The results are compared to a synthetic methane and electrification scenario. In the hydrogen scenario, the total need for distribution grids is decreasing until 2050 by at least 130,000 km. The network length of the synthetic methane scenario is slightly lower and that of the electrification scenario drops to zero. The annual operation costs are lower in all scenarios as gas demand and infrastructure are reduced. Nevertheless, the total annual cost in the hydrogen scenario is potentially two times higher than in the case of the synthetic methane scenario and more than four times higher than in the electrification scenario. Based on the present results, it is questionable whether an advantage of the continued use of the existing gas distribution grid infrastructure in case of synthetic gas or hydrogen scenarios exists.

Can distribution grid infrastructure accommodate residential electrification and electric vehicle adoption in Northern California?

In this paper we ask: in what ways will utilities need to upgrade the electric distribution grid to accommodate electrified loads, and what will those upgrades cost? Our study focuses on the PG&E service area in Northern California, which serves 4.8 million electricity customers and is subject to aggressive targets for both EV adoption and electrification of residential space and water heating. We create spatio-temporally detailed electricity demand forecasts, and compare that demand to distribution infrastructure limits across a range of technology adoption scenarios. We find that electrification of residential space and water heating will lead to fewer impacts on distribution feeder capacity than EV charging, but that both transitions will require an acceleration of the current pace of upgrades. We also find that timing and location have a strong influence on total capacity additions in important ways: for example, scenarios that favor daytime EV charging have similar impacts to those with managed nighttime residential charging, but uncontrolled nighttime residential charging could have significantly larger impacts. We project that these upgrades will add at least $1 billion and potentially over $10 billion to PG&E’s rate base. We conclude that measures that enable the completion of a high number of upcoming upgrade projects—including addressing workforce and supply chain constraints, and pursuing non-wires alternatives like energy storage and demand response—are critical to successful electrification.

Impact of electric vehicle charging – An agent‐based approach

Several European countries have launched programs to increase the market penetration of battery electric vehicles (BEV). Similarly, politicians in Switzerland have targeted a 15% BEV share of new car registrations by 2022. As each electric car increases the power demand, new challenges are posed to the operation of existing distribution grid infrastructure. Here, a new bottom-up physical approach is presented that couples agent-based traffic simulations through an unsteady vehicle power consumption model with distribution grid power flow simulations. The impacts on hourly powerline loads from charging a car fleet with an 8.5% BEV share are quantified in the real distribution grid for the canton of Zurich. The grid is composed of 12,000 buses and 9,800 powerlines, providing power to 398,000 individual customers. Results indicate that the risk of overloaded powerlines is highest in low-level distribution grids. In our most critical future scenario, with simultaneous 8.5% BEV charging at 8 pm with 11 kW, peak line loads reach up to 132% of rated capacity. Hence, in a potential energy transition towards a decarbonised future, each individual distribution grid could face critical loads at specific temporal and spatial bottlenecks. Thus, grids should be assessed individually to limit uncertainties and risks of critical power system situations.

Smart metering field implementation with power line communication in low voltage distribution grid

Smart Grids (SG) enable power generation, distribution, transmission, customers and utilities to transfer, predict, monitor and manage energy usage effectively. In order to provide them, SGs need to be fully realized by integrating communication technologies infrastructures. Today, SGs have some main systems. These are Advanced Meter Reading (AMR), distributed renewable energy, energy storage, electric vehicle and smart city-home implementations. AMR is the most prominent SG component between all SG main systems. Because it provides to follow all consumers remotely and momentarily using their Smart Meters (SM). AMR system is based on SM, gateway, meter data management software and wired or wireless communication method. Nowadays, Power Line Communication (PLC) is the most popular wired communication method for remote meter reading because of try to use existing electric distribution grid infrastructure. On the other hand, GPRS/EDGE/3G is one of the widespread wireless communication method for remote meter reading implementations but its costly and external dependence has started the search for new communication methods instead. In this paper, practically twelve electric meters are tried to be read remotely with PLC in Yeşilırmak Electric Distribution Company field until the distribution transformer. These remote meter reading results that captured with PLC will evaluate in AMR software. Then an AMR system model is put forward thanks to this field implementation. Beside this a hybrid communication method has been suggested for smart metering. PLC key parameters will find out. In addition, data concentrator (DC), meter and gateway that has PLC features equipment field configurations will research.

Spatial analysis of distribution grid capacity and costs to enable massive deployment of PV, electric mobility and electric heating

Rapid deployment of solar photovoltaics (PV), electric heat pumps (HP) and electric vehicles (EV) is needed to decarbonize the economy. However, the integration of these technologies into the power system creates challenges for the distribution grid infrastructure. It is therefore vital to analyse to which extent grid reinforcement is needed to enable decarbonization strategies while also studying alternative flexibility measures. In this GIS-based study, we model the impact of the deployment of PV, HP and EV on a low-voltage distribution grid network serving 170’000 households in Switzerland, and analyse scenarios for their penetration in the years 2035 and 2050. Using a detailed grid model in collaboration with a distribution system operator, we find that PV leads to 18.5% and 13.7% more voltage violation issues compared to HP and EV respectively, which on the other hand, cause slightly more line overloading, 0.5% and 2.5%, respectively. We also find that grid reinforcement costs markedly depend on the type of urban setting ranging between 51–213 CHF/kWp, 46–1’385 CHF/kW and 34–143 CHF/kW for PV, HP and EV, respectively, with the higher limit corresponding to rural areas. The total distribution grid reinforcement costs can amount up to 11 billion CHF until 2050 i.e. 2’900 CHF per household in Switzerland. Interestingly, we find that batteries, even with current costs, have the potential to defer grid reinforcement for up to 15% of the transformer stations with the highest specific grid reinforcement costs. Our study aims to inform various stakeholders about the required grid investments to enable the massive deployment of low carbon technologies.

Sustainable and Resilient Distribution Systems With Networked Microgrids [Point of View

Grid modernization calls for increasing requirements of electric grid operation with enhanced sustainability and resilience [1] . In particular, distribution grids serve as a critical venue to bridge bulk upstream transmission and generation systems and a large number of downstream end users on the customer side, playing a significant role in modern electric grids for multiple purposes (e.g., renewable energy integration, power flow distribution, and end-user power quality enhancement) [2] . Under a normal grid operation condition, the increasing penetration level of renewable energy sources imposes new challenges on conventional distribution grid infrastructure (e.g., protection malfunction [3] and voltage violation [4] ); on the other hand, in an extreme grid operation scenario, it is urgently needed to restore grid services after severe power outages, such as those caused by natural disasters [5] . In particular, for critical infrastructures, an efficient grid service restoration strategy should be implemented to avoid further damage over an extended period of time.

Microgrid Controller Design, Implementation, and Deployment: A Journey from Conception to Implementation at the Philadelphia Navy Yard

The Philadelphia Navy Yard is a fast-evolving community microgrid, currently home to over 150 companies and four Navy activity centers occupying nearly 7.5 million ft2 of buildings in which approximately 12,500 people are employed. The Navy Yard (TNY) is a national center of excellence for energy research, education, and commercialization, focused specifically on community microgrid design and development. TNY microgrid is equipped with the most cost-effective and sustainable means for meeting electric capacity and energy needs through renewable resources, energy efficiency, and distribution grid infrastructure. This article briefly describes how the community microgrid was conceived and planned to produce a great success story of microgrid implementation and the details of the design, development, and implementation of TNY's microgrid controller.

Hierarchical control for DC microgrid clusters with high penetration of distributed energy resources

In this paper, a real-time tertiary control algorithm for DC microgrids will be developed and implemented. Tertiary control, in the context of this paper, refers to the control layer that transcends the boundaries of a single microgrid, and hence supervises a group of microgrid central controllers (MGCC). Microgrids are considered as dynamic resources and loads that can inject or draw active and/or reactive power to/from the grid, depending on their loading condition. This paper focuses on microgrids with high penetration of renewable resources. To overcome renewable energy intermittency, the developed algorithm virtually aggregates neighboring microgrids into clusters, which virtually exchange energy through the distribution grid infrastructure stabilizing the main power infeed. For improved short-term planning, the developed algorithm periodically forecasts the net available energy from each microgrid. In addition, it solves a set of load flow equations, governed by predefined constraints, to determine (near-) optimal set points to the various microgrids, which consequently improves the efficiency and voltage stability of the distribution network, and increase its level of survivability. This study highlights some key examples of how the microgrids can be used to support the operation of the main grid, e.g. enhancing the voltage profile on a distribution feeder. The algorithm was validated experimentally using a laboratory scale testbed setup.

Reactive power support in residential LV distribution grids through electric vehicle charging

Abstract This article discusses the impact of reactive power support of single-phase electric vehicle chargers, during charging, in a low-voltage residential distribution grid. For a representative Flemish case study, reactive power support is investigated for three different electric vehicle charging strategies: uncoordinated charging, residential off-peak tariff charging, and vehicle-based peak shaving. For an increasing electric vehicle penetration rate and an increasing amount of reactive power injection, the impact on the residential voltage deviations, peak load, and grid losses is calculated. The results of the case study show that the implementation of a capacitive load behavior in electric vehicle chargers has a beneficial impact on the voltage deviations. Furthermore, for a capacitive power factor of 0.95 or higher, there is no disadvantage with respect to the residential peak load and the residential grid losses. However, the cost related to the increased apparent power rating of the vehicle chargers, required to supply the reactive power, should be assessed compared to the mentioned advantages. If the benefits outweigh the costs, reactive power support could be considered in the grid compliance requirements of electric vehicle chargers, as it allows deferring distribution grid infrastructure investments.

Life-cycle assessment of electricity in Portugal

The Portuguese electricity mix is undergoing a significant shift away from the technologies that have dominated generation for the past decades. This article aims at assessing the environmental life-cycle impacts of electricity generation and supply in Portugal (PT), including: (i) modeling the main electricity generation systems; (ii) modeling the transmission and distribution (T&D) grid infrastructure; (iii) characterizing the evolution of the electricity sector in PT from 2003 to 2012; and (iv) discussing how the recent changes in the technology portfolio affected the environmental performance of the electricity generated and supplied. The life-cycle assessment methodology was used to quantify impacts in: non-renewable fossil energy demand (nREn), global warming (GW), abiotic depletion (AD), acidification (AC), eutrophication (ET), photochemical oxidation (PO) and ozone layer depletion (OD). From 2003 to 2012, an overall reduction of the environmental impacts was achieved. In particular, since 2008, electricity generation impacts in AC and PO dropped sharply as a result of the installation of desulphurization (62% reduction in AC; 74% reduction in PO) and denitrification (5% reduction in AC) systems in coal power plants (PP), as well as the phase out of large fuel oil PP. For NREn, AD and GW, the reduction of impacts was less pronounced (9–22% in the generation mix; 14–22% in the supply mix). T&D grid added 5–14% to the environmental impacts due to infrastructure (<5%) and T&D losses (5–9%). Despite the large increase in renewable capacity (especially wind) and the investments in lower-carbon fossil fuel technologies (natural gas), electricity generation still relies heavily on coal. There is, however, potential to further reduce environmental impacts in key categories (NREn, AD and GW) since there is significant available capacity of natural gas combined cycle currently underutilized.

Scientific grid computing: the first generation

The scientific user's computing demands are becoming increasingly complex and can benefit from distributed resources, but effectively marshalling these distributed systems often introduces new challenges. The authors describe how researchers can exploit existing distributed grid infrastructure to get meaningful scientific results.

Improving scientists' interaction with complex computational–visualization environments based on a distributed grid infrastructure

The grid has the potential to transform collaborative scientific investigations through the use of closely coupled computational and visualization resources, which may be geographically distributed, in order to harness greater power than is available at a single site. Scientific applications to benefit from the grid include visualization, computational science, environmental modelling and medical imaging. Unfortunately, the diversity, scale and location of the required resources can present a dilemma for the scientific worker because of the complexity of the underlying technology. As the scale of the scientific problem under investigation increases so does the nature of the scientist's interaction with the supporting infrastructure. The increased distribution of people and resources within a grid-based environment can make resource sharing and collaborative interaction a critical factor to their success. Unless the technological barriers affecting user accessibility are reduced, there is a danger that the only scientists to benefit will be those with reasonably high levels of computer literacy. This paper examines a number of important human factors of user interaction with the grid and expresses this in the context of the science undertaken by RealityGrid, a project funded by the UK e-Science programme. Critical user interaction issues will also be highlighted by comparing grid computational steering with supervisory control systems for local and remote access to the scientific environment. Finally, implications for future grid developers will be discussed with a particular emphasis on how to improve the scientists' access to what will be an increasingly important resource.

Improving National and Homeland Security Through a Proposed Laboratory for Information Globalization and Harmonization Technologies (LIGHT)

A recent National Research Council study found that: there are many private and public databases that contain potentially relevant to counter terrorism programs, they lack the necessary context definitions (i.e., metadata) and access tools to enable interoperation with other databases and the extraction of meaningful and timely information [NRC02, p.304, emphasis added] That sentence succinctly describes the objectives of this project. Improved access and use of are essential to better identify and anticipate threats, protect against and respond to threats, and enhance national and homeland security (NHS), as well as other national priority areas, such as Economic Prosperity and a Vibrant Civil Society (ECS) and Advances in Science and Engineering (ASE). This project focuses on the creation and contributions of a Laboratory for Information Globalization and Harmonization Technologies (LIGHT) with two interrelated goals: (1) Theory and Technologies: To research, design, develop, test, and implement theory and technologies for improving the reliability, quality, and responsiveness of automated mechanisms for reasoning and resolving semantic differences that hinder the rapid and effective integration (int) of systems and data (dmc) across multiple autonomous sources, and the use of that by public and private agencies involved in national and homeland security and the other national priority areas involving complex and interdependent social systems (soc). This work builds on our research on the COntext INterchange (COIN) project, which focused on the integration of diverse distributed heterogeneous sources using ontologies, databases, context mediation algorithms, and wrapper technologies to overcome representational conflicts. The COIN approach makes it substantially easier and more transparent for individual receivers (e.g., applications, users) to access and exploit distributed sources. Receivers specify their desired context to reduce ambiguities in the interpretation of coming from heterogeneous sources. This approach significantly reduces the overhead involved in the integration of multiple sources, improves data quality, increases the speed of integration, and simplifies maintenance in an environment of changing source and receiver context - which will lead to an effective and novel distributed grid infrastructure. This research also builds on our Global System for Sustainable Development (GSSD), an Internet platform for generation, provision, and integration of multiple domains, regions, languages, and epistemologies relevant to international relations and national security. (2) National Priority Studies: To experiment with and test the developed theory and technologies on practical problems of data integration in national priority areas. Particular focus will be on national and homeland security, including data sources about conflict and war, modes of instability and threat, international and regional demographic, economic, and military statistics, money flows, and contextualizing terrorism defense and response. Although LIGHT will leverage the results of our successful prior research projects, this will be the first research effort to simultaneously and effectively address ontological and temporal conflicts as well as dramatically enhance quality. Addressing problems of national priorities in such rapidly changing complex environments requires extraction of observations from disparate sources, using different interpretations, at different points in times, for different purposes, with different biases, and for a wide range of different uses and users. This research will focus on integrating both over individual domains and across multiple domains. Another innovation is the concept and implementation of Collaborative Domain Spaces (CDS), within which applications in a common domain can share, analyze, modify, and develop information. Applications also can span multiple domains via Linked CDSs. The PIs have considerable experience with these research areas and the organization and management of such large scale international and diverse research projects. The PIs come from three different Schools at MIT: Management, Engineering, and Humanities, Arts & Social Sciences. The faculty and graduate students come from about a dozen nationalities and diverse ethnic, racial, and religious backgrounds. The currently identified external collaborators come from over 20 different organizations and many different countries, industrial as well as developing. Specific efforts are proposed to engage even more women, underrepresented minorities, and persons with disabilities. The anticipated results apply to any complex domain that relies on heterogeneous distributed data to address and resolve compelling problems. This initiative is supported by international collaborators from (a) scientific and research institutions, (b) business and industry, and (c) national and international agencies. Research products include: a System for Harmonized Information Processing (SHIP), a software platform, and diverse applications in research and education which are anticipated to significantly impact the way complex organizations, and society in general, understand and manage critical challenges in NHS, ECS, and ASE.