With the rising adoption of Electric Vehicle (EV) technology and Renewable Energy Sources (RES), electric distribution grids are facing new challenges regarding congestion management. The present work steps into the topic of controlled charging mechanisms to reduce physical grid extension by utilizing flexible loads from EV. Although, existing research concludes a positive impact on congestion relief, less attention is given to a holistic and light system that is implementable under current circumstances. This thesis develops a novel system towards micro-auctions for local flexibility allocation amongst EVs to reduce grid congestion. A functional software prototype simulates a virtual market and grid environment. Each EV acts as an autonomous agent submitting bids to the local flexibility market, offering 15-minute charging breaks. Based on individual risk preference and state-of-charge, bidprices vary amongst EVs.
The Distribution Grid Operator (DSO) constantly asses grid status and contracts positive capacity during critical phases by accepting current bids. It can be shown, that regardless of the penetration rate of EVs, the proposed model balances the tested grid topology below the maximum workload and within a predefined range. According to simulation assumptions, a ninefold increase of EVs can be accommodated with the proposed model. Although, with monotonically increasing penetration rate, average charge-increase converges to zero. Due to the proposed intervals, EVs are grouped to continues batches with demandresponse latency. Once contracted, EVs remain charging or not-charging for 15 minutes. The assignment to certain batches does not change over simulation time. Based on the proposed request control mechanism, critical grid conditions can be reduced by 49%. Whereas quantitative results are limited to the proposed simulation assumptions, qualitative effects are generalizable to a certain extend.
Inhaltsverzeichnis (Table of Contents)
- Executive Summary
- Introduction
- Motivation and Problem Identification
- Research Question and Objectives
- Structure of the Thesis
- Theoretical Foundations
- Brief History of the German Energy Grid.
- Distribution and Transmission
- Energy Markets
- Energy-Only-Markets
- Capacity Markets
- Contractual Balancing
- Auctions in Competitive Electricity Pools
- The Problem of Balancing and Congestion
- Grid Congestions and Frequency Balance .
- Congestion Mechanism
- Balancing Mechanism.
- Local Flexibility: A Novel Approach
- The new importance of Distribution System Operators
- Definition of Flexibility .
- The Problem of Low Demand Flexibility
- Flexibility from Electric Vehicles
- V2G ..
- Current Limitations of V2G
- Controlled Charging
- Current Research to Controlled Charging.
- Local Flexibility Markets .
- The Traffic Light Concept
- Historical Background
- Concept
- Focus of this work .
- Simulation Software: Concept and Design
- Problem Definition and Goal.
- Conceptual Design
- Applied Grid Environment
- Traffic Light Thresholds
- DSO and Flexmarket Concept
- EV Concept
- Communication and Information Concept
- Architectural Design
- Simulation Framework
- System Design
- Input values.
- Agent Behaviour Modeling
- Evaluation
- Evaluation process and tools
- Time-Series Simulation
- Grid Workload
- Completed Charging Requests
- Bid Acceptanc Ratio
- Price of Bids
- Charging pattern of Example EV
- Summary Time-Series Simulation
- Sensitivity Simulation
- Auction Cost, EV Profit and SoC Increase
- Completed Charging Requests . .
- State of Charge and Optimal EV penetration
- Summary Sensitivity Simulation.
- Identified Effects
- Request Control.
- Latency
- Batching.
- Robustness against Dynamic Inputs
- Initial Sate of Charge.
- Arrival and Departure Time
- Risk Preferences
- Random Seed
- Limitations
- Forecasting Demand Structure.
- Dynamic Charge Power.
- Optimal Segmentation
- Balancing Group Problem
- Price Cap and Price Function
- Conclusion, Discussion and Outlook
Zielsetzung und Themenschwerpunkte (Objectives and Key Themes)
This thesis examines the growing use of renewable energy systems and the rise of electric vehicles as potential solutions to grid congestion issues, particularly in the context of electrical distribution systems. The research focuses on optimizing flexibility in the electrical distribution grid by controlling the charging patterns of electric vehicles, and proposes a novel approach to allocating local flexibility using micro-auctions.
- The importance of flexibility in managing grid congestion
- The potential of controlled charging for electric vehicles as a solution to grid congestion
- The development of a micro-auction-based system for allocating local flexibility
- Simulation and evaluation of the proposed system in a virtual market and grid environment
- Analysis of the effects of the system on grid performance, charging patterns, and economic factors.
Zusammenfassung der Kapitel (Chapter Summaries)
- Executive Summary: Briefly summarizes the key findings and contributions of the thesis.
- Introduction: Introduces the problem of grid congestion in the context of renewable energy and electric vehicles. Defines the research question and outlines the structure of the thesis.
- Theoretical Foundations: Provides background information on the German energy grid, distribution and transmission systems, and different types of energy markets. Discusses the challenges of balancing and congestion, focusing on the role of distribution system operators.
- Local Flexibility: A Novel Approach: Discusses the growing importance of local flexibility in managing grid congestion. Explores the potential of electric vehicle charging as a source of flexibility, highlighting the benefits and limitations of various approaches. Introduces the concept of local flexibility markets and the Traffic Light concept, which forms the foundation of the proposed system.
- Simulation Software: Concept and Design: Details the conceptual and architectural design of the simulation software used for evaluating the proposed system. Outlines the grid environment, traffic light thresholds, DSO and flexmarket concept, EV concept, and communication and information flow within the system.
- Evaluation: Presents the results of simulations conducted using the developed software. Evaluates the system's performance in terms of grid workload, completed charging requests, bid acceptance rate, price of bids, and charging patterns. Also analyzes the sensitivity of the system to various factors, including auction cost, EV profit, SoC increase, and EV penetration.
Schlüsselwörter (Keywords)
Key words include: electrical distribution grids, grid congestion, flexibility, electric vehicles, controlled charging, micro-auctions, local flexibility markets, simulation, time-series analysis, sensitivity analysis, distribution system operators.
- Quote paper
- Clemens Pizzinini (Author), 2019, Optimal Flexibility Allocation in Electrical Distribution Grids, Munich, GRIN Verlag, https://www.grin.com/document/583990
