Technology Transformation to Support Flexible and Resilient Local Energy Systems

Lead Research Organisation: Imperial College London
Department Name: Electrical and Electronic Engineering

Abstract

Deep changes are happening in the supply side of energy systems. The UK has halved carbon emissions from electricity system from over 150 million tonnes in 2012 to under 70 in 2018 and China is adding about 20 GW of wind generation capacity per year and has replaced all buses in the city of Shenzhen with electric busses. Very clearly there is much more to do: the remaining decarbonisation of electricity, the electrification of other sectors and sourcing alternative, zero-carbon fuels.
Cities have traditionally been huge consumers of energy brought in from their hinterland and yet load growth in energy networks is inevitable as more services, notably transport, are decarbonised through electrification and building density increases through re-development of with taller buildings. The traditional response to this, adding more plant and equipment, is recognised as being an inefficient. An interesting trend is the emergence of Local Energy Systems (LES) and Multi-Energy Micro-Grids (MEMG). LES and MEMG are a means for raising self-consumption of local energy resources; tapping into sources of flexibility in how the services derived from energy; using local services for both local and national control and moving to a smart ways of ensuring resilience. The recent power outage in the UK (9/8/19) highlighted that transport systems and other urban infrastructure are particularly vulnerable. A re-imagining of how resilience is provided in the urban setting could hugely reduce that vulnerability.
Despite the differences between the histories and geographies of cities in China and the UK, we find common challenges and a complementary set of research expertise. This project brings together experts in power electronics, optimisation, control and fault-management from UK and China.
Existing energy networks, especially electricity networks, were designed assuming power enters a city from remote power stations and the network inside the city distributes this. This led to a radial set of lines spreading out from substations. This structure is unable to support the formation of flexible microgrids around local generation and storage resources. We propose to re-structure the legacy networks using power electronics devices that give controlled power flows between previously unconnected networks points. This opens up dynamically restructuring the power flow in urban areas to allow greater local self-consumption of energy, for instance moving solar power residential properties to work-place charging of electric vehicles. It also allows islands to be formed in reaction to power cuts that keep essential services running while placing non-essential services on hold.
We also look at hardware and control issues. The hardware for electronic routing of power has been discussed in principle but it is too large and not efficient enough to be used in urban settings. We will work on new forms of modular power converter that raise efficiency, reduce physical volume and provide resilience to component failures.
Control systems for energy networks are centralised: they gather data from across large areas, make decisions and then issue commands. The microgrid concept changes this to a decentralised approach. A key benefit of decentralisation is the ready access to information about flexibility in energy consumption, e.g which electrical vehicles could delay charging or might supply power to aid with a power cut. Local control also gives opportunities to run the heat/cooling of buildings, the transport energy system and the electricity system as an integrated whole. This can lead better integration of renewable energy and therefore deep decarbonisation but requires a major step forward in managing uncertainty over the local energy resources and demands. We will bring the techniques of stochastic optimisation and machine learning to bear on this problem and devise a control and operations framework for smart urban energy systems.

Planned Impact

Academic impact: The academic sectors that will benefit from the methodological approaches developed in this project include: power electronics - by creating circuit techniques that break the design trade-offs that have previously limited progress on footprint and losses and incorporating resilience models into converter evaluation; operation of Multi-energy system in cities - by addressing the optimal coordination mechanisms among alternative energy resources to enhance urban resilience; energy system control - by developing a joint-forecasting-aided decentralised MPC algorithm for urban energy system under limited communication resource; and fault management - by characterising fault current and converter impedances and developing signal processing and machine learning method to analyse travelling waves in uncertain networks
We plan to disseminate learning through a number of impact routes. First, results will be published in leading international journals and conferences. Secondly, project partners will disseminate results through personal networks, including the Energy Futures Lab, the Universities High Voltage Engineering Network and the FLEXIS network. Thirdly, by sharing findings through the Energy System Integration Group (www.esig.energy).

Economic impact: Energy is the lifeblood to these urban economies and essential to continued prosperity. By developing new technologies and methods to enable maximum flexibility and resilience on existing network infrastructure, expensive network reinforcements can be avoided and solutions which provide the best possible value to bill-payers and taxpayers can be achieved. These ideas will then be presented as policy evidence directly to Energy Networks Association (ENA), National Infrastructure Commission and others. We will also publish in the Policy Briefing Papers and Technical White Papers of Energy Futures Lab to bring evidence to the wider policy community. Prof Strbac has a strong track-record of creating impact from such techno-economic evidence through adoption in industry standards and regulatory policy. We will build on this experience.
We expect to make policy contributions on the economic benefits decentralised energy networks with advanced real-time control such as peer-to-peer (P2P) trading, vehicle to grid (V2G) systems and coordinated operation of multi-energy vectors. We believe these technologies could lead to lower bills for customers and a benefit to economic activity in the UK through new business creation.
We will work closely with project partners (covering network operators, control system vendors and energy market innovators) to maximise opportunities for field trials and demonstration projects.
The UK's leading position in decarbonisation of energy gives and opportunity for UK companies to demonstrate new technologies in their home market and then create export sales of products and consultancy services.

Societal impact: A re-imagined provision of energy services to urban communities is a major research outcome of this project that has broader societal benefits beyond the economic. By encouraging self-consumption of local renewable and recovered energy, through perhaps community energy groups, a dialogue can be promoted in communities on how the transition to a zero-carbon energy system can be turned to the advantage of the community. There are also benefits in local air-quality. We will engage Community Energy South to help understand the nature of this opportunity. We will also target dissemination across FLEXIS partners such as local authorities and the Welsh Assembly.

Publications

10 25 50
 
Description This proposal addressed four top-level questions and key findings are listed for each.
(1) How can the barriers of density, reliability and cost can be overcome so that network equipment based on power electronics can deliver its potential operational flexibility?
Investigations were performed on modular power converters to improve reliability. Balancing of voltage between modules is complex task requiring feedback of many sensor signals to a central unit. A form of circulant modulation was developed that provides inherent balancing of voltages. Proofs were created for both steady-state and dynamic conditions with necessary conditions identified. Thus, sensor failure can be tolerated and reasonable performance maintained or, further, it may be possible to remove sensors certain sensors (many of the voltage sensors in this case).

(2) What operational strategies can be created to exploit and enhance the flexibility and cost-effectiveness of multi-energy microgrids?
Operational strategies were developed to enhance the resilience of supply by making use of local backup generation, district heating system infrastructure, energy storage (thermal and electrical), smart appliances and vehicle-to-grid services by electric busses, taxies, fleet vehicles and private vehicles. Evidence was developed that coordinated control of multi-energy system can radically enhance resilience of supply through appropriate energy exchange across different energy sectors. A decentralised framework for resilience-oriented coordination of networked micro-grids, based on the reinforcement learning concept, has been developed that is more computationally efficient than standard analysis. Furthermore, models for long-term planning of urban multi-energy systems have been developed that focus on resilience. The models demonstrate that resilience can be enhanced at low costs through the application of advanced control of future multi-energy microgrids.
The team also proposed a rapid safety assessment and weak link identification method based on an energy hub model for urban energy systems. Based on this, Tsinghua team created a system planning method for urban energy that is resilience-oriented and considers flexible resources from the supply, network and demand sides to determine the optimal topology of urban energy systems.
For one particular resource, the energy storage in communication base stations, a resource assessment tool was created and used as the basis for incorporating the dispatchable capacity of this energy storage into the day-ahead optimization dispatch of the power system.

(3) Can the scalability and uncertainty barriers to optimised use of local resources be overcome through decentralisation and real-time stochastic control?
One strand of investigation, the avoidance of interactions between controllers of inverter-based resources, took on increased significance during the project. A series of papers were published showing that it is possible to represent all aspect of an inverters control system in an impedance spectrum form. This is a type of connection-port transfer function and thus allow vendors to make limited disclosure of their dynamic properties. They important next step was to show that the residues in a pole-residue form of the transfer function reveal the dependence of the damping of oscillatory modes on the scale of the impedance. This opens up a method of tracing root-cause of poor damping in networks with many inverters.

A second strand investigated the possibility of hybridizing centralised and decentralised control strategies for networked microgrids. Such a hybridization can leverage both the optimality of a centralised control strategy under normal operation and the resilience of decentralised control strategy under extreme events. The key outcomes of this investigation are 1) proven feasibility of such hybridization through computer simulation and hardware-in-the-loop simulation, 2) identification of the criticality of co-design of the pre-event centralised control, the transition process and the post-event decentralised control, 3) illustration of the potential role of data-driven approaches to further enhance such control.


(4) How can fault-management principles evolve to ensure resilience is maintained or improved against a background of new equipment with different fault characteristics?

Key findings here are that the limited fault current of inverter-based resources present difficulties in conventional protection techniques when fault currents from two ends of a line are different in magnitude but especially different in phase. A variety of approaches to raising fault current were investigated at device-level (using phase-change material to limit temperature rise), circuit-level (changing configuration of modular converters) and system-level (tap-changing interface transformers) but with none seen to be complete solutions.
Exploitation Route The findings on impedance spectrum methods for root-cause analysis of insufficient damping in power system oscillations is being progress further in collaboration with National Grid Electricity System Operator
Sectors Energy

 
Description The work on using impedance spectrum representations of grid system dynamics has been progressed to a higher technology readiness level in collaboration with National Grid Electricity System Operator. NG ESO used funding via OFGEM's Network Innovation Allowance scheme to support the further work at Imperial College London. An improved method of assessing the strength of a grid (in terms of its ability to resist or damp oscillatory behaviour) has been validated. In a second strand a method of measuring impedance spectra during normal live operation of the grid has been identified. It avoids the use of specialised equipment to perform frequency scanning and instead uses steps in load impedance achieved by equipment switching. The work in collaboration with NG ESO is ongoing and steps toward deployment will be taken. Deploying these methods would lead to avoidance of costly constraint payments to generators by better identifying causes of oscillations and reduction in constraints to avoid them. The work on resilience of microgrids has been taken forward in collaboration with National Grid Electricity Transmission (NGET) in a project from the Strategic Innovation Fund known as "Wellness". The project is developing a new standardised approach to embed resilience into whole energy network decision making. This will include assessment of the role and value of smart micro-grids in supporting cost-effective enhancement of resilience of supply. Researchers from Imperial joined those from our partners in Tsinghua University to present our joint research on micro-grid resilience and network planning State Grid Corporation of China. Our partners in China, in particular Tsinghua University, applied their urban energy system simulation software to the energy flow planning and dispatch operation in various regions, including the Beijing Tongzhou Municipal Administrative Centre and Taiyuan Science and Technology Innovation City. Evidence has been provide to China's National Development and Reform Commission on the topic of "Implementation Opinions on Strengthening the Integration and Interaction between New Energy Vehicles and the Power Grid".
First Year Of Impact 2023
Sector Energy
Impact Types Economic

 
Description OFGEM RII0-2 Challenge Group
Geographic Reach National 
Policy Influence Type Membership of a guideline committee
Impact Ofgem established the RIIO-2 Challenge Group with the objective to provide challenge to the energy network companies on their Business Plans for RIIO-2 and to Ofgem on their framework for RIIO-2, on behalf of existing and future consumers. Independent report was delivered to OFGEM.
URL https://www.ofgem.gov.uk/system/files/docs/2020/01/riio-2_challenge_group_independent_report_for_ofg...
 
Description Prof Goran Strbac appointed as Lead Author in the Intergovernmental Panel on Climate Change Working Group III
Geographic Reach Multiple continents/international 
Policy Influence Type Membership of a guideline committee
Impact This will provide evidence to all governments related to the climate change mitigation, assessing methods for reducing greenhouse gas emissions, and removing greenhouse gases from the atmosphere. It is expected that work will be the core for the development of national and International policy frameworks to ensure cost effective reduction of carbon emissions at the global level.
 
Description Prof Goran Strbac appointed as a member of SAPEA - "Science Advice for Policy by European Academies" Working Group member of "A systemic approach to the energy transition in Europe"
Geographic Reach Europe 
Policy Influence Type Membership of a guideline committee
Impact Informing the EU about many possible pathways towards a carbon-neutral future - it is demonstrated that it can be achieved by 2050, but this requires urgent action. This is the central conclusion of SAPEA's evidence review report on the energy transition, and the corresponding Scientific Opinion of the European Commission's Group of Chief Scientific Advisors.
 
Description Professor Goran Strbac appointed as a member of the Joint EU Programme on Energy Systems Integration of the European Energy Research Alliance
Geographic Reach Europe 
Policy Influence Type Membership of a guideline committee
Impact The Joint Programme in Energy Systems Integration seeks to bring together research strengths across Europe to optimise EU energy system, in particular by benefiting from the synergies between heating, cooling, electricity, renewable energy and fuel pathways at all scales. The energy elements of the water and transport system are also included, as well as the data and control network that enables the optimisation. The Joint Programme in Energy Systems Integration is designed to develop the technical and economic framework that governments and industries will need to build the future efficient and sustainable European energy system. It is fully aligned with the recently published SET Plan Integrated Roadmap and potential impact include increased reliability and performance, minimisation of cost and environmental impacts and, in particular, increased penetration of renewable energy sources. This is informing the EU about the development of future energy research projects.
 
Description Professor Goran Strbac appointed as a member of the Open Networks Challenge Group of Energy Networks Association
Geographic Reach National 
Policy Influence Type Membership of a guideline committee
Impact Given the objectives of Ofgem and Department for Business, Energy and Industrial Strategy (BEIS), the Challenge Group provides challenge on policy and regulatory progresses to ensure that the programme remains ambitious in delivery and implementation of key proposals related to development of framework for flexibility. The Challenge Group is giving stakeholders an increased role in challenging and shaping flexibility proposals and ensuring that the programme is sufficiently ambitious in its scope and is delivering change at pace.
 
Description Data-Driven Online Monitoring and Early Warning For GB System Stability
Amount £360,000 (GBP)
Organisation Ofgem Office of Gas and Electricity Markets 
Sector Public
Country United Kingdom
Start 03/2023 
End 12/2024
 
Description Strength to Connect
Amount £282,000 (GBP)
Organisation Ofgem Office of Gas and Electricity Markets 
Sector Public
Country United Kingdom
Start 07/2022 
End 02/2024
 
Title SimplexPowerSystem 
Description A set of tools and models configured to run in Matlab has been created and made available in open-source form on GitHub. The tools allows basic data about an electrical power gird to be assembled in Excel spreadsheet form and converter into a SimScape model suitable for running time-domain simulations and a matching small-signal state-space model available for stability analysis using standard Matlab tools. Underpinning this area set of standard models for grid-forming and grid-following inverters and synchronous generators. Models and tool were created to allow rapid verification of new techniques for participation analysis but are more widely useful than that so are being made available to the research community. They will be expanded by adding further equipment types as our work continues. Alongside the tolls are documentation and example grids that can be used in tutorial fashion. 
Type Of Material Computer model/algorithm 
Year Produced 2020 
Provided To Others? Yes  
Impact No impacts at this early stage 
URL https://github.com/Future-Power-Networks/Power-System-Analysis-Toolbox
 
Description Flexible Energy Systems (FLEXIS) 
Organisation Government of Wales
Department Welsh European Funding Office
Country United Kingdom 
Sector Public 
PI Contribution The research is focused on looking at low carbon electrical networks to include characterisation studies, modelling and interaction with other research teams from 3 Universities. The FLEXIS project is a large, multidisciplinary consortium in Wales.
Collaborator Contribution Collaboration with other Universities is a key part of this project. This allows a full understanding of multi-vector, whole system, as well as societal aspects of energy networks. In addition, close links with a large consortium of industry partners and government bodies supports the steering of the research towards the benefit of society and the country.
Impact Michail papers Amine's papers Chinese papers
Start Year 2021
 
Description National Grid Strategic Framework Agreement 
Organisation National Grid UK
Country United Kingdom 
Sector Private 
PI Contribution This project was facilitated through the National Grid framework agreement between National Grid and Cardiff University. The main objectives are to examine system safety based on a new proposal for a second earth wire. The project will conduct extensive modelling and field testing.
Collaborator Contribution National Grid have contributed system date, insights into system operation and insights into practical aspects of communication.
Impact Initial stages of the research (£98k funded project).
Start Year 2021
 
Description A talk in Global ICT Energy Efficiency Summit 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Industry/Business
Results and Impact Gave a keynote speech on ICT clean energy solution through cloud-edge VPP.
Year(s) Of Engagement Activity 2023
 
Description EERA (European Energy Research Alliance) ESI (Energy System Integration) workshop - presentation focused on Resilience of Multi-energy Micro-Grids (September 2022) 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact The focus of the presentation was on the role of corrective and preventive control including investment in mulct-energy infrastructure, which can reduce the load shedding caused by power interruption in HILP events, to make the investment choice fully economical, while enhancing resilience of supply in urban areas. This is now getting on the agenda in EERA ESI and is informing EU policy.
Year(s) Of Engagement Activity 2022
 
Description Industry webinar "CYBER SECURE Grids of the Future: 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact 24% of all cybersecurity incidents in the UK in 2021 targeted the energy sector, making it the most attacked industry and 56% of utilities report at least one attack involving a loss of private information or an outage in the OT environment in the past 12 months. The threat is changing, listen to our experts as they discuss how to keep networks secure.

Join us throughout this series as we dive deeper into how digital technologies are going to shape our Grids of the Future!

Up next, CYBER SECURE Grids of the Future. Hear from our panel of;
Host: Ben Gray, Schneider Electric - Marketing Manager Power & Grid UK&I
Luc Manfredi - Director Cyber Security, PWC
Dr Fei Teng - Director of Education at Energy Futures Lab and Lecturer at Imperial Collage London
Year(s) Of Engagement Activity 2022
URL https://community.se.com/t5/Power-Events-Webinars/CYBER-SECURE-Grids-of-the-Future/ba-p/402683
 
Description Panel Presentation at ESIG Spring Workshop 2021 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Two-hour on-line panel discussing the cases for using grid-forming inverters in future inverter dominated electricity grids. Panel comprised 3 system operators, 2 equipment manufacturers, 1 engineering consultant and Prof Tim Green as an academic researcher
Panel was an open session of the ESIG (energy Systems Integration Group, https://www.esig.energy) Spring Workshop with 330 attendees from Australia, Europe and North America, mostly drawn from industry (system operators, equipment manufacturers and consulting engineers).
Recording available via ESIG YouTube channel at https://www.youtube.com/watch?v=BXHxtUWwy7I
Year(s) Of Engagement Activity 2021
URL https://www.youtube.com/watch?v=BXHxtUWwy7I