DESCRIPTION OF EDISON
The EDISON project has utilised Danish and international competences to develop optimal system solutions for EV system integration, including network issues, market solutions, and optimal interaction between different energy technologies. Furthermore, the Bornholm electric power system has provided an optimal platform for demonstration of the developed solutions. The project has been organized in seven work packages and an additional work package for administration and dissemination activities.
The main goals for the project were:
- To develop system solutions and technologies for Electric vehicles (EVs) and Plug-in hybrid vehicles (PHEVs) which enable a sustainable, economic and reliable energy system where the properties of EVs are utilised in a power system with substantial fluctuating renewable energy.
- To prepare and provide a technical platform for Danish demonstrations of EVs with emphasis on the power system integration aspects.
- To develop standard system solutions for EVs, which are applicable globally, by utilising the Danish leading knowledge within distributed energy resources and operation of energy systems with high wind power penetration, and thereby, release the potential for Danish export of technology, system solutions, and knowledge.
The EDISON project was built on the Danish Energy strategy implying approximately 50 % wind power in the Danish power system by 2025; during the project (March 2012) the political goal changed to 50 % in 2020. The EVs were foreseen to act as buffers for the fluctuating wind power production with what we called “intelligent charging”. In 2008 this was a relatively ground-breaking concept, and it caused a lot of international interest in the project. The first meetings with EV manufacturers early in the project period showed that they were reluctant to involve their products in market set ups where EV batteries would be used for power system services. Their concerns were user acceptance and uncertainties about battery wear. The general view was that electricity is a commodity that always is available when connecting an appliance to the grid.
The consortium developed a three-level conceptual EV system architecture, and five EV charging scenarios have been suggested which are listed below.
- Charging whenever needed (dumb charging)
- Charging with local control (timer based or price signal based charging)
- Charging with aggregated control (EVPP as a balance responsible party)
- Charging with aggregated control (EVPP under a balance responsible party)
- Advanced scenario (coexistence of decentralized and aggregated control concepts )
By introducing a fleet operator to aggregate the consumption of a number of EVs and handle their interaction with the electricity market as one unit with a centralized/direct control, gives the EVs an opportunity to participate in the marked for regulation power. This is the major concept in the EDISON project. However, the electricity market study mainly focuses on power markets, prices and price signals, and how EVs can be an integrated part of the power market independent of the contract structure of the EVs (i.e. single market player or handled together through direct control, be a fleet operator etc.).
To demonstrate the possibility for EVs to participate in both power market and the market for regulating power an Edison EV Virtual Power Plant (EVPP) was develop. EVPP is the resulting server-side management system containing analytics technology and featuring standards based interfaces to DERs and grid stakeholders. The EVVP were tested successful during the project, where EVPPs take on the role of Fleet Operators (FO) for individual EVs (in Zurich, Copenhagen, Bornholm) and support also larger simulated fleets driving on Bornholm, in real-time coordinating their charging in private homes, company parking lots, and at charging stations.
To insure that the EVPP got the necessary information from the individual EVs during connection to the grid and during the charging, the EDISON project developed a reference model for a public charging spot which has been used during COP15 for concept development.
The public charging spot has also served as a reference platform for interoperability test with Better place, for demonstration at the public workshop at RISØ, and for the demonstration on Bornholm.
After the end of the project, the EDISON charging spot is used as a reference platform in the establishment of the future 'Nordic Electric Vehicle Interoperability Centre – NEVIC ' at DTU RISØ.
Besides the development of “Intelligent charging” a lot of effort was put in to gain more knowledge of battery technology and especially about how different charging schemes could influence on battery lifetime. Since this was seen as one of the major obstacles to introduce intelligent charging, in case it has a negative influence on the battery lifetime.
Both a mathematical model was developed and a lot of laboratory test on batteries were performed at SYSLAB. The physical test was to test different charging algorithms and, in addition, to test the influence on high power charging (e.g. fast charging) on battery lifetime. Test showed good results, and with the right knowledge on batteries different charging schemes concluded that intelligent charging schemes can be performed without any negative influence on the battery lifetime. Laboratory tests also showed that batteries with the Battery management system, BMS, are very complex components, which should be handled with great care. So the need for battery knowledge should not be underestimated in the future development of EVs and intelligent charging schemes.