In the framework of SGMS, concepts for interaction portals, visualizations and user interfaces for electromobility customers were established (V2G Interfaces project), and the technological and economic effects of grid-to-vehicle and vehicle-to-grid implementation  on the electricity network were evaluated (V2G Strategies and ElectroDrive Model Region projects). These make it possible to better assess future options for the systems-level integration of electromobility in urban and rural regions and to perform field tests (Model Community Köstendorf / DG Demo Net Smart Low Voltage Grid project).
Experiences from the project show that the intelligent integration of electric vehicles into the electricity network is strongly dependent on the individual patterns of mobility for each user, specific vehicle characteristics and the communication infrastructure that is used. V2G Interfaces came to the conclusion that the cost of interfaces, for example, for smartphones or tablet computers, make up around 2 % of the total cost, which includes the vehicle, infrastructure and electricity, from the perspective of residential customers, when these interfaces are purchased by the customers themselves. If the interface is offered by the mobility operator as part of a bonus package, this results in a significant reduction in cash value of up to 30 % of the business model “Monthly Electromobility Subscription”. For this reason, the use of existing devices is to be preferred.
Figure 1: Example of a residential customer interface for electromobility
The interface should be easy to use and should have the following functions:
- Charge now,
- Charge at lower tariff or eco charge,
- Enter departure time,
- Enter distance to travel.
An example of how an interface of the future might look was developed in the Smart Web Grid project and is in use in the Model Community Köstendorf (see Figure 1). In the future, integrating the interface in the vehicle is a possible alternative.
A further result from the Model Regions VLOTTE and ElectroDrive Salzburg is that charging is usually done at home and at work; because of the amount of time the car spends sitting in both of these situations, a charging station between 3.5 kW (single-phase) and a maximum of 10.5 kW (three-phase) is sufficient. Mode 2 (IEC 61851) charging using a household electrical socket is only possible to a limited degree due to a risk of overheating the socket an installation. Mode 3 (IEC 61851) charging using a charging station and a mandatory installation check is therefore recommended. This however contravenes, quite understandably, the preference of residential customers and electromobility service providers  namely to be able to charge cheaply and quickly. An information campaign is therefore necessary to point out that slower charging at low loads meets the mobility needs of customers sufficiently, uses the infrastructure much more efficiently and keeps down charging costs. In the V2G Strategies project, the technological and economic effects of integrating electromobility into the power grid and the electricity market were evaluated. First important result of the project was to identify, outline and define a framework for integrating electromobility into the electric power system from uncontrolled charging and controlled charging to adaptive charging.
The term “uncontrolled charging” refers to the charging of vehicle batteries immediately after reaching a defined location equipped with charging infrastructure. With this type of charging, the charging process begins immediately after the vehicle is plugged in and ends when it has a full charge or is unplugged prematurely.
The strategy of “controlled charging or discharging” is based on scheduled charging or discharging. These schedules help to fulfil individual target functions for controlled charging that is defined by the V2G Strategies project as market oriented, load oriented or generator oriented. Real-time measurements of the condition of the grid or the charging level of the vehicle, for example, cannot be used in scheduling with this strategy but they are implicitly included based on empirical data in the scheduling process and therefore facilitate a significantly more efficient integration into the system than with uncontrolled charging.
Using real-time information  “adaptive charging" offers the possibility to achieve the optimum level of system integration for electromobility using different target functions based on the condition of the system as a whole. The monitoring of this multi-dimensional strategy can, for example, be performed comparing predefined schedules to the condition of the grid or be fully automated using suitable control units. In general, it should be noted that adaptive charging would be based on data collected from users in conformity with the Data Protection Act of Austria.
Based on this definition, the project examined the three strategies in real medium and low voltage networks and conducted economic analyses on market integration. The results of the project quantified that the effects of different charging strategies are greatest in low voltage networks, where there were congestions, necessitating further action at this level of the network.
In general, uncontrolled charging is generally more favorable for grid operation than market-oriented controlled charging since the latter means a large number of vehicles charging at once. Beginning at a density of 40 %  for electromobility, however, uncontrolled charging leads to congestions throughout a low voltage network. Projections indicate that this may be the case starting around 2030. Using suitable measures such as slower charging and symmetrical distribution of charging through three-phase chargers, the widespread use of electromobility can and should however be optimized from the start in order to make the system efficient; otherwise, a huge amount of existing reserves will be consumed. In addition, it must be noted that in parts of the network stretching over many kilometers that have a high utilization and network nodes at the end of long feeders, network congestions could potentially be experienced earlier. Depending on the charging power that is used, this is the case in 7 % (for 3.5 kW) and 35 % (for 10.5 kW) of low voltage lines in Salzburg. These network congestions are made more severe by quite understandable attempts on the part of electromobility service providers to offer market-oriented charging in order to optimize the purchase of electricity. Since so many vehicles are charging at once, this causes congestions to begin appearing at a concentration of 25 % and uses additional reserves from the existing infrastructure that were for future fluctuations in load and generation.
Controlled charging can reduce this consumption of reserves by 15 % for load-oriented controlled charging in a low voltage network with high utilization, but it does not offer an optimal solution for the system as a whole. Hence, controlled charging can reduce the negative effect of consuming reserves over the short term, but this problem can really only be solved through adaptive charging.
A further type of market-oriented controlled charging and discharging strategy would be allowing electric vehicles to participate in the control energy market. Figure 2 shows the number of electric vehicles needed throughout the day to be able to deliver a constant level of 30 MW of tertiary control power. This would require the highest number of electric vehicles between 4 and 8 am. A maximum of 22,500 electric cars would be needed for the “charge and discharge at home” scenario and approximately 17,000 cars for the “charge and discharge at home and at work” scenario. This corresponds to between 6 and 8 % of the total number of cars in the province of Salzburg.
Figure 2: Number of electric cars needed for 30 MW of tertiary control power over the course of 240 minutes; charging and discharging at a maximum of 3.5 kW at home (blue) or at home and at work (red)
Accordingly, the consortium of the V2G Strategies project recommends that in order to efficiently integrate a high concentration of electric vehicles into the electric power system, the needs of residential customers, of vehicles, of the electricity market and of the grid must equally be taken into account, necessitating the development of adaptive charging. Only adaptive charging can achieve the optimum amount of system integration from a technological and economic standpoint. This requires the creation of a suitable infrastructure such as a smart grid to calculate the input parameters for an adaptive charging system that can implement the different pricing strategies on the electricity market and take the restrictions of the grid into account.
At a higher level, adaptive charging supports the key recommendations of the V2G Strategies projects, which can be subsumed as follows:
- In order to be able to use the existing grid as long and as efficiently as possible, slow charging (3.5 kW) is to be preferred. Symmetrical load distribution via three-phase charging should be adopted.
- Purely market-oriented controlled charging with a high number of cars charging at once should be avoided. Market-, load-, and generator-oriented controlled charging should therefore be conducted with fewer cars charging at once in order to be able to apply aspects of the market and to use existing network infrastructure efficiently. In order to make the system as efficient as possible, a scheme for adaptive charging should be developed at the same time. Adaptive charging should be introduced as soon as the necessary functionality in the power grid is present or, as anticipated in the V2G Strategies project, when the level of controlled charging has reached the critical point at which the energy system can no longer adequately handle the integration of electromobility.
- Vehicle-to-grid delivery of electricity is not feasible based on current market conditions and in the cases examined here, since the current costs exceed the achievable benefits by a factor of two.
Also, in the V2G Strategies project, the following open research questions were identified as key to preparations for an adaptive charging scheme:
- It must be established whether the chargeable costs for putting a system for controlled charging in place are less over the long term than the benefits achieved. While the former may contain a share of charging and control infrastructure and higher charging costs for residential customers, the benefits would include additional profit for electromobility service providers, savings in the power grid and fewer backup power plants. In this context, a macroeconomic evaluation should be performed to estimate whether optimizing the system will mean more effort in installing the socket and charging infrastructure or whether the effects of unbalanced charging that have been demonstrated should be overcome by greater investment in expanding the grid. This discussion should be carried out by those responsible for developing standards and not solely based on the individual business considerations of the different stakeholders involved.
- There is a need to clarify how a flexibility operator or aggregator will be constructed in order to efficiently combine the different target functions of individual stakeholders such as electromobility service providers, grid operators, balance group representatives, etc. into a systematic whole. To do this, a data model has to be developed which regulates access to the necessary input values for adaptive charging and the corresponding commands for the charging infrastructure.
The next steps to be taken to efficiently integrate electromobility as a system are therefore:
- In order to implement three-phase charging at low loads, coordinated decision-making between the stakeholders involved (grid operator, vehicle charging station manufacturers, electromobility service providers) should be carried out and the appropriate technical and organizational regulations should be agreed.
When the benefit of adaptive charging exceeds the costs, the charging infrastructure will have to support adaptive charging. The deliberative bodies that will have to define the necessary standards (IEC 151118, for example) are to be informed.
 Grid-to-Vehicle involves the charging of a vehicle based on the requirements of the electricity system (controlled or adaptive charging), Vehicle-to-Grid additionally involves feeding electricity from the vehicle battery back into the grid.
 In this report an electromobility service provider is a business that offers electromobility as a service (in the form of car sharing, for example) so that products and services can be optimized for customers connecting their vehicle to the grid (charging stations incl. installation check, electricity purchasing, etc.).
 This information could be measurements from the grid, changes in the price of electricity on the market and changes in the supply from photovoltaic units, for example.
 In the V2G Strategies project a scenario was chosen in which the widespread adoption of plug-in hybrids and electric vehicles is the consequence of a sharp increase in the oil price, higher taxes on fossil fuels and tax incentives for the purchase of efficient vehicles. Technological learning is taken into account. The grid analysis were based on this ambitious scenario which foresees an electromobility adoption rate of approx. 40 % in 2030 and approx. 100 % including hybrids and range extender for 2050 and integrated these into the low- and medium-voltage networks.