In the framework of different projects (in particular C2G, PEEM and Smart Web Grid), the role of residential customers and their integration (SGMS project) into the electric power system was examined. These projects focused on feedback on patterns of electricity use and on recommendations for ways to shift electricity use to times that are favorable for the system as a whole. The following findings and theses were derived from the projects.
In the C2G project, different methods for providing feedback on electricity use were examined. Among these were the so called Wattson  monthly electricity bill, home displays and a web portal  (see Figure 1) and a control group with a yearly bill. In a year-long field trial, no significant differences in the reduction of electricity consumption could be discovered between the different feedback methods.
Figure 1: Three of the five energy-use feedback methods examined a) C2G home display, b) C2G web portal, c) Wattson
Compared with the previous year, the average reduction in electricity consumption across all groups in the trial (including the control group with a standard yearly bill) was 6.7%, with a minimum value of 2.5% and a maximum value of 10.9%. Due to the high level of variance, these energy savings are however not sufficiently separable from each other statistically. Between the different feedback methods, there were no significant differences in electricity consumption. A comparable reference group with 68 households that did not take part in the trial and was therefore not at all influenced by any of the measures in the trial, showed a reduction in consumption during the time of the trial of 2.7% in comparison to the previous year . The test subjects nonetheless frequently reported experiencing an increase in the level of awareness about the subject of household electricity use and found energy-use feedback to contain valuable information. At the beginning, test subjects question their own behavior, which leads them to change their patterns of consumption. Even related subject areas such as sustainable mobility, which wasn’t a direct target of the feedback, were reflected on by the trial participants. Over the course of time, however, the intensive concentration on the information in the feedback decreases. This is in large part due to the fact that after the introductory phase, residential customers experience very little increase in knowledge and cost savings, for example, which would increase the value of what they were doing. In order to maintain the attention level of customers, it would seem beneficial to provide immediate real-time feedback for individual consumers. On the whole, detailed information on consumption (down to the level of household appliances) is of great significance to consumers.
In general, it can be said that electricity-use feedback was studied in detail by the test subjects at the beginning, but over the long term in a stable environment such as one's home it was only used sporadically to check individual levels. Between the different feedback methods, there were no significant differences in electricity consumption. Electricity-use feedback methods should therefore accompany users through different phases of their use. Customers are also only ready to pay for feedback if the cost does not exceed the savings.
A comparison of the effectiveness of the five feedback methods produced two clusters. The first cluster comprises state-of-the-art methods which are easy to implement, carry little information and few functions, and spring into action when triggered. In the C2G project monthly bills were used, which were extremely easy to implement. A further study could examine whether a monthly bill is necessary (similar to a monthly telephone bill) or whether monthly information on electricity consumption is sufficient.
The other cluster encompasses innovative methods which are much more difficult to implement but also have a higher level of functionality and make more information available to the consumer.
Based on the quantitative results of the C2G project, there are two different strategies for designing energy-use feedback methods:
- Easy implementation combined with minimal implementation cost for the method that is adapted to the savings potential.
- Use synergies derived from more innovated methods that balance out the advantages and disadvantages of the individual methods (such as constantly available home display with simple real-time feedback + monthly information on electricity consumption) and meet the newest technological standards.
It can be concluded that the constant presence of feedback methods (in the form of hardware, for example, as is the case with home displays) serves as a reminder to use the feedback, making this method advantageous. In addition to this constant availability, regular (monthly) information pushed to users is important so that the user doesn’t have to request this information him/herself. This reduces any extra effort required to access electricity-use feedback from a cognitive standpoint (no need to remember) but also from a logistics standpoint (no need to turn on the computer).
Furthermore, it is important to offer residential customers additional functionality besides electricity-use feedback in order to maintain their interest over the long term. This could be in the form of prognoses or concrete recommendations for steps to take, as was the case with FORE-Watch in the PEEM project.
Electricity consumption at different times
In the PEEM project, the electricity-use feedback method FORE  -Watch (see Figure 2) was developed. In addition to simple feedback on electricity consumption, it uses colors to inform users when the "good" (green), "average" (yellow) and "bad" (red) times for the power system are to use electricity. This technology helps to provide residential customers with the support they need to change their behavior and their attitude toward a more sustainable use of electricity.
FORE-Watch was seen by trial participants as a good means of reaching the goal of changing their electricity-use behavior. An analysis showed only a loose connection between consumer behaviour and FORE-Watch recommendations. This is however not statistically significant . Trial participants adjust some of their electricity consumption based on recommendations about times. The time of use especially for washing machines, dryers and dish washers were shifted. Barriers for residential customers to change their patterns of consumption, however, are convenience and old habits. In order to overcome the feeling of a loss of convenience, consumers have to experience a clear benefit or advantage.
The expected benefit stated by a majority of trial participants was a monetary one. Trial participants said they would adjust their behavior to the clock if it enabled them to save money.
A possible approach to achieve this adjustment in patterns of use would be to offer a pricing /tariff  models based on time-of-use. Still, the introduction of variable pricing according to time would probably mean little saving for residential customers.
Figure 2: Newly developed feedback method: FORE-Watch
Aside from the financial factor, altruistic motives also play a considerable role. For several participants, the fact that they were making a contribution to saving the environment and therefore contributing something positive to the good of society was enough of an incentive for them to adjust their consumption to the FORE-Watch recommendations. This factor is even more important to residential customers who are also producers, since FORE-Watch allows them to adjust their consumption to their generation.
The effort required of consumers should be kept as little as possible, for example by automated cycling on and off of household controllable appliances according to the times recommended by FORE-Watch. The user should, however, always be able to intervene in all of the relevant processes.
Combination with other services
Due to the findings from the C2G and PEEM projects, focusing solely on providing feedback on electricity use is only of marginal interest to residential customers. It seems therefore necessary to combine information and services from additional sources. It would be worthwhile to integrate feedback on heating, gas and water use, since they are often a greater source of cost to consumers than electricity.
Furthermore, it would be useful to develop new services like monitoring conditions within the home (Has everything been turned off?), alert functions (information on what to do when something goes wrong) as well as services that are independent of energy efficiency (security, ambient assisted living ).
Figure 3: A design for a modified FORE-Watch with additional services
Based on results from C2G and PEEM, the HiT project will use interaction technology to combine electricity-use feedback with other services. The FORE Watch from the PEEM project is shown in modified form on the start screen of a tablet computer. Figure 3 shows how this might look. In addition to recommendations for basing electricity use on the time of day, clicking the My Home [Meine Zuhause] button calls up the home automation web application. This web app makes it possible for people with flats or houses which are suitably equipped to access data about the technology in the building and to change the settings. The My Energy [Meine Energie] button provides user access to the energy-use web portal, which shows electricity, heating and water use. With the Car Sharing button, users can reserve an electric vehicle.
This combination of approaches, solutions and demands from the smart grid with those from home automation offers numerous advantages. It allows the following aspects and needs to be covered:
- Relevant tasks such as the load balancing, optimization of one's own energy use, etc. can be automated instead of requiring the constant attention of the user, with no loss of comfort.
- Additional services (like alert functions) that offer further benefits to residential customers can be developed using the available data and sources.
- The integration of home automation has additional potential to offer secure solutions at the local level, therefore keeping the control over data "nearer" to the user.
- Cost synergies may also be created since the investment will be spread out over different parts of the system and are therefore easier to make.
- Automation also makes it easier for customers to make permanent changes in their households.
Whether the additional advantages of integrating home automation will lead to prolonged interest in energy-use feedback methods on the part of residential customers and therefore to improved energy efficiency is a question further research will have to answer.
Privacy & acceptance
It became apparent that consumers are wary of the gathering, storage and transmission of detailed energy data (i.e. extremely exact with regard to usage times). For this reason, it is absolutely necessary that customers have the possibility to have control and to intervene in order to willingly participate in demand response programs, for example.
Furthermore, regarding data privacy concerns, mechanisms to protect privacy must be taken into account in designing a smart-grid information and communication technology from the very beginning. In general, the benefit for consumers derived from providing their data must be clearly visible; otherwise, they will have difficulty accepting this technology.
Centralized vs. decentralized data transfer
C2G field trials used real-time feedback methods with decentralized data transfer (Wattson) and with centralized transfer (home display), which collected data from a smart metering system, processed it and sent it back to the display using the internet. The initial investment in the centralized version was disproportionately high in comparison to the low energy savings potential. The decentralized version on the other hand was much more economical to implement and, because data is processed onsite, also operates in accordance with the data minimization principle of the Data Protection Act of Austria (DSG). Moreover, the decentralized version delivered energy-use feedback in real time, while the centralized version (i.e. the home display method) provided feedback almost in real time with a delay of 2-3 minutes. Since real-time information is used by residential customers to monitor the energy use of household devices, a longer delay doesn’t deliver the desired benefit.
In addition, the data minimizing approach of the decentralized version fulfils the regulations set out in the Data Protection Act because only the data used in billing
or to provide legally mandated information (depending on the model, a load profile or daily usage statistics, for example) are transferred to the grid operator. The real-time data remains in the household, is processed there and transmitted to the consumer in the form of feedback. Wattson uses independent current-transformer measurements instead of a smart meter. In the future it would make sense to make use of smart meters with the decentralized version too, by transferring real-time measurements using a unidirectional communication interface, which is also provided for in the 2011 law outlining requirements for intelligent meters [IMA-Verordnung] , directly to the display or another local gateway.