# A Review of Systems and Technologies for Smart Homes and Smart Grids
## 6 Discussion
### Challenges, Benefits, and Motivations Related to the Users  
Due to the direct involvement of end-users in the energy management of the power grid, the issue of load level has gained increasing interest in the last few years also considering that the unpredictable human factors can have significant influences on DR system's performance and the energy management of homes. A study conducted in Denmark investigated the heat usage in 290 identical homes. It was found that the highest heat consumption was up to twenty times higher than the lowest due to the occupant's behavior [114]. Users' habits play a key role related to energy use [115; 116]. Other studies [34; 111; 117] pointed out that users can efficiently operate in a real-time frame to optimally control all major residential energy loads, storage and production components while properly considering the customers' preferences and comfort level. The main objective functions for the operation of each household appliance are electricity payment minimization [22]. Therefore, users are becoming aware that they can manage energy resources and have an active role in the operation of the energy system by using the following strategies related to smart grids via their smart home technologies:  
1. Rationalizing the amount of energy required from controllable loads: smart grids enable providers to better control and plan production and to adjust the price levels of electricity. Previous studies have systematized approaches to home energy management, which may belong to one or any mix of the following three categories: (i) a technology-oriented approach; (ii) an economically-oriented approach or (iii) an environmentally-oriented approach.  
2. Wisely scheduling running times for smart appliances that are likely to be shifted in time. Households' involvement in cutting their overall energy demand and the evening peaks in energy usage is still being explored. Currently, a lot of interest is being directed to making homes more flexible energy users. This flexibility aims to modify households' load shape thanks to feedback on real-time energy usage and an indication from them of which tariff information they found useful in relation to optimizing their energy costs.
3. Turning themselves into potential carbon-free generators of energy, through the use of renewable resources: so far, the focus of smart grid technologies has been on integrating RES into the grid to reduce the cost of power generation. Integrating these resources requires storage systems. Load/generation shifting can be used by customers, utility providers, or renewable power producers to take advantage of the different electricity rates available at various times of the day [113].  
Although the potential benefits of an active management of homes' energy use are significant, households as energy users are still subject to several concerns that could inhibit a rapid adoption of smart home technologies. The most significant concern is that, in order to maximize the benefits of smart grids, utility providers' and suppliers' of energy management solutions must adapt existing technological infrastructures to new bidirectional and dynamic loads. Therefore, the capabilities and the advantages of these systems are currently not fully deployed. This is one reason why widespread adoption of smart technologies in homes has been hindered [118]. Several experiments conducted on users' behavior have demonstrated that energy management systems for residential applications allow energy costs to be reduced by about 18%, while preserving the user comfort [22].