Steps toward Smart Energy Self-Sufficient Buildings
By Claude Ziad El-Bayeh, Khaled Alzaareer
Nowadays, energy demand is increasing rapidly worldwide due to the unprecedented comfortable lifestyle that people are becoming familiar with. The newly introduced heavy electrical loads such as electric vehicles and battery storage systems require much energy. The main problem is that they can introduce peak demands in certain periods, which would affect the stability of the grid. To solve this problem, renewable energy sources such as PV, wind turbines, concentrated solar power technologies are promoted. To install such systems, large land use is needed, while fewer land requirements are needed to install traditional coal or fuel-based thermal power plants. Some challenges can complicate the installation of renewable energy technologies, such as the high price of a land and lack of land area to install such systems. Therefore, a viable solution is to use the rooftop to install PV systems, wind turbines, and other renewable energy technologies to generate electricity and energy (heating/cooling). The available surface on a building including rooftop and facades may not be sufficient to generate electricity that supplies the whole energy demand of a building. The main question is how to create sustainable and self-sufficient buildings using only the existing and available surface of the building? This article attempts to answer this question with a few steps and recommendations to follow.
1. Problem Statement
In the last decades, there were many attempts to go a further step toward sustainable cities and to shift from traditional fossil-based to renewable-based power plants. After recent natural disasters, such as wildfires in Australia and Amazon caused by climate change, it has been realized that more efforts are needed to shift to a greener and sustainable community with less impact on nature and the environment. One of the solutions is to integrate renewable energy technologies into buildings. This allows a local energy production, which may supply part of the energy demand of the building. Many limitations are using renewable energy technologies for buildings, such as their low efficiency, the large surface is needed to install the system, and high storage cost. Therefore, it becomes challenging to supply the total load demand in the building relying on just renewable energy systems. Another direction in the research community is to schedule and manage energy demand in buildings and homes using sophisticated optimization algorithms and models. This allows the householders to minimize their electricity bill. A third solution is to work on the net-zero energy building in which the total bought and sold energy to the grid is equal to zero at the end of a certain period. This requires the installation of renewable energy sources and while reducing energy consumption. The limitation of this method is that it is always dependent on the grid. However, in rare extreme conditions, when the electric network faces blackout, the net-zero energy building may have a high-power demand in that period which cannot be supplied by the renewable energy system. Hence, it is necessary to work on a more sophisticated building that can be self-sufficient in terms of energy without the need to buy energy from the grid. To do so, this article combines the three previously mentioned solutions to increase its energy independence.
2. Definition of Energy Self-Sufficient Building
Energy Self-Sufficient is the ratio between energy generation and consumption during a certain period. A ratio equal to one means that the generated energy is equal to the consumed energy for a period of time. A ratio lower than one means that the generated energy is not sufficient to supply the total energy demand of the building during this period. Hence, additional energy is required to be supplied by external sources, such as the distribution grid. A ratio higher than one means that the building is generating energy more than its demand. Hence, the additional generated energy is either sold to the power grid or stored in energy storage systems, such as batteries or phase-change materials, etc.
3. Steps toward a self-sufficient building
Two main goals should be attained to maximize the energy self-sufficient building ratio.
- Minimize the energy demand in a building by:
- Using highly efficient electrical appliances, which may reduce energy use by about 20-30%
- Using motion and occupancy sensors, which can detect the movement of the residents and act accordingly by turning on/off some appliances. Thus, it saves about 20-40% of energy
- Applying smart building/home energy management systems and optimization algorithms, which control and schedule the power consumption of electrical appliances and equipment. This may reduce energy waste and increase the efficiency of the building.
- Maximize energy production from renewable sources by:
- Using rooftop, facades, and windows to install solar and other renewable energy technologies. These technologies can be PV, wind turbines, or concentrated solar power technologies.
- Using energy storage systems, such as batteries, phase-change materials, or solar water heater.
- Using highly efficient renewable energy technologies which may increase the local energy production by using the same surface
- Using optimization algorithms to choose the best renewable energy technology and model for a specific building in a way to minimize the investment cost, payback period and maximize energy production.
By minimizing energy consumption and maximizing energy production, a building becomes more independent and energy self-sufficient. Hence, there is no or little need for extra energy from other external sources.
4. Tools and Equipment to be Considered
To minimize the energy consumption in buildings following tools can be used: motion sensors, current and voltage sensors, smart meters, highly energy-efficient appliances, such as LED bulbs instead of fluorescent and incandescent bulbs, star energy appliances (save about 30% of energy use), Microcontrollers (ESP32, Raspberry PI, DSP), internet, Additionally, energy storage systems can be installed, such as batteries and phase-change materials. Besides the hardware, a software is also needed to program the energy management system. In this case, optimization algorithms and software tools are used to optimize and schedule the work. Artificial intelligence and machine learning are also used with data acquisition tools to increase the performance of the system.
To maximize energy production in buildings, renewable energy technologies can be installed on the rooftop, facades, and windows. For example, photovoltaics, wind turbines, dish Stirling, solar water heaters can be installed on the rooftop. The photovoltaic film is used for windows. Building-integrated PV and thermal systems are installed on facades. Waste to energy micro plants are installed inside the building.
An Energy self-sufficient building is a promising solution that each building can produce its own energy without the need for an external source. In this way, buildings can be considered as autonomous and self-sufficient units without a need to build or invest in transmission and distribution infrastructures. The only limitations and barriers to attaining such a self-sufficient building are the low efficiency of renewable energy technologies and the high price of batteries. Fortunately, in the future, when the commercialized PV system has a higher efficiency over 40% as in the laboratories, the energy -self-sufficient building concept would become a reality not only for small buildings but also for large buildings.
Khaled Alzaareer received a B.Sc. and M.Sc. degrees in electrical power engineering from Yarmouk University, Jordan, in 2010 and 2012, respectively. He is currently a Ph.D. student in electrical engineering at Quebec University (École de Technologie Supérieure), Montreal, QC, Canada. His research interests are smart grids, Renewable energy Integration, Energy Management, voltage stability, and control.
Claude Ziad El-Bayeh (S’16, M’18) received a B.Sc. degree in electrical and electronic engineering from the Lebanese University Faculty of Engineering II, Lebanon, in 2008. M.Sc. degree in Organizational Management from the University of Quebec in Chicoutimi, Canada, in 2012, a Master of Research degree in Renewable Energy from Saint Joseph University, Beirut, Lebanon, in 2014, and a Ph.D. degree in Electrical Engineering and Renewable Energy from the University of Quebec - Engineering School (École de Technologie Supérieure), Montreal, Canada, in 2019. His research interests include Energy Management, Operations Research, Smart Buildings, Smart Grid, Renewable Energy, Power and Distribution Systems.