Energy Management Technology for Smart Communities

3.1 Position of office buildings in a smart community

Consumer premises in a smart community must be connected to a network and be active in dispatching information to the outside while being appropriately controlled in accordance with requests from the supply side. Energy management systems such as the home energy management system (HEMS) and building and energy management system (BEMS) can provide the technology needed to meet these requirements. Among consumer premises, it is extremely important that office buildings in particular be controlled owing to the following features that set them apart from homes.

• They are concentrated in urban areas with high individual energy consumption.
• They frequently include power/heat storage facilities and power generation equipment that can act as a buffer in controlling energy supply and demand such as in facility-capacity control.
• They will have a major impact on society if their energy supply runs out.

Despite these features, it has not been very common in the past to connect office buildings to the outside world and to control their energy demands for the following reasons.

• Information obtained from measurements can differ depending on the source, making it difficult for the supply side to identify and manage.
• Energy consumption characteristics can be complicated and nonlinear, making demand forecasting difficult.
• Information networks have had a closed format.

Recently, however, it has become possible to make BEMSs compatible with IP networks and open-system technologies. In this way, BEMSs will be able to contribute to the stabilization and optimization of energy supply and demand in buildings and in smart communities.

3.2 Cloud-based BEMS and automatic demand response (ADR)

The usual practice in the BEMS field was to sell maker-specific systems. As a consequence, the operation of these systems differed from building to building, and the systems themselves tended to be complicated and expensive. The end result was that systems of this type came to be deployed only in buildings of a certain scale or larger. NTT FACILITIES took this into consideration and decided to focus its efforts on providing a low-cost, highly functional building management service that separates the BEMS server function and makes it available for common use. This scheme negates the need for one company to install all system equipment in each building as long as highly reliable network facilities exist. The total service image of this system is shown in Fig. 3.

Fig. 3. Total service image of cloud-based BEMS.

The deployment costs of this system are reduced, and advanced monitoring and control capabilities are provided because in each building, only the minimally required amount of equipment for operating that building (such as switches, detectors, and sensors) is installed, and the functions for monitoring and controlling the equipment (servers, centralized monitoring functions, etc.) are placed on the cloud for execution over an IP network. This is called a cloud-based BEMS. The conversion of BEMS to a cloud-based format has the following advantages in addition to reducing costs:

• All information can be uniformly collected and managed, enabling advanced data analysis to be carried out.
• BEMS applications and services can be easily updated or added.
• Operations for each building are the same, making building management more efficient.

Demand response (DR) is a technique for temporarily suppressing the demand for power during times of tight electric-power supply-and-demand conditions; it is implemented by notifying consumers of changes in the price of electricity and offering them incentives for reducing power usage during peak periods designated by power companies or aggregators and shifting that use to other time periods. Efficient execution of DR requires prompt response to DR requests and reduction of the operations needed for DR execution. An effective mechanism for meeting these requirements is to provide an online connection between power-companies/aggregators and consumers and to execute DR automatically.

In fiscal year 2013, NTT FACILITIES teamed up with ENNET Corporation to construct a system in which our FITBEMS^® was connected online to the ENNET system (Fig. 4) and to hold a field trial of automatic demand response (ADR) using an actual building. This field trial was conducted to evaluate the results of prior simulations that quantified the amount of power demand that could be reduced by applying ADR and any subsequent effects on the indoor environment. The results revealed that halting the operation of air conditioners and other facilities in response to 35 ADR requests made over a one-year period reduced the power demand by 2074 kWh without affecting the indoor environment.

Fig. 4. Configuration of automatic demand response system.

3.3 Composite renewable energy system

It is necessary to provide a stable power supply even during times of commercial power outage as a disaster prevention measure. Likewise, from the viewpoints of saving energy and preserving the environment, there is a need for efficient energy-use techniques that can make maximum use of the output from clean distributed generation including solar power generation. As a forerunner to such a system, composite renewable energy systems have been developed, such as the one shown in Fig. 5. During normal, everyday operation, a composite renewable energy system reduces or shifts peak power demand through prioritized use of distributed generation, and at the time of a commercial power outage, it shifts immediately to automatic operation mode to deal with a long-term power outage through the use of distributed generation and storage batteries. Accordingly, if composite renewable energy systems are to be linked with xEMS^* in the future, not only can they provide a stable and highly reliable power supply, but they also hold the possibility of becoming a key device in smart communities as a consumer-side facility that can coordinate energy supply and demand in a building or area.

Fig. 5. Composite renewable energy system.

3.4 Mega-solar systems

The deployment of mega-solar systems has been expanding greatly in recent years, as they are an important source of power in smart communities. The collection of measurement data in a mega-solar system is generally done with the aim of monitoring the system’s output, which fluctuates according to the weather, and checking the health of the system. In the future, we can expect mega-solar systems to be increasingly reflected in the regional coordination of energy supply and demand and used in predicting power-generation levels in the system planning stage.

3.5 Cloud-based CEMS

The target of conventional energy management using ICT has been facility groups in specific areas such as BEMS in office-building areas, a mansion/condominium energy management system (MEMS) in condominium areas, and HEMS in home areas. However, to achieve comprehensive energy management across an entire community, there will be a need for a community energy management system (CEMS) that can collect demand-related information across such EMSs on the consumer side and absorb information from the power-grid and distributed-generation side.

A smart community aims to promote the introduction of renewable energy, improve energy conservation through effective use of local energy, and achieve urban development that is robust against disasters, so we can expect CEMS to play a centralized role in optimizing energy supply and demand across the entire community. Furthermore, a CEMS implemented on the cloud provides a number of benefits; not only is it flexible to the addition or removal of power-consuming and power-generating facilities within the target area, but it also enables high-speed and close information exchange with other cloud-based consumer-side EMSs.