Making best use of information and communications knowledge Aiming for energy conservation by creating freedom of choice in electric power selection

The information and communications landscape has changed greatly in less than half a century. Black telephones have given way to cell phones, letters are ceding ground to e-mail – progress has been striking. In contrast, electric power supply is still an analog circuit, made up of power supply, transformers, transmission lines and load. Professor Takashi Hikihara of Kyoto University Graduate School of Engineering is aiming at construction of a highly efficient energy supply system that will allow individual households to control power supply. He plans to do this by incorporating the know-how of ICT (Information and Communication Technology) into the undeveloped area of power management.

Under conventional power distribution in the home, power obtained from the distribution network and power sources in the home flows in a constant direction, as determined by circuit configuration.

Load

An element incorporated in an electric circuit, and functioning as power output. In direct current circuits, resistance is the load. In alternating current circuits, in addition to resistance, inductance, and capacitance form the load.

The core issue is maintaining living standards while conserving energy

The Obama administration set the Smart Grid as a cornerstone of economic recovery. This is the opportunity for power control technology to quickly become mainstream. In Japan, the Hatoyama administration declared Japan will “reduce greenhouse gas emissions by 25% below the 1990 level by 2020.” The extremely high level of difficulty in achieving this target was another factor behind rising interest in power control technology. Professor Hikihara, who has been engaged in research of power conversion control since about 2001, feels the time for society to rouse itself has arrived.

The overall goal of the project is to achieve energy conservation and at the same time maintain “quality of life.” While still using power supplied by power companies to homes and offices, users will be able to achieve optimal energy management in keeping with their lifestyles, through coordination with household-generated power (solar power, fuel cells, etc.), storage batteries and load. For example, when running an air conditioner, the user can specify the power to be used and the period of use. With computerized control and power management for individual appliances, power supply can be allocated to various loads according to demand level and need.

Smart Grid

The Smart Grid, or ‘intelligent power network,’ is a new technology integrating the existing electric power network and the information and communications network. The term began to spread after President Obama advocated the Smart Grid along with his economic policy, Green New Deal.

“Packetization” for sending information to the power supply is the key to practical use

Integration of the existing power supply network and information & communications network is essential for establishment of such a management & control system. Professor Hikihara proposes “packetization of power” as the ultimate solution. “Truly, this would be a power supply version of packets as used in information and communications. Large amounts of power would be divided into small units. Each unit comes with a distribution information tag, is color tagged, or otherwise coded to show the source of the power and its destination. This is a rational method for transmitting the appropriate amount of power and minimizing loss. Furthermore, as the type of power and the number of packets can be identified, the user’s ecological awareness rises.”

The equipment for actually creating power packets from electricity uses connecting equipment derived from ICT, such as interfaces and routers. While converting and regulating power of different frequencies, this equipment gathers power packets, stores them temporarily (memory) and sends them to loads as needed. The goal is a mechanism for unrestricted receipt and transmission without circuit restraints, regardless of whether the power comes from a power company, or is generated in the home or office. A new semiconductor device capable of smooth power conversion is said to be accelerating the practical application of this mechanism.

With the network method, which uses power packets and routing, the power is continuously tagged and assigned directional information. Based on this information, power can be channeled back and forth, as needed, between utilities, power sources, storage and routers.

“Silicon, which is currently the main element used in semiconductors, is not suitable for high-speed processing of large quantities of power. It also generates large losses during switching. To get around the problem, we are teaming up with various semiconductor manufacturers in joint research of next-generation semiconductor devices (power devices) – wide bandgap semiconductors using silicon carbide (SiC). They will be very useful for construction of our system. And that is not all. It is said that if the power circuits of all electronic equipment were replaced with next-generation semiconductor power devices, the resulting reduction of loss would save energy equivalent to the output of one nuclear reactor (about 1 million kW).”

Semiconductor device

An electronic circuit element that uses a semiconductor (a material having electrical resistance with a value between that of metal and insulator).

Wide bandgap semiconductor – silicon carbide (SiC)

A semiconductor device developed for processing high power levels. It can tolerate high voltages, undergo high-speed switching and function in temperatures above 300℃.

Reducing household power consumption to about 60% of the present level

As well as domestic enterprises, overseas corporations are developing and offering new elements derived from research related to Professor Hikihara’s project. Additionally, some 30 manufacturers of consumer home electronics, facilities for houses, computers, and so on are strengthening their involvement in the project. As the industry network expands, the environment for a power control & management infrastructure will continue to improve. Furthermore, the current dilemma of pursuing ecological improvement while maintaining living standards should then be resolved.

Professor Hikihara predicts: “Sooner or later, we will see the day when individual household power consumption is reduced to about 60% of the level today. When that happens, we will be able to make ecologically sound choices about power supply, whether to live solely on home-generated electricity, to trade electricity within a set region, and so on.”

In the near future, we will no longer be restricted to simply receiving power, while having no clear idea of its circumstances. Along with the emergence of interfaces for packetizing electric power, we will soon be able to ‘choose’ and ’see’ power as information.

project on integration technology for information