This report presents a proposal for R&D strategy on fundamental technologies of the low voltage distribution network and energy demand of households connected with the network beyond 2050.
　As of 2050, large volume of photovoltaic (PV) in homes is assumed to be penetrated, and excess amount of power will be supplied to end-users. This means that consumers in homes will play dual roles in both energy supply and consuming, that is to say, in 2050, the energy supply and demand structure in the low-voltage distribution network will change drastically. Based on these circumstances, this report aims to explore and propose technology to promote for the ideal situations of low voltage distribution network as well as human behaviors on energy demand in homes.

　In May 2016, the Plan for Global Warming Countermeasures was decided by the Japanese Cabinet. The plan defines a path to achieve a mid-term target of 26% greenhouse gas emission reduction by 2030 compared to 2013, and sets a long-term goal to pursue 80% reduction by 2050. In order to accomplish 2050 long-term goal, it must be important to decarbonize electric power supply ultimately. Large-scale introduction of renewable energy, especially PV including household use is a promising option.
　However, the power supply from PV, as well as wind tends to fluctuate and thus is classified as Non-dispatchable power. Large-scale penetration of PV is concerned to be harmful for power grid load balancing
　Toward 2030, countermeasures such as demand response, prediction method for PV power and ICT for smarter grid, etc. have been improved. However, further deployments to meet with large amount of PV residences is not sufficient. 　Based on the above, mainly two bottlenecks emerge. The first is the process to capture power generated from PV systems in homes and utilize in the power grid system under the appropriate balancing condition. Considering the speed of expanding PV until 2030, the situation will be different in terms of the volume. The second is the expected change of home energy demand, and its responsiveness in 2050. Energy demand is "derived demand" which is consumed in the form of lighting, heat and cool, ICT, etc. Therefore, to deduce the change of energy demand, further analysis would be necessary to look deep into human behavior to consume power.
　In order to overcome these bottlenecks, we will consider R&D items in the long term. For the first issue, current centralized power system has a difficulty as the number of decentralized devices which generate electricity uncontrollably increases. To solve this problem, it is considered that autonomous function should be installed in the low voltage distribution network based on the conceptual idea for ICT, which results in replacing centralized telephone system and promoting various innovations. It is important to consider such autonomous decentralized technologies / systems proactively in order to respond to a wide variety of electric power system needs in future.
　To realize the systems, it is necessary to develop a comprehensive R&D for autonomous decentralized power flow control including power flow control technology, mechanism design for the market. Regarding energy demand in homes, research for a human energy consumption behavior modelling and behavioral science and economics is necessary.
　Specific research and development items for the two tasks are shown below.

(1) R&D of Autonomous Decentralized Low-Voltage Distribution Network

• Power flow control technique by autonomous distributed system of power and ICT
• Power control in homes and other related systems
• Power and equipment and materials development in the network and home
• Market mechanism in low-voltage distribution system / mechanism and method of electronic transaction
• Model for evaluation of institutional design in the electricity market
• Model that can evaluate the holistic power system

(2) R&D related to energy demand science

• Modeling of energy demand, measurement and analysis
• Research on behavioral science, behavioral economics related to energy use

　To promote the proposed R&D, a consortium to share information among industry, academia and government, where they verify concept and develop technology from the both fundamental and applied aspects mutually, demonstrate the effect and endeavor to extend the local installation to the whole network.