Abstract
Japan’s energy consumption in 2018 was about 2.5 times that in 1975, with the increase in the household sector being the largest at 28%. Most of primary energy is still fossil fuel, and it is urgent to reduce energy consumption in the household sector. The purpose of this paper was to identify ways to reduce household energy consumption without compromising the quality of life in residence. However, the reduction methods vary by region, building specifications, household type, equipment specifications, season, and weather. The value of this paper is based on a systematic analysis of home energy management systems (HEMS) data from about 50,000 households under various conditions. We are analyzing ways to reduce energy consumption. Few studies have analyzed this much back-up data, which is likely to lead to a reduction in CO2 emissions across the household sector. To explore ways to reduce energy consumption in this sector, the company has introduced and provided services for home energy management systems (HEMS) since 2011 and is currently collecting HEMS data for up to 50,000 households. In order to grasp the actual state of energy consumption in each household, HEMS data are systematically analyzed, necessary conditions for energy reduction and self-sufficiency rate (SSR) improvement are analyzed, and energy consumption under certain conditions is estimated using storage batteries (SB) and heat pump water heaters (HPWH). In addition, energy consumption was investigated by actual measurement and simulation for several hundred households. Since power generation and consumption vary greatly depending on the region, building specifications, household type, equipment specifications, season, weather, etc., it is necessary to analyze these factors systematically. As a conclusion, in order to improve SSR, it is necessary to (1) reduce surplus power consumption and energy consumption of heat pump water heaters (HPWHs), (2) increase solar power generation, and (3) increase the size of SB. This study contributes to the spread of advanced housing and the reduction of CO2 emissions in the household sector.
Highlights
In the Paris Agreement signed at the 21st Conference of the Parties conducted by the United Nations, Japan committed to reducing CO2 emissions by 26% by 2030 compared to the FY 2013 levels
Using the most recent and large amount of home energy management systems (HEMS) data, the analysis was carried out for the case where the heat pump water heaters (HPWH) was combined for each capacity of the PV power generation system and the storage batteries (SB), and a regression model was obtained for each capacity of the PV, the SB
To plan a house with a high self-sufficiency rate (SSR) with less expenditure, studying methods to reduce the energy consumption is necessary by analyzing further energy consumption with HEMS data, as well as by improving high-efficiency equipment and thermal insulation performance
Summary
In the Paris Agreement signed at the 21st Conference of the Parties conducted by the United Nations, Japan committed to reducing CO2 emissions by 26% by 2030 compared to the FY 2013 levels. Promote the introduction of photovoltaic (PV) power generation, storage batteries (SB), and home energy management systems and improve the self-sufficiency rate (SSR) of each household. These two approaches are important for popularizing advanced housing and reducing CO2 emissions in the household sector by balancing the environmental and economic aspects. As of March 2020, ~50,000 houses are using HEMS This novel study examines the possibility of energy and CO2 reduction in the home sector by analyzing actual power generation, power consumption, and charge/discharge quantity by classifying them into residential areas, types of households, building specifications, equipment specifications, and building years from significant amounts of actual data and not from simulation. This study aims to enable the future energy-saving policies and renewable energy to popularize advanced houses with a low system power load by clarifying the problems in popularizing houses with low CO2 emissions and high SSRs
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