Electricity or gas? Evaluation of energy saving, CO2 reduction, and cost saving potentials in residential house in Japan

Yukio Nakano and Wataru Urabe, Central Research Institute of Electric Power Industry (CRIEPI), Japan

Keywords

Japan, energy saving potential, CO2 reduction potential, cost saving potential, residential house, thermal insulation, air tightness, electric appliance, heat pump water heater with CO2 refrigerant, induction heating cooking range, gas fired appliance, latent heat recovery gas water heater

Abstract

Japan’s energy consumption accounts for approximately 6 % of the world. Various countermeasures are being applied to reduce the energy consumption and the CO2 emission consequently. But we are not successful to suppress increase in the energy consumption, especially in residential, commercial, and transportation sectors. This paper shows energy saving, CO2 reduction, and cost saving potentials of a typical residential house in Japan by adopting recent commercially available techniques and equipment for household. The energy consumption of the residential sector accounts for 15 % of the total of Japan. In order to clarify priorities of countermeasures of energy saving for the residential sector, the potentials are classified into heating, cooling, hot water, cooking, and refrigerators.

In heating and cooling, effectiveness of thermal insulation and air tightness for residential house are evaluated. In heating, hot water, and cooking, electric and gas fired appliances are compared. In electric appliances, the newest models are compared with current ones. These evaluations are carried out from the viewpoint of reduction in primary energy consumption, CO2 emission, and energy charge. In the analysis, the latest technical improvement and invention of electric and gas fired appliances, such as a heat pump water heater with CO2 refrigerant which have made an outstanding progress in efficiency of electricity usage, are taken into account. The primary energy saving, CO2 reduction, and energy cost saving rates through use of these energy saving techniques and equipment are calculated at about 28 %, 34 %, and 41 % respectively.