CO₂-emissions reduction potential and costs of a decentralized energy system for providing electricity, cooling and heating in an office-building in Tokyo

Decentralized energy systems are thought to have great potential for supplying electricity, cooling, and heating to buildings. A decentralized system combining a solid oxide fuel cell (SOFC) with an absorption chiller-heater is proposed. The CO₂-emissions and costs of using different configurations of this SOFC-based system to provide an office building in Tokyo with electricity, cooling, and heating are calculated by using an SOFC-model and an absorption-chiller model together with data for cooling and heating loads measured at an office building in downtown Tokyo. In the model, the size of the building does not have much influence on the CO₂-emissions reduction potentials, because all of the equations for the calculations of the CO₂-emissions are linear, and the cooling/heating loads vary linearly with the size of the building. The potential for greater CO₂-emissions reduction potentials from economies of scale by constructing larger buildings is likely to be small. The price to pay to achieve the CO₂-emissions reduction potentials is still very high: an increase of ∼ 70% compared to the base system. However, there is evidence that the price of manufacturing SOFC will decrease in the future and therefore make the SOFC-based system more attractive.