Nonlinear optimization of biomass fueled combined heat and power boilers in district heating systems in Japan

To accelerate the transition toward zero net carbon emissions, developing the technologies which are already mature enough to be integrated technologically and economically in existing systems is essential. Most of the recent studies are focusing on large scale energy systems which require lot of assumptions such as linear approximations. This paper presents the economical optimization of combined thermal and electrical supply of multiple cities in Japan through utilization of combined heat and power boilers. A nonlinear approach is used to consider phenomena including combustion efficiencies variations or effect of scale. Different technologies of combined heat and power are modeled with different properties and fuels such as household wastes and multiple biomass woods. The cost is used as the objective function to minimize considering current energy costs. With each boiler modeled and sized, optimization results show an optimal operation of 100% renewable resources, especially biomass power with accurate indicators on the operating mode of those technologies. Graphical abstract