*Article* **Novel Use of Green Hydrogen Fuel Cell-Based Combined Heat and Power Systems to Reduce Primary Energy Intake and Greenhouse Emissions in the Building Sector**

**Jordi Renau 1,\*, Víctor García 1, Luis Domenech 1, Pedro Verdejo 1, Antonio Real 1, Alberto Giménez 1, Fernando Sánchez 1, Antonio Lozano <sup>2</sup> and Félix Barreras <sup>2</sup>**


**Citation:** Renau, J.; García, V.; Domenech, L.; Verdejo, P.; Real, A.; Giménez, A.; Sánchez, F.; Lozano, A.; Barreras, F. Novel Use of Green Hydrogen Fuel Cell-Based Combined Heat and Power Systems to Reduce Primary Energy Intake and Greenhouse Emissions in the Building Sector. *Sustainability* **2021**, *13*, 1776. https://doi.org/10.3390/ su13041776

Academic Editor: András Reith Received: 30 December 2020 Accepted: 2 February 2021 Published: 7 February 2021

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**Abstract:** Achieving European climate neutrality by 2050 requires further efforts not only from the industry and society, but also from policymakers. The use of high-efficiency cogeneration facilities will help to reduce both primary energy consumption and CO2 emissions because of the increase in overall efficiency. Fuel cell-based cogeneration technologies are relevant solutions to these points for small- and microscale units. In this research, an innovative and new fuel cell-based cogeneration plant is studied, and its performance is compared with other cogeneration technologies to evaluate the potential reduction degree in energy consumption and CO2 emissions. Four energy consumption profile datasets have been generated from real consumption data of different dwellings located in the Mediterranean coast of Spain to perform numerical simulations in different energy scenarios according to the fuel used in the cogeneration. Results show that the fuel cell-based cogeneration systems reduce primary energy consumption and CO2 emissions in buildings, to a degree that depends on the heat-to-power ratio of the consumer. Primary energy consumption varies from 40% to 90% of the original primary energy consumption, when hydrogen is produced from natural gas reforming process, and from 5% to 40% of the original primary energy consumption if the cogeneration is fueled with hydrogen obtained from renewable energy sources. Similar reduction degrees are achieved in CO2 emissions.

**Keywords:** hydrogen; PEM fuel cells; cogeneration; building sustainability; energy saving
