In 2012, in the United States, 4.6 million small commercial buildings across the nation consumed 47% of the overall primary energy and an additional average growth of 1.6%/year from 2012 to 2040 has been estimated by the Department of Energy. A fruitful way to reduce the energetic and environmental impact of these buildings might by distributed generation with renewable energy technologies, such as photovoltaic panel arrays. As a matter of fact, due to dismatches between power demand and power production, photovoltaic panels have their greatest potential when coupled to a storage device. Also fuel cells are gaining interest at international level as a promising technology for distributed generation. Their main limitations, though, are production and distribution of hydrogen - the best candidate fuel for these devices - due to lack of adequate infrastructures. For the above-mentioned reasons, photovoltaic panels may be coupled to a unitized regenerative polymer electrolyte membrane fuel cell as storage/backup system, where hydrogen is produced by the cell when working as electrolyzer. Moreover, hydrogen on-site production can be increased by reforming of biogas produced by an anaerobic digester fed with food waste available from the same commercial building. A battery pack is also included in the plant as secondary storage/backup system. The energetic effectiveness of the same polygeneration plant in different climate zones has then been assessed, including a sensitivity analysis on the biogas production.