The Octagon (Roosevelt Island)

The new apartment complex utilizes both solar panels and fuel cell installations. A 50 kW array of solar panels and a 400 kW fuel cell enable the building to generate more than 50% of its power.[6] The fuel cell is a combined heat and power system that converts natural gas to electricity and heat via a combustion-free, electrochemical process. This system provides power and heat that meets the majority of the building's energy demand, and the efficiency it achieves is higher than the energy received from the power grid. Not only does the system provide more efficient energy usage, the heat from the process is also used for the building's space heating and domestic water requirements. Thus the Octagon is projected to reduce its carbon emissions by 790 metric tons annually.[7]

The Octagon received the largest initial award of New York State Green Building Tax Credits and was recognized in the first New York City Green Buildings Competition with the "Green Apple Award" for leadership in applying sustainable design principles to residential development. In 2006, a newly constructed residential building was built on the site, modeled on the original structure. It received LEED Silver status from the U.S. Green Building Council in 2008.[8]

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  The main building in 1893
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  Rotunda as it appeared in 1970
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  Original interior stairway, second floor
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  As depicted in Ten Days in a Mad-House
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  Appearance in 2017