When Carbon Neutral Buildings Don’t Add Up

Mario Cucinella is one of the greener architects in Italy; I loved his Casa 100K euro that we featured earlier. His Satander building is interesting too, billed as the first “Zero CO2 office building in Milan.” But the three storey building sits on stilts, so everyone will probably take the elevator, which they might not have done if it sat on the ground like a conventional building. The Centre for Interactive Research on Sustainability in Vancouver, on the other hand, takes carbon neutral to another level.

Indeed, there is a lot going on here. But if you are telling a green story, why put a three-storey building 42 feet up in the air so that everyone has to take an elevator to just get in? And what is the carbon footprint of making over half an acre of photovoltaics? After all, processing a tonne of silicon produces a tonne and a half of CO2, and a square meter of solar cells appears to carry a debt of 75 kilograms of CO2, or 187 Tonnes. Production of semiconductors like solar cells also uses a lot of chemicals like sulfur hexaflouride or nitrogen trifluoride, both notorious greenhouse gases. The engineer says that the photovoltaics will “avoid the pollution of 175 Tonnes of CO2 per year” so that carbon debt is paid off fast, but it still matters.