New York City is a role model for energy efficiency. Its per capita energy use is much lower than in other parts of the US. Cities in general seem to be an eco-friendly place – at least for their hinterland and the environment. In this regard the global trend of urbanization – more than 50% of the earth’s total population live in cities – is to be appreciated. The cities’ energy efficiency has numerous reasons.
– the higher density of population in cities than in suburbs or rural areas leaves space for nature
– heating and cooling on a big scale, e.g. in apartment buildings and skyscrapers, is very efficient and less energy is lost through exterior walls because the area in contact with the outside per inhabitant is smaller than in detached houses in the countryside
– distances are shorter and can be covered by foot or by public transportation rather than by car as it is mostly the case in suburban or rural areas
All these effects appear even if there are no special efforts by the cities to become greener. But if some cities put effort in further increases of efficiency and environment-friendly technology, even further energy, emissions and money can be saved. For example, parts of the exterior of a skyscraper could be covered with ultra-thin solar panels. The influx of natural light could be used to reduce artificial light and the electricity bill. Water from the conduits could be used to cool the building in summer. Better insulation would help to reduce cooling costs in summer and heating costs in winter. There is a lot of potential for further efficiency increases and saving lots of money.