In most sectors, New York City’s most energy intensive large buildings typically use three to five times the energy of the least energy intensive buildings, according to a report by the city’s Office of Long-Term Planning and Sustainability.
Large buildings – defined as those over 50,000 square feet, or multiple buildings with a combined total area of over 100,000 square feet – from the hotel, multifamily and office sectors that rate in the 95th percentile for energy intensity use, respectively, 3.2, 4.4 and 4.5 as much energy per square foot as those from their sectors’ fifth percentile for energy use intensity, according to the New York City Local Law 84 Benchmarking Report. But the difference can be even larger. Retail spaces in that sector’s 95th percentile use almost eight times as much energy per square foot than those in the 5th percentile.
If all comparatively inefficient large buildings were brought up to the median energy use intensity in their category, New York City could reduce energy consumption in large buildings by roughly 18 percent and greenhouse gas emissions by 20 percent, the report says. If all large buildings improved to the 75th percentile, the potential savings would be around 31 percent for energy and 33 percent for greenhouse gases. As large buildings currently account for 45 percent of the city’s carbon emissions, these improvements would translate into a city-wide emissions reduction of 9 percent and 15 percent respectively.
Office buildings account for a quarter of the square footage surveyed but just 11 percent of the total number of surveyed buildings. The report says that targeting this sector for energy reductions makes strategic sense, as offices use so much energy in relatively few buildings. Targeting efficiency in the residential sector would be more problematic because the buildings are so numerous – 80 percent of the total number of buildings surveyed.
The city began benchmarking buildings under Local Law 84 of 2009. The law mandates that all privately-owned properties with individual buildings over 50,000 square feet or multiple buildings with a combined square footage over 100,000 square feet annually measure and report their energy and water use. Through benchmarking and measurement New York City hopes to reduce its greenhouse gas emissions by 30 percent from 2005 levels by 2030.