Instead of grading buildings on how much energy they use, engineering consultancy Buro Happold has come up with a more nuanced measure of energy efficiency: whether every bit of energy consumed is being put to good use.
In 2011, the New York City skyline suddenly became a beacon of energy data transparency, all because of Local Law 84—a requirement that every building over 50,000 square feet submit an annual energy benchmark. "This was a big deal. For us in the energy world, data wasn't always available. Maybe we had some light databases of energy data," explains Steven Baumgartner, an associate at Buro Happold, where he leads energy and sustainability projects. "Overnight, available in a big spreadsheet, was a huge set of information for almost all buildings in New York City."
As you might expect, people quickly began comparing energy consumption in various buildings around the city. Not everyone liked what they saw. The law revealed, for example, that One Bryant Park, a LEED platinum building, consumes twice as much energy as the Empire State Building.
"EUI is an intensity metric—energy per square foot—and people that are energy-driven professionals were making the fundamental mistake in calling EUI 'efficiency.' They were saying, 'My building is more efficient than yours because it has a lower EUI,'" says Baumgartner. So Buro Happold came up with an alternative metric, called the building-energy-efficiency coefficient, that measures energy use per unit of economic output, instead of energy use alone.
While energy use data is freely available in NYC, economic information on individual buildings is not. Buro Happold worked with CoStar, a commercial real estate information company, to find the standard industrial classification codes for NYC buildings, which can be linked to GDP data. That data can then color in a very rough estimate of the economic output of a building. "To me, efficiency is how productive you're being with energy. You're using energy to drive commerce," says Baumgartner.
For now, Buro Hapold can only measure the building-energy-efficiency coefficient of NYC buildings—and thus far, no one has really latched onto it. But the company is already thinking about bringing the metric to other cities as they begin to open up their energy data. "There's room to build on this," says Baumgartner.