Here Are the First Steps to Cutting Building Carbon Emissions

Buildings are New York City's biggest polluters, which is why the Climate Mobilization Act will require most co-op and condo boards to reduce their buildings’ carbon emissions sharply in coming years. The first deadline is the end of 2024, which is not far away. The first step all boards must take is to figure out exactly how much carbon their building is emitting. 

Boards might want to leave that job to the same professional who calculates annual energy benchmarking for Local Laws 84 and 133. That's not only because the formula is complicated but also because it uses the benchmarking figures, which get entered into the federal Environmental Protection Agency's database and its measurement tool, the Energy Star Portfolio Manager. 

"The first step is to understand where you are right now," advises Kelly Dougherty, director of energy management for the FS Energy division of FirstService Residential. "Based on information readily available from your Local Law 84 benchmarking process, you can calculate what you're currently emitting." 

There are many variables to that calculation. Different "occupancy groups," like a co-op or condo's residential and retail spaces, are assigned different emission limits. There are also “coefficients" for each of five commodities: natural gas, No. 2 oil, No. 4 oil, electricity, and Con Edison’s district steam, which is created at three natural-gas-fueled plants. 

"If you take the square feet of the occupancy group and the [carbon] amount you're allotted times square footage of those spaces, that gives you your total emissions cap," explains Dougherty. "Then you go to how much energy your commodities used the previous year. You multiply each commodity by the coefficients provided in the law, and the difference is where you're above or below the emissions level." 

Yes, it's complicated. But the pertinent thing to realize is that there's a standard way for any board or its professionals to calculate that figure. 

Now that you know where you stand, Step 2 is to create a strategy. "No one measure does it all," says Michael Scorrano, an engineer and the founder and managing director of the energy consultancy En-Power Group. "It may be a bunch of smaller measures, or it could be capital-improvement projects – maybe it’s time to upgrade your heating system. Maybe it’s time to look at your ventilation and air-conditioning system." 

The specific capital-improvement projects that can help reduce your greenhouse-gas emissions will vary from building to building. Typical projects, says Scorrano, include an absorption chiller, a refrigeration unit that converts heat into energy that drives a cooling system, and cogeneration, a natural-gas power plant in your building that generates both heat and electricity. A third project is a boiler replacement. 

Boards might also consider solar-panel arrays and green roofs, the latter involving vegetation that absorbs rainwater, provides insulation, and helps mitigate the "heat-island effect" that makes urban areas warmer than rural ones. Advanced projects might include: converting from a fossil-fuel-based central boiler to electric-powered heat pumps; trigeneration, in which a second cogen unit combined with a chiller provides air-conditioning; and battery energy-storage systems (BESS), in which you can store the cogen electricity you generate, further reducing energy costs. 

Such an array of choices can be confounding. Where do you start? One place is the Retrofit Accelerator, a free city assistance program. "We operate this program for people like boards who want to know ‘How do I start?’ and ‘How do I assess our energy performance?’” says Mark Chambers, director of the Mayor’s Office of Sustainability. “That will start conversations about what their options are. We give building owners straight advice and connect them to other resources. It's kind of a one-stop shop."

Smart boards realize it's time to start shopping.