When discussing the topic of greenhouse gas emissions, we tend to think about transport. However, the construction sector actually has a higher carbon footprint and cities like New York are already working to address this issue. Local Law 97 of 2019 will apply emission limits to buildings over 25,000 square feet. from 2024, based on occupancy and usable area.
Get a professional energy audit, reduce your utility bills, and avoid Local Law 97 penalties.
By understanding the carbon footprint of each energy source, you can reduce emissions more effectively. The 2019 LL97 provides emission factors for the following sources:
- Electricity
- Natural gas
- #2 fuel oil
- #4 fuel oil
- District steam
The law requires you to calculate the emissions caused by all energy sources used in your building. However, these five sources represent the majority of energy consumption. Here we'll rank your carbon footprints from largest to smallest while discussing some viable strategies for minimizing your emissions.
1) Fuel Oil No. 4: 75.29 g of CO2 equivalent per kBTU
Among the five main energy sources considered by Local Law 97, No. 4 fuel oil is the most polluting. Unfortunately, this energy source is still used for space heating and hot water in many buildings. When the LL97 penalties go into effect, building owners who still rely on #4 fuel oil will have a hard time staying below their limit. However, there is still time to improve energy efficiency with building upgrades while switching to cleaner sources.
Another disadvantage of No. 4 fuel oil is the dependence on scheduled deliveries, which can be interrupted by adverse weather conditions. Steam, electricity and natural gas are delivered as utilities, meaning you no longer have to worry about deliveries.
2) Fuel Oil No. 2: 74.21 g of CO2 equivalent per kBTU
No. 2 fuel oil has a slightly lower environmental impact than No. 4 fuel oil, and the emissions factor used in LL97 is 1.4% lower. However, referring to #2 fuel oil as a “cleaner” energy source is misleading. For the owner of a building subject to high sanctions, switching to a slightly less polluting source will not have a significant impact.
With #2 fuel oil, you still have the limitation of relying on truck deliveries. There are cleaner energy sources that also offer the convenience of being public utilities. If you currently rely on fuel oil for heating and need to reduce your emissions, consider a high-efficiency natural gas boiler or electric heat pump.
3) Natural Gas: 53.11 g of CO2 equivalent per kBTU
Natural gas is also a fossil fuel, but its carbon footprint is considerably smaller compared to No. 4 or No. 2 fuel oil. Another advantage is that natural gas is delivered through a piped connection, and you are no longer dependent on supplying oil to keep your building and water warm during the winter. By upgrading to a modern natural gas boiler and improving your building envelope you can significantly reduce heating costs and associated emissions.
However, it would be a mistake to describe natural gas as a clean energy source, even when it has the word “natural” in its name. Building owners may be able to avoid 2024 emissions limits by switching from oil to gas, but stricter limits will be introduced in 2030. If you want to heat your building with zero emissions, consider an energy-operated electric heat pump system. renewable.
4) District Steam: 44.93 g of CO2 equivalent per kBTU
New York City has the advantage of offering steam as a utility service and has a smaller carbon footprint than the three energy sources described above. However, steam is only available in some parts of New York, and your building's heating system must be specifically designed to use it.
Con Edison depends on cogeneration systems to produce much of its steam, reducing the environmental footprint of this public service. Buildings that have their own steam boilers have much higher emissions, as they must burn fuel oil or natural gas directly. In this case, you must use the corresponding fuel emissions factor – the district steam factor only applies if you use steam directly from the ConEd service.
5) Electricity: Emissions Depend on the Source
There are multiple energy sources that can be used to generate electricity, and the carbon footprint per kilowatt-hour will depend on the source used. For example, if we use coal to generate energy, we can expect emissions of more than 1,000 g per kilowatt-hour. On the other hand, electricity from solar panels and wind turbines is almost emission-free.
Local Law 97 provides an emission factor of 0.000288962 metric tons of CO2-eq per kWh. This equates to just under 289 g of CO2 equivalent per kWh. However, this value only applies to electricity consumed from the grid. If you generate your own power with solar panels or other clean technology, those kilowatt-hours don't count toward your building's emissions limit. This has another implication for New York building owners: Electric heating is emission-free if it uses clean energy sources.
