LL97 Penalties Aren’t What Most Calculators Show The $268/Tonne Problem NYC Local Law 97 is one of the most aggressive building performance standards in the United States. Buildings larger than 25,000 square feet can be fined $268 per metric tonne of CO₂e above their annual emissions limit. After reviewing hundreds of LL97 estimates, I noticed the same issue repeatedly appearing in reports and calculators: the carbon math is often wrong. Most tools use the EPA eGRID electricity emissions factor for NYISO ( 0.000371 tCO₂e/kWh ). LL97 does not use EPA eGRID values. That difference alone can completely change a building’s projected penalties.…