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Estimated 2019 marginal emission rates

"Average" CO2e emission rates underestimate the effect of weekly peak period electric use -- and so dramatically undervalue grid-interactive efficient buildings, local distributed PV and energy efficiency.


Properly calculated CO2e emission rates reflect NYISO Security Constrained Unit Commitment (“SCUC”) in the day-ahead market; and thus the generators responsible for most of New York City's emissions.

The example at left illustrates the large difference between SCUC-based marginal emission rates and the "average" emission rates issued by the U.S. EPA and by NYC under LL97. (Click to download QCo's underlying analysis)

Early in the week, NYC temperatures reached the mid-90’s, later in the week the mid-80’s.  Significant local emissions reduction was achievable by eliminating the local marginal baseload generator from operation -- by targeting the few peak days and hours that dominated SCUC.

“When” electricity is used is just as important as “how much” is used.

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