Markets & Operations


PJM’s marginal emissions graph reflects the marginal emissions rates of carbon dioxide (CO2), nitrogen oxides (NOx) and sulfur dioxide (SO2). The marginal emissions are the emissions caused by producing the last megawatt of energy on the system. Any variations in dispatch patterns to ensure system-wide reliability may change the set of marginal units. Therefore, a significant change in dispatch could shift the marginal generating unit, and thus, the marginal emission rates accordingly.

This information is based on annually reported average data from electric generators within the PJM footprint. PJM does not receive real-time emissions data from plants.

Marginal Emissions for PJM-RTO

As of


Data Miner

Allows retrieval of historical energy pricing data.

Tool | Information

Data Viewer

Shows real-time data about the grid and electricity markets.

Tool | Information