In this webinar we will examine recent trends and characteristics of one important benefit of transmission infrastructure—congestion relief. Specifically, we examine the marginal value of potential transmission links as indicated by nodal pricing (LMPs) from 2012 through the first half of 2022. We find, for example, that many links have hourly average pricing differences in 2021 that exceed $15/MWh—equivalent to $130 million per year for a 1000 MW link. We will examine trends in the transmission value over the past decade. We will explore how extreme conditions and high-value periods play an outsized role in the value of transmission. For example, we find that 50% of transmission’s congestion value comes from only 5% of hours. These high value transmission hours are only partially attributable to designated extreme weather or grid-stress events identified by NERC, with the remainder of the high-value hours representing periods that are natural features of actual market operations (possible causes include uncertain generation or other infrastructure outages, fuel price volatility, forecast errors, and electric demand volatility). We will discuss the broad implications of these findings, key limitations, and importantly, the challenge of adequately representing transmission congestion value in transmission planning studies.