PJM Interconnection is a regional transmission organization which as of 30 April 2004 coordinated the dispatch of 76,000 megawatts (MW) of generating capacity over 20,000 miles of transmission lines in all or parts of Delaware, Maryland, New Jersey, Ohio, Pennsylvania, Virginia, West Virginia and the District of Columbia. From basic physics, electricity flows between PJM and other power grids follow the path of least resistance and thus, depending on system conditions, the actual path of the electricity flow between grids may not equal the scheduled flow. The difference between the actual and scheduled flows between two power grids are known variously as unscheduled flows, loop flows, and inadvertent flows. System operators such as PJM view these flows as a significant operational issue with adverse impacts on electricity spot market efficiency. In the least harmful case, some of an importing grid's interchanges receive more electricity than scheduled while others receive less such that the net unscheduled flow over all interchanges equals zero. The more serious case is when the net actual interchange between a particular power grid and its trading partners is not equal to the net scheduled interchange. One example of this is provided by the PJM power grid where actual imports of electricity were systematically less than scheduled imports over the period 1 April 2002 through 30 April 2004.

This study uses local (groundbased) magnetometer data as a proxy for geomagnetically-induced currents (GIC) to address whether space weather contributes to the inadvertent flows into PJM. It is hypothesized that GICs contribute to inadvertent flows because of GIC induced energy losses and transmission constraints. The starting point of the analysis is the finding that unscheduled flows between PJM and the New York power grid are statistically related with a GIC proxy. The analysis then estimates the relationship between the GIC proxy and PJM's inadvertent flows using a multivariate econometric model that takes into account ambient temperature and other factors that can affect inadvertent flows. The results of this analysis are expected to be of interest to system operators, policy makers, and the general space weather community.