Geomagnetically Induced Currents and Electricity Flows between the Ontario Power Grid and the United States

The Independent Electricity System Operator (IESO) of Ontario balances the supply and demand of electricity within Ontario, Canada. In cooperation with other system operators, it also facilitates the scheduling of transmission services between Ontario and other electricity control areas. Two of Ontario's most important interconnections are with Michigan and New York. From basic physics, the actual electricity flows between IESO and other control areas follow the paths of least resistance and thus, depending on system conditions, the actual electricity flow with another electricity control area may not equal the scheduled flow. The differences between the actual and scheduled flows between two electricity control areas are known variously as unscheduled flows, loop flows, and inadvertent flows. System operators view these flows as a significant operational issue given that the stability of a particular electricity control area requires that generation plus net electricity flows from other control areas equal load at all times.

There are large differences between Ontario's scheduled and actual electricity flows with the United States. Over the period 1 January 2004 through 31 December 2008, Ontario was on average, a scheduled importer of electricity from Michigan but on average, was actually a net exporter to Michigan. Over this same time period, Ontario's average hourly net exports to New York were substantially less than scheduled. Moreover, there was significant variation in the loop flows of electricity from one hour to the next.

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