MISO’s new ‘pseudo-ties’ process boosts reliability, market efficiency

Bad things can happen when someone starts up a power plant or changes its output of electricity without fully understanding how such actions would affect the local transmission system.

That’s why MISO worked closely with its stakeholders to develop a new process for “pseudo-ties,” which allow electricity generating units that are physically located within MISO’s boundaries to be operationally controlled and dispatched by a neighboring system operator, such as PJM Interconnection.

This new process, filed on February 28, 2017 with the U.S. Federal Energy Regulatory Commission (FERC), will help ensure continued grid reliability and other market and operational efficiencies when generating units or load pseudo-tie out of (or into) the MISO region.

“Pseudo-ties can pose significant challenges for MISO and the broader industry, which is why this new process is so important,” said David Zwergel, MISO’s consulting advisor of interregional operations, who helped craft the new policy.

The term pseudo-tie refers to the real-time transfer of control of a generating unit or load from the “native” Balancing Authority (BA) in which it is physically located to an “attaining” BA in a different location. For example, a unit that is physically located in the MISO BA could be controlled by the PJM Interconnection BA via a pseudo-tie. In this example, PJM would transfer the unit’s energy into its territory by utilizing elements of the transmission system that are under MISO’s functional control.

Changing times

Historically, such arrangements have not been problematic because most of the MISO-based units that have opted to pseudo-tie out of the region have been located near MISO’s seams, were the units’ attaining BAs had some (limited) ability to identify and ameliorate issues that could otherwise impact the MISO-controlled portion of the grid.

But in a shift away from this historical pattern, MISO is now receiving an increasing number of pseudo-tie requests from units that are located deep within the MISO footprint, where their attaining BAs have very limited ability to model their impact on the MISO transmission system. And that limited modeling capability could a host of problems.

For example, an attaining BA might instruct a pseudo-tied unit to increase its output of energy without realizing that doing so would overload a local transmission element, jeopardizing reliability in the MISO system.

MISO-Based generation pseudo-tied into PJM is expected to increase sharply in 2016-17 (values shown in megawatts)

MISO, in turn, may have to guard against that possibility by committing one or more of the higher-priced units under its functional control to provide sufficient “counterflow” energy to ameliorate any potential congestion. And that could cause market-inefficiency and cost-related issues, because the costs of committing those units—whether they actually ran for congestion-management purposes or not—would be borne by MISO Market Participants.

New tools and safeguards

The new process that MISO filed at FERC this week is designed to address these and other issues. This new process is set forth in an agreement that the owners of all new pseudo-tied units and/or loads will enter into with MISO, as well as a new business practices manual that explains how the new process works. Highlights of the new process include:

  • MISO and attaining BAs will benchmark congestion-management models and add any missing details to ensure that the operation of pseudo-tied units will not undermine system conditions.
  • Generating units or load that wish to pseudo-tie into or out of MISO must obtain firm transmission service to ensure that they are able to follow the dispatch instructions of their attaining BAs.
  • MISO and the neighboring transmission provider will agree on the requirements for which transmission service will be granted.
  • Entities that wish to retire their pseudo-tied units must notify MISO at least six months in advance, which will improve MISO’s insights into system conditions and give MISO some ability to utilize pseudo-tied units in emergency situations.
  • This new pseudo-ties process underscores the importance that MISO puts on working with neighboring system operators while ensuring that customers in the MISO region continue to receive reliable, low-cost energy.

Leave a Comment