The PJM Interconnection Board has suspended the Artificial Island transmission project and directed PJM to perform a comprehensive analysis to support a future course of action. The announcement came in a letter to PJM members.
The board asked for the review to be completed by February 2017, at which time, it said, PJM will be in a better position to decide how best to proceed.
"The board is concerned about the project's estimated costs and changing scope in light of new estimates and technical information it has received," said Andrew L. Ott, PJM president and CEO. "We need a firmer understanding of the changes that have occurred since the project was initially approved to ensure that we have the best path forward."
PJM has been working with transmission owners and developers to resolve voltage and stability problems at the Artificial Island generating complex in southern New Jersey. The problems require grid operators to make complex operational adjustments to ensure continued reliable electricity service in the area.
In 2015, the PJM Board approved a proposal to build a 230-kilovolt transmission line under the Delaware River. It designated LS Power to build the line and Public Service Electric & Gas and Pepco Holdings Inc. for other portions of the project including electric substation work.
Because of the complexities of design at two substations, PSE&G's construction estimates were higher than the initial estimates prepared by PJM. Questions also have arisen about whether proposed system protection and control upgrades would perform as intended.