TEPCO Power Grid provided incorrect information in 61% of the 31,313 preliminary grid connection consultations it conducted between September 2019 and December 2024, including wrongly telling companies that no capacity was available, the Tokyo TSO-area grid operator said on February 13, 2025.
The errors included understating available capacity due to thermal constraints and capacity available without grid upgrades to avoid reverse power flow, and failing to indicate whether reverse power flow would occur, the company said.
TEPCO Power Grid did not disclose a breakdown of the 18,977 affected cases by error type.
“In December 2024, we received an inquiry from a solar power generation company about the information provided as part of a [preliminary consultation].’ Upon reviewing our response, we confirmed the presence of errors,” said TEPCO Power Grid about what prompted the full-scale audit.
TEPCO Power Grid cited the lack of guidelines for responding during preliminary consultations as a likely reason behind the situation. “We will investigate the root cause and take measures to prevent recurrence,” said its statement.
The grid operator informed METI about the situation and started the process of informing affected project owners about the errors in the responses they received.
While the preliminary consultation is less detailed than a full-scale study that follows after an application is made, it plays a key role in project development. Because of that, the errors may have delayed or led to the scrapping of some projects.
