The case touches on EU principles on creating an equal internal market for energy, newspaper Jyllands-Posten reports.
Danish industry representatives say they hope Vestager’s commission will use the case to highlight EU free market principles, including for energy.
“This is equivalent to someone in Germany preventing export of bacon or Lego from Denmark. That’s not allowed either,” Carsten Chachah, special consultant with interest organisation Dansk Energi, told Jyllands-Posten.
“Denmark is good at producing green energy and establishing it. But that requires a functional market,” Chachah added.
The issue relates specifically to German transmissions company TenneT, which has since 2011 regularly provided reduced capacity than was available for electricity transmission between Jutland and Germany.
Capacity was in some instances reduced to as little as five percent of potential, according to the report.
That has resulted in losses of up to 500 million Danish kroner (67 million euros) annually for Nordic energy producers, Dansk Energi said.
A formal inquiry into the issue was initiated by Vestager in March.
The European Commissioner, a Danish politician, said at the time that it was “crucial that electricity connections remain open for cross-border trade”.
Negotiations over the electricity market are currently ongoing between EU countries.
Danish Minister for the Environment Lars Christian Lilleholt told Jyllands-Posten in an email that “Denmark supports the application of the principle of free movement of goods to electricity trade.”
A spokesperson for TenneT noted in an email the company temporarily offered a minimum-capacity connection and is currently awaiting an outcome in the inquiry.