About 100 feet beneath Kendall Square, a massive project is taking shape.

Top floor of Eversource building, distribution line exits. Credit: Alex Degterev. BXP proposed the current underground space in response to the controversy, winning approval from the Cambridge Redevelopment Authority and the City for 800,000 square feet of additional space for commercial development in Kendall Square’s mixed development zone.

The adjacent residential tower is visible through the opening of the oversize elevator shaft of the substation project during a tour on May 21. One of the largest utility projects in the area's history is a fully underground substation set to be more than 100 feet underground, projected to be finished in 2030. Lane Turner/Globe Staff

Executives from the City, Eversource and elected officials gather at a ground-breaking ceremony for the Greater Cambridge Energy Program.