The firm bought the 33 Cadogan Street scheme known then as the Grid with planning.
Now it has secured equity funding from Swedish State Pension Funds to progress the project, which has been designed by architect Cooper Cromar.
The construction project, which will be completed in 2024, is understood to be worth more than £50m.
Paul Richardson, investment manager at CEG, said: “The start on site with this speculative development is testament to CEG’s confidence in the Glasgow market. The city is suffering from an acute lack of Grade A office supply and 33 Cadogan Street will help to remedy that.
“A best-in-class office development, targeting the highest sustainability credentials, it will respond to occupier’s demands for Net Zero Carbon in operation office space, as well as providing fantastic amenities and a healthy and productive place to work.”