In 1956, Zakłady Sieci Energetycznych [Energy Network Plants] and Zakłady Zbytu Energii Elektrycznej [Electricity Marketing Plants] were transformed into Zakłady Energetyczne [Power Plants]. The intensive development of electrical networks has necessitated the creation of organisational units dedicated exclusively to the construction of medium and low voltage networks.

To do this, Samodzielne Oddziały Wykonawstwa Inwestycyjnego (SOWI) [Autonomous Departments of Investment Project Deliveries] have been established at Zakłady Energetyczne [Power Plants].

The development of SOWI allowed to extend the company’s activity with construction works and major repairs of low, medium and high voltage networks, including 110 kV lines.

Since 1970, the range of services offered by SOVI has been completed by design works. It was possible through the acquisition of design office of Zakład Energetyczny [Power Plant].

In July 1976, Zakład Wykonawstwa Sieci Elektrycznych Toruń with its official seat in Toruń was created. based on the former SOWI at Power Plant Bydgoszcz, Power Plant Toruń, and Power Plant Olsztyn. Also, manufacturing branches in Bydgoszcz, Toruń, and Olsztyn were established.

Zakład Wykonawstwa Sieci Elektrycznych Bydgoszcz emerged as a result of privatisation of ZWSE Toruń, and in 1991, it was incorporated as a limited liability company.

In 2007, ZWSE MEGA-POL Spółka z ograniczoną odpowiedzialnością [limited liability company] was transformed into ZWSE MEGA-POL Spółka Akcyjna [joint stock company].