The creation of VELCO’s first transmission lines was an efficient solution for moving newly available St. Lawrence power into Vermont. In response to rising demand for services and the oil embargo of the early 1970s, VELCO's role grew to include acting on behalf of Vermont's utilities as the agent for out-of-state power contracts. Assuming this responsibility saved money and substantially increased reliability through newly interconnected operations. Later, VELCO was specifically tasked to serve as representative for Vermont's combined utilities at what was the precursor to today's ISO-New England, where VELCO gave Vermont’s utilities a strong unified voice. VELCO's construction of the Highgate Converter made interconnected operations with Hydro-Québec possible and so played a role in securing the HQ power contract.
The initial 224-mile 115 kV VELCO system was placed in service in September 1958. Since that time, VELCO has expanded its facilities and services as required by law, the needs of its participants and the development of the industry. Currently, it manages a transmission system consisting of 738 miles of transmission lines* from 115 kV to 450 kV direct current, 55 substations, a 200 MW back-to-back high-voltage direct current converter** and over 13,000 acres of rights-of-way. To monitor and control this system VELCO uses extensive fiber optic communication networks.
*686 miles owned by VT TRANSCO, LLC, 52 miles VETCO (HVDC)
**Highgate converter is jointly owned by several Vermont utilities (Burlington Electric Department, Vermont Electric Cooperative, Green Mountain Power, Vermont Public Power Supply Authority and Village of Johnson Electric Light Department).
- 1956: VELCO formed
- 1968: NERC & NEPOOL established
- 1972: Vermont Yankee begins commercial operation
- 1981: Rutland headquarters built
- 1982: VETCO formed
- 1991: Fiber optic cable installed for control and communication
- 1997: ISO-New England created
- 2003: Northeast blackout
- 2004: ISO-New England given system planning authority by FERC
- 2006: Vermont Transco LLC formed
- 2006: NERC certified as the electric reliability organizations for the US
- 2006: First Vermont Long-range Transmission Plan published by VELCO
- 2007: NERC reliability standards made mandatory and federally enforceable
- 2007: Vermont System Planning Committee established in Public Service Board Docket 7081
- 2011: First commercial wind to directly connect to transmission system
- 2013: First transmission project deferral