Ontario’s Electricity Grid

Ontario’s Electricity System is one of the cleanest systems in North America. We were among the first areas to eliminate coal from our supply mix and throughout the Province, systems are getting smarter and more reliable. Niagara-on-the-Lake Hydro is among the leaders of investing into our own system, installing smart switches and increasing the voltage along our lines to reduce line loss.

Supply Mix

The following are the sources of Ontario’s Electricity System in 2016:

Electricity Sources Ontario Electricity Mix*
Water (Hydro-electric) Power  23.3%
Alternative Power Sources 9.5%
Solar 2.2%
Wind 6.8%
Biomass 0.5%
Waste 0%
Nuclear Energy 58.5%
Natural Gas** 8.2%
Other 0.4%

*This includes both Tx (direct) and Dx (embedded) connected generation (Ontario Ministry of Labour). **Includes duel-fueled facilities that are predominantly natural gas (e.g. Lennox Generating Station).

Installed Capacity

The Province has over 40,000MW of installed capacity in the transmission and distribution system and occasionally imports electricity when needed. The following is the breakdown of installed capacity in the Province as of September 2017 (figures taken from the IESO).

Fuel Type Installed MW % of Total
Nuclear 13,009 32.47%
Gas/Oil 10,277 26.30%
Hydro 8480 21.76%
Wind 4213 11.96%
Biofuel 495 1.51%
Solar 2,377 5.93%
Other 24 0.06%


The System

The Province has an array of transmission lines that take electricity from generators to local distribution companies (LDCs). The province is grouped into several regions with their unique levels of requirements. For an interactive map of Ontario’s Electricity system that shows how they co-exist.

If there is anything about the grid that you’d like to know more about, let us know.