The notion isnt as twisted as it seems: the thousands of megawatts continuously cruising the provinces web of transmission lines are kept in near-perfect harmony with demand loads to ensure the grid remains stable.
But a lightning strike at the intertie between Alberta and B.C., the provinces main source of imported power, could throw off the balance between supply and demand if industry continues to suck power from the grid.
Hence the new Line Load Shed Service Imports LSSi announced Wednesday by the Alberta Electric System Operator.
The contracted project ensures six large power consumers in the province will immediately trim back their demand if there is a sudden drop in imports, said Kris Aksomitis, AESO manager for demand response.
This allows us to more fully utilize existing physical infrastructure, Aksomitis said.
The intertie with B.C. has a capacity of 1,200 megawatts for imports, but currently Alberta is limited importing 600 MW. The program would allow another 100 to 200 MW of power to flow in case of an emergency, say a lightning strike on the border, he said.
It balances off that instantaneous shortage by tripping loads, so it rebalances the system near instantaneously, he said.
The program is triggered when imports exceed 400 to 500 MW, at which point the participants are alerted to switch on specialized monitors. If frequency on the grid drops to 59.5 hertz from the normal 60 Hz. the monitors immediately trim power demand.
It allows us to import more because we can maintain stability after an event due to this service, Aksomitis said. Without this service we would have to limit how much we could import on the basis that if that supply disappeared we still have to maintain reliability.
The AESO selected 432 MW of load capacity for the program from Alberta Newsprint Company Ranger Board, a division of West Fraser Mills EnerNOC Ltd. ERCO Worldwide, A Division of Superior Plus LP Millar Western Forest Products Ltd. and Slave Lake Pulp Partnership.
Contract vary from one to three years. Terms were not released.
Industrial use represents 60 per cent of the power demand in Alberta, different from most other jurisdictions in Canada where residential use drives electricity loads.