Flexible transmission for high penetration

Google Translate

A new understanding of how to plan a transmission network for efficient uptake of sizeable penetrations of wind power is being demonstrated by the Alberta Electric System Operator, which has applied for regulatory approval of its forward looking investment plan for new wires

Transmission upgrades designed to connect thousands of megawatts of wind energy across the southern part of the Canadian province of Alberta over the next ten years are now awaiting regulatory approval. The Alberta Electric System Operator (AESO) filed a "need application" with the Alberta Utilities Commission (AUC) in December, proposing a 240 kV loop system that will gather output from a series of so-called "wind interest zones" and channel the electricity into the grid. The expansion will be built in three stages at a cost of C$1.83 billion, with work on the first to begin as soon as all the regulatory approvals are in place. The two later stages will be triggered by wind proposals as they mature through AESO's interconnection process.

"It's critical the transmission system has a flexible plan for development," says AESO's Neil Millar. "By applying to the AUC for all the development, but actually building it in stages as it's needed, we are in a better position to respond to the development pattern of wind in Alberta." The approach enables "prudent management" of the cost of new transmission wires, adds Millar. The first stage carries a price of C$750 million, while the remaining two phases will cost an estimated C$800 million and C$280 million, respectively.

Alberta has more than 11.5 GW of wind projects in its interconnection queue, about 7.5 GW of which are located in the south. "It's an understatement to say this transmission is needed," says Kevin Van Koughnett, managing director of wind resources planning for TransAlta Wind, a Calgary wind project developer and owner that would like to build at least 500 MW in the region over the next five years and has twice that amount in the interconnection queue. "If it is not put in place then none of these projects are going to move."

First step

The application is just the first step in the process, says Van Koughnett. Once the AUC approves the need for the new lines, which he hopes will be by mid-year or the third quarter of 2009, the transmission facility operator in the region still has to apply for a permit to construct and licence to operate (P&L) based on its detailed siting plan. "They've kicked it off, but what we need is good traction and drive to get it done," he says.

The looped system is a departure from the norm for the Alberta grid, but one that provides greater reliability and more options for generators, continues Van Koughnett. "If you have a looped system and it's covering a fair amount of geography, that means the flexibility for a generator to be able to interconnect at various places is really quite enhanced."

AESO has also "shifted to a new level" in its approach to planning transmission for wind by sizing the upgrades in a way that is going to serve the initial need as well as expansion for the future," he says. "I think AESO has stepped up here and has come up with a reasonably good plan. You never know how this is going to play when you get around to routing decisions, but they have done a lot of work and also a lot of consultation to put this plan together."

Enough for 4 GW

Total installed wind capacity in Alberta is currently 524 MW on a system that has about 12 GW of total generation. The application says the proposed upgrades will allow the interconnection of 2700 MW of additional wind in the south over the next decade, but Van Koughnett believes that is a conservative estimate. He expects the new lines could provide transfer capacity for as much as 4000 MW. Although that is less than the capacity of all the wind projects on the books in the region, Van Koughnett says it is a realistic volume to be planning for in Alberta's competitive power market. "A 2:1 ratio of proposed projects going to actual completion ain't too bad in my view. I think back to the gas turbine world and I bet you it was one project that proceeded for every ten proposed."

Alberta has not seen any major new transmission built in 20 years, despite a load growth of 28% since 2000 and an annual peak demand growth that is forecast to average 3.4% over the next 20 years. But efforts to get more wires capacity have so far proven to be a struggle.

The wind industry has been waiting nearly four years for a planned new 240 kV line in Alberta between Pincher Creek and Lethbridge that will allow connection of 600 MW of capacity in the southwest. Regulators approved the need for the C$133 million upgrade back in May 2005, but the AUC's hearing into the P&L application was not held until December 2008. The latest estimate is that the new facilities will be in place in the second quarter of 2010, assuming the permit is granted early this year.

Van Koughnett is hoping for a greater sense of urgency in getting the latest round of proposed upgrades in place. While the AESO application does not put a timeline on development, he believes the first critical piece -- a new double circuit link between the Peigan substation and Calgary with nearly six times the transfer capacity of the current line -- could be in place in 2012 or "with some optimism" in 2011. Another double circuit line to Medicine Hat in the southeast could be ready a year later.

Economic boost

Van Koughnett is also optimistic there will not be a lot of negative reaction to the plan in the largely rural south. "That's a tough question, but I would say, these days, for sure, anybody out there with their head screwed on right is not going to turn down economic development in any way, shape or form."

He points out that the plan will enable C$8-10 billion worth of capital investment in wind projects. "That's a huge amount of economic development in rural Alberta, where it is needed the most and appreciated the most. It is everything from property taxes to jobs to you name it," he says. "I have more concerns as you get closer to Calgary with the acreages and that kind of thing. But then again, the people closer to Calgary are more used to industrial development."

Have you registered with us yet?

Register now to enjoy more articles
and free email bulletins.

Sign up now
Already registered?
Sign in