Energy Expo: How Are New Transmission Projects Built in Alberta?
- Samantha Hoffman, P.Eng.
- Oct 17, 2017
- 5 min read
These posts are intended for everyone. The purpose is to explain some of the technical and economic concepts behind the power news in Alberta.
The Question
How Are New Transmission Projects Built in Alberta?
As discussed in last week's Energy Expo on regulation in Alberta, part of the Alberta Electric System Operator's (AESO's) mandate is:
Planning for the current and future needs of market participants and ensuring that the transmission system meets those needs (including forecasting);
Initiating new transmission projects to meet those needs.
This week's post will discuss how the system is planned and how new projects are initiated.
Alberta Transmission
Unlike generation in Alberta which is deregulated, transmission and distribution are regulated industries. Since it doesn't make economical sense to have competing power lines covering the same areas, Alberta is divided into service territories that are represented by transmission companies.
The major transmission companies in Alberta include ENMAX (Calgary), EPCOR (Edmonton), ATCO (mostly northern Alberta) and AltaLink (mostly southern Alberta).
In order to ensure that these companies don't overbuild and unfairly charge Albertans, new transmission projects must be approved by the Alberta Utilities Commission (AUC).
Project Types
For the transmission system, there are three main project types:
Connection Projects are initiated by customers and can include new generation facilities or new customer load. These projects can also be initiated to maintain an acceptable level of reliability for distribution customers.
Unlike transmission, for which reliability is the same across the province, distribution facility owners (DFOs) write their own reliability standards.
It's more cost effective to provide greater reliability to areas with higher population densities and urban customers typical expect higher levels of reliability. For this reason, there is not a one size fits all distribution solution for Albertans.
ENMAX and EPCOR have stricter reliability standards than Fortis which serves rural customers.
Typically customer connections only require additional breakers or transformers to feed the new load and convert the generated power to transmission voltages. In some cases, a new substation and transmission lines are required.
Transmission Facility Owner (TFO) Initiated Projects are initiated by TFOs when equipment has reached end of life or if equipment ratings are expected to be exceeded (for example short circuit currents or harmonic levels).
AESO approval is not required for these projects. TFOs write business cases to justify these projects and they are approved by the Alberta Utilities Commission (AUC) when TFOs seek approval for their rates of service.
System Projects are initiated by the AESO after studying the transmission system for deficiencies.
The AESO determines which areas require new transmission infrastructure to remain compliant with Alberta Reliability Standards.
The Transmission Planning (TPL) Standards outline the requirements for new transmission projects.
The projects are typically the largest projects built in the province. The remainder of this post explain how the how system projects are initiated.
Planning the System
Every two years, the AESO develops a Long-Term Transmission Plan for Alberta. The plan details the general timing and location of projects required to meet Alberta's electricity needs 20 years into the future.
Building Base Cases
In order to determine what new infrastructure is required, the AESO develops simulation base cases for future time frames (typically 5, 10 and 20 years ahead). For each time frame, approved projects are simulated and load is modeled based on the AESO Long Term Outlook.
The AESO will typical use multiple load and generation scenarios (for example low growth, high growth, high renewable integration, etc.) in order to stress the bookends.
Since the AESO must guarantee reliability at all times of the year, the base cases studied focus on the days with the highest load.
The system typically peaks in the summer and winter (when it is very cold when consumer heating stresses load and when it is very hot when air conditioning stresses load). These are called the summer and winter peaks.
Contingency Analysis
Once these cases are built, study engineers run contingency analysis on the base cases.
Contingency analysis systematically goes through every possible outage and determines whether any equipment becomes overloaded (if power flow through the equipment exceeds the equipment power rating).
The TPL standards require that no equipment become overloaded in normal operation (when all facilities are in service) and following the loss of a single piece of equipment.
The TPL standards allow for controlled loss of load (black out) for the loss of two pieces of equipment. These scenarios are studied for maintenance which is done in the spring and the fall when the provincial load is at its lowest.
The AESO may also study the impacts of more severe events (the loss of several pieces of equipment) if the impact of the event is severe and if the event is relatively probable.
Solutions to Deficiencies
Once the AESO determines where the system deficiencies exist and whether scenarios at which they appear are probable, they work with TFOs to find cost effective, holistic, long term solutions to the deficiencies.
This usually involves increasing equipment ratings of transmission lines and auto-transformers or building new substations, transmission lines and auto-transformers.
To visualize: if too much power flowing through a line, if the line is bigger or if a second line is built to provide a new path for power to flow, this will eliminate the overload.
However there are other ways to resolve overloads, for example phase shifting transformers can redirect power flow and some jurisdictions outside of Alberta have experimented with batteries to reduce demand during peak load.
The AESO summarizes the proposed projects in their Long Term Plans.
Initiating New System Projects
When the AESO identifies that a new project is required to maintain reliability. They work with the TFO that is responsible for the project's service territory to develop a Need Identification Document (NID).
This document outlines why the project is needed and what their proposed electrical solution to meet the need is. It is approved by the Alberta Utilities Commission.
Impacted stakeholders have the ability to provide feedback on the project through the Public Involvement Program (PIP) that is required for all projects. They can also provide feedback to the AUC during the project's hearing.
Once the AESO's NID is approved, the TFO files a Facility Application (FA) and a Proposal to Provide Service (PPS) which outlines in detail how the proposed project will be physically constructed.
Tha FA typically receives the most public push back since this application details how residents are impacted.
Once the Facility Application is approved, construction can begin on the project.
Bill 50
In 2009, the Alberta Government under Ed Stelmach legislated Bill 50 which gave his cabinet the ability to mandate future transmission facilities as Critical Transmission Infrastructure and bypass the regulatory process.
The government approved four transmission projects which included the two HVDC lines: Eastern Alberta Transmission Line (EATL) from Brooks to Redwater and Western Alberta Transmission Line (WATL) from Edmonton to Calgary.
It also included a new 240 kV substation in southwest Calgary and two lines running from Edmonton to Fort McMurray.
However in 2012, the Electric Utilities Amendment Act removed this authority under Alison Redford's leadership.
Future Questions
Do you have any other burning questions about electricity or power generation for future Energy Expos?
Comment below or send them to info@skhoffman.com
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Further Reading
For more detailed information on this topic, check out these resources:
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