Technical considerations

What drives the need for transmission system expansion?


We evaluate the impact of transmission congestion on energy market prices and study projects to determine economic savings to offset most or all of the congestion and loss costs. An example is evaluating increased access to markets outside our footprint.

Solution: Two projects have been completed, two are planned, four are proposed, and another two provisional projects are being studied.

Renewables/Public Policy

All of the states in which we operate and most other Midwestern states have adopted renewable portfolio standards.

Solution: We are participating in several regional transmission studies to identify the transmission needed to integrate renewable generation, including wind, much of which could be located in areas remote from large load centers.

Load growth

Demand for electricity during peak usage periods is projected to grow at a rate of approximately 0.9 percent across our service territory from 2013 through 2022.

Solution: More than 110 projects are planned for assuring reliability, at least in part due to load growth.

Distribution interconnections

The transmission system is dynamic; changes in the marketplace, as well as changes in generation – new plants coming on line, older units being retired – drive the need for additional transmission-to-distribution interconnections.

Solution: 197 interconnections are planned in the next 10 years. More than 297 new or improved T-D interconnections have been made since 2001.

New generation

When a new generating facility is proposed, we conduct a system impact study and, if requested, a facilities study. If the existing transmission system is inadequate to ensure generator stability or reliable transmission service, we will determine what system expansion will be needed.

Solution: 11 generators are active in our generation queue, and many reflect the growing development of wind energy. 24generators added since 2001 required construction of transmission facilities.

Asset renewal

Keeping transmission lines, substations and related equipment in good operating condition extends the life of the facilities, improves system performance and safety, and minimizes the potential for outages. Part of the $3.9 to $4.8 billion investment ATC will make over the next 10 years is dedicated to asset renewal. Major projects at substations include replacing circuit breakers, protective relays, lightning protection and transformers. Major work on transmission lines involves rebuilding or upgrading aging power lines, including the replacement of structures, conductors, insulators and other equipment.

Solution: More than 100 projects to address asset renewal needs are planned in the next 10 years.

Transmission service requests

Virtually all entities that own power plants or provide electric service to customers, or both, seek to buy and sell electricity with other entities. We evaluate those requests to determine whether the transmission system will operate reliably if the request is granted. If the request can’t immediately be granted, we will identify transmission system reinforcements needed to grant the request.

Solution: More than 35 projects to meet transmission service requests have been completed since 2001.

Generator retirements

Similar to new generator requests, when a large generator is retired due to age or other reasons, we will determine how system requirements will be affected. Environmental regulations, market conditions and other factors are expected to impact retirements across the U.S. in the next 5 to 10 years.

Solution: Generation uncertainties are growing due to a number of factors. We are working closely with generation owners and MISO to anticipate reliability impacts to our transmission system.

Regulatory environment

Physical and cyber security and reliability standards continue to increase, which affect planning criteria.

Solution: We are participating in the NERC standards process to help anticipate the future impacts of these changes on our planning processes and systems.

Integration of new technologies

Demandside management, variable generation, distributed resources and smart grid technologies all require changes in how the grid is planned and operated to maintain reliability.

Solution: The type of flow-control device between Upper and Lower Michigan will be one of few utilized in the U.S.