Technical considerations

What drives the need for transmission system expansion?


We evaluate the impact of transmission congestion on wholesale power 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.

Solutions: Two projects based on economics have been completed and two more are proposed.

Public policy

Pending air quality regulations, a maturing wholesale energy market and renewable energy mandates have introduced uncertainty and complexity in transmission.

Solutions: We work closely with our customers to determine what changes in their operations will impact the transmission system. We also 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.

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. Changing economics, age and recently issued EPA rules are expected to impact retirements across the U.S. in the next five to 10 years.

Solution: We are working closely with generation owners and MISO to anticipate reliability impacts to our transmission system.

Distribution interconnections

The transmission system is dynamic; changes in load forecasts, replacing aging distribution facilities, new customers and existing customers adding load all drive the need for additional and/or modified transmission-to-distribution interconnections.

Solutions: 110 planned in the next 10 years. More than 362 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.

Solutions: 12 generators are active in the ATC footprint of the MISO generation queue, and many reflect the growing development of wind energy and natural gas.  24 generators 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 $3.3 to 3.9 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.

Solutions: More than 110 projects to address asset renewal needs are planned in the next 10 years.

Load growth

Demand for electricity during peak usage periods is projected to grow at a rate of approximately 0.7 percent across our service territory from 2015 through 2024.

Solutions: More than 90 projects are planned for assuring reliability, at least in part, due to load growth. Approximately 3 projects were cancelled, in part, due to slower load growth rates.

Regulatory environment

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

Solution: We are participating in the North American Electric Reliability Corp.’s standards development process to help anticipate the future impacts of these changes on our planning criteria and facility design standards.

Integration of new technologies

Demand-side 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 three utilized in the U.S.