American Transmission Co. has completed its annual electric transmission system assessment and has identified $2.5 billion in necessary improvements over the next 10 years. The total includes $1 billion for transmission network upgrades, along with $1.5 billion in interconnection and asset renewal projects, infrastructure replacements and relocations, and other smaller network reliability improvements. That is down from the 2008 10-year assessment of $2.7 billion, although the current forecast may change due to regional initiatives to build transmission infrastructure to support renewable generation.

“While ATC has made significant progress since beginning operation in 2001, we continue our process to assess and reassess the needs of our customers to determine and evolve, over time, the best set of transmission projects to meet those needs,” explained Flora Flygt, director of transmission planning at ATC. “Now, more than ever, we are committed to an open, collaborative process to select best-value projects that resolve multiple electric system issues over a broad region.”

The $1 billion investment in new transmission infrastructure includes:

• 131 miles of new transmission lines.
• upgrades to more than 399 miles of existing lines.
• 21 new transformers and 29 new capacitor banks.

The ATC report lists nine regional collaborative planning initiatives in which ATC is leading or participating, including the SMARTransmission Study to identify extra-high voltage transmission infrastructure needed to move wind power within a nine-state region from the Dakotas to Ohio, as well as the Regional Generator Outlet Study being conducted by the Midwest Independent System Operator.

“While our reliability performance data indicates that our system is performing well, we are including more detailed information in this year’s assessment to acknowledge how we manage the risk of aging infrastructure,” added Paul Roehr, ATC director of reliability and interconnections. Previous assessments have discussed near-term asset renewal efforts, but this year’s report provides more detail of potential projects through the full 10-year planning horizon. That work would include:

• maintenance on aging equipment.
• connections to power plants.
• infrastructure replacements and relocations.
• distribution interconnections.
• other smaller network reliability improvements.

Since 2001, ATC has invested $2.1 billion in its transmission system, including:

• upgrades to more than 1,400 miles of transmission line.
• improvements at130 electric substations.
• construction of 36 new transmission lines (476 miles).

These reliability projects have reduced energy losses on the system that equate to

• 15.3 million megawatt hours of electricity saved (enough to power 35,500 homes each year).
• 14.2 million tons of carbon-dioxide emissions eliminated (associated with producing lost energy).
• averting the need for a 122-megawatt generating plant to serve peak demand.