About 41% of New York State’s 11,600 miles of high-voltage transmission lines are so old that they will need to be replaced during the next 30 years at a cost of more than $25 billion, according to a new study by an electric utility group. The study, the second phase of a long-term NYS transmission system assessment, identifies another $2.5 billion worth of incremental upgrades to existing lines and construction of new lines. The assessment includes current and future infrastructure demands and suggestions to improve the system’s reliability.

The study outlines several possible fixes to various parts of the transmission system, which faces challenges including a lack of capacity to handle current and future congestion. Bottlenecks in the system cost consumers $1.1 billion in 2010, according to the State Transmission Assessment and Reliability Study (STARS). It cites benefits of upgrading or replacing transmission lines including easing congestion, improving reliability, as well as creating jobs and economic growth.

Recommendations include new projects to increase transfer limits on lines that would be located in existing rights-of-way or with minor expansion of existing rights-of-way. These include a line running from Leeds in Greene County to Pleasant Valley in Dutchess County.

The study also suggests upgrades of several transmission lines that are approaching the end of their useful lives. Examples include an upgrade using the existing rights-of-way to a 345-kilovolt line that runs between Marcy in Oneida County and Rotterdam in Albany County.

The first phase of the study focused on identifying the need for additional transfer capability with the existing transmission system. Phase two aims to identify suitable, cost-effective transmission alternatives to meet additional transfer capability taking into consideration the age of the infrastructure and integration of renewable resources.

The state’s interconnected bulk power system is owned by six transmission owners—Central Hudson Gas & Electric Corp., Consolidated Edison Company of New York Inc./Orange & Rockland Utilities Inc., Long Island Power Authority, National Grid, New York Power Authority, New York State Electric and Gas Corp./Rochester Gas & Electric Corp.—all of which funded the study with support from the New York Independent System Operator and consultant ABB.