Electric transmission FAQ

Electric transmission lines carry electricity from power generation facilities to areas where electricity is needed. The Ohio Power Siting Board (OPSB) reviews and certificates the siting of electric transmission lines and associated facilities of 105 kilovolts (kV) or more within Ohio.

What is behind the recent increase in electric transmission upgrades?

Several factors have influenced a recent increase in electric transmission upgrades in Ohio. The recent retirement of several coal-burning power plants has affected the supply of electricity in Ohio and across the region. In order to meet these changes and maintain and improve system reliability, Ohio’s utilities are installing new transmission infrastructure to reroute power across the electric grid. Certain transmission upgrades are required by PJM Interconnection, the regional transmission organization that is charged with monitoring the reliability of the electric transmission grid in Ohio. The growth of the oil and gas industry in eastern Ohio, and the corresponding increase in demand for electricity to serve processing facilities and liquids fractionation plants, has also been a contributing factor. Additionally, as the electric transmission system ages, regular repairs and upgrades are needed.

Where are electric transmission lines constructed?

Electric transmission lines are constructed within a right-of-way owned by a utility company or acquired under an easement with the property owner. Utilities may choose to acquire new right-of-way, rebuild existing structures with a current right-of-way, utilize “open-arm” positions on an existing structure, or combine these scenarios to site a new transmission line.

What are substations?

Electric transmission lines connect to substations – facilities comprised of transformers, circuit breakers, and other electricity control equipment. Substations perform multiple purposes: stepping electricity levels up or down, transferring power from the transmission system to a distribution system, collecting power from generation facilities, or functioning as a switching station for rerouting electricity on the grid. A substation is considered a transmission facility under OPSB jurisdiction if the voltage into and out of the station is equal to or exceeds 100 kV.

How do utilities present their transmission line applications to the OPSB?

Depending upon the scope and purpose of the project, utilities are required to submit a standard certificate application, letter of notification application, or construction notice application to the OPSB. These three methods of seeking Board approval dictate the length of the review process.

In a standard certificate application, utilities must provide a “preferred” and an “alternate” route to the OPSB. These dual proposals are based on route studies, and both routes must be viable for construction. Utilities may also seek the OPSB’s approval to submit projects with a “common route,” where parts of the proposed preferred and alternate routes run in the same location. Use of a common route is often sought when the routes use existing right-of-way or when environmental constraints limit the number of viable route locations.