MIDDLETOWN — The new National Grid electrical substation located on Jepson Lane is in its final stages of construction.

Work is expected to be completed this fall and the new facility will begin serving Aquidneck customers shortly thereafter, according to the National Grid website. Deconstruction of the old Jepson substation, located across the street from the new site, is scheduled to begin in spring 2021 and will be maintained as an open green space once the substation is completely removed.

The "OnIsland" project represents a substantial upgrade to the electrical system in all three communities on Aquidneck Island. Here are some of the highlights, according to National Grid:

• The new substation is an upgrade from 69 kilovolt to 115 kilovolt, replacing an outdated facility built in the 1950s. The new substation will consist of two transformers supplying six 13.8kV feeders and two more supplying three 23kV supply lines.

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• A new 69/13.8kV Newport substation will be built with a single transformer supplying four 13.8kV feeders, reconfiguring the area distribution system and adding 60MW of new 13.8kV capacity in Newport for greater electricity reliability in both Newport and southern Middletown.

• The Dexter substation will undergo a reconfiguration following the removal of some existing equipment. However, the substation footprint will remain intact.

• The North Aquidneck, South Aquidneck, Bailey Brook, Vernon and Jepson substations will be retired from service, addressing some environmental and equipment deterioration concerns.

• Two transmission lines, Lines 61 and 62, located in National Grid-owned rights-of-way, will be upgraded from 69kV to 115kV.

• The project replaces and upgrades various parts of the local distribution system (the lines in the streets that tie into homes and businesses) in Middletown and Newport to ensure the more reliable delivery of electricity.