PORTSMOUTH — Local residents will have their chance next week to see and comment on National Grid’s $93 million infrastructure upgrade plan and what it means for customers.

The utility company is hosting an informational meeting on Wednesday, March 16, to discuss its “Onisland” project, formally known as the Aquidneck Island Reliability Project. The meeting will run from 6:30-8 p.m. in the Portsmouth High School cafeteria, 120 Education Lane.

Town Administrator Richard Rainer made a point Tuesday of sending out a press release about the meeting, saying National Grid’s proposed changes to its infrastructure could affect local residents.

“I just want to make sure that we get the word out to as many residents as possible so people are informed,” Mr. Rainer said, adding that National Grid is sending out notices to all abutters about the project. “We’re just trying to make things as transparent as possible.”

He urged residents to read up on the project (http://onislandngrid.com) and attend next week’s meeting. “I think people need to know. If they have concerns, that’s a great venue to voice them,” Mr. Rainer said.

Under the proposal, National Grid will rebuild two transmission lines that run 4.1 miles through the center of the island along the utility’s right-of-way between substations on Dexter Street in Portsmouth and Jepson Lane, just over the Middletown line.

The transmission lines would be converted from 69 kilovolts to 115 kilovolts and be replaced on new, taller structures in a more streamlined configuration, according to National Grid.

Exactly how much taller is unclear, but National Grid’s website includes photographs of the existing lines and substations as well as renderings of the proposed structures for comparison. The poles for at least one of the new transmission lines, off Hedly Street, appear significantly taller than the existing ones.

“Because they’re going to be replacing the high-tension lines almost throughout the whole island, there’s going to be a new tower design and they’e going to be carrying more power,” said Mr. Rainer. “They are going to be higher, but they have a slimmer silhouette.”

On Tuesday David Graves, spokesman for National Grid, said he didn’t have the exact dimensions of the new towers, but acknowledged they will reach higher off the ground than the current ones.

“They are taller because it’s a vertical array,” Mr. Graves said, adding that because the lines run along the right of way, “people aren’t going to see it very much.”

He said next week’s open house is the second such meeting National Grid has hosted in Portsmouth. The first one, held last year, drew about “20 to 30 people” with few negative comments, he said.

Other improvements

The plan also calls for building a new and upgraded substation on National Grid property on Jepson Lane in Middletown, which will replace an existing substation across the street in Portsmouth.

The current station was built in the 1950s and is outdated, according to National Grid. Several other substations are being retired due to environmental concerns and equipment deterioration, according to National Grid.

In addition, the substation off Dexter Street in Portsmouth will undergo a reconfiguration following the removal of some existing equipment, although the site footprint would remain intact under National Grid’s plans.

Mr. Graves said the upgrades are vital to meet customer demand and maintain reliable service.

“We’re getting very close to the breaking point,” he said. “We no longer have the system in place that can meet the demands of the customer. We have to keep up with the demand on the island and that requires increasing the capacities of those power lines.”

Mr. Rainer said he doesn’t doubt National Grid’s need for a major overhaul of the island’s outdated electrical system.

“Something needs to be done,” he said. “Otherwise, in 10 years from now we’re all going to be having brownouts.”

Timeframe?

National Grid hopes to complete the Onisland project sometime next year, said Mr. Graves, adding the utility has another major project on its plate: a $107 million, 30-mile undersea cable system between Block Island and the mainland. Work on that project has already begun in Narragansett.

Residents unable to attend the March 16 forum still have the opportunity to comment on the project by calling a 24-hour hotline at 401/400-5862 or 800/568-4558; sending an e-mail to OnIsland@nationalgrid.com; and following the company on Twitter — @OnIslandNG — for the latest updates, event information and general National Grid news.