Thursday, October 1, 2026
As Propel NY Energy moves closer to construction of its proposed $3.26 billion transmission project, local officials and environmental advocates are raising concerns about how underwater construction could affect Hempstead Harbor, including its shellfish populations, water quality and recreational uses.
The project calls for submarine cables to be installed beneath the harbor as part of an 89-mile transmission system intended to strengthen Long Island’s electrical grid. The work will have minimal environmental effects, according to Propel, while opponents and local officials argue that safeguards should be established before construction begins rather than after potential damage occurs.
Eric Swenson, executive director of the Hempstead Harbor Protection Committee, which has neither opposed nor supported the project, said the organization’s primary concern is the portion of the project that will be constructed in the harbor. Since 2024, more than 2 million oysters have been planted in Hempstead Harbor as part of restoration efforts, according to Swenson. He emphasized that the oysters are intended to improve water quality and help restore the harbor’s biodiversity rather than for commercial harvesting.
“If all of those 2 million oysters grow to full size, they have the capability of filtering 100 million gallons per day of seawater,” Swenson said, referring to the species’ ability to remove harmful chemicals like nitrogen from the water.
The proposed construction, he added, would involve four roughly 9-foot-deep trenches. He is concerned that jet plowing — whereby high-pressure water jets are used to clear the harbor floor — could disturb sediment and cause it to spread to nearby oyster beds.
“It doesn’t take much to smother oysters in order to kill them,” Swenson explained.
The Hempstead Harbor Protection Committee has requested turbidity curtains around the oyster beds, lower speeds for cable laying vessels and lower pressure during jet plowing. Those requests, Swenson said, have not been incorporated into the project’s plans.
Propel spokeswoman Marykate Guilfoyle wrote in a statement that the company has conducted extensive underwater surveys and modeling, and plans to conduct jet trenching trials before installing the cables. She also said that the water will be monitored for turbidity during the trenching.
“Our team is committed to delivering a project that provides urgently needed upgrades to our electric grid,” Guilfoyle wrote, “while protecting Hempstead Harbor through robust environmental safeguards, proven construction methods, and regular monitoring.”
She added that Propel’s modeling indicates that sediment disturbance will not reach areas oyster areas. “No oysters were found along the cable route in Hempstead Harbor,” the statement read, going on to say that the route’s mud substrate and central location in the harbor are not considered suitable oyster habitat.
The project has also raised concerns about potential impacts on hard clams. Propel’s Hard Clam Impact Minimization Plan assumes 100 percent mortality in certain areas affected by horizontal directional drilling and vessel anchoring.
Guilfoyle wrote that Propel estimates that a total of 9 to 54 clams could be affected by those activities.
“We do not anticipate measurable impacts to the overall hard clam population in Hempstead Harbor,” her statement read, “given the project’s limited footprint, temporary construction activities, and the low, patchy distribution of hard clams observed during surveys.”
Bruce Kennedy, Sea Cliff’s village administrator, previously told the Herald that the village has focused on protecting the harbor throughout its participation in the project’s regulatory process. He added that Sea Cliff has requested deeper burial of the cables to preserve existing uses of the harbor, including recreational anchoring. He also said that the village requested turbidity curtains to limit the spread of suspended sediment.
“They refused,” Kennedy said of Propel. “They will not put in sediment curtains.”
Kennedy also raised concerns about the timetable for assessing and addressing potential environmental damage. The project’s Joint Proposal, he said, ties a post-construction survey to “full energization” of the project.
“They tied the environmental damage survey to ‘full energization’ of an 89-mile project, a term they do not even clearly define,” Kennedy wrote in a recent statement. “Then they give themselves up to two more years to survey the damage and another six months to report what they found, with no firm deadline for completing remediation. That is not environmental protection — it is an after-the-fact autopsy.”
Kennedy said Sea Cliff has opposed the Joint Proposal because village officials believe that important environmental protections remain unresolved.
Christine Panzeca, a Glen Head resident who has opposed the Propel project, said she was concerned that years of work to restore Hempstead Harbor could be undermined by construction.
“I think we’ve done a great job, both federally and locally, as well as with private money,” Panzeca said, “to take great lengths to clean up the harbor.”
She said that residents use the harbor for swimming, boating and fishing, and that she was concerned about what might happen if construction disturbs contaminated sediment. Panzeca also questioned the project’s overall justification, and whether the potential environmental consequences are warranted.
“I don’t believe in a project that is promoted to protect the environment,” she said, “when it destroys the entire environment of the host communities it’s impacting.”
Propel maintains that construction impacts will be localized and temporary. Guilfoyle wrote that project modeling predicts that conditions will return to normal within hours of the trenches being dug, and that environmental monitoring requirements allow construction to be modified or temporarily paused if established thresholds are exceeded.
“The Propel NY project team has spent years engaging with local communities, incorporating stakeholder feedback, and conducting extensive environmental studies to help shape the project,” Guilfoyle wrote. “We are committed to delivering a project that will help prevent blackouts and brownouts on Long Island, while protecting Hempstead Harbor through robust environmental safeguards, proven construction methods, and regular monitoring.”
