ALAMEDA — A data storage company wants to siphon water from the bay here to cool its equipment, a process it says is greener and more sustainable than using traditional air cooling.

But the idea is not winning over some environmentalists, because the water will warm slightly by the time it’s returned to the bay and they say that could potentially damage marine wildlife.

Earlier this month, Nautilus Data Technologies of Pleasanton presented its idea for the project to the Alameda City Council, which must sign off on the innovative project. Nautilus wants to lease three buildings at the former U.S. Navy base and run about a mile of pipeline.

It would install an intake system under a wharf where ships from the United States Maritime Administration are docked.

The water would pass through the data storage center before it was again piped offshore, where it would travel along the sea bed until it was discharged across from the Water Emergency Transportation Authority’s ferry maintenance facility.

An estimated 10,000 gallons of water would be piped each minute.

The council gave the proposal a mostly favorable reception, though it has not taken a final vote. And several state and federal bodies still must OK it.

What worries some is that the water will be warmer when it gets pumped back into the bay, especially since the discharge site is a spawning area for Pacific herring and a place where seabirds forage.

Harbor seals also rest on a nearby specially built floating dock, where they escape the bay’s chilly waters to lounge in the sun.

Councilman Jim Oddie said he fears the potential fall-out if the cooling technology fails.

“To me, the risks totally outweigh the rewards,” Oddie said at the May 7 council meeting.

“Some of these environmental disasters, once they happen, you are too late,” he said. “Like if the seals get disturbed and they don’t come back. That’s too late. They’re gone.”

Sometimes called server farms, data centers are centralized locations where computing and networking equipment is kept to collect and process large amounts of data. The centers store websites, run email, and provide other computing services, including some for governments and businesses.

The centers usually rely on air cooling systems. But more and more are turning to liquid cooling as demand on centers has grown, including through increased smartphone use and growing broadband connectivity.

Water cooling is more energy efficient than air conditioning because it requires less electricity, decreases air pollution and lowers greenhouse gas emissions, according to Nautilus.

Last year, Google opted to use a liquid cooling system that includes traditional plumbing for its newest hardware for artificial intelligence after the heat generated overwhelmed its previous cooling technology.

Along with Nautilus, companies such as Ebullient, Asetek and Green Revolution Computing are promoting liquid cooling as a green alternative.

Berkeley City Councilwoman Sophie Hahn told the council in a May 7 letter that it should reject the plan from Nautilus, alleging the higher water temperature could cause toxic algae blooms.

“The San Francisco Bay and its delicate marine ecosystem is already under enough pressure,” said Hahn, who chairs the Sierra Club’s Northern Alameda County Group. “Adding another impact from warm water discharge is too risky, especially when there is no compelling reason for a data storage facility on the bay shoreline.”

Nautilus is currently piloting its water cooling technology using a barge at the Port of Stockton.

“Our company was founded to be a solution to a very bad problem, which is the current technology,” CEO James Connaughton told the council.

The piped water is expected to increase about 4 degrees Fahrenheit as it passes through the system, Connaughton said. But he said the water temperature where it emerges likely will be “less than one-tenth of a degree Fahrenheit” different from the rest of the bay because it will immediately mix into the colder waters.

The annual average temperature in San Francisco Bay, which changes with the seasons, is about 56 degrees, according to the National Oceanic and Atmospheric Administration.

The marine consultant who helped develop the haul-out for the seals said the cooling system will have no impact on the pinnipeds, according to Nanette Mocanu, Alameda’s assistant community development director.

“If something like that were to happen, we don’t want to do the project,” Connaughton said. “That is not the objective of the project.”

Richard Bangert, an amateur environmentalist who monitors wildlife at the former Navy base, said the piped water should be discharged into the Oakland Estuary, where it would emerge colder because it would have traveled about twice the distance from the current proposed discharge location.

Only Oddie indicated he would not support a lease for Nautilus when it returns before the council for approval within the next few weeks.

Other council members wanted the terms tweaked to provide additional safeguards, including independent monitoring of the siphoning and discharge, as part of their anticipated approval.

Securing the lease does not guarantee Nautilus can move forward.

The San Francisco Bay Conservation and Development Commission, the state Department of Fish and Wildlife, and the U.S. Army Corps of Engineers are among those which must review and sign off on the plans.

“I am satisfied that regulations are in place that will address the concerns that people have raised,” Councilman Tony Daysog.

The proposed 15-year lease calls for Nautilus to rent a 82,251-square-foot building at 120 West Oriskany Ave., plus two smaller adjacent buildings. The city of Alameda is the landlord.

The company is pledging $6 million to renovate the main building, including installing a new roof, as well as an additional $1.5 million for infrastructure upgrades at the former base, which the city hopes will spur other redevelopment in the area.

The monthly base rent will kick in after the first 12 months and will start about $46,060. It will increase incrementally.

When fully up and running, the data center will have about 30 employees, Nautilus said. It’s projected to pay up to $2.5 million in annual revenue to Alameda Municipal Power, the city’s nonprofit electric utility.