(TNS) — Anxieties about accelerating climate change are less global and more local as U.S. senators from New England press the region’s electric grid operator to more aggressively promote carbon-free energy.

As states increasingly look to reduce greenhouse gas — Connecticut announced Thursday its biggest wind power project yet — eight U.S. senators say ISO-New England is moving at a glacial pace to make zero-emission energy sources more of a priority.

“New England states take the threat of climate change seriously and have adopted some of the most ambitious climate and clean energy laws in the country,” the senators wrote to the Holyoke, Mass., based grid operator in November. “ISO-NE appears to be pursuing a patchwork of market reforms aimed at preserving the status quo of a fossil fuel-centered resource mix.”

Gordon van Welie, ISO’s president, defended its policies while emphasizing its critical responsibility: to keep electricity flowing without interruption.

“New England’s competitive wholesale markets have kept the lights on while simultaneously achieving dramatic reductions in emissions, resulting in one of the cleanest, most efficient fleet of resources in the country,” he said in a response posted on ISO’s website.

Carbon dioxide, a driver of climate change, has fallen by 34% in New England between 2001 and 2017, according to to ISO and the U.S. Environmental Protection Agency.

The dispute, which has engaged state officials and is now being ratcheted up by the federal legislators, focuses on rules and federal regulations governing a six-state energy market serving 7.2 million retail electricity customers. State officials promoting wind and solar energy see the regional grid as essential for plugging in zero-emission sources of energy.

“Sadly, there’s some missed opportunities and missed leadership at the ISO to help achieve state policies,” said Katie Dykes, commissioner of the Connecticut Department of Energy and Environmental Protection.

Dan Dolan, president of the New England Power Generators Association, said players in New England’s energy markets have long been pressing ISO to align its energy sources with state policy.

“We’ve been banging this drum for almost a year and a half for changing the way electricity markets are integrated to state contracted resources,” he said.

Dolan compared ISO to an ocean liner that can’t easily turn around.

Sen. Richard Blumenthal, D-Conn., was more critical, saying ISO officials have “institutional tunnel vision.”

“They have one lane, and their institutional mindset operates in that one lane,” he said. “They’re resistant to innovation and consumer interests."

In addition to Blumenthal, senators who wrote to ISO include Chris Murphy of Connecticut, Edward Markey and Elizabeth Warren of Massachusetts, Jack Reed and Sheldon Whitehouse of Rhode Island, Bernie Sanders of Vermont and Angus King of Maine. All are Democrats except Sanders and King, who identify as Independents.

In their letter to ISO, the senators said the grid operator “has charted its own path forward and pursued unpopular initiatives” such as policies that force state-sponsored renewable energy to wait for fossil fuel generators to retire before “clean resources” can enter the market.

ISO’s van Welie said the grid operator has advocated carbon pricing that would help reduce or eliminate fossil fuel-based energy. The policy has failed to win support from the states, he said.

However, Greg Cunningham, director of clean energy climate change at the Boston-based Conservation Law Foundation, said van Welie is referring to carbon pricing within ISO markets. Several New England states are crafting their own carbon pricing policies, he said.

“The suggestion that ISO New England has made an effort in this regard I would suggest is a vast exaggeration,” Cunningham said.

The senators also criticized an ISO policy known as energy security improvements intended to make sure sufficient power is available during periods of extreme cold, such as the polar vortex when demand spiked during bitterly cold winters. The policy “appears to ignore the reliability and other benefits of clean energy and further delays market reforms that recognize and facilitate state public policies to grow clean energy and address climate change,” the senators said.

ISO said its energy security improvements policy is intended to reward energy resources — zero emissions or carbon-based — that ensure reliability.

“For example, a solar facility with battery storage has the same opportunity to provide these reliability services as a natural gas plant with a contract for liquefied natural gas or an offshore wind farm that operates at a high capacity factor during winter,” van Welie said. “All may be rewarded under the ESI design.”

ISO’s energy security improvement policy could accelerate the transition to zero carbon, renewable resources and storage technology by recognizing and compensating the resources for their reliability, he said.

Anne C. George, ISO’s vice president of external affairs and corporate communications, said officials at the grid operator do not believe they’re being pressured by state officials and members of Congress.

“We feel a little frustrated," she said. "We’re proposing pathways that are taken off the table.”

©2019 The Hartford Courant (Hartford, Conn.). Distributed by Tribune Content Agency, LLC.