A fossil-free National Grid? Critics call it a pipe dream.

National Grid today released a plan to go fossil-free in order to meet Massachusetts’ 2050 net-zero climate emission targets.

The company’s “clean energy vision” is designed to transform the way the gas utility provides heat throughout its New England territory, while continuing to rely on its vast gas infrastructure.

Currently, most homes and businesses in the region burn natural gas for heat, which National Grid distributes to customers through a network of pipelines. By mid-century, if the company fails to change its business model, the net-zero requirements of the state climate law will essentially put it out of business.

Methane, the main component of natural gas, has a shorter lifespan than carbon dioxide, but is far more effective at trapping heat. Thousands of miles of pipes in Massachusetts leak methane, and are being repaired and replaced at an estimated cost of $20 billion.

The key to National Grid’s plan is using their same pipeline distribution system, but providing a different mix of gas, said Stephen Woerner, regional president of the utility: “We eliminate fossil fuels and we replace them with renewable natural gas and green hydrogen.”

Renewable natural gas — or RNG — is methane produced by decomposing organic matter. The utility plans to capture methane produced on farms, landfills and waste treatment plants and pipe it through its network.  "Green" hydrogen would be produced by offshore wind farms that split water into oxygen and hydrogen, with no carbon emissions. The company envisions a new gas mix including 30% RNG and 20% green hydrogen by 2040, and 80% RNG and 20% green hydrogen by 2050.

The company says it can meet Massachusetts’ climate goals and lower home heating costs 15-20%, while allowing customers to keep using their current home furnaces. During the transition period renewable gas will cost more; the utility plans to develop voluntary tariffs for customers who want it.

”We're not forcing customers to make any investments in replacing their infrastructure any earlier than they normally would,” said Woerner. He claims electrifying heating, as many environmentalists advocate, would require extensive and expensive additions to the regional electric grid. “This is the most cost-effective way to move forward, compared to the electrification scenario.”

One of the environmental groups calling for electrification of the region’s heating system is the Massachusetts-based Conservation Law Foundation. The group also advocates for the use of electric heat pumps and neighborhood geothermal heating, which uses the Earth as a battery to provide heat in winter and cooling in summer.

Caitlin Peale Sloan, vice president of CLF for Massachusetts, called National Grid’s plan “a false solution, just a way for the company to stay in business using their existing network of pipelines to distribute climate-disrupting gas.”

“Any plan that still counts on burning methane is not a decarbonization plan," Sloan said. She notes that methane, regardless of the source, is still a climate threat.

National Grid is the first of the five investor-owned utilities in the state to commit to a carbon-free system. Regional president Steve Woerner said the plan relies on advancing energy efficiency in buildings, and proving green hydrogen can be produced cost-effectively.

"We don't have all the details worked out, but we’re confident enough that we're ready to make this announcement as a company," he said. “Really, for us, it's a vision."