There is the natural gas that heats your home. And there is the natural gas that lights up millions of homes.

It’s necessary to keep that in mind in thinking about these things.

The 550-megawatt natural gas power plant that Texas-based Panda Powers Fund is proposing for the old Century Brass plant in New Milford is one of the latter.

The proposal comes as big natural gas power plants, and the pipelines that were supposed to carry gas to them, have come under increased scrutiny. People who used to be reluctantly in favor of them are increasingly skeptical about the whole enterprise.

They acknowledge natural gas burns cleaner than coal or oil. It’s cheaper. But given companies mine that gas — the messy, methane-leaking process known as fracking — they’re deciding the pollution may not be worth the price.

“I was a big fan of natural gas two or three years ago,” said Connecticut-based energy consultant Joel Gordes. “Not so much now.”

Environmental groups — including the Connecticut Fund for the Environment and the Sierra Club — are doing a sort of watchful waiting on the New Milford project.

“Right now, we’d like a little more information about it,” said Margaret Miner, executive director of the Rivers Alliance of Connecticut. “But it does raise red flags. We are concerned.”

The New Milford project comes at a time when grand plans to increase the amount of natural gas coming into New England have stalled.

Kinder Morgan, a Houston-based petroleum company, dropped its plans to build a new pipeline to the region in May.

And last month, the Connecticut Department of Energy and Environmental Protection dropped out of its participation in the Access Northeast project, which would have greatly expanded the capacity of the Algonquin pipeline in the region.

DEEP spokesman Dennis Schain said the DEEP stepped away from Access Northeast when a Massachusetts court said electric bill ratepayers in that state could not be forced to pay the cost of building the pipeline through higher bills.

Schain said that decision shifted too much of the cost of the project onto Connecticut ratepayers.

“So we’re saying ‘Let’s back off that,’” Schain said.

However, the problem of how to provide enough energy for New England remains.

Because natural gas is cheap, clean-burning and plentiful, it now is the fuel source that’s generating most of the power in the region. The older, more polluting oil or coal plants are going off-line.

Schain said the problem comes in the peak cold days of winter, when natural gas flows into homes to keep them warm. When that happens, there’s not always enough natural gas to spin the generators at power plants.

Some of those plants can switch over and go back to burning oil, Schain said. ISO New England, which manages the power grid for the region, can also buy electricity from outside the region and use it here.

Which is why the New England states decided to work cooperatively to bring more natural gas to the region. Absent the new pipelines, it’s not clear where those collective plans are going.

Connecticut is bringing more energy into the state — though renewable energy. It recently announced it will join with Massachusetts and Rhode Island to buy energy from nine solar and wind projects that will collectively produce more than 400 megawatts of power.

“Connecticut is a big purchaser of renewable energy and increasingly so,” said Greg Cunningham, director of clean energy and climate change programs for the Conservation Law Foundation in Boston, which, like other environmental groups, is aware of the New Milford project.

Cunningham and Joel Gordes said the not-far-off game-changer will be when some company develops batteries to store energy produced by the sun and the wind, then feed that energy back into the grid. The arguments made against solar and wind energy — their inconstant nature — will go away.

Now, remember the homeowners who want natural gas? About 30 percent of homes in the state use natural gas, compared to about 50 percent in the rest of the Northeast.

Spectra Energy is now expanding sections of the existing Algonquin pipeline in the state, and building more powerful compressors along the line, in hopes of supplying them.

And Cunningham said the Conservation Law Foundation — which does not favor pipelines or big power plants — is OK with that.”

“It’s smaller and more incremental,” he said. “The reasons make sense.”

Contact Robert Miler at earthmattersrgm@gmail.com