WASHINGTON » Like manna from heaven, thousands of dollars in new revenue is raining on a group of congregations here from the unlikeliest of sources: the utility bill.

The windfall arose after 11 churches and a nonprofit youth group got together to solicit reduced-rate bids for electricity — most of it from renewable energy sources — from local suppliers. In the first year of its contract, which ends in May, the group expects combined savings of nearly $100,000.

As the good word has spread, and it gears up to negotiate a second contract, the original group has swelled to 40 members. The bigger alliance plans to exercise even more leverage in the next round of negotiations by requiring bidders to extend the same discounted rate to individual parishioners and members.

And more revenue is on the way: The group is planning to take a cut of those residential savings as a kind of eco-tithe.

"These are not the kinds of things that are taught at seminary," said the Rev. Dr. Donna Claycomb Sokol, pastor of Mount Vernon Place United Methodist Church, which is joining the bulk purchasing this year. "How to save money with our energy — it’s innovative and exciting."

With their cavernous sanctuaries, large meeting spaces and multi-use buildings often open day and night, churches, synagogues and other religious spaces are particularly clobbered by utility bills that can run into the thousands of dollars each month. Beyond dollars and cents, many congregations also consider environmental measures such as reducing B greenhouse gas emissions as part of theirB duty to care for God’s creation.

The Energy Star program, which created a certification system for houses of worship a year and a half ago, calculates that by cutting energy use by at least 10 percent, the nation’s estimated 370,000 religious buildings could save a combined $315 million a year and reduce emissions by the equivalent of taking 240,000 cars off theB road.

"That $315 million would be available for their missions helping the poor and the needy," said Maura Beard, a spokeswoman for Energy Star.

Many congregations already treat the environment as a fundamental part of their mission. Officials with Interfaith Power & Light, a network of religious institutions with affiliates in 38 states, said members are installing solar panels, undertaking energy-saving retrofits, buying green power, instilling a love for the earth in sermons and lobbying elected officials for clean energy alternatives.

"It’s about values and moral responsibility," said the Rev. Canon Sally G. Bingham, the Episcopalian minister who founded the network in San Francisco in 2000 and has seen it grow to 14,000 members, with nearly half of them signing on in the last four years.

"Some are doing it for financial reasons, but most do it because of the devastating effects of pollution on poor people," she said. "Every mainstream religion has a mandate to serve each other, especially the poor."

The churches in Washington forged their alliance with help from the Washington Interfaith Network, which does community organizing for member congregations and is now receiving a 10 percent cut of the overall electricity savings. The other group that helped bring the churches together, the DC Project, is a nonprofit that promotes weatherization and green energy jobs.

Felipe Witchger, lead organizer with the DC Project, said that the next contract will require participants, which now also include synagogues and affiliates like unions and advocacy groups, to either buy renewable energy or commit to energy-efficiency upgrades. For the upgrades, he said, workers from neighborhoods with high unemployment and poverty rates would be hired.

At St. Columba’s Episcopal Church in northwest Washington, an environmental committee was created from the congregation of 3,800 several years ago to come up with energy-saving measures like installing motion sensor lights and purchasing wind power through the local utility.

Still, said Paul J. Barkett, the church’s chief operating officer, St. Columba’s faced monthly energy bills that averaged $8,000, mostly to heat and cool of two buildings housing the church, which opens its showers, washers and dryers to about 35 of the community’s homeless people.

St. Columba’s expects to save up to $12,000 a year after joining the purchasing group. The church operates on an annual budget of $2.4 million that is mostly drawn from parishioners’ contributions, he said.

"Every dollar we’re not giving to Pepco for electricity," Barkett said, referring to the local utility, "it’s a dollar we can put into our mission and ministry and furthering our presence."

It is not unusual for businesses, municipalities, schools and other institutions to come together to buy electric power in bulk for a discounted price, said the Retail Energy Supply Association, a trade group. But congregations banding together across denominations — and working into their contract energy efficiency improvements and residential discounts for members — are fairly new, some energy companies said. This is possible in markets like Washington and 16 other states where multiple power suppliers compete for business.

In its first year, this approach will result in electric bills that are 15 percent to 20 percent lower and annual savings that range from a few thousand dollars to $33,000 per institution, according to the DC Project.

Some companies are particularly excited about the potential to add thousands of residential customers through the religious group.

"We’re now getting new customers in the D.C. marketplace in a very innovative way," said Nelson Reyneri, vice president for national accounts at Liberty Power, the national retail energy company based in Florida that won the group’s first contracts and plans to bid again. But not all congregations are buying green power, which sells for about $1 more per megawatt hour than conventional energy.

"I’m not sure that I understand the whole green thing," said the Rev. Al Hammer, an associate pastor at Foundry United Methodist Church.

"You’re not really buying green power," he said. "You’re basically buying credits, and it gets really confusing. I’d rather move away from that until they get it clear."

So for now, he said, he will stick with conventional power and use the savings to fix the church’s drafty windows.

The Rev. Thomas J. Knoll of First Trinity Lutheran Church said he worries that energy savings may not be sustainable themselves if electricity prices fluctuate too much and an increase shrinks the pot of money his church is relying on.

Though cautious in his enthusiasm, Knoll said the expected discounts, in particular for individual members of his 140-member congregation, would come in handy as a recruiting pitch.

"I’d say to people: if you join this church, you can also apply for a lower electric rate," he said. "Why wouldn’t I do that? It’s the truth."

© 2011 The New York Times Company