"We think that the meters probably aren't harmful, but there are people who claim they have some effects on them," Czarski added.
Libber, a Baltimore attorney who took smart meters on as a cause after retiring from the Environmental Protection Agency, argued that an industry-cited study that says smart meters emit a much lower level of radio frequency radiation than cellphones is inaccurate. He pointed to a rebuttal from a nuclear-policy lecturer at the University of California, Santa Cruz, who said an apples-to-apples comparison of exposures shows a far higher level from smart meters.
Because studies conflict about the cancer risk from cellphone use, the World Health Organization's International Agency for Research on Cancer classified radio frequency fields as "possibly carcinogenic."
With cellphones, at least, consumers have control, Libber said.
"The smart meter will be going 24/7," he said. "There will be no escape from it. … We really should know, before we start pouring lots of radiation into people's homes, what the impact will be."
Rockel, president of the Greater Timonium Community Council, is in the undecided camp. He brought BGE officials out last fall to talk to residents about smart meters, and his impression of the devices is "generally" good, but he hopes to invite an anti-smart-meter speaker out this spring. Then he'll make up his mind.
Of course, no one knows yet what the alternative will be.
"It sounds like they're headed in the right direction," he said of the Public Service Commission, "but I think the real devil is … what's the cost going to be."
Smart-meter advocates, insisting the device is safe, are voluble in its praises. The Smart Grid Consumer Collaborative, whose members include electric utilities, industry vendors and nonprofits, sees meters as a critical step in modernizing a system reliant on called-in outages and in-person meter reading.
Consumers with smart meters can go online to track their energy use by the hour. They can also access new types of energy deals. In Maine, for instance, customers now may sign up for "time of use" plans that charge less for energy used at off hours — between 8 p.m. and 7 a.m. — and more at peak times.
Energy suppliers might follow suit in Maryland. BGE, for its part, says it will offer rebates for pulling back on particularly high-usage days but no penalty for not doing so. Customers whose smart meters are up and running by July will be able to participate in that incentive program, with all smart-meter customers eligible by the summer of 2015.
More than 10 percent of BGE customers have smart meters so far. The company began installing them in the southern part of its territory last May — Anne Arundel and Prince George's counties are almost done now — and expects to finish the $482 million deployment at the end of 2014.
BGE has been phasing out its 100 meter-reading jobs — some employees have switched to other positions in the company — and also expects to save on trucks and fuel. Besides eliminating the need for manual reads, the meters allow utilities to remotely start or stop service and notify them about outages, cutting down on wasted trips in the aftermath of storms, BGE said.
Michael Butts, director of smart grid for BGE, said Hurricane Sandy in October gave the company a taste of the future. Officials knew exactly which homes had power and which didn't in neighborhoods with smart meters.
"With only about 10 percent of our meters installed, we avoided about 387 truck rolls," he said. "So if you extend that to the full system [in a] similar-sized storm, we're saving thousands of truck rolls."
BGE eventually will seek to recoup from customers the $282 million in smart-meter costs that weren't covered by a federal grant. But Robert L. Gould, a BGE spokesman, said the savings also will be passed on to customers — all of it. He said the utility expects to save about $2.5 billion over 10 years.
"This is not something that's going back to the bottom line of the utility," he said. "It's directly passed on to the customer."
That's another debated point in the smart-meter brawl, because opponents doubt anyone will see benefits but the utilities. Some officials agree: Illinois Attorney General Lisa Madigan argued in a 2011 Chicago Tribune opinion piece that smart-meter deployment in her state was turning in disappointing results on consumer savings.
Patty Durand, executive director of the Smart Grid Consumer Collaborative and a former Sierra Club official, has heard all the arguments against smart meters and thinks they "don't stand up under scrutiny."
But calls for opt-outs are tricky to ignore.
"To be fair, it's hard to say that consumers shouldn't have choice," she said. "That's not a message that works."