Harry Christian knocked on the door of a rowhouse in North Philadelphia, but the resident who had agreed to allow a Peco Energy Co. technician to install a new electric meter was not home.

"She went to work," said a neighbor sweeping leaves on North Lambert Street.

Peco Energy has installed 1.7 million new-generation smart meters in its six-county service territory, more than 99.2 percent of a planned deployment over five years. But the last remaining customers are a chore.

"Now we're down to the hard-core accounts," said Christian, who set off for a rear alley to see whether the customer's meter was accessible.

Peco has spent $733 million on advanced metering infrastructure, including a wireless communications network linking the devices. The Obama administration kicked in a $200 million federal stimulus grant in 2009, part of a $3.4 billion investment to modernize the nation's power-distribution grid.

Smart meters allow the utility to establish two-way communication with each customer, giving Peco instantaneous and granular insights into a vast network whose on-the-ground operations could not previously be monitored in such detail.

Still in need of new meters: only 12,970 electric customers.

The program has encountered obstacles. About 50 Peco customers filed challenges with the Pennsylvania Public Utility Commission, seeking to opt out of the meters. The PUC ruled that the 2008 law ordering state-regulated electric utilities to install the devices allowed no exceptions.

In 2012, the safety of the digital devices was called into question after several new meters overheated and caught fire. Peco suspended installations, regrouped, changed vendors, and replaced 186,000 newly installed meters. It improved installation practices and meter-testing procedures.

"We have not incurred any overheating incidents in the course of the 1,700,000 installs since then," said Derrick Dickens, Peco's director of advanced metering infrastructure strategy.

Smart meters were trumpeted as a way for customers to monitor energy consumption, ushering in hourly "dynamic" rates that would incentivize users to shift load to off-peak hours, more efficiently using the system's resources.

But the new consumer revolution has not really materialized.

Peco's website now allows registered customers to monitor their hourly power use, and to compare their consumption with that of their neighbors. But no competitive suppliers have stepped up to offer them time-of-use residential rates. And manufacturers have not introduced many smart-grid gizmos to connect to the new meters, such as appliances wired to operate at night, when rates might be lower.

The utility maintains that smart meters have benefited consumers in meaningful but less visible ways, by reducing outages and by cutting costs.

The new digital meters allow Peco to connect or disconnect customers remotely, thus avoiding 105,000 vehicle trips last year, said company spokeswoman Cathy Engel Menendez.

Smart meters, integrated into the larger smart-grid system, allow the distribution system to automatically detect faults and to reroute power to minimize disruptions.

During storm outages, Peco says, the smart-grid system allows it to more efficiently dispatch repair crews, and to better detect "nested outages" of customers whose service remains disrupted after power is restored to the surrounding area.

The technology helped reduce power-restoration time by a day after a June 23 storm, and helped the company restore service to customers two to three days more quickly after a massive ice storm in February 2014.

Tampering by customers can be detected by smart meters, and they can send alarms to Peco if a customer's service is overheating.

"Now that the system is in, we can really start to extract the value," said Dickens. "There's so much data there that we have to sit down and figure out how to mine it."

It's that very data that worry some customers. Some privacy advocates suggest the meters are part of a government scheme to ration resources, and they have declined Peco's requests for access. But legislative efforts to allow Pennsylvania customers to opt out have failed to advance.

Peco says that the meter's wireless data transmissions are encrypted so the "microbursts" of information can't be hacked, and that the data measure only overall consumption and do not identify which appliances are in use.

About 2,800 Peco customers initially refused to allow smart meters to be installed for privacy or safety reasons, or because of concern about emissions of radio waves. Of the 985 customers who still refuse, nearly half cite health worries, mostly about electromagnetic radiation.

Susan Kreider, 58, of Germantown, a registered nurse who believes she suffers from electromagnetic hypersensitivity, is one of Peco's more tenacious opponents. She said she suffered "deleterious health effects" after Peco installed the meter, including elevated blood pressure and poor sleep. But she said her health improved after she paid an electrician to replace her smart meter with an old-style analog meter she bought on the Internet.

In September, the PUC voted to allow an administrative law judge to hear Kreider's claims. The ruling raised alarms at Peco, which called on the commission to reconsider the order, saying it was contradicted by many previous PUC rulings.

"Now is not the time to change the rules of the road related to universal installation of this technology," Peco said.

There is no science to support claims about health effects, the utility says. It also says the new smart-meter technology emits fewer radio waves than the wireless meters being replaced.

On Oct. 1 the PUC voted to reconsider its order. The matter is unresolved.

Active protesters such as Kreider account for a fraction of the 12,970 customers who still don't have smart meters. Most did not respond to Peco's requests to access their meters.

Such as on the recent autumn morning when Christian, confronted by the no-show resident on North Lambert Street, went on a woodsy exploration through backyards.

Hoping that the customer's rear yard was accessible, Christian ventured though vacant lots filled with weeds, discarded mattresses, and construction debris. A dog barked. Christian shouted, "Electric!" as he approached, so he wouldn't be confused with a prowler.

But the homeowner's gate was locked. Christian is not authorized to climb fences.

"It's impassable," he said. The utility would reschedule an appointment, and step up threats to shut off the service for noncompliance. So far, service to four customers has been terminated.

But Christian's bushwhacking mission was not without reward. He noticed a missing electric meter on a boarded-up house nearby that appeared to be undergoing repairs. A lightbulb burned in the basement.

He put on his fireproof mask and gloves, and removed a plastic bag that was stuffed into the void where the meter should be mounted. He yanked out the wires that had been installed to make the illegal connection.

"I can't leave it in an unsafe condition," he said.

After checking the wiring on the meter board, Christian installed the smart meter that had been intended for his initial target. The device awakened and reported its GPS coordinates to the Peco system. The lightbulb inside the house came back on.

One more smart meter deployed.

The owner of the house, a Montgomery County landlord with a history of tax and utility arrearages, will be contacted by Peco's Revenue Protection Unit to settle up.

215-854-2947@maykuth