Note: The following story by David Baker appeared in the San Francisco Chronicle on May 31, 2010.
Faulty calibration. A component that shakes loose. Software that accidentally reboots.
Pacific Gas and Electric Co. has found a number of reasons why almost 45,000 of its SmartMeters haven’t worked as planned.
Since last summer, California’s largest utility has faced a customer uprising over the meters, which were designed to measure power use with precision and wirelessly transmit their data to PG&E.
Angry homeowners have accused the meters of gross inaccuracy, blaming them for monthly bills that in some cases doubled without warning. California energy regulators have launched an independent investigation, expected to last four to six months, that will subject the devices to a battery of tests in the field and in the lab. About 5.7 million have been installed so far.
PG&E insists that most of the soaring bills blamed on SmartMeters were actually caused by high electricity rates and heat waves. However, the company’s internal investigation has found several recurring problems with the meters and their installation. PG&E’s findings so far don’t explain every customer complaint about SmartMeters, and there remain a handful of meters spotted by PG&E that failed for reasons the utility doesn’t yet understand. All of the problems identified to date can be easily fixed, says PG&E.
The Chronicle spoke at length with Helen Burt, PG&E’s chief customer officer, and Bill Devereaux, senior director of the SmartMeter program, about those problems and their solutions. Two of the companies that make SmartMeters or their components – Landis+Gyr and Silver Spring Networks – also supplied information for this story.
Problem: installation errors
(Number of meters affected: 23,200)
The most common SmartMeter problem boils down to human error. Or rather, several different errors, most involving meters that measure natural gas usage.
PG&E SmartMeters that record electricity use are entirely new devices that replace old, analog predecessors. Gas SmartMeters, in contrast, are small modules that installers attach to existing gas meters to record and relay data.
PG&E found about 14,000 modules that weren’t attached tightly enough to their meters. While that sounds like a minor issue, it caused a magnet inside each module to be jarred loose. Those modules registered no gas usage at all, Burt said.
“What happened is the customer would be billed zero,” she said.
PG&E replaced the modules and worked with the company that made them, Aclara RF Systems, to change its manufacturing processes, Burt said.
Gary Moore, president of Aclara RF Systems, disputed that account, saying, “We have not made any changes to those modules. We haven’t had any incidents reported to us saying a magnet was falling out.” PG&E, however, stands by Burt’s comments.
Other gas modules – about 6,300 – weren’t properly calibrated to work with their meters. As a result, they either doubled the apparent usage or cut it in half. Fixing the problem requires sending a technician to the customer’s home or business to recalibrate the module.
One type of installation error affects SmartMeters that measure electricity.
SmartMeters for homes record electricity use once an hour, while those for businesses record once every 15 minutes. But in roughly 2,900 cases, workers installed the wrong kind, giving homeowners meters meant for businesses or vice versa. Putting the wrong meter on an account can confuse PG&E’s computer system. Burt said that problem could affect customer bills, although she wasn’t aware of any specific cases in which that happened.
The solution: Have the correct meter installed.
Problem: data storage
(Number of meters affected: 12,736)
In some meters, a software glitch causes the component that stores energy-use data to reboot itself occasionally, losing some but not all of the data in the process. Not every customer who experiences this problem will notice it.
“It’s not damaging to customers, because it would actually cause them to be billed for slightly less than they used,” Burt said.
To fix it, PG&E installs a software patch, much like the ones your computer regularly downloads from the Internet. The company has installed the patch in all meters that are awaiting installation, Devereaux said.
Problem: communication failures
(Number of meters affected: 9,000)
SmartMeters operate as a network, not as isolated machines.
They send their data to PG&E through “access points,” receivers typically placed on telephone poles. While some meters contact the access points directly, most transmit their data to other meters nearby, the information taking several “hops” before it finally reaches a meter communicating with an access point.
That system works for the vast majority of meters. But in some cases, meters have had trouble reaching the network, or reaching it on a regular basis. Customers may receive estimated bills as a result.
The meters may be located in an area where PG&E has just started installing SmartMeters and there aren’t yet enough meters and access points nearby for the network to work.
“Then we install more,” said Eric Dresselhuys, chief marketing officer for Silver Spring Networks, the Redwood City company that designed the network and makes communications components for the meters. “The problem self-cures as we build out the system.”
Or, individual meters may be located in rooms with poor wireless reception. Moving the meter can solve the problem. So can connecting it to an antenna that leads outside the room.
“To my knowledge, we’ve never drilled through someone’s home or dismantled a house,” Dresselhuys said.
Problem: measurement errors
(Number of meters affected: 9)
For all the complaints PG&E has received about inaccurate SmartMeters, Burt and Devereaux say the company has only found nine that don’t measure energy use correctly.
All are electric meters. Three of them undercounted energy usage, six of them overcounted. PG&E still doesn’t know why they failed.
“There doesn’t seem to be a common thread at all,” Burt said.
The company will ask the Structure Group, a consulting firm hired by the California Public Utilities Commission to investigate SmartMeters, to perform an “autopsy” on the defective devices. Landis+Gyr, one of the companies that makes SmartMeters, is already trying to figure out why one of its meters failed.
“We take this matter seriously given that, to date, we have delivered more than 2.5 million leading-edge smart meters to a wide variety of North American utilities without client complaint,” said Stan March, the company’s senior vice president of corporate communications.