In response to concerns about the accuracy of its smart meters, Pacific Gas & Electric earlier this year began comparing measurements of electricity use between conventional meters and smart meters mounted side-by-side on the same homes. Tests show that its first generation smart meters on average measure less energy use than conventional meters and its second generation smart meters on average measure more energy use. Bob Alvarez, chief of staff for Senator Dean Florez (D-Shafter), expressed surprise at the results and suggested that they are significant, even though he said the utility maintains they show variation within an acceptable range. PG&E did not comment on the results when asked. Florez highlighted concerns about the accuracy of smart meters in a series of hearings late last year and earlier this year in the Central Valley, which prompted the California Public Utilities Commission to order a third-party evaluation of their performance. The hearings also prompted the utility to run the side-by-side tests. Since PG&E began the tests around the end of April, its first generation meters have cumulatively measured an average of 14.8 kWh less energy use per household than its conventional meters. Its second generation meters on average have measured 4.6 kWh more power. At an average price of 16.3 cents/kWh--the bundled residential rate the CPUC reports for the utility--that would amount to an under-collection by PG&E of $2.41/household over a little more than three months for homes outfitted with first generation meters. On the other hand, over the same period customers with second generation smart meters would have overpaid PG&E by 75 cents. If the readings are accurate, extrapolating the difference to all 5 million PG&E customers would result in under-collections of $12 million over three months if all homes had first generation smart meters. Over-collections would amount to $3.75 million if every customer had a second generation smart meter. PG&E found higher variances for individual meters. For instance, one first generation smart meter measured 83 kWh more power usage compared to a conventional meter and another meter read 57 kWh less. For those households, based on average residential power prices, PGE respectively would over-collect $13.53 and under-collect $9.29. Second generation meters showed variation from meter to meter, though within a narrower band.