An Illinois utility’s plan to accelerate and expand deployment of smart meters won approval from state regulators Thursday.

The Illinois Commerce Commission voted unanimously in favor of allowing Ameren Illinois to install advanced metering systems across its entire service territory, representing 1.2 million customers, by the end of 2019. Previously, the utility had planned to make the upgrades to just 62 percent of its service territory over the same time period.

“The state has gained confidence that we really are improving the delivery system,” said Victoria Busch, a spokesperson for Ameren Illinois, in response to the decision. “It’s paying off in that we’ve been able to reduce the number of outages, and we have actually been able to share some cost savings. Customers are engaged and interested in more ways to save.”

Thursday’s approval is one step in a massive overhaul of the state’s electricity sector. Ameren Illinois, along with ComEd, the largest utility in Illinois, are investing billions in upgrading the systems that generate, transmit, and ultimately deliver the power to consumers.

Smart meters – also called “advanced meters” – are seen by supporters as a critical component of a modernized grid, enabling utilities to wirelessly collect more detailed information about energy usage on a more frequent basis. Ultimately, they also give consumers an opportunity to view their energy usage data online, and to participate in pricing programs that help balance electricity supply and demand across the broader system.

Currently, over 330,000 Ameren Illinois customers have the advanced meters installed. Since 2012, the advanced meters and other infrastructure upgrades have improved system reliability resulting in 238,000 fewer outages and saving customers an estimated $47 million per year, according to the company. Ameren Illinois customers can expect to receive a notification letter about 60 days in advance of their smart meter installation.

The revised plan is expected to cost $324 million over a period of 20 years with benefits in operational efficiency, more accurate meter readings, and other improvements totaling $874 million, according to documents filed with the ICC.

The Environmental Defense Fund (EDF), an environmental group, and Citizens Utility Board (CUB), a nonprofit that advocates on behalf of Illinois ratepayers, were largely in favor of the revised plans, but with conditions.

“While Ameren identifies broad categories of customer benefits which I generally agree are possible, whether customers ever see these benefits should not be left to chance,” Andrew Barbeau, a consultant for EDF, said in testimony before the ICC in July. “The utility needs to take steps to make sure these benefits are realized, and as they do, they need to report to the Commission and others on their progress in doing so.”

CUB and EDF proposed that Ameren Illinois implement additional tracking mechanisms, offer additional pricing programs, and incorporate greater amounts of renewable energy deployment into its cost/benefit analysis. The ICC rejected all of these conditions.

“I think all Ameren customers deserve to benefit from the new meters, so this is a step in the right direction,” Jim Chilsen, CUB’s director of communications, said in an emailed statement Friday. “However, Ameren has to prove that it can do the smart grid right. If customers are paying for these new meters, they deserve to see benefits from these new meters. So we’ll be pushing Ameren to do this job right.”

More broadly, some critics have raised questions about data privacy and security in an era of increasing grid connectivity. In Illinois, the 2011 Energy Infrastructure and Modernization Act requires that utilities “secure the privacy of the customer’s personal information” and not use that information for mailing lists or other commercial purposes.

“The energy [data] that is used in a home or business will still be the same,” Busch said. “The only difference is that now we’ll be able to send that energy usage [data] wirelessly rather than manually reading it. So it reduces the amount of times that there are estimated bills, which customers don’t like.”

Note: This post was updated late Friday with more recent reliability data from Ameren Illinois.

David started writing for Midwest Energy News in 2016. His work has also appeared in InsideClimate News, The Atlantic, McClatchy DC and other outlets. Previously, he was the energy editor at The Christian Science Monitor in Boston, where he wrote and edited stories about the global energy transition toward cleaner fuels.