veto session” this fall, she said. A lot more batteries are being added to rooftop solar systems in Illinois, Anderson noted — a byproduct of the state clawing back net-metering compensation for solar-equipped customers starting this year. Similar dynamics have played out in Hawaii and California after regulators reduced the value of solar power that customers send back to the grid, making batteries that can store extra power and further limit customers’ grid consumption much more popular. Rooftop solar advocates have fought hard to retain net-metering programs across the country. But Jenny Chase, solar analyst with BloombergNEF, noted that most mature rooftop solar markets have shifted away from rewarding customers for sending energy back to the grid at times when it’s not needed. “ In some ways that’s justified, because net metering pushes all responsibility and cost of intermittency onto the utility,” she said. VPPs flip this dynamic, turning rooftop solar and batteries from a potentially disruptive imposition on how utilities manage and finance their operations to an active aid in meeting their mission of providing reliable power at a reasonable cost. Utilities have traditionally been leery of trusting customer-owned resources to meet their needs. But under pressure from lawmakers and regulators, they’re starting to embrace the possibilities. In Minnesota, utility Xcel Energy has proposed a ​