The net-metering program, narrowly approved by a vote of 3-2 by the California Public Utilities Commission, will require that new solar customers pay a one-time interconnection fee, estimated between $75 and $150, and begin paying fees of a few cents a kilowatt-hour that most other customers already pay. Those charges fund low-income and energy efficiency programs.

Solar customers will also be compensated at different rates depending on when they send their excess power to the grid, a change that will alter the economics of the system but not undo its appeal, experts said.

The changes do not affect customers who already have solar panels or who install them before the utilities in their area reach certain levels of rooftop use in their service territories, which the California Solar Energy Industries Association, a trade group, estimates will happen by early next year. And regulators, who are to re-examine net metering again in 2019, left open the possibility that they could revise or add charges.

“Our course is not for the rooftop solar industry or for the utilities or the community clean energy aggregators,” Michael Picker, the utility commission president, said in a prepared statement. “Our decision today is another big step toward giving California consumers more choice, more control and more responsibility over energy and climate change issues.”

Bernadette Del Chiaro, executive director of the California Solar Energy Industries Association, said the decision was an important statement that California would continue to develop microgrids and decentralize energy production.

“It’s a more 21st-century way of generating our electricity,” Ms. Del Chiaro said. “It’s not just net-metering 2.0, it’s grid 2.0 that this decision essentially ushers in.”

Solar executives concurred. “Solar customers have to pay more, but it’s still a viable solution and it will still allow for a growth market in the state, and at the same time provide more benefits to the grid,” said Lyndon Rive, chief executive of SolarCity, the country’s leading rooftop solar provider.