CARSON CITY, Nev. - The Nevada Public Utilities Commission voted unanimously to move forward with a new rate structure for customers with rooftop solar panels, in spite of loud and persistent protests from installation companies that say the switch will usher in a doomsday for their industry.

The three-member commission adopted a proposed order Tuesday that would reduce by 75 percent the amount NV Energy pays customers for excess power their solar panels produce and change the flat service rate for customers with solar panels. The changes in so-called net metering policies would phase in over five years, starting Jan. 1.

The exact amounts of the changes haven't been decided, but solar companies say they expect their customers' base service charge to double or triple over the five years. Base service charges are one part of an electric bill, which also include charges based on how many kilowatt-hours a customer uses.

"While the people of Nevada have consistently chosen solar, the state government today decided to take that choice from them, and damage the state's economy," said SolarCity CEO Lyndon Rive. "Gov. Sandoval's Public Utilities Commission has protected NV Energy's monopoly, but everyone else loses with this decision."

The company previously said the proposal would force SolarCity to cease operations in Nevada, although spokeswoman Chandler Sherman said shortly after Tuesday's vote that SolarCity hadn't decided on its next steps. An NV Energy spokeswoman, Jennifer Schuricht, said Tuesday that the company was reviewing the order to determine how it would impact customers.

The commission says the current rate structure shifts costs from Nevada's more than 17,000 net-metering customers to people without solar panels. A new structure would phase out subsidies that have been in place since 1997 and better reflect the cost of serving solar customers, who still use NV Energy transmission lines and tap into the utility's power at night or when their panels aren't generating their energy.

Commissioners did side with solar companies in declining to approve a new "demand charge," saying it could confuse customers and overwhelm them at a time when other rate changes are taking effect. The charge is more typically used for large commercial energy customers and reflects the cost of serving a customer when they're using the most energy.

Solar companies argued that customers would see a spike in their bill, for example, if they happened to have a blow dryer, a toaster and an iron going at the same time one morning, even though they kept their energy usage low in general.

The commission left the door open for future consideration of demand charges, noting they're gaining popularity around the country.

Solar companies are unhappy that the new rate structure would apply to customers who bought solar panels in years past, not just new ones signing on.

"The Nevada government encouraged these people to go solar, and now the government is putting them at great financial risk," Rive said in a statement.

The PUC staff wrote that the state needs a consistent rate structure regardless of when someone purchased solar panels, and that customers generally understand that utility rates are subject to change.

The decision caps nearly a year of high-profile debate about the future of rooftop solar policies in Nevada. State lawmakers deliberated this spring about a cap on the number of customers who can participate in net metering but decided to leave detailed solar policy-setting to the regulators at the Public Utilities Commission.

Still, solar companies upset with proposed changes have staged protests, circulated petitions and even filed a public records lawsuit against Gov. Brian Sandoval, saying he might be colluding with NV Energy lobbyists and they need to look through his text messages to find out. They have also faulted him for failing to intervene in the final decision of the PUC, whose members are appointed by the governor.

Sandoval has countered that the commission is a quasi-judicial body that acts independently of his office.

"I cannot, and will not, interfere with its deliberations or try to influence decisions issued by the PUC as it meets its statutory obligations," he said in a statement Tuesday. "I am hopeful that the commission will find a solution that takes into consideration the thousands of jobs created by this emerging industry while balancing the interests of all ratepayers."