Rhode Island regulators have approved new electric rates that would raise monthly bills for consumers in that state between 16 and 21 percent.
The increase could be an early warning to consumers in Massachusetts, where utility companies are expected to seek similar adjustments this fall.
The Rhode Island Public Utilities Commission voted in favor of the new rates following a lengthy public hearing Tuesday.
The new rates will be in effect Oct. 1-March 31.
National Grid is expected to file for a rate increase for Massachusetts customers in September to take effect Nov. 1-April 30.
According to the commission, the increase is due to the higher cost of energy, which utilities pass on to their customers. National Grid is prohibited by state law from profiting on the cost of energy, only its distribution.
Distribution costs, which make up about half a consumer’s bill, were not affected by Tuesday’s rate increase.
The increase boosted the cost of power to residential customers from 6.3 cents to 9.2 cents per killowatt hour.
Gov. Gina Raimondo said the higher rates will have economic consequences, particularly for those on limited incomes.