PROVIDENCE (AP) — Most Rhode Island residents would see a considerable increase in their electric bills around October under new National Grid rate proposals. The state’s largest utility called for a 53 percent hike in the standard service rate, from 6.3 cents a kilowatt hour to 9.5 cents. The increase would mean an average customer’s monthly bill would jump from about $89 to about $106 for 500 kilowatt hours of power, according to the Providence Journal. The increase covers the cost of power, which National Grid is not allowed to profit from under state law. The company is not proposing an increase in delivery fees, which account for about half of a customer’s bill.A National Grid spokesman said that a deficit in the regional power supply had been caused by the retirement of major generating plants in New England, including Vermont Yankee, Brayton Point, and Salem Harbor. If the increase is approved by state utility regulators, it would be the first rate hike for the company’s 460,000 electric customers since the beginning of 2015.