Protesters Thursday picketed outside the Old Erie County Building to call on National Fuel Gas to return to its customers possible excessive earnings that were made by the utility since 2008.

Last week, the State Public Service Commission approved a series of temporary rates for National Fuel that will freeze its delivery charges while state regulators conduct a broader review of the utility’s rates. If the PSC determines that the Amherst-based utility has been charging too much, customers could be in line either for a refund or a rate cut when the permanent rates are set.

“They overcharged their customers,” said Brenda Miller, a community organizer with PUSH Buffalo. “So they need to be held responsible by giving us our money back, and not just credit our accounts.”

An audit by the PSC found that National Fuel’s earnings from its New York utility business have been significantly higher than the targets set by the commission in its rate plan that took effect at the beginning of 2008. The utility earned a return equal to 12.4 percent of its equity, according to the PSC staff’s calculations, which is significantly higher than the 9.1 percent earnings target set by the PSC.

The possible overcharges could top $10 million over the course of a year, according to the PSC.

If the commission determines that there were, indeed, overcharges to National Fuel’s 516,000 customers in Western New York, Miller said she would like to see the excess used to support a weatherization program that would help reduce customers’ utility bills.

“Pay us our money back or invest it into another weatherization program,” she said.

National Fuel officials have argued that the utility’s earnings were reasonable and due entirely to its cost-cutting and productivity efforts.

Meanwhile, the Erie County Legislature on Thursday voted to suspend a resolution in support of requiring National Fuel to refund any overcharges to the utilities residential and business customers.

“The resolution that we put forth last week may not be relevant right now,” said Legislature Chairwoman Betty Jean Grant.

“We’ll take a look at what the PSC is doing and make sure that we put forth the right resolution. ... Our resolution might be amended,” Grant added.