Electric bills will rise more than 12 percent over the next three years after the state Public Service Commission voted Thursday to adopt a rate-increase plan for Consolidated Edison.

A typical monthly New York City residential electric bill would increase four percent in each of the next three years.

The rate plan will increase Con Ed revenue about $420 million each year, starting on April 1st of this year.

The company must issue all customers a proportional share of a one-time $36 million credit this summer. That comes from the utility's overspending on capital expenditures in the past. It will come in the form of a one-time credit of $5.35 on customers' August or September bill.

In addition, a low-income program has been expanded to serve a total of 375,000 eligible customers and will include an increased monthly discount of $8.50.