Retail electricity prices have risen much more in states that adopted competitive pricing than in those that have retained traditional rates set by the government, new studies based on years of price reports show.

The findings, by advocates for both sides in the market-versus-regulation debate, raise questions about the reasons market competition produced higher retail prices than government regulation.

The difference in prices charged to industrial companies in market states compared with those in regulated ones nearly tripled from 1999 to last July, according to the analysis of Energy Department data by Marilyn Showalter, who runs Power in the Public Interest, a group that favors traditional rate regulation.

The price spread grew from 1.09 cents per kilowatt-hour to 3.09 cents, her analysis showed. It also showed that in 2006 alone industrial customers paid $7.2 billion more for electricity in market states than if they had paid the average prices in regulated states.