HONOLULU -- Some powerful state senators are seeking an explanation for why the power went out the day after Christmas and why it took so long to restore it.

The chairman of the Senate committee on energy and environment announced Sunday he'll hold a hearing later this month to look into the power outage.

Parts of Oahu were without electricity all night Dec. 26 and into the next day.

On Sunday, Sen. Mike Gabbard called a news conference at the Capitol to announce what he called an "informational briefing" to be held Jan. 14.

"The purpose of the briefing will be to investigate the causes of the recent outage of power here on Oahu Dec. 26, which left the entire island without power. We'll also be focusing on the reason for the delay in restoring the power and possible solutions," he said.

Local businesses will testify about how much money they lost because of the outage.

Win Schoneman runs an ice cream store in Hawaii Kai and he said the length of the outage hurt his business, Bubbies Ice Cream.

"The additional eight hours of loss of power caused all my ice cream to melt, which cost me at least $4,000," he said.

Hawaiian Electric officials said they are gathering information and preparing for reports on the incident.

"Whenever we have a situation like this one, we do complete a thorough investigation and we report to the PUC regulators and Legislature as soon as we can," Hawaiian Electric Co. spokesman Peter Rosegg said. "So we look forward to briefing and have the information to share with you."

State lawmakers will look at whether new policies or regulations should be enacted to help assure that power comes back on more quickly next time.

Hawaiian Electric officials said they will present their preliminary findings to the PUC by the end of the week. Then they'll testify at the legislative hearing the following week.