Two former public utility commissioners from the mainland critiqued NextEra Energy Inc.’s history with rooftop solar at the company’s Florida electrical utility during a hearing Monday to review NextEra’s proposed purchase of Hawaii’s largest electrical utility.

Kristin Mayes, former commissioner of the Arizona Corporation Commission, and Karl Rabago, former commissioner of the Public Utility Commission of Texas, spoke at a hearing hosted by the Hawaii Public Utilities Commission to review NextEra’s proposed $4.3 billion purchase of Hawaiian Electric Industries.

Mayes, called as an expert witness on behalf of the County of Hawaii, said the history of NextEra’s Florida utility, Florida Power &Light, with customer-sited energy and its open “hostility” to resident-sited energy is worrisome.

“What I see from FPL scares me and would scare me if I were a commissioner here,” Mayes said.

Rabago, an expert witness for the state Department of Business, Economic Development and Tourism, echoed Mayes’ concerns and said that NextEra energy’s low number of customer-sited solar, being 10 times larger than HEI in its amount of capital and renewable generation, is unimpressive.

“Ten times bigger with this amount of solar is not a really strong track record,” said Rabago.

Roughly 3,000 of FPL’s 4.8 million customers have rooftop solar systems — less than 1 percent of FPL’s customers. NextEra has said this is because of low electrical bills in the state.

“The biggest barrier to rooftop solar throughout (FPL) company’s service area is very simple: Our customers pay electric bills that are the lowest in Florida and 30 percent below the national average,” said Rob Gould, NextEra spokesman. “It makes absolutely no economic sense for (FPL) customers, who are about to see their fourth rate reduction in 16 months, to pay the thousands of dollars required for a rooftop solar system when their bills are already as low as they are today.”

In November electrical rates in Florida were roughly 8 percent lower than the national average, according to the U.S. Energy Information Administration. Hawaii’s electrical rates are more than twice the national average.

Mayes said the image HEI CEO Connie Lau painted in an email that NextEra considers the Hawaii utility a “snack” on its way to buying other regulated utilities should be concerning for the PUC.

“This commission doesn’t know what NextEra will bite off next,” Mayes said. “The company has made it clear in documents in this case that it is extremely acquisitive. We don’t know who they are talking to right now. We don’t know how many companies they are looking to acquire right now, and we don’t know how risky the profile of those companies are.”

Later during the hearings, NextEra’s counsel questioned Alicia Moy, CEO of Hawaii Gas, about the sale in 2006 of the gas utility to New York-based Macquarie Infrastructure Co.

Bryan Anderson, managing attorney for FPL, noted that sale generated little controversy and attention.

Anderson compared the nearly 30 groups involved in the review of NextEra’s purchase of HEI and the 500 to 600 conditions posed by those intervenors to the 14 commitments offered by Macquarie when purchasing Hawaii’s only gas utility for $238 million. The only intervenor included in the review was the state consumer advocate.

PUC Chairman Randy Iwase interrupted the lawyer multiple times asking about the relevance of the questions but allowed him to continue.

“What happened 10 years ago happened 10 years ago,” Iwase said. “Ten years ago I had hair.”

Iwase said that there are 23 witnesses left in the proceeding. The hearings hosted by the PUC at the Neal S. Blaisdell Center are open to the public and will continue through Wednesday.