Attorneys for members of the Arizona Corporation Commission told a judge Tuesday he should block a bid by one of the panel's members to investigate whether financial help they got or are suspected of getting from Arizona Public Service for their elections tainted their vote to allow the company to collect more money from customers.

The state's largest electric company has now poured more than $30 million into its bid to convince Arizonans not to force it and other utilities to use more renewable resources.

Claiming he's been defamed, Attorney General Mark Brnovich is suing the backers of the Proposition 127 campaign for telling what he said are lies about him.

If money is speech, the state's largest electric utility is not going to have the only voice this year in trying to affect who gets elected to the Arizona Corporation Commission.

California billionaireTom Steyer has spent more than $18 million so far in his bid to convince Arizonans to support a constitutional mandate that half of all electricity come from renewable sources by 2030.

Public health advocates urged voters Tuesday to support a renewable energy mandate on the November ballot even though not one of them could say how much of a difference it actually would make in ground-level air pollution.

It ultimately may not matter if Arizonans vote in November to require utilities to generate more of their electricity from renewable sources.

Two companies that were negotiating to take over a coal-fired power plant on the Arizona-Utah line ended the effort Thursday, saying the challenges were too great.

Democrat Sandra Kennedy said Thursday there would be no need for voters to impose a renewable energy mandate if state utility regulators would do their job.

State regulators have been assured that Arizona electric utilities should have energy reserves to cover peak demand on the hottest days of the upcoming summer.