California’s electric utilities have taken their fight to change wildfire liability rules to the television screen, backing ads throughout the state.

That the companies back the ads, however, isn’t obvious from the commercials themselves.

Instead, the ads urge viewers to support the BRITE Coalition, a group pushing to reform the state’s liability rules concerning fires triggered by utility equipment. All three of the state’s large investor-owned utilities — Pacific Gas and Electric Co., Southern California Edison and San Diego Gas & Electric Co. — are members.

So are various chambers of commerce, a wind-energy association, a climate-change education group and the main union representing PG&E employees.

The utilities have spent months lobbying Sacramento legislators to change a system known as inverse condemnation, which holds them liable for wildfire damage tied to their equipment even in cases where the company did nothing wrong.

California fire investigators have blamed PG&E’s equipment for starting 16 of the wind-driven wildfires that tore across Northern California last fall. In 11 of those fires, investigators with the California Department of Forestry and Fire Protection, known as Cal Fire, found evidence that PG&E violated safety laws. Estimates of the company’s potential liability range as high as $17 billion. Cal Fire has not yet announced the cause of the most destructive wildfire last fall, the Tubbs Fire in the Wine Country, which tore through neighborhoods in Santa Rosa.

Gov. Jerry Brown has proposed ending the system of automatically holding utilities financially liable for wildfire damage linked to their power lines, although his proposal would not apply to last year’s fires.

The issue has touched off a pitched battle of lobbyists and groups representing people and companies with a stake in the outcome.

Some of the lawyers and homeowners suing PG&E have their own advocacy group, Up from the Ashes, trying to thwart the utilities in the state Capitol. Insurance companies have another, bluntly titled Stop the Utility Bailout.

The BRITE Coalition (the acronym stands for Building Resilient Infrastructure for Tomorrow’s Economy) is ramping up its efforts as the end of the legislative session nears. With three weeks left, the group held a press conference Tuesday in Sacramento, and its smoothly produced television ads — also popping up on social media — started running early this month.

“If a tree falls in a forest and hits a power line through no fault of anyone’s, the utilities are now the insurers of all that fire loss, and that’s not fair,” said Rob Fong, a former Sacramento city councilman, at the BRITE press conference. “And more importantly, it’s not healthy for the financial stability of this state.”

To its opponents, BRITE is nothing more than an “astroturf” group, a campaign backed by corporations but designed to look like a grass-roots effort.

“It’s nothing more than a name to put on the end of a television commercial other than PG&E,” said Jamie Court, president of the Consumer Watchdog advocacy group. “It’s as phony as they come.”

The coalition may have a hard time persuading lawmakers to tackle such a sensitive and complicated issue in the session’s waning days. Tuesday afternoon, two of the state Senate’s top Republicans called for delaying any action on inverse condemnation, saying the Legislature should focus on fire prevention instead.

“We believe it is in the best interest of the public for the Legislature to defer discussion of inverse condemnation to a later time,” wrote Republican leader Patricia Bates of Laguna Niguel (Orange County) and Jim Nielsen of Gerber (Tehama County), chairman of the Senate Republican Caucus, in a press release. “The Legislature should instead focus on more immediate issues that we can realistically address by the end of this month, such as improving the safety of electricity delivery systems, and reducing the risks of wildfires by fixing laws and regulations that have led to a proliferation of unmanaged forests and unprecedented levels of fuel.”

PG&E touts BRITE as a broad-based effort. The utility, California’s largest, views the wildfire liability fight as part of a much larger issue: how the state will pay for the damage wrought by climate change. Massive wildfires, the company argues, have become more common in recent years because global warming and the recent drought have killed an estimated 130 million trees in the state.

“We believe this is frankly the most critical issue facing California today, and we believe it’s really important that voices are heard on this,” said Steven Malnight, PG&E’s senior vice president of strategy and policy, speaking of the BRITE Coalition. “It’s a substantial group. That’s why we’re proud to be a part of it.”

Malnight, speaking Tuesday with Chronicle editors and reporters, declined to say how much PG&E has donated to the group. A search of the state website that tracks campaign financing and lobbying expenses turned up no records with the group’s name.

A form PG&E filed with the state detailing its lobbying expenses for this year’s second quarter listed $1.14 million spent on “grassroots and other advocacy” related to state wildfire legislation.

The Bay Area Council, a business-backed public policy group, has also joined BRITE. Geisha Williams, the CEO of PG&E Corp., sits on the group’s executive committee.

But Jim Wunderman, the council’s president, said that regardless of that personal connection, the group does not want to see the current liability system bankrupt PG&E. The utility filed for bankruptcy once before, during the state’s electricity crisis of 2000-01.

“We do not want to end up with a bankrupt PG&E,” he said Tuesday. “We’ve seen that before, and it wasn’t pretty. Our residents require a functional utility.”

The same fear also motivates the International Brotherhood of Electrical Workers, another BRITE member. The union often backs PG&E on issues it considers a threat to the company or the utility industry.

“We learned this from our experience with PG&E going bankrupt during the energy crisis — the bankruptcy court has the latitude to cancel our labor agreement, has the latitude to remove the pension fund and use it to make payments to creditors,” said Hunter Stern, business representative for IBEW Local 1245, speaking with reporters Tuesday after the Sacramento press conference.

San Francisco Chronicle staff writer Melody Gutierrez contributed to this report.

David R. Baker is a San Francisco Chronicle staff writer. Email: dbaker@sfchronicle.com Twitter: @DavidBakerSF