It’s Palen, not Palin, but it’s still proving to be controversial and unpredictable.

Seemingly dead in December, then indicted in the press last month as a likely wanton bird incinerator, the Palen Solar Electric Generating System now looks like it might get the go-ahead.

A California Energy Commission committee recommended approval of a scaled-down version of the solar power tower plant – one 750-foot-tall power tower, not the two that had been sought by developers BrightSource Energy and Abengoa Solar. The tower would be surrounded by 85,000 heliostats, giant mirrors that direct light onto a tower-top boiler, heating water to produce steam and generate electricity.

In their 1,182-page decision, revealed late last week and released on Monday [PDF], the California regulators allowed that “a single power tower will still cause significant unmitigated (albeit reduced) impacts to biological, cultural, and visual resources.” But they said that on balance California had more to gain from the project than it had to lose.

One factor that weighed in the plant’s favor, according to the regulators, was that with various other logistical and legal clearances nearly in place, construction could begin soon, bringing the 250-megawatt plant online in 2017 and allowing it to help boost California toward its 2020 goal of 33 percent renewable energy.

Another plus was that although the plant won’t initially be outfitted with energy storage, such an upgrade wouldn’t be a technical challenge. That gives Palen “the potential to evolve toward the realization of large scale renewable baseload that could conceivably replace even natural-gas facilities,” and “the people of California and beyond have a vital interest in the acceleration of that evolution.”

The decision was an about-face for the CEC committee, which last December was prepared to reject the Palen plant, deducing then that “When we compare the PSEGS’ entire suite of benefits against its suite of impacts, we find that the impacts outweigh the benefits.”

The plant developers managed to stave off a final decision, however, and got a new hearing to address the regulators’ concerns, which were many but focused heavily on avian mortality from solar flux.

That rehearing revolved to a great extent around the Ivanpah plant that began its commissioning last fall and went into operation in earnest early this year. With three 450-foot-tall towers, it’s by far the biggest power tower plant ever built. Palen opponents used new, higher bird mortality projections from Ivanpah to argue that Palen, with its even taller towers and wider heliostat fields, would be a bird blood bath. BrightSource said the data so far on Ivanpah showed solar flux to be a minor risk, particularly when compared to other killers of birds (including cats).

After hearing those claims, the regulators in their new decision said they couldn’t make the call one way or another on solar flux’s impact – and the only way to know for sure was by plunging ahead.

“The nascent nature of the power tower technology will require a period of operating experience,” the regulators wrote in their recommendation. “Over time, the unknowns that surround the solar flux impacts and mitigation will become known, but that knowledge will only come through the experience gained from allowing the project to operate with the rigorous monitoring, mitigation, and adaptive management” the commission set out.

Critics denounced the decision. Mark Butler, a former superintendent at nearby Joshua Tree National Park, told the Desert Sun newspaper that the plant “will irrevocably harm Joshua Tree National Park’s sweeping scenic vistas, as well as migrating and protected bird species like the golden eagle that travel through the park.” The National Parks Conservation Association reiterated that view, saying in a statement that “the Palen solar power tower would kill migrating eagles, raptors and songbirds from deadly solar flux, caused by radiating heat from the solar panels, and avian collision.”

Palen is set to be built right off Interstate 10, east of Joshua Tree. The company Solar Millennium had in December 2010 received approval to build a concentrating solar power plant there, using older parabolic trough technology. But steep declines in the price of photovoltaic solar made CSP challenging, and in late 2011 Solar Millennium went bankrupt. BrightSource picked up the project rights, brought in Abengoa as a partner, and proposed a two-tower Palen SEGS.

The new recommendation from the CEC committee, which was chaired by CEC member Karen Douglas, will be opened up for a 30-day comment period and a public hearing will be held on Oct. 6 before a final decision on adoption, modification or rejection is made on Oct. 29.