On Dec. 4, the Star-Advertiser’s Insight section featured three related commentaries under the theme, “Renewables: Reenergize or Revise?” One was a plea by religious leaders. Another was from an ‘Iolani School student, hoping someone will “do something.” A third was an excellent review and action plan by the Practical Policy Institute of Hawaii. There have been several such focuses by this paper on renewables, which have been all but ignored.

A follow-up letter proposed that there is “plenty of time to address clean energy reliability.” I’m not sure what part of “reliable” or “dependable” the writer isn’t concerned about, but it is, in fact, the major roadblock to the state’s 100% renewable energy goal for 2045. Hawaii cannot achieve that goal without planning for uninterrupted power, as Hawaiian Electric has provided for decades.

Maintaining dependable renewable power is a function of technology, weather and storage, none of which Hawaiian Electric can plan for without guidance from the Legislature and the Public Utilities Commission as to the state’s definition of renewable dependability. It’s not just solar farms, windmills and batteries.

In August, I wrote a commentary debunking the widespread notion that battery storage will provide dependability (“Plan for dependable renewable energy lacking,” Island Voices, Aug. 14). Suffice it to say, batteries cannot close the gap. Nor can excess solar or wind capacity. When the sun doesn’t shine brightly, renewable production goes down. No matter how many panels you put up, they all go down together. Without a backup, the lights go out.

Today, most renewable capacity being built by developers for Hawaiian Electric has battery storage of four times the nameplate capacity of the renewable source, typically solar. It is common to think of these batteries as backup, but they are not, and Hawaiian Electric has made this clear. Even the massive battery farm in Kapolei will not provide backup. This storage helps Hawaiian Electric balance loads, and it is up to its grid management whether and when to use available battery storage.

The size of the backup that each county needs is equal to the projected total demand, since that is what Hawaiian Electric provides now, and what we all expect. When a weather event occurs, as it inevitably will, rolling brownouts for days as the company allocates the load to provide what renewable power it’s got available, will not be acceptable.

Today, with renewables growing fast, there is no problem with dependability, since the shortfall in renewable contribution is seamlessly made up by Hawaiian Electric’s existing system. However, the company’s “2020 Integrated Grid Planning Inputs and Assumptions” contains a schedule for the planned shutdown of some fossil-fueled generators. Presumably, they will be replaced with renewable firm generation, but that starts with an understanding of what the future backup requirement will be.

The same document forecasts 2045 Oahu demand, prospectively all renewable, of 8,025 gigawatt-hours. At that level, running on 100% renewable sources like solar, backup-generating capacity for 10 days (a prolonged weather event) would be about 1.5 gigawatts of some sort of mix of instantaneous renewable power that can be activated in minutes. How many days of backup we will need to provide for is a big issue that should be studied and determined by government now, not deferred by unfounded assumptions. There’s an old saying: “If you don’t know where you’re going, any road will get you there.”

Hopefully, in the 2023 Legislature, our elected officials will consider a bill that will direct a state agency to produce a study of meteorology, expected days below capacity, areas affected and hurricane survivability, which will provide marching orders for Hawaiian Electric for the next 20 years. It will easily take that long to put a dependable renewable backup system in place. With all due respect to the letter writer, there is not “plenty of time.”

Brian Barbata is a former energy executive, a founding director of the Kauai Island Utility Cooperative, and former owner of Hawaii Photovoltaics LLC.