Participants in the docket have verified that solar and solar-plus-storage buildout in the state would have been a cheaper alternative than the approved natural gas expansion in the long term, although cost analysis remains confidential, according to Daniel Tait, Chief Operating Officer of nonprofit membership organization Energy Alabama. "We know as parties to the case what those numbers are," he told.

The solar-plus-storage option was the only option to increase capacity without raising costs for customers, Tait said. The solar-plus-storage projects "would actually put negative pressure on rates, so it would dispatch instead of more expensive coal or gas assets that are already on the system," he said, whereas the gas projects are "going to add to the customer bill. I can't say what those specific numbers are, but that's why we keep saying these are cheaper projects."