Arizona Public Service plans to replace old natural gas generators in its Ocotillo Power Plant in Tempe. It’ll take out two 1960s-era units and replace them with five new units that it says are more water and fuel efficient.
Steven Gotfried with APS says faster units will provide a reliable energy backup to fluctuating solar energy.
But the Sierra Club has filed an appeal of the power plant’s air permit. The organization is concerned with the level of greenhouse gas emissions the plant would produce — specifically while the generators idle when not in use.
The Sierra Club suggests the utility company use batteries instead to store energy for times when renewable sources are not enough. But Gotfried said the bids for the project that involved batteries were notably more expensive.
Utility companies have to balance demand with clean energy with cost. Karin Wadsack, a project director at Northern Arizona University who works in the College of Engineering, Forestry and Natural Sciences, talked about the dispute between APS and the Sierra Club.