The Flatiron Powerplant discharges into Flatiron Reservoir, which regulates the water for release to the foothills storage and distribution system. The afterbay storage in Flatiron Reservoir and the forebay storage in Pinewood Lake enable Flatiron Powerplant to meet daily power loads. The Flatiron reversible pump (Unit 3) lifts water from Flatiron Reservoir, a maximum of 297 feet, and delivers it through Carter Lake pressure conduit and tunnel to Carter Lake. When the flow is reversed, the unit acts as a turbine-generator and produces electric energy.

Flatiron units one and two are on AGC and provide VAR support and are occasionally used for spinning reserve.

Open-loop Pumped Hydro Storage