Firm Hybrid Resources (FHRs) combine variable renewable energy with firming provided by battery storage to offer an alternative to dispatchable fossil generation. This research compares the costs of FHR power, new gas combined cycle units, and combustion turbines for five U.S. states (Arizona, Colorado, North Carolina, New York, and Texas) across firm peaking, baseload, and 2016 output profiles for sample gas-fired units. While renewable energy is competitive with gas on an energy basis, the analysis finds that adding full firming to delivery (i.e., never having to draw on the grid to meet the contracted profile) can be costly due to the need to add extra generation and energy storage to counter the effects of renewable resource variability. Absent substantial FHR cost reductions and/or strong policy support, FHR power costs were found to be higher than for gas-fired alternatives across the delivery profiles and locations studied.