The objective of the FLExible Carbon Capture and Storage (FLECCS) program is to fund the development of carbon capture and storage (CCS) technologies that enable power generators to be responsive to grid conditions in a high variable renewable energy (VRE) penetration environment. This includes retrofits to existing power generators as well as greenfield systems with a carbon-containing fuel input and electricity as an output. The value of such CCS technologies will be evaluated by their impact on the system LCOE of a net-zero carbon electricity grid, as determined by capacity expansion modeling. ARPA-E does not expect every CCS technology itself to be a net-zero carbon process; instead the cost and performance of each project selected under this FOA will be evaluated in the context of a net-zero carbon system which may include negative emission assets.