Table S4.

CO₂ EFs and energy efficiencies of various power plant types (with and without CCS) (columns 2 and 3)

Power plant type	EFs,† g CO2 per megajoule	Energy efficiency, %	Net energy penalty‡, %	Net CO2 removal efficiency‡, %
Supercritical without CCS	94.3	40§	11	82
Supercritical with CCS	9.43	31¶	15	89
Ultrasupercritical without CCS	94.3	42§	11	83
Ultrasupercritical with CCS	9.43	32¶,#	15	89
NGCC without CCS	55.8	49†	9	86
NGCC with CCS	5.58	42¶	11	90
IGCC without CCS	94.3	45||	10	83
IGCC with CCS	9.43	39¶	12	89

Net energy penalty and net CO₂ removal efficiency resulting from electricity used to operate CCS with SNG production (columns 4 and 5).

^†Data from GAINS model.

^‡Calculations for net energy penalty and CO₂ removal efficiency are illustrated in SI SNG Production–Energy Penalty of CCS.

^§Data from Shen et al. (49).

^¶Data from Metz et al. (54), who report that CCS energy penalties for supercritical coal, NGCC, and IGCC power plants are ∼31%, 17%, and 16%, respectively. Using the equations in Metz et al.’s study, ΔE = (η_{w/o CCS}/η_ccs) − 1, we calculate the energy efficiency for supercritical, NGCC, and IGCC power plants with CCS as shown in the table. Goto et al. (55) found the same energy penalty for ultrasupercritical power plants and supercritical power plants for conducting CCS; thus we calculate the energy efficiency for ultrasupercritical power plants with CCS as shown in the table.

^#Data from Goto et al. (55).

^||Data from Kunze and Spliethoff (56).