The combined cycle cannot easily be used to back up solar energy because it takes too long to start the boilers for the Rankine portion. Thus, there is a trade-off between using solar energy with low-efficiency gas turbines, or using high efficiency gas turbines without solar. Assume solar energy contributes for roughly 8 hours per day. In essence, therefore, the low-efficiency plant need only generate 2/3 of the power throughout the day. (Treat it as though it only needs to generate this amount at all times.) Meanwhile, the high efficiency plant that runs without solar must supply the entire power demand at all times. If the actual efficiency of the combined cycle is 0.60, what minimum efficiency must the low-efficiency cycle have for solar energy to emit less carbon