WORKING MEDIUM CHARACTERISTIC DIFFERENCE POWER GENERATION SYSTEM AND WORKING MEDIUM CHARACTERISTIC DIFFERENCE POWER GENERATION METHOD IN WHICH SAID POWER GENERATION SYSTEM IS USED

To provide a power generation system and a power generation method that can use thermal energy in a natural world as a thermal source, and can perform power generation while suppressing loss of thermal energy as far as possible.A first heat exchanger 1A, a first thermal engine 2A, and a first power generator 3A are included on a first working medium line L1 that circulates a first working medium W1, a second heat exchanger 1B, a third working medium supply means 5 that supplies a third working medium W3, a mixing means 6 that mixes a second working medium W2 and the third working medium W3, a second thermal engine 2B, and a second power generator 3B are included on a second working medium line L2 that circulates the second working medium W2, and on both of a downstream side of the first thermal engine 2A on the first working medium line L1 and a downstream side of the second thermal engine 2B on the second working medium line L2, a third heat exchanger 1C is included, and a third working medium discharge means 10 for discharging the third working medium W3 to the third heat exchanger 1C is included.