When ethanol is used as a transport fuel, it is mixed in different percentages (1% - 10%) with regular gasoline. The combined fuel mixture will have a different caloric heat value (the amount of thermal energy that can be obtained when the fuel is burned) that affects fuel performance depending on the mixing ratio. So the phrase ガソリン換算熱量　is comparing the heat value of an ethanol fuel mixture against that of regular gasoline.

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