Depends on the source you read, but maintaining cruise at highway speeds only takes low double digits in horsepower. Having more mainly comes in handy for asce

Depends on the source you read, but maintaining cruise at highway speeds only takes low double digits in horsepower. Having more mainly comes in handy for ascents and acceleration, though electrical loads are a bit more constant. (Another gripe of mine is how big engine sizes are in North America, it's not like Europe has low speed limits and no mountains)