[Draft] Where do hybrid systems exist? #

In contemporary American consumers’ mind, the word “hybrid” is likely to trigger the image of a hybrid car. The reason these cars are called hybrid is because of their dual power source - gasoline engine and electric motor, in this case. The hybrid system can also exist in fuel sources. Early generation hybrid cars used only gasoline as fuel. Newer plug-in hybrids can use both gasoline and external electric power source. If we zoom out and look at the fuel types used by the regular cars globally, then we also find a hybrid setup. Some cars use diesel, some cars use unleaded gasoline (i.e., petrol and octane), some cars use electricity. Using a single type of fuel for all cars in the world seems unreasonable due to efficiency variance of different fuel types. Hence, a hybrid fuel system existed from the early days of cars. At this point, we can zoom out a little more and look at fuel types of different types of vehicles. Passenger cars, commerical buses, ships, aircrafts, and locomotives use different types fuels and power sources. Hybrid systems have always existed. It is just a matter of perspective and scope! Hybrid systems can exist globally, even if individual components of the system are not hybrid. Local hybrid systems can also exist, even if the global system is not hybrid. Hybrid systems can also be hyper-local!