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Reply to "Metra converting to battery power"

I took electronic technology. There is a loss involved in every conversion of power from one form to another. There is an efficiency loss in the power plant boilers, another in the turbine/generator combination which creates the electricity, transmission losses from the generating site to the point of use, more loss in the charging process and finally loss in the conversion from electricity to mechanical energy in the vehicle.

This sounds like an awful lot of "free lunch" talk. I will bet you a dollar to a donut that quite a few of these losses were purposely ignored so that the study's findings would support some green political agenda.

Yes, you have to go through the entire energy chain.

I am going to ignore the pumping of oil or extracting coal from the ground and transporting it and refining as this washes out for either electric vehicles where the source is from a fossil fuel plant and internal combustion motors.

While there are some advanced designs such as the Toyota internal combustion motor at 38% efficiency, most gasoline combustion engines average around 20 percent thermal efficiency.

Thus, for most cars 100 horsepower of fuel consumed results in 20 horsepower to move the car.

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For an electric vehicle one has to start at the power plant. The average coal-fired power plant in the United States operates near 33% efficiency. Simple Google search.

That means for 100 horsepower of coal consumed at the coal fired plant results in 33 horsepower worth of electricity.

Now, that electricity has to be transmitted over power lines. That is not for free. Super conductors at room temperature do not exist yet. The power lines have resistance and roughly 20% of electrical energy is lost in transmission. That 33 horsepower becomes 26.4 horsepower at your electrical plug.

Now the electric vehicle has to be plugged in and the battery charged. That is not for free. The battery gets warm when being charged. That warmth is waisted energy. The charging of the battery is about 85% efficient.  That 26.4 horsepower at the plug translates into 22.4 horsepower in the battery.

The electric vehicle itself is very efficient. Did you know that an EV can be more than 70% efficient from the moment you turn it on. Well, 22.4 x 0. 7 = 15.7 horsepower to propel the car.

So the calculations give for 100 horsepower of fuel consumed results in:

20 horsepower of motion for a car with internal combustion motor

16 horsepower of motion for an electric car.

Another take is EVs convert over 77% of the electrical energy from the grid to power at the wheels. That would result in overall (0.77 x 26.4 = 20.3) 20.3 horsepower of motion for an EV. A wash at best.



This is not to put down EV's. There is one big advantage. Pollution from a point source such as a power plant is much more controllable than from millions of individual sources. So pollution from EV's is much more controllable from gasoline powered cars.



Also what needs to be factored in the 20 or so % of electrical generation that comes from hydo, wind, and other clean sources.

Last edited by WBC

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