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Electricity meters: Kilowatts and kilowatt hours, the most important metrics for our inevitably predominantly electrified future, are still not part of general education in Germany
Photo: Torsten Asmus / iStockphoto / Getty Images
A few quiz questions to get you started.
1. You hear the following sentence: "And then she went through the city center at 95."
What is this about?
A) An older lady goes shopping in the pedestrian zone
B) A city guide looks after a very large tour group
C) A driver was traveling much too fast in city traffic
2. Or when you hear: “It needs eight liters.”
What is it about?
A) A man's weekly wine consumption
B) The volume of a new bathroom trash can
C) The fuel consumption of a car
3. “He can do up to 135.”
What is this about?
A) The top speed of a scooter in kilometers per hour
B) The peak performance of a weightlifter in kilograms
C) The maximum power with which an electric car can be charged, in kilowatts
4. “He only needs 120.”
What is this about?
A) The monthly financial needs of a high school graduate in euros
B) The amount of sugar in grams required for a cake batter
C) The annual electricity consumption of a refrigerator with a freezer compartment in kilowatt hours
My guess is: you didn't have any major problems with questions one and two.
The fact that the number means 95 kilometers per hour is clear straight away, almost without any context, and experience shows that eight liters probably refers to the consumption per 100 kilometers of a car with a combustion engine.
Of course, C is the answer you are looking for in both cases.
We lack reference systems
In questions 3 and 4, however, many readers probably did not know reflexively what they were looking for.
Here, too, C was meant, but was that immediately clear to you?
Answer 3C means: An electric car charges quite quickly.
Did you know that 120 kW charging power is quite a lot?
Answer 4C: If it is a large refrigerator, then it is quite economical.
Would you have been aware of that straight away?
Kilowatts and kilowatt hours, the most important metrics for our inevitably predominantly electrified future, are still not part of general education in Germany.
For these values - performance and energy consumption (more precisely: power consumption) - we have no coordinate systems in our heads, no developed "reference system", as it is called in perceptual psychology.
We learn such reference systems in many areas from an early age.
When you hear that someone is 6'3", you have a general idea of how tall they are.
You spontaneously know that an air temperature of 30 degrees Celsius is quite warm and that when it's 5 degrees outside you'd better wear a lined jacket.
For most people in this country, this doesn't apply to information in feet and inches or degrees Fahrenheit - we don't have a reference system for that, we have to laboriously convert values in our heads.
kWh/100 km – yes, that’s confusing
To this day, kilowatts and kilowatt hours are almost as foreign to most residents of this country as inches and Fahrenheit.
Or do you spontaneously know how many kilowatt hours your television uses per year?
And how much of it in standby mode?
Or your refrigerator?
In other areas it is completely different.
Everyone knows what is meant by a “three-liter car.”
Without thinking.
Anyone who is thinking about buying an electric car for the first time is probably developing new coordinate systems.
The consumption of electric cars is usually measured in kilowatt hours (kWh) per hundred kilometers.
So “kWh/100 km”.
This is really confusing: we actually urgently need a more catchy term.
Liters/100 km is easier to remember.
That needs to change.
What is the difference between kW and kWh?
Two other important dimensions for electric cars are the capacity of the power storage, i.e. the battery.
A normal electric car battery can hold around 50 kilowatt hours, and the largest models currently on the car market can hold over 100. How far the electric car can go depends, of course, not just on the size of the battery.
Just as the size of the tank of a combustion engine alone does not determine its range.
Interestingly, ranges per tank of fuel for cars with combustion engines are not a measure that is communicated too aggressively.
It's the consumption per 100 kilometers that counts, because that tells you how much it costs to drive a car in everyday life.
When it comes to electric cars, however, the claimed range and the range subsequently measured by independent testers is currently a central selling point.
This will gradually change, with even better batteries and, above all, a better charging network.
We are entering a new world and change is still in full swing.
All functionally illiterate people
Another selling point is the charging speed, and that in turn depends on that other measurement that hasn't really sunk into the collective subconscious: kilowatts.
Many people have difficulty distinguishing kilowatts from kilowatt hours.
One (kW) indicates how much energy flows through the line at a given moment - for example into or out of the battery.
The other (kWh) refers to the amount of energy that is consumed or provided over one hour with an output of one kW.
High kW values are therefore desirable when charging - the more that flows into the battery at once, the faster it will be full again.
A good fast charger charging capability is currently beyond 120 kW, while a home wallbox usually only delivers 11 kW.
Or 22 kW for certain models, but you not only have to register this (you always have to), but also have it specifically approved by the local network operator.
If you find this all confusing, it is.
This is not least because we are all largely functionally illiterate when it comes to the enormously important question of what drives our civilization beyond fossil fuels (“3-liter car”).
Kilowatts and kilowatt hours, power consumption and performance, these are still topics for technology nerds today.
For people who read pages of tests before buying a refrigerator.
For electric car fans.
Who benefits?
The friends of the fossil.
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This widespread functional illiteracy when it comes to energy and energy consumption plays into the hands of those who, for example, have used absurd disinformation to create a mood against heat pumps that are clearly and clearly superior in terms of energy.
Or those who want to continue to sow doubts that electric cars are vastly superior to combustion engines when it comes to energy efficiency and emissions.
Or those who still act as if there is an alternative to the actually unstoppable triumph of renewable energies and storage technology.
If you don't even understand the crucial measurements correctly, it's easier to load.
All of this must change quickly: the future is undoubtedly electric - it is time we learn the language in which this future is spoken of.