1 kwh, what is it?

[jmarc3]

1 kWh, by definition, is the energy consumed in 1 hour by a 1kW power appliance.
This is roughly the energy consumed by a modern washing machine for laundry and is billed around 10 euro cents by your preferred electricity supplier.
So it's almost nothing, hardly if you make the effort to bend down to pick up 10 cents… and yet:
1 kWh is also the energy it takes to raise 1200 liters of water to a height of 300m! Imagine yourself with your buckets of water on the stairs of the Eiffel Tower to fill fifteen baths located at the top and you will have understood the real value of kWh!

Conclusion: even if the bill sometimes seems expensive (because we consume too much and unnecessarily), we pay the energy at a ridiculous price which does not motivate us to make the savings essential to the survival of the planet.

[dirk pitt]

I like the stories that put ideas back in place. this is one of them.
I heard a similar one about the energy contained in gasoline:

we asked people at what price they would consider reasonable the cost of the "function" to take them and their family (4 people) to the neighboring town of 20kms. (excluding salary and investment)
the average response was around $ 20

knowing that the energy spent to transport these 4 people by car at 20kms is contained in 1.5litre of gasoline, the liter of gasoline should be at least $ 13 per liter!

it cites the memory figures, the order of magnitude is there but it was surely not exactly that.

[Did67]

It is necessary to excavate on the Manicore site, but it is also the story of the slaves of Jancovici.

The mechanical energy we have is as if each of us had 100 slaves ... (I can't remember the exact number - check it out on Manicore).

Yes, few people are aware of the fact that almost everything is due to the fact that energy is worth nothing !!!

Then we are surprised that the fact that it snows in winter is an event which the media water us for a week! Without underlining the extreme fragility of our technical choices (where Cro-magnon got out!).

[I Citro]

1 kWh is also the energy it takes to raise 1200 liters of water to a height of 300m!

I find it huge, you have sources, a calculation methodology.

Thanks in any case for this topic. Realizing our waste and the true value of energy is good.

If I extrapolate your values, one km with my electric car is equivalent to mounting 240 liters at 300m in height ...
It is better than the Volvo it replaces and which consumed 1kWh of fuel per km ...

[dirk pitt]

I find it huge, you have sources, a calculation methodology. ...

1200kg x 9.81 x 300m (height) / 3600 (J for 1Wh) = 981 Wh

QED

[Remundo]

yes but there is confusion between thermal and mechanical energy.

Typically, 3 kWh of thermal energy is required to obtain 1 kWh of mechanical energy.

However, this does not detract from the moral of the story of Jean Marc3.

[I Citro]

I find it huge, you have sources, a calculation methodology. ...

1200kg x 9.81 x 300m (height) / 3600 (J for 1Wh) = 981 Wh
QED

Thank you Dirk, it's so much better by writing it.

And then I feel a lot smarter now.

[I Citro]

yes but there is confusion between thermal and mechanical energy.

Typically, 3 kWh of thermal energy is required to obtain 1 kWh of mechanical energy.

You guys are in good shape.
Could you, Remundo, we demonstrate it, as just so brilliantly Dirk.

[jmarc3]

there is no confusion but equivalence between all forms of energy (I did not take into account the yields, of course).

I will try to be as clear as possible:

1kwh is 1000W x 3600s or 3600 kilojoules.

1 joule is the work of a force of 1 Newton on 1 meter.

1 kg (or 1 liter of water) represents a force of 9,81 Newton due to the Earth's attraction (I rounded up to 10 Newton)

1 liter of 300m high water therefore represents:
300 x 10 = 3000 joules

and 1200 liters of 300m high water:
1200 x 3000 = 3600 kilojoules or 1kwh

[jmarc3]

With the same idea:

When the steam engines began to replace the horse, an attempt was made to measure their power in relation to the power that a horse could develop.
A horse being able to lift a mass of 75 kg at the speed of 1m / s, we deduce an equivalent power of 736W.
It is also the value of the 'ch din' which is used to measure the power of car engines. With your 100 hp din vehicle, you are effectively in control of a team of 100 'animal' horses! Imagine the stable!
We even talked about a steamer donkey which is worth about 1/3 of a horse. This is about the power that a man in good shape develops, so 1 man = 1 donkey (which we already knew elsewhere)