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rollulus 2 hours ago

That’s because of the primary energy fallacy: https://medium.com/@jan.rosenow/have-we-been-duped-by-the-pr...

TL;DR: the efficiency of converting fossil energy resources into something useful is poor.

criddell 2 hours ago | parent [-]

That chart is measuring joules of energy. I'm not sure efficiency comes into play here, does it?

Coal provides 175,000,000 TJ of energy. Solar and wind provide 21,000,000 TJ.

I was mostly surprised at how critical coal still is.

https://www.iea.org/world/energy-mix

gpm an hour ago | parent | next [-]

The problem is where it's measuring joules of energy. To use cars as an example:

It measures joules of energy as in "how much heat the gasoline we burn produces", some of which we convert to mechanical energy to drive the car, but the majority is just waste heat going out the tailpipe.

By comparison an electric car powered by solar has no tailpipe. There's still a bit of waste heat from electrical resistance, but nowhere near as much.

If we measure like this, by converting a gasoline car to electric (powered by solar for the sake of ignoring some complexity), and driving the same distance, we somehow managed to cut our "energy demand" in half. Despite the fact that we're demanding the exact same thing from the system.

If we measured "joules delivered to the tires of the car" we wouldn't have the same issue. At least until someone starts arguing about how their car is more aerodynamic so joules delivered to the tires should count for more in it.

Edit: We could also go in the other direction. Instead of reporting it as 1kw of solar energy (electricity) it could be 4kw of solar energy (the amount of sunlight shining on the solar panels)... No one does this for obvious reasons, but it's more similar to that primary energy number for fuel in many ways.

icegreentea2 an hour ago | parent | prev | next [-]

The total energy supply figure is a primary energy mix - for the fossil fuels it represents the thermal energy of the fuel. You can look at the final energy consumption section a bit lower to get a different picture taking into account conversion losses.

jeffbee an hour ago | parent | prev [-]

That is still subject to the primary energy fallacy. Those reports are in terms of primary energy, i.e. how much heat is released by combustion of fossil gas. But in order to replace fossil gas in a chemical plant, you need much less electricity than the primary energy of the fossil gas suggests.