The shocking thing about that chart isn't how much energy is taken from natural gas and coal ... but the "rejected energy" category accounts for 2/3 of the input. Yes, that means that 2/3 of the input is just plain lost to assorted inefficiencies such as friction, electrical resistance, surplus heat (your car radiator), etc. See https://energycultures.org/2014/07/rejected-energy-much-energy-unloved/
So roughly ... every watt you pledge to save has mother nature kicking in a double-matching gift!
p.s. this is partly why electric cars are so efficient. Something like 90%+ of the battery energy actually goes into making the car move. There is some electrical resistance loss, some heat in the motors - but nothing like the excess heat of an ICE and nothing close to the friction losses either.
That is actually a really useful chart. Thanks for posting it.
Agreed that there is a LOT of wasted energy. Unfortunately not all of that energy can be recovered even under ideal circumstances. Basic thermodynamics states that for most power conversions, especially those involving a working fluid (which is most of them), the best efficiency one can hope to expect is about 67% or 2/3.
The good news is that since at present we only harvest about 1/3 of all energy generated, we can potentially harvest about another 1/3 with better conversion efficiencies (Supercritical CO2 can really boost the rate of conversion efficiency in electrical generation).
The bad news is that we will never get that last third, but boosting efficiency by an additional 30% could be very significant.
Indeed! Losses in transmission and conversion are a real thing. I suppose its unfair to consider that "wasted" because it is simply a cost of the activity. A car generates increasing wind resistance as it accelerates, but we don't consider that energy used to overcome it "wasted" - although it sure is inefficient to go fast!
My point, if its not clear, is that NOT using a unit of electricity, gas, whatever has greater and largely unseen savings.
One could also make some conclusions about grid vs localsolar in terms of rejected energy - it doesn't change the immediate economics but it can change your thinking.
Whoa, thanks for the chart! That’s a interesting but lame energy system, limping along, energy system. We need a break through urgently. But it is fairly diversified these days. But it seems the majority of people abstain from practicing Permaculture. I’m the only person in my family who thinks about it.
Using power carefully can make a big difference in how much needs to be generated and thus how much is rejected. My solar has rejected energy but on such a tiny scale. And if I take the time I can whittle down the rejected energy bit by bit. Using a heat pump for example. Insulating cookers for example. Installing dump loads for example.
It seems to me as long as heating is desired then rejected thermal energy should be used somehow. The combined generation and cogeneration models make a lot of sense. They are more complex however. And as mentioned can only be roughly 2/3 efficient.
George Bush Jr loved rejected energy....for a warmer more comfortable climate. Argh! I have a couple friends who agree. I’m on the fence.
I wonder if residential electricity usage is up during this shut down? My guess is it’s up a little.