Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Primary energy vs final energy: why replacing fossil fuels may not be so hard

bloomberg.com

Post reply on HN
Print view View original

11–20 of 113 posts

Re: Primary energy vs final energy: why replacing fossil fuels may not be so hard

#11

Post by dudus »

akshatrathi wrote: post #4
dudus wrote: post #2

The article tries to explain the difference between primary, final and useful energy to justify why moving to renewables would be easier than at first glance. But I just don't feel like I got convinced in the end. If anything I'm more confused now than before. In special this part about air conditioners being 300% efficient sounds to me like maybe they don't know what they are talking about. “Electrical devices can s…

I wrote the story. The efficiency here isn't breaking the first law of thermodynamics. It's just the industry's way of measuring how much work gets done for a certain amount of input. If the work is heating or cooling, then shifting heat from in one direction or another can be done using heat pumps, which move three units of thermal energy for every unit of electrical energy consumed. Might that explain the conundrum…

But then aren't you comparing apples and oranges when you call both that and the loss as heat and noise from coal as "efficiency"?

Re: Primary energy vs final energy: why replacing fossil fuels may not be so hard

#12

Post by [deleted] »

dudus wrote: post #2

The article tries to explain the difference between primary, final and useful energy to justify why moving to renewables would be easier than at first glance. But I just don't feel like I got convinced in the end. If anything I'm more confused now than before. In special this part about air conditioners being 300% efficient sounds to me like maybe they don't know what they are talking about. “Electrical devices can s…

[deleted]

Re: Primary energy vs final energy: why replacing fossil fuels may not be so hard

#13

Post by nickff »

dudus wrote: post #10
jcampbell1 wrote: post #6

Earlier quoted context omitted.

What is wrong with the concept of a heat pump? A resistor converts electricity into heat 100% efficiently, and a heat pump is often 3x as efficient at heating a house vs electric baseboards.

Ok then the electric baseboard is 30% efficient vs the heatpump which is 100% efficient.

How are you calculating efficiency? It's usually:

efficiency = useful work / energy input

Efficiency is not calculated relative to the best performing machine.

Re: Primary energy vs final energy: why replacing fossil fuels may not be so hard

#14

Post by Homunculiheaded »

It's too bad that reality doesn't really care if you have clever accounting tricks to show that "things aren't really as bad as they look!"

The only number that matters at all is global green house gas emissions. We need to get that to zero, and it has continued to go up.

Imagine you have a drinking problem and your doctor tells you you need to stop drinking alcohol or you will suffer liver failure. You can argue all day about what percentage of your drinks are alcoholic. "Doctor, I drink 3 cans of coke and only 12 G&Ts now, not 1 can of coke and 24 beers like I used to, I went from 4% of my drinks being non-alcoholic to 20%!" If your daily total alcohol consumed keep rising you have a problem.

That's the situation we're in with co2 emissions. There are many clever ways to make it look like everything is fine, but reality doesn't care. If our global CO2 emissions continue to rise we have absolutely no hope.

Re: Primary energy vs final energy: why replacing fossil fuels may not be so hard

#15

Post by bungle »

dudus wrote: post #2

The article tries to explain the difference between primary, final and useful energy to justify why moving to renewables would be easier than at first glance. But I just don't feel like I got convinced in the end. If anything I'm more confused now than before. In special this part about air conditioners being 300% efficient sounds to me like maybe they don't know what they are talking about. “Electrical devices can s…

Another example is to light up a candle, then use a peltier element and a heatsink to generate electricity. Then use that electricity to power a led. The outcome is that you have some of the candle light, but you will have a much more light from the led.

Re: Primary energy vs final energy: why replacing fossil fuels may not be so hard

#16

Post by thatcherc »

dudus wrote: post #10
jcampbell1 wrote: post #6

Earlier quoted context omitted.

What is wrong with the concept of a heat pump? A resistor converts electricity into heat 100% efficiently, and a heat pump is often 3x as efficient at heating a house vs electric baseboards.

Ok then the electric baseboard is 30% efficient vs the heatpump which is 100% efficient.

But a resistor converts 100% of the electrical energy it consumes into heat. So if you were to take the same amount of electrical energy and run a heat pump, you could get 3x more heat into a room. In that sense, the heatpump is 300% efficient.

Re: Primary energy vs final energy: why replacing fossil fuels may not be so hard

#17

Post by akshatrathi »

Homunculiheaded wrote: post #14

It's too bad that reality doesn't really care if you have clever accounting tricks to show that "things aren't really as bad as they look!" The only number that matters at all is global green house gas emissions. We need to get that to zero, and it has continued to go up. Imagine you have a drinking problem and your doctor tells you you need to stop drinking alcohol or you will suffer liver failure. You can argue all…

Totally right that what matters is greenhouse gases in the atmosphere. Tackling them, however, is going to take all our muscles. Many climate deniers have used the 80% of primary energy from fossil fuel figure as a way to claim it's too hard to do anything about the problem or to say there's been little progress. That's misleading and I wrote the article to explain to correct that narrative.

Re: Primary energy vs final energy: why replacing fossil fuels may not be so hard

#18

Post by wnevets »

akshatrathi wrote: post #17
Homunculiheaded wrote: post #14

It's too bad that reality doesn't really care if you have clever accounting tricks to show that "things aren't really as bad as they look!" The only number that matters at all is global green house gas emissions. We need to get that to zero, and it has continued to go up. Imagine you have a drinking problem and your doctor tells you you need to stop drinking alcohol or you will suffer liver failure. You can argue all…

Totally right that what matters is greenhouse gases in the atmosphere. Tackling them, however, is going to take all our muscles. Many climate deniers have used the 80% of primary energy from fossil fuel figure as a way to claim it's too hard to do anything about the problem or to say there's been little progress. That's misleading and I wrote the article to explain to correct that narrative.

>That's misleading and I wrote the article to explain to correct that narrative.

There is your first mistake, you can't reason someone out of a position they didn't reason themselves in to. There are literally people denying covid is real/serious while they or their love ones drown in their fluids.

Re: Primary energy vs final energy: why replacing fossil fuels may not be so hard

#19

Post by lettergram »

Homunculiheaded wrote: post #14

It's too bad that reality doesn't really care if you have clever accounting tricks to show that "things aren't really as bad as they look!" The only number that matters at all is global green house gas emissions. We need to get that to zero, and it has continued to go up. Imagine you have a drinking problem and your doctor tells you you need to stop drinking alcohol or you will suffer liver failure. You can argue all…

It’s funny, I’m not a claimant change denier, but I don’t view emissions as a problem. An insanely large portion of the CO2 is simply us and our livestock breathing. There’s also volcanos, etc.

I’m a lot more worried about chemicals outside of CO2. Such as lead or pesticides. CO2 fluctuates massively throughout the year. Presumably the world can much more quickly (due to vegetation) remove CO2 compared to those other chemicals. CO2 is also far less damaging to the body.

Not saying it’s not important, just I think we’d be better off focusing on issues such as pesticide contamination

Re: Primary energy vs final energy: why replacing fossil fuels may not be so hard

#20

Post by renewiltord »

dudus wrote: post #11
akshatrathi wrote: post #4

Earlier quoted context omitted.

I wrote the story. The efficiency here isn't breaking the first law of thermodynamics. It's just the industry's way of measuring how much work gets done for a certain amount of input. If the work is heating or cooling, then shifting heat from in one direction or another can be done using heat pumps, which move three units of thermal energy for every unit of electrical energy consumed. Might that explain the conundrum…

But then aren't you comparing apples and oranges when you call both that and the loss as heat and noise from coal as "efficiency"?

Well, we're not interested in a thermodynamic comparison. We're interested in a useful-energy-obtained for useful-energy-spent comparison. For instance, if I leave a block in the sun and then bring it inside, I have only expended the energy to move the block out and then move the block in. It doesn't make sense for me to include the sun's contribution to the system because that's not a cost I incur.

The actual apples to apples comparison in efficiency _is_ the heat emitted by the block in my house divided by the cost of moving the block.

Post reply on HN