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

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

#61

Post by bigbubba »

notthemessiah wrote: post #36
aardvarkr wrote: post #31

Is no one pointing out that this isn’t the part that makes replacing fossil fuels hard? This is focusing on a completely irrelevant metric. It’s a great motivator for why we need to shift but it has no impact on how hard it will be to replace oil. There’s 100 practical reason for why it’s hard, namely that clean energy sources are not under our direct control to scale up and down as we need more/less. We can’t tell t…

This problem is way overstated, as most fossil fuel and nuclear power can't be easily or efficiently ramped down either. We also have energy storage technologies other than batteries: the most common being pumped-storage hydroelectricity (basically a reversible hydroelectric dam, where we pump water up during excess power usage and use the generators during high demand).

> most [...] nuclear power can't be easily or efficiently ramped down either.

As you say, most, but naval reactors are very responsive. Responsive reactors can be designed when that property is desired.

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

#62

Post by alacombe »

serpix wrote: post #51
lake-effect wrote: post #47

“Electrical devices can sometimes offer higher than 100% efficiency,” said BNEF analyst Matthias Kimmel. That might seem odd. How can there be more energy as output than input? But that’s exactly what heat pumps and air conditioners do. They use electricity to shift heat from the outside to inside, or vice-versa, and typically provide three units of energy service for one unit of energy input, meaning an efficiency o…

well my 80m2 apartment is fully heated to about 22.5C with an air heat pump drawing about 600W with an outside temperature of 0C. So take from that what you will about efficiency.

That's no particular feat, you can heat a forge to 1200C with enough insulation and just 600W. Also, this is just considering a limited referential, ie. the one impacting the most your wallet. If you consider a bigger referential, your efficiency will drop below 1 for sure. Not to mention that your system will leak refrigerant (it's really not a matter of "if" but "when"), which is likely to have greenhouse effects.

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

#63

Post by konjin »

toomuchtodo wrote: post #40
aardvarkr wrote: post #31

Is no one pointing out that this isn’t the part that makes replacing fossil fuels hard? This is focusing on a completely irrelevant metric. It’s a great motivator for why we need to shift but it has no impact on how hard it will be to replace oil. There’s 100 practical reason for why it’s hard, namely that clean energy sources are not under our direct control to scale up and down as we need more/less. We can’t tell t…

South Australia already has days when solar alone is providing most of it's power [1] [2]. It's not that hard. You scale up renewables, and build curtailing (throwing away excess clean energy) into your cost model (until storage gets cheaper, which it will; Tesla is shipping almost 800 MW of utility scale battery storage per quarter). Australia's entirely grid will be clean by 2030 at their current rate of renewables…

I worked as a quant for a power company in Australia. Solar and wind are a great way for power companies to make money and a terrible way to run an industrial society.

Running anything but an aluminium smelter off renewables is impossible. Because people have the nasty habit of wanting elevators to work even when it is raining.

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

#64

Post by alacombe »

akira2501 wrote: post #39
notthemessiah wrote: post #36

Earlier quoted context omitted.

This problem is way overstated, as most fossil fuel and nuclear power can't be easily or efficiently ramped down either. We also have energy storage technologies other than batteries: the most common being pumped-storage hydroelectricity (basically a reversible hydroelectric dam, where we pump water up during excess power usage and use the generators during high demand).

> being pumped-storage hydroelectricity Which isn't great as far as the "Power Generated" : "Land Used" ratio is concerned.. the same is true of most hydro-electric solutions.

Neither are solar or wind farms.

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

#65

Post by Gibbon1 »

alacombe wrote: post #53
notthemessiah wrote: post #36

Earlier quoted context omitted.

This problem is way overstated, as most fossil fuel and nuclear power can't be easily or efficiently ramped down either. We also have energy storage technologies other than batteries: the most common being pumped-storage hydroelectricity (basically a reversible hydroelectric dam, where we pump water up during excess power usage and use the generators during high demand).

> as most fossil fuel and nuclear power can't be easily or efficiently ramped down either. Ramping it down is irrelevant, you can always use the extra to process aluminium at cheaper rates, pump water back in reservoir, etc. The ramping up is critical, as you expect the light to turn on when you flick the switch, not 3h later.

Every time I see hysterical comments (not from you) about how terrible it would be if excess solar and wing power regularly crashed the price of electricity I see and opportunity instead. Seriously regular periods where electric power is 'free' is a serious opportunity. You could smelt aluminum, electrowin iron. Run electric furnaces in mini-mills.

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

#66

Post by alacombe »

jcampbell1 wrote: post #6
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…

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.

> What is wrong with the concept of a heat pump?

Something overlooked is that heat pump will leak refrigerant. It's not really not a matter of "if" but "when", physical systems fail.

Refrigerants are pretty nasty greenhouse gases.

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

#67

Post by lutorm »

kortilla wrote: post #44
toomuchtodo wrote: post #40

Earlier quoted context omitted.

South Australia already has days when solar alone is providing most of it's power [1] [2]. It's not that hard. You scale up renewables, and build curtailing (throwing away excess clean energy) into your cost model (until storage gets cheaper, which it will; Tesla is shipping almost 800 MW of utility scale battery storage per quarter). Australia's entirely grid will be clean by 2030 at their current rate of renewables…

> Let us not use edge cases to guide our path forward. Funny you should say that after presenting an edge case. In North America during the winter the sun is setting during peak demand in the Northern states. That means we need to overbuild wind so much that we can run entirely on wind on non-windy days. The economics do not support that. Storage is critical to make the US case work.

Storage or better transmission infrastructure...

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

#68

Post by notthemessiah »

bigbubba wrote: post #61
notthemessiah wrote: post #36

Earlier quoted context omitted.

This problem is way overstated, as most fossil fuel and nuclear power can't be easily or efficiently ramped down either. We also have energy storage technologies other than batteries: the most common being pumped-storage hydroelectricity (basically a reversible hydroelectric dam, where we pump water up during excess power usage and use the generators during high demand).

> most [...] nuclear power can't be easily or efficiently ramped down either. As you say, most, but naval reactors are very responsive. Responsive reactors can be designed when that property is desired.

Sure you can reduce power production, just insert control rods, but that comes at a severe cost to efficiency, costs that at large scale become far more of a concern, especially when nuclear is already nearly prohibitively expensive.

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

#69

Post by ben_w »

lettergram wrote: post #19
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…

In addition to everyone else’s points, I’d like to note anthropogenic sources produce CO2 at 60-70 times the rate of volcanic emissions.

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

#70

Post by fuoqi »

philipkglass wrote: post #46
robertlagrant wrote: post #27

The article seems incomplete. Sure we may be burning three times more coal than we'd have to if we could perfectly convert it to energy. That has literally never factored into an argument I've seen about renewables - it's always "we currently produce X GigaWatts 24x7, and renewables don't let us do that". Saying we burn coal at 30% efficiency isn't addressing anything useful. And it's one of those articles where many…

It's a factor in arguments where people say "we don't need to just clean up electricity, we need to replace all fossil energy." They're usually referring to primary energy in these arguments. If you look at barrels of oil consumed per day in the US, then just plug the barrel-of-oil numbers into a unit converter to see how many terawatt hours it comes to, it looks hopeless to put a dent in oil consumption with electri…

But electricity is not 100% efficient either. At the very least you have transmission loss (to compensate for renewables intermittency you have to transfer energy farther), round-trip energy storage efficiency, EV efficiency. Also during cold weather you would have to spend electricity to heat car interior, while for gasoline cars this heat is "free". And don't forget that maintenance of renewable plants requires more energy, due to the low density of the exploited energy sources.

In the very best scenario for vehicles you would get somewhere around 1:2 ratio, not even close to an order of magnitude.

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