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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

#81

Post by colechristensen »

bigbubba wrote: post #74
Gibbon1 wrote: post #65

Earlier quoted context omitted.

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.

I don't think it's that simple. What does your aluminum smelting plant do when the power isn't free, sit there unproductively? Or purchase electricity when it's expensive? Either will cost you money. Maybe you can still come out ahead in either of these cases, but that depends on quite a few factors.

You have variable pricing on electricity, and heavy industrial users build up business plans that take advantage of the market. Prices will adjust until the inefficiencies are eaten up by market forces.

It’s not “maybe you can come out ahead” the occasional abundance of very cheap electricity creates an opportunity that will be filled by whoever can make the most of it.

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

#82

Post by omgwtfbyobbq »

fuoqi wrote: post #70
philipkglass wrote: post #46

Earlier quoted context omitted.

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 mor…

That depends on the refined gasoline. Someplace like California, where petroleum is really heavy and needs a lot of energy to extract/refine, uses roughly 13kWh of natural gas, electricity, etc, to deliver one gallon of gas (page 5).

https://ww2.arb.ca.gov/sites/default/files/classic//fuels/lc...

Most of that 13kWh is natural gas, so you can't use it directly in an EV. It can be used to generate electricity in a high efficiency natural gas power plant though, which would provide ~6-7kWh to consumers.

By avoiding extraction/refining/transportation of petroleum and the associated natural gas/electricity used in those steps, we can instead use that to generate electricity, which would power an average EV at ~250Wh/mile roughly 25 miles.

In places where petroleum doesn't need as much natural gas for extraction, that figure is lower, but the idea still applies.

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

#83

Post by philipkglass »

fuoqi wrote: post #70
philipkglass wrote: post #46

Earlier quoted context omitted.

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 mor…

The 2018 Corolla has a combined driving cycle fuel consumption of 7.6 liters/100 km [1]. 7.6 liters of gasoline contains [2] 7.6 * 34.2 = 260 megajoules of primary energy. The standard Tesla Model 3 has a combined driving cycle electricity consumption of 16 kilowatt hours per 100 km [3]. 1 kWh is 3.6 megajoules, so it consumes 57.6 megajoules over 100 km.

The Model 3 consumes 22% as much energy to travel the same distance as the Corolla.

It's true that there are upstream energy losses before the BEV battery is charged up. About 5% [4] of generated electricity is lost to transmission and distribution in the United States. But there are also upstream energy losses before fuel goes into the Corolla's tank. The refining process that turns crude oil into motor fuel loses about 7% of primary energy along the way [5]. "Together the 96 EU mainstream refineries consume nearly 50 Mtoe total energy per year, which is equivalent to about 7% of their crude oil intake. This means that 93% of the energy content of the crude oil processed by the refinery is ultimately available in the refined products."

[1] https://www.guideautoweb.com/en/makes/toyota/corolla/2018/sp...

[2] https://en.wikipedia.org/wiki/Energy_density

[3] https://en.wikipedia.org/wiki/Tesla_Model_3

[4] https://www.eia.gov/tools/faqs/faq.php?id=105&t=3

[5] https://www.concawe.eu/wp-content/uploads/2017/01/rpt_12-03-...

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

#85

Post by jxramos »

Seems like a simplistic but a very conceivable short sighted overlooked detail in touting fossil fuel advantage to quote so called primary energy for fossil fuel, and yet it kinda feels like a straw man is hiding somewhere. Are there actual past articles and literature that conflates the two when speaking of fossil fuels? Setting the bar too high for renewables would be a big fallacy, but where has that happened exactly? It'll be cool to look back at old articles and twitter posts and spot this conflation or at least to ask for clarification.

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

#86

Post by sokoloff »

alacombe wrote: post #56
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.

> a heat pump is often 3x as efficient at heating a house vs electric baseboards. Not if you consider the whole "indoor + outdoor" referential, in that case you will always get below 100% efficiency.

True, but no one cares if they make the outside air 0.05ºC hotter in the summertime or 0.1ºC colder in the wintertime.

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

#87

Post by jxramos »

jxramos wrote: post #85

Seems like a simplistic but a very conceivable short sighted overlooked detail in touting fossil fuel advantage to quote so called primary energy for fossil fuel, and yet it kinda feels like a straw man is hiding somewhere. Are there actual past articles and literature that conflates the two when speaking of fossil fuels? Setting the bar too high for renewables would be a big fallacy, but where has that happened exac…

Here's an example from the linked article @mcwone shared below that may present us with an opportunity to spot the fallacy in play:

    Meanwhile, with batteries, it costs roughly $200 to store
the energy equivalent to one barrel of oil. Lazard, “Lazard’s Levelized Cost of Energy Analysis”; utility-scale lithium battery LCOE (levelized cost of energy) @ $108–$140/MWh converts to $180– $230/BOE (barrel of oil energy equivalent).

We'll I'm struggling to track that quote in the article to its primary source assuming I landed on the right place https://www.lazard.com/media/451419/lazards-levelized-cost-o...

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

#88

Post by colechristensen »

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…

> Air conditioners and heat pumps do not output more energy than they consume.

They absolutely do.

A heat pump will output more heat where it is wanted than would be output by flowing the electricity through a big resistor.

You put 100 W into a heat pump and you can get 300 W of heat out. You are not cheating thermodynamics, but using energy to move energy.

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

#89

Post by philipkglass »

hinkley wrote: post #84

In the spirit of Fermi’s paradox: So then why haven’t we?

Because there are multiple decades' worth of investment in fossil fuel assets that need replacing, and renewables started competing on price alone (ignoring global warming externalities) in just the past few years. That's also why Germans pay eye watering prices for renewable electricity; Germany installed renewables on a large scale before the costs came down.

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

#90

Post by aardvarkr »

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…

Hey, not to be too harsh but you do realize that was only for 1 hour in the middle of the day when usage is near its lowest? It’s impossible for solar to provide 100% of the power used in a day because the sun doesn’t shine for 24 hours. It also doesn’t reduce the amount provided by baseline power sources because they can’t scale down quickly (they take days to start up and slow down) so they ended up generating a wild excess of energy those days. The amount of power generated != power used and if there’s no one to use it then it goes unused. On top of that, that first link was great and showed just how much solar fluctuates week over week and day over day making it hard to predict.

Renewables are fantastic, don’t get me wrong, and I’m a huge proponent of them. Problem is they’re just one piece of the bigger picture and making wildly infeasible claims like 100% renewable energy just makes it that much harder to implement a reasonable and highly effective strategy that relies on growing renewables while maintaining a robust grid that can provide power cheaply. Southern Australia is one of the most expensive power markets in the world so it’s not really a good example and the world shouldn’t be following their model.

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