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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

#91

Post by Steven_Vellon »

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…

Bear in mind this cuts both ways. Replacing a gas heater (which directly produces thermal energy from chemical reaction) with an electric heater now means this energy has to be produced, transmitted, and run through a heating element. If this heater is being run at night, it likely has to go through an energy storage system, too.

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

#92

Post by roywiggins »

Steven_Vellon wrote: post #91
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…

Bear in mind this cuts both ways. Replacing a gas heater (which directly produces thermal energy from chemical reaction) with an electric heater now means this energy has to be produced, transmitted, and run through a heating element. If this heater is being run at night, it likely has to go through an energy storage system, too.

In many locations you can replace a resistive heater with a heat pump and more than make up for the losses.

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

#93

Post by roenxi »

toomuchtodo wrote: post #73
roenxi wrote: post #57

Earlier quoted context omitted.

South Australia was famous recently [0] for having not only the most expensive electricity in Australia, but competing for the most expensive energy in the world. I would encourage the world to be cautious about copying whatever it is they are doing. And if the South Australia Big Battery is an example of utility scale storage, store's about 1-2 hours worth of energy from a small plant. It isn't capable or expected t…

If you refer to your citation (from 2017), it states that electricity prices were high because of natural gas shortages and coal generator closures, and that the payback period on storage and solar is down to 7 years (storage systems have 10 year warranties, rooftop solar and their inverters typically have 25 year warranties, so after your payback period, your power produced is free to you). Renewables drive down the…

> were high because of natural gas shortages and coal generator closures, and that the payback period on storage and solar is down to 7 years

That isn't as compelling as you might think. If they screwed up their energy grid by closing down gas and coal generators then (1) solar would look better than nothing and (2) would have a short payback period.

That fact could just as easily be cited in an argument as "these clowns really need more gas and coal". The lack of fossil fuels is linked to very high power prices.

> Renewables drive down the cost of power [1]

Your link doesn't actually support that. It says they drive down the cost of wholesale power. That is how it typically plays out when countries go heavy on renewables (same thing happened in Germany). Wholesale prices drop, retail prices rise because of there is too much energy when it isn't wanted.

> The "South Australia Big Battery" at the Hornsdale Power Reserve, recently expanded, has saved electrical consumers $150 AUD million

Again, proabbly evidence of a mismanaged grid. Given that it was built in SA rather than somewhere important, it seems likely Big Battery is fixing up losses from installing an unstable amount of wind and solar.

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

#94

Post by toomuchtodo »

aardvarkr wrote: post #90
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…

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 wi…

You’re not being harsh. I do realize it was only for an hour. How else would you expect an energy transition to occur? First an hour. Concept proven. Then multiple hours at a time. Finally, those remaining fossil generators sit idle so long they’re decommissioned (or converted to burn hydrogen or ammonia generated from renewables). The South Australian state itself has set its 100% renewables target before 2030. You set ambitious targets, and then you work to meet them. This isn’t any different then the UK pulling their new petrol vehicle sales ban forward to 2030 from 2035 because EVs have been proven out.

Cheap, dirty power isn’t good energy policy, and it’s likely others follow this lead in order to meet their zero emissions targets.

https://www.cleanenergycouncil.org.au/news/south-australia-s... (“The South Australian Government has recognised the incredible success of renewable energy to date, and has now set a firm plan for getting to 100 per cent renewable energy. This is the future, and the Clean Energy Council looks forward to working with the South Australian Government to make this a reality.”)

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

#95

Post by dudus »

NovemberWhiskey wrote: post #23
dudus wrote: post #10

Earlier quoted context omitted.

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

No; you're missing the point - 100% of the energy in an electric baseboard system is converted into heat. It's 100% efficient. There is no more effective way to turn electricity into heat than resistively. A heat pump doesn't turn electricity into heat. It moves heat from one place (outside) to another place (inside); and can seem more efficient because the system isn't closed.

Ah makes sense. Thanks for taking the time to explain

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

#96

Post by [deleted] »

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…

[deleted]

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

#97

Post by ip26 »

kortilla wrote: post #41
ip26 wrote: post #34

Earlier quoted context omitted.

FWIW long distance transmission lines work too. Solar peaks a few hours earlier than demand. So ship that power east two timezones.

And which solar panels power California?

If California is the only market powered by batteries, that's a huge reduction in battery-scope. Washington has a lot of hydro, etc.

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

#98

Post by ActionPlankton »

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…

This discussion of heat pumps makes me want to add that we may also ignore cogeneration too much. We just don't think about heat flows and temperature enough.

There is, of course, the communal thing, done in Sweden and Russia and college campuses, with a power plant and steam pipes going to apartments.

But what about an appliance for suburban America? Like, combine a gas turbine generator with an HVAC system and hot water tank (pretty sure you can buy things like this in Germany). No unsolved technical problems here. You generate electricity for your home, heat it with waste heat, and absorb temporary excesses in capacity by usefully heating water. You could imagine integrating other things too: If you need more heat than you use electricity, then you might as well use the electricity to do something high-value (cryptocurrency is a crime against the environment, but you might as well compute some hashes in your resistive heater). All this becomes an elaborate way to burn natural gas to make heat, but you get a bunch of other things out besides. The "smart controller" aspect then becomes interesting -- but even that is "just simple automation", not super-difficult AI.

Maybe logistically, the "everything is electric; electricity comes from renewables/nuclear; and heat comes from heat pumps" solution is easier in the long run?

But this more "decentralized heat engines" solution has the "advantage"(?) that it could run on biomass, which is easy to store (however, I am aware of the problems of wood pellets and deforestation).

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

#99

Post by throwawayxd »

konjin wrote: post #63
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…

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.

>I worked as a quant for a power company in Australia

This type of work sounds very interesting to me, do you mind sending me an email (see my bio)? As a university student, I'd really like to know what I can be doing on the side to land a position like this.

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

#100

Post by SuoDuanDao »

konjin wrote: post #63
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…

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.

Good thing most of us are transitioning to a knowledge society ;)
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