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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

#101

Post by SuoDuanDao »

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.

heat pumps generally deliver three joules of heat per joule of electricity used to run them.

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

#102

Post by [deleted] »

alacombe wrote: post #66
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.

> 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.

[deleted]

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

#103

Post by chris1993 »

konjin wrote: post #59
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…

Not to mention that it has destabilized the national Australian grid to the point where a 35C day means that you get rolling blackouts across multiple states. Currently the only way you can be sure you have power on a hot summer day in Australia is to share a substation with a hospital designated to provide life support to patients.

When has Australia ever experienced these rolling blackouts across states due to solar? The most recent substantial blackouts (2019 in victoria) were due to extreme heat causing the power stations to be unable to meet demand, plus some stations being offline [0]. This is totally unrelated to the uptake of solar which ameliorates peak demand for aircon power. [0] https://www.abc.net.au/news/2019-01-26/victorian-blackouts-w...

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

#104

Post by alacombe »

sokoloff wrote: post #86
alacombe wrote: post #56

Earlier quoted context omitted.

> 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.

On an individual level for sure, multiply this by a state / country population, and you get non-negligible impact.

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

#105

Post by ClumsyPilot »

alacombe wrote: post #64
akira2501 wrote: post #39

Earlier quoted context omitted.

> 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.

What's wrong with wind farms? They literally take no land, you can graze cattle / farm right under them.

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

#106

Post by foldingmoney »

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…

This is a property of _what the device is doing_ (moving heat from one place to another) as opposed to being a property of how it's powered, though.

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

#107

Post by imtringued »

roenxi wrote: post #93
toomuchtodo wrote: post #73

Earlier quoted context omitted.

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 cl…

>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.

There is too much energy because obsolete base load plants can't keep up with a modern grid. The primary source of excess energy isn't renewables because we want to use every single renewable kWh. Excess energy is energy that isn't wanted not just because we don't need it but also because we don't like how it was created. Coal plants not only force flexible power generators to turn off prematurely, they also generate CO2. So any insistence on protecting coal plants is completely misguided considering their fatal flaws as a technology.

>it seems likely Big Battery is fixing up losses from installing an unstable amount of wind and solar.

Is this supposed to be some kind of joke? Flexible power generators cannot increase grid instability because their response time is measured in minutes or seconds. You can turn solar panel on/off immediately. You can turn on/off turbines at any time with a slight delay. The Tesla battery stores an insignificant amount of energy so it can't even do what you are talking about. It's primary purpose is frequency stabilization which was usually done with peaker plants and unconventional energy storage like flywheels.

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

#108

Post by imtringued »

bigbubba wrote: post #80
Gibbon1 wrote: post #78

Earlier quoted context omitted.

Even if you are running an aluminum smelter 24/7 having periods when the price of electricity goes to zero helps your bottom line a lot. Aluminum is difficult case because the electrolytic cells have to be kept hot. I've saw paper describing electrowinning iron. The process used aqueous sulfate electrolyte. One assume the capital cost of the cells themselves would be minimal.

Yes but if the average price of the clean energy is sufficiently high, brief periods of free clean energy may not be enough to offset that.

It's the opposite. Low whole sale energy prices in Germany cause policy failures that increase the EEG surcharge.

Here are some made up numbers. If the wholesale price is 0.10€ per kWh but the subsidized price is 0.20€ per kWh then the EEG budget has to make up the 0.10€ difference. That difference is added to the retail price so you end up paying 0.10€ for the electricity itself and 0.10€ per kWh for the EEG surcharge.

Industrial users are exempt from the surcharge so consumers end up paying electricity bills for the biggest energy consumers.

You actually end up paying 0.10€ for the electricity, 0.10€ for the EEG surcharge and 0.05€ for the EEG portion that industrial companies didn't pay for. Total: 0.25€ which is higher than even the subsidized price. Meanwhile industrial users only pay the wholesale price of 0.10€.

Of course I have simplified grid costs and taxes but this is the general problem with the EEG surcharge.

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

#109

Post by sokoloff »

alacombe wrote: post #104
sokoloff wrote: post #86

Earlier quoted context omitted.

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

On an individual level for sure, multiply this by a state / country population, and you get non-negligible impact.

Draw a boundary around a city and any lasting temperature change is solely an energy balance question.

Any heat that you move into the house in the winter leaks out within the day (asymptotically), so this doesn’t become a localized runaway effect.

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

#110

Post by tertius »

ardit33 wrote: post #42
mcwone wrote: post #25

I found this article interesting: https://media4.manhattan-institute.org/sites/default/files/R...

The guy that wrote is is a big Oil lobyist, and the Manhattan Institue is a conservative/big oil think tank It is like someone from the early 1900s saying: Combustion engines will never take over, steam is 98% of power... etc.. etc.. yet in 10 years they did take over, first cars, then larger vessels (trains and boats). Coal/Steam power generation for trains was seen as a super polluting thing and unwanted in cities…

"That's like saying this other situation that we can look back at by analogy and overlay it on the future that hasn't yet played out."

Nope.

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