Can clean energy replace fossil fuels?

[Bandersnatch]

Thank you Covid, we wouldn't have done it without you.

 

[bobob]

My main question, however, is "Can fossil fuels be replaced by clean energy at all?"

First, you would need to define "clean energy." If it means a source of energy that doesn't result in some real negative consequences, then there aren't too many sources of clean energy. Solar gets mentioned a lot, but clean here basically means "does not produce CO2." Manufacturing semiconductor involves lots of unpleasant chemicals and the loar panels themselves contain some unpleasant chemicals, which in one type of panel is Cadmium Telluride. All of that Cadmium has to be obtained and eventually disposed of somewhere. Talk about recycling or assurances of safe disposal is wishful (unless it turns out to be significantly cheaper than obtaining a new supply of the material.) It will require taking advantage of lots of different technolgies where each has a particular advantage and reducing consumption rather than hoping one or two technologies can replace fossil fuels and everything goes along as it has.

 

[BWV]

Maybe, but Peak Oil ain't what it used to be.

Yes, this is good for a few laughs

https://www.physicsforums.com/threads/peak-fossil-fuels-by-2017.417307/

All the experts were convinced a decade ago that it would be impossible to ever extract shale oil economically (although actually the energy industry sort of proved them right)

 

[lookingforsolutions]

This isn't really a technical question as such

The purely technical answer to the question "is it feasible to replace fossil fuels with alternatives that do not emit nearly as much CO2" is obviously yes. When people answer "no" to that (or similar) question they are really saying that they believe it would be too expensive and/or would negatively affect society in some other way (e.g. cause unemployment).

Hence, this is ultimately a political question and has to do with priorities.

I am confused about this debate about CO2
Animals inhale O2 and exhale CO2
Plants inhale CO2 and exhale O2
what have I missed ?

 

[BWV]

I am confused about this debate about CO2
Animals inhale O2 and exhale CO2
Plants inhale CO2 and exhale O2
what have I missed ?

maybe that burning the remnants of long-dead plants and animals releases their CO2 back into the atmosphere, disrupting this balance?

 

[lookingforsolutions]

maybe that burning the remnants of long-dead plants and animals releases their CO2 back into the atmosphere, disrupting this balance?

The way I see it, the relationship cycle is driven by the relentless effort to achieve balance. Should balance be achieved all motion & change would stop. It's like looking at the ashes in your fireplace. What you see is the end point that can not go any further

 

[russ_watters]

I am confused about this debate about CO2
Animals inhale O2 and exhale CO2
Plants inhale CO2 and exhale O2
what have I missed ?

You missed global warming... which seems unlikely.

The way I see it, the relationship cycle is driven by the relentless effort to achieve balance. Should balance be achieved all motion & change would stop. It's like looking at the ashes in your fireplace. What you see is the end point that can not go any further

That sounds like gibberish.

 

[lookingforsolutions]

I am confused about this debate about CO2
Animals inhale O2 and exhale CO2
Yes ( ) No ( )
Plants inhale CO2 and exhale O2
Yes ( ) No ( )
what have I missed ? ​

Cut and past the above in your response with an "X" marking the spot
Thanks in advance
(:-

 

[berkeman]

I am confused about this debate about CO2 -- X

 

[bob012345]

When I ask the question can clean energy generation replace all energy generation by using fossil fuels, I mean all energy, including the energy needed to transport people and products by sea, road and air, as well as the energy that is necessary for the working of machines. as used in industry, road construction, etc.

I believe yes but not with the usual forms of alternative energy such as wind and solar. There needs to be deployment of new invented energy sources that meet the clean definition.

 

[Nick tringali]

I just don't understand why there is so much discussion about solar and wind amongst society when nuclear would solve all of our issues if ran properly.

 

[anorlunda]

I just don't understand why there is so much discussion about solar and wind amongst society when nuclear would solve all of our issues if ran properly.

Many people agree with you. Many don't.

 

[Ad VanderVen]

I just don't understand why there is so much discussion about solar and wind amongst society when nuclear would solve all of our issues if ran properly.

It's all about "... if ran properly." We saddle our posterity with nuclear waste. Do you know a solution for that?

 

[Ad VanderVen]

I don't see a real solution to the energy problem, other than adjusting the combustion engine to eliminate all CO₂ emissions. This is a project of the same importance as the Manhattan project that led to the development of the atomic bomb. New President of the United States Joe Biden should start another similar project with the goal of a CO₂ clean combustion engine. Of course, there will be people who say this is impossible, arguing that splitting CO₂ into C and O₂ takes exactly the same amount of energy as combining C and O₂ into CO₂. Still, there must be a solution to this dilemma.

 

[anorlunda]

Still, there must be a solution to this dilemma.

No. Maybe but not must be.

Edit: scratch the maybe.

 

[Dale]

other than adjusting the combustion engine to eliminate all CO₂ emissions.

I think that is a bad idea to propose. We don't need to eliminate all CO2 emissions, the world can tolerate some level just fine. By setting the bar unrealistically high you risk losing political support which is essential for accomplishing something. Far better to aim for 80% reduction and get 50% than to aim for 100% and get 0% due to entrenched political opposition.

 

[Vanadium 50]

Far better to aim for 80% reduction and get 50% than to aim for 100% and get 0% due to entrenched political opposition.

True, but you are assuming that the goal is to reduce CO2 emissions. The goal may be to enact other wonderful and worthy goals and CO2 is just the motivator.

 

[russ_watters]

It's all about "... if ran properly." We saddle our posterity with nuclear waste. Do you know a solution for that?

There are several solutions to nuclear waste. Dry cask storage, for example -- and you can put them anywhere, you don't have to bury them in a mountain in Nevada. It's not a significant problem, either literally or figuratively. Like most problems related to energy, it's a political one, not a technical one (or even an economic one).

I don't see a real solution to the energy problem, other than adjusting the combustion engine to eliminate all CO2 emissions. This is a project of the same importance as the Manhattan project that led to the development of the atomic bomb. New President of the United States Joe Biden should start another similar project with the goal of a CO2 clean combustion engine. Of course, there will be people who say this is impossible, arguing that splitting CO2 into C and O2 takes exactly the same amount of energy as combining C and O2 into CO2. Still, there must be a solution to this dilemma.

That really doesn't make any sense. The chemistry is what it is. "The solution to this dilemma" is to stop burning fossil fuels in combustion engines.

Caveat: I agree with the prior posts about a 100% elimination policy goal being potentially counterproductive.

 

[BWV]

While gasoline and other transportation fuels can store a large amount of energy in a relatively small mass, most of that energy is lost to heat in an internal combustion engine (ICE). Electric motors are ~3x more efficient than ICEs, so if you can get reasonably close to the mass/energy storage with a battery (or a fuel-powered generator like in a hybrid), electric motors win.

 

[gmax137]

While gasoline and other transportation fuels can store a large amount of energy in a relatively small mass, most of that energy is lost to heat in an internal combustion engine (ICE). Electric motors are ~3x more efficient than ICEs, so if you can get reasonably close to the mass/energy storage with a battery (or a fuel-powered generator like in a hybrid), electric motors win.

Well it depends on how the electricity is being generated. But whatever the source, it is a lot of electricity.

Here's a little reality check:
US gasoline consumption = 140 billion gallon/year (google)
Gasoline heat content = 124,000 Btu/gal (google)
ICE efficiency = 25% (a guess)

So the useful energy from gasoline =
140 E9 gal/yr * 124,000 Btu/gal * 0.25 *(MW hr/3413000 Btu) = 1.27 E9 MW hr per year = 1270 TW hr/yr
or an average of 1.27 E9 MW hr / yr * (yr/ 8760 hr) = 145,160 MW

That's about a third of our current average generation (4178 TW-hr/yr per google); or adding 140 more large nuclear plants.

Maybe someone will check my arithmetic looking for errors (factors of 1000 or 32.2 are common mistakes)...

 

[BWV]

Well it depends on how the electricity is being generated. But whatever the source, it is a lot of electricity.

Here's a little reality check:
US gasoline consumption = 140 billion gallon/year (google)
Gasoline heat content = 124,000 Btu/gal (google)
ICE efficiency = 25% (a guess)

So the useful energy from gasoline =
140 E9 gal/yr * 124,000 Btu/gal * 0.25 *(MW hr/3413000 Btu) = 1.27 E9 MW hr per year = 1270 TW hr/yr
or an average of 1.27 E9 MW hr / yr * (yr/ 8760 hr) = 145,160 MW

That's about a third of our current average generation (4178 TW-hr/yr per google); or adding 140 more large nuclear plants.

Maybe someone will check my arithmetic looking for errors (factors of 1000 or 32.2 are common mistakes)...

The generation source matters with EVs, the well to wheel efficiency is higher with renewables

The total WTW (well to wheel) efficiency of gasoline ICEV ranges between 11–27 %, diesel ICEV ranges from 25 % to 37 % and CNGV ranges from 12 % to 22 %. The EV fed by a natural gas power plant shows the highest WTW efficiency which ranges from 13 % to 31 %. While the EV supplied by coal-fired and diesel power plants have approximately the same WTW efficiency ranging between 13 % to 27 % and 12 % to 25 %, respectively. If renewable energy is used, the losses will drop significantly and the overall efficiency for electric cars will be around 40–70 % depending on the source and the location of the renewable energy systems.

https://www.adlittle.de/sites/default/files/viewpoints/ADL_BEVs_vs_ICEVs_FINAL_November_292016.pdf

while US electricity consumption is around 4000TWH, total generation capacity is ~1.1TW, so at 8760 hrs /year that would unrealistically be nearly 10K twh if everything ran at full capacity 24/7 for a year - this won't happen, but electric battery recharging does take off-peak capacity, so no need for brand new generating capacity for 100% of the incremental 1270 TWH, some will come from existing capacity. Also, conversion to EVs will happen incrementally even under the most aggressive assumptionshttps://www.eia.gov/energyexplained... photovoltaic electricity generating capacity.