Can clean energy replace fossil fuels?

[russ_watters]

Its not that difficult - wind and solar ger cheaper as production and infrastructure scales. They are currently the lowest cost source of new, utility-scale electricity generation. As PV cells are a semiconductor technology, we can expect the ‘moore’s law’ like exponential decline in cost that occurred over the past ten years to continue.

No, we really can't. Solar arrays are made primarily of structural steel, concrete and human labor. Also, large electrical switchgear, wires and regulators/inverters. Those things do not follow Moore's law.

And I don't even think the semiconductor nature of the panels has any relevance here. The underlying technology and its capabilities have changed very little over time. PC processors got cheaper because as the manufacturing technology advanced, the manufacturers could pack more circuits into the same size package without much more effort. Chips didn't primarily get cheaper, they "just" got faster. Solar panels haven't changed much at all in decades. What I think drove the cost down is primarily economy of production scale.

What’s happened to solar electricity costs is very orthodox economics: when a technology scales up, it becomes cheaper (this is known as Wright’s Law, and was formulated in 1936), which he summarises this way:

“Every doubling of cumulative production leads to a percentage change in cost.”

In the case of solar, the cost of the electricity produced declines “smoothly” in line with how much solar power is deployed.

https://www.solarquotes.com.au/blog/ramez-naam-solar-cost/

And as I frequently point out, the intermittency problem is real and it's big. And we're just getting to the point where enough solar has been implemented that it can't be ignored anymore. The "overbuilding" idea averages out to solar getting 4x more expensive on average, while the marginal cost rises exponentially. It can be done, but I think we're close to if not already past the point of solar getting cheaper and moving toward it getting more expensive.

 

[BWV]

No, we really can't. Solar arrays are made primarily of structural steel, concrete and human labor. Also, large electrical switchgear, wires and regulators/inverters. Those things do not follow Moore's law.

Fair enough, the analog to Moore is Swanson's Law, which is roughly a 20% decline in price for every doubling of shipped volume - as you note, this is about manufacturing efficiency, not transistors.

https://en.wikipedia.org/wiki/Swanson's_law

From what I could see, module costs are about 30% of total utility-scale installations, so a doubling in PV shipment would result in a 6% decline in total installation costs. This does not assume any efficiency gains, which have definite physical limits, but still could be meaningful. Importantly, installed costs of conventional energy are not declining and solar is already cheaper.

The intermittency issue is solved in the short term by combined cycle gas and in the long term by storage. A fully renewable grid would have to generate surplus power at peak sun and wind times that was then stored for later use.

 

[Dale]

The intermittency issue is solved in the short term by combined cycle gas and in the long term by storage. A fully renewable grid would have to generate surplus power at peak sun and wind times that was then stored for later use.

Which should be included in the cost comparison, but often is neglected

 

[BWV]

Which should be included in the cost comparison, but often is neglected

Solar and wind intermittency tends to be negatively correlated (more wind at night, and less wind when it is hot and sunny). Geographic diversification also reduces the issue. TX is an entirely isolated power grid with 25% wind compared to the 7% national average and works just fine. it is a solvable engineering problem under active study, but not a real issue until renewables become a far larger percentage of total power generation.

 

[Dale]

it is a solvable engineering problem under active study, but not a real issue until renewables become a far larger percentage of total power generation

I completely realize that it is a solvable issue, but the costs still need to be included in the analysis and often are not. Especially when we are talking about a complete replacement for fossil fuels

 

[HAYAO]

I used to work with a company that dealt with solar cells, but as far as their results suggest, solar cells are not yet a viable option for mass replacement of conventional energy sources.

Solar cell efficiency and lifespan is quite keen to environment compared to conventional energy sources. So everything becomes a balance of various factors. Many large scale solar cell grid tend to target desert near equator because high energy production per lifespan and cost tend to be realized. They have the most stable sunlight throughout the year and do not suffer from weather (because it's mostly sunny). At the same time, they will suffer from accumulated heat (reaches as high as 80 degrees Celsius) that lowers efficiency and also accelerates degradation. A typical solar cell have a lifespan of of 30 years, but this could quickly fall to 15 - 20 years in such environment until they need to be replaced. The company I used to work with stated that they will not sell any product that will fail to adequately maintain their efficiency for shorter than 20 years, which means they are willing to raise cost of production for higher durability. What I'm trying to say here is that a "typical lifespan" or "typical cost" doesn't explain well the scalability of energy sources that is keen to environment.

Meanwhile, things like nuclear energy (which I consider them to be a "clean energy") generates tremendous amount of energy. Constraints may be the fact they can only be built around the coast (main parts are too big that they have to be transported through ships), but they don't consume too much land and generates large amount of energy. I don't understand country like Germany (no offense to Germans here) and their hypocrisy in saying that they are going to eliminate nuclear power, while buying electricity from France that relies heavily on nuclear power. I also don't understand the irrational fear of nuclear power; it has killed one of the, if not, the least amount of people per unit energy production.

I know I'm not supposed to talk political here, but I can't imagine a situation where people can politically push through with the agenda of new sources of energy as a mass replacement of conventional energy and actually make it work, when they can't even accept nuclear energy as "clean energy" despite data suggesting that they are one of the cleanest and safest energy out there.

 

[HAYAO]

I completely realize that it is a solvable issue, but the costs still need to be included in the analysis and often are not. Especially when we are talking about a complete replacement for fossil fuels

I would add that vehicles that use fossil fuels have significantly increased their fuel consumption efficiency. And at least over here in Japan, hybrid cars have evolved from a luxury to a fairly mainstream option. You can buy new hybrid cars as low as 15k US$ here. That makes replacement options of fossil fuels to be even less attractive. So you are absolutely right that cost effectiveness is definitely something that needs to be included in the analysis, and that they should be done from both domains.

Furthermore, "clean energy" (most people's definition excludes nuclear energy, which I disagree) has been studied and engineered for several decades now but hasn't reached a point where they are truly a cost-viable option. Now you can make an argument that "clean energy" doesn't have the same span of time of development compared to fossil fuels so they are sure to eventually catch up, but it's hard to agree on something that has not been practically fully developed yet.

 

[Ivan Seeking]

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

I have long been convinced that advanced alternative fuels are the solution; in particular, fuels derived from algae.
https://corporate.exxonmobil.com/Research-and-innovation/Advanced-biofuels?utm_source=google&utm_medium=cpc&utm_campaign=XOM+|+Corp+|+ELH+|+Traffic+|+Non+Brand+|+Technology+|+Biofuel+|+Algae+|+Exact&utm_content=Non+Brand+|+Algae+|+Biofuel+|+V2&utm_term=algae+biofuel&&gclid=EAIaIQobChMIr9Cb9OGk7QIVNQPnCh18hwCTEAAYASAAEgKpOPD_BwE&gclsrc=aw.ds

 

[BWV]

Peak Oil Is Suddenly Upon Us
https://www.bloomberg.com/graphics/2020-peak-oil-era-is-suddenly-upon-us/

 

[russ_watters]

Peak Oil Is Suddenly Upon Us
https://www.bloomberg.com/graphics/2020-peak-oil-era-is-suddenly-upon-us/

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

 

[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.