Interesting, but it would have been even more interesting if you had compared the amount of fossil fuels used in various “non-fossil” energy technologies: wind, nuclear, solar, hydro, and so on. Such studies have been done already, primarily as part of EROI work, e.g. Weissbach 2013.

There’s a lot of good progress being made in making the raw material for plastic from biomass. Also, given electricity, you can convert biomass to methane, which is the primary source of heat in a blast furnace. You could also get the carbon needed from biomass using electricity to purify it. Likewise, given electricity, you can farm algae, which can be a source of diesel.

Or to look at another way, I understand the energy return on investment for wind is quite positive, so that means that with some creative chemistry, it should be possible to make it all work.

I am a little bit confused.  You state that we cannot make steel and concrete without fossil fuels, but you show that the production of these materials cannot be accomplished without intrinsic carbon dioxide emissions due to the chemical reactions necessary to produce the material.  These are not the same.  you would need to show that (for steel production) carbon monixde cannot be produced without fossil fuels.  The same follows for cement production.  It is my (possibly incorrect) understanding that insofar as the chemistry goes you are correct in stating that we cannot eliminate these emissions.  However, the energy used to run these processes (i.e. the application of heat) can most definitely be provided by CO2 free electricity (think about the Columbia River hydropower system that attracted industry in the WW2 era, and a little closer to my home, the St. Lawrence River that attracted the high energy intensity aluminum smelting operations of Alcoa).  Could you tell us more about the processes that occur and whether using heat from electricity would be expected to be more/less efficient that using a fossil fuel to produce heat?

You do make a good point of showing that lifecycle emissions matter, but without knowing how emissions are broken out, readers (or at least me) are left a bit wanting.    

Nate

This article is factually correct, I have been making the same argument to people for years.  I would add to it that the big trucks and cranes required to transport and install the turbines also carry the same dynamics of being manufactured from steel and run on fossil fuels.

An analagous argument can be made for solar panels which use plastic polymers in the coatings, significant mineral resources and energy intensive manufacturing.  

Fortunately there are ways to at least improve the emissions profile on these processes.  

Maritime shipping is beginning the transition to LNG fuels which produce far less carbon emissions and nearly eliminate criteria pollutants compared to dirty bunker fuels that are far dirtier and carbon laden than on-road diesel.  LNG is cheaper in today’s market and much better for the environment and public health. Trucking and big mining operations are also looking at LNG for cost reasons, but they are not being forced to change due to emissions requirements the way that maritime shipping is.

Portland cement can be replaced by coal fly ash which reduces the embodied energy of cement, GHG emissions and contributes to cleaning up the world’s largest solid waste problem.

Ford is now making the F-150, the world’s most popular pickup truck, out of aluminum.  Curious to know what the emissions profile is for aluminum manufacturing versus steel and if more use of aluminum would help in this regard.  

This analysis does not consider the fossil energy to overhaul and/or recycle a wind turbines materials. I would assume that if wind turbines can be designed for easier parts replacement in a complete overhaul this would be somewhat labor intensive but maybe far less fossil energy intensive. A recycle of all the metal components would obviously be done – but probably not the blades because they are composites -although who knows. If blade recycle becomes a problem using some of the newest monocrystalline aluminum could work. The concrete footing if designed properly should have a very long if not indefinite fatigue life depending on the climate and possibly some other minor factors and even the steel tower if designed properly could have a very long fatigue life. A new study I just read from actual long term data sets wind turbine life at 25 years with some drop off of production and getting better. So the second,third or forth time around should use significantly less fossil fuels.

PS to below post: I suspect that the majority of metals in a nuclear power plant can not be recycled 

because of embedded radiation. I have no idea what it would take to recycle all of the materials or if it’s practical to overhaul a nuclear plant at end of life.

Robert, the economics behind the preferential use of coal and fossil gas in steel and concrete production instead of hydrogen (or ammonia or even biomass and bio-methanol), are similar to the situation with other direct heating applications as well as transportation.  Hydrogen works just as well as coal and gas for industrial heat (and chemical reduction of iron ore, see Sustainable Materials, p.139), the only problem is that it currently costs much more.  

So all you are really saying is that you do not believe in the “hydrogen economy”.  Fine.  But to justify this position, shouldn’t you make an argument that it’s ok to keep using fossil fuels (at least for these high-priority applications) until they are depleted?  And why should high priority applications be restricted to iron and concrete?  Transportation gets just as big an advantage from the special properties of fossil fuel (in other words, with half of all fossil fuel use coming from “high priority” applications, we’ll never reduce fossil fuel use enough to offset the growing energy needs of the developing countries). 

I’m pretty sure the reactor vessel is a small fraction of the steel in a nuclear plant.  I would think re-bar and all of the high pressure steam plumbing would be the majority.

On the net steel used though,  this 2005 paper from the University of California at Berkeley found that nuclear power plants use an order of magnitude less steel than wind farms for the same average power output.  The nukes also last about 3x as long.  

Either way, the Earth has inexhaustible iron resources, and it is clearly possible to refine iron ore with electricity or hydrogen, neither of which is so energy intensive to destroy the EROI of wind or nuclear.  So there’s no way that steel shortages will keep us from power future society with wind or nuclear power. 

I didn’t realize that steel and concrete production create almost 12% of the excess CO2 problem. Thanks. It will take proper CCS and lots of clean energy in order to almost completely transition from FF’s (and, advanced materials to take their place). It will also require the wisest use of the fossil store in order to prevent depletion scenarios. Thus, we need to build the least expensive non fossil option with the highest EROEI. Some say wind requires too much material inputs, however, I believe it still requires less energy to make than current solar PV.

What does seem trivial is the use of hydrocarbons for non combustionables such as all our plastic stuff because that is a small amount compared to all the gas we use and coal burned on our behalf. Therefore, we should be able to rely on hydrocarbons for a much longer time if we develop the best energy sources a little sooner.

I don’t believe hydrogen will be of much use because it is just another energy carrier unless it can be made “cheaper than it is inefficient”. Closed cycle nuclear’s high process heat could make it (or liquid fuels) at a greater efficiency than electricity (I believe, because the steam cycle is omitted) but those fuels will undoubtedly be less efficient in their end use than pure electricity. At least, it is possible to come up with such fuel should concrete and steel not be made properly with electricity alone.

I used to think that biofuels would never amount to much but perhaps they can at least be able to power the equipment needed for industrial transport. Could they be an easier path than nuclear produced fuels in a world where (largely nuclear) electric is used for “everything else”?

Solar is but one option. PV, with its rather low eroei might be better off for smaller scale needs, such as for lighting and off grid. It is an amazing invention but it does not mean that it’s the best one to replace FF’s with.

I doubt the biomass required to power the biomass industry (in place of diesel) would also be able to power the turbines (at the usual 60% or so loss to thermo inefficiency) to generate the electricity to convert over to methane. It would seem to be easier to use corn ethanol (admittedly, at a very low eroei) to power just the industrial equipment needed to build whatever is the least expensive non fossil capacity with the highest eroei. I believe that would be some form of closed cycle nuclear. Wind turbines are just another amazing invention but not really the best to replace FF’s with.

Carbon nanotube type material made with molecular 3d printers would be more of a possibility than wooden structures, for powering the large requirements of today’s world. It will require a lot of as of yet undeveloped machinery to make wind turbines without (much) FF’s but it might be simply easier for these inventions to trump wind and or solar altogether.

Just a quibble

BOS steel coming primarily from blast fruances and thus raw ore accounts for ~70% of the worlds production. Scrap is used in BOS steel accounting for 25% of each melt. EAF steel coming mainly from scrap accounts for ~30%. So there is a substantial amount of recycling going on though obviously it is the minor route. Recycling rates estimates ar below.

http://www.unep.org/resourcepanel/Portals/24102/PDFs/Metals_Recycling_Rates_110412-1.pdf

The world steel has a blurb pdf on wind.

http://www.worldsteel.org/dms/internetDocumentList/case-studies/Wind-energy-case-study/document/Wind%20energy%20case%20study.pdf

Nate

There are 4 main ways for making steel that could be green excluding CCS (note many of these are for iron making, a step in the steelmaking process, usually the most intensive)

• 100% recycling and no ore. This would be a 100% electric route as EAF’s would be used
• Electrolysis of iron ore
• Use of charcoal from biomass
• Substitute hydrogen for carbon as the main reducing agent (etc)

The first is possible for a large amount of applications and 30% of the worlds steel production is recycled scrap. However steel from this route tends not to be as strong as from primary ores and while that is improving, it has gotten to the state of marginal improvements. 

The second option has been looked at for years. I am no expert but the main issues seem to lie in the fluid and cathode materials. This is lab scale with 5kg/day experiments being proposed but not yet active.

The third is the historical method for making iron and there are a number of charcoal furnaces in Brazil. Charcoal furnaces can produce iron of better quality but cannot deal with the most common type of iron ore and are limited in size due to the lower strength of charcoal to coke. Coke furnaces can reach 14,000 tons per day. Charcoal is limited to 600. Without getting into forestation issues, world consumption of steel would have to dramatically drop.

The fourth is hydrogen. This creates technical issues and has been considered in the past but without a hydrogen economy, little research has been done. What has been done in this area is direct recycling of top gases from a BF. The gas efficiency of a BF is about 50% meaing that about half of the carbon leaves as CO and half leaves as CO2. This could lead to a 20% reduction without CCS and has been demonstrated on a small scale. In this area you also come up against nitrogen. Blast furnaces are blown with hot air and nitrogen accomplishes very little in this process. Replacing this with oxygen is theoretically possible and is done to a certain extent in current furnaces but a new type of furnces is probably needed.

Electric blast furnaces have been used in the past mainly in Sweden and Norway but their use ceased by the 1970’s due to poor performance versus coke furnaces.

ULCOS is the European research arena for steel. You will see also the DRI route mentioned here.

http://www.ulcos.org/en/index.php

Robert, all of your attacks on wind energy were comprehensively rebutted in this literature review of every peer-reviewed publication on the lifecycle CO2 emissions of every energy source. The result? Wind energy’s lifecycle impact is a fraction of all fossil-fired energy sources, and significantly lower than almost all non-emitting resources, including nuclear power.

http://www.nrel.gov/analysis/sustain_lca_results.html

Michael Goggin,
American Wind Energy Association

Weißbach, D., et al. “Energy intensities, EROIs (energy returned on invested), and energy payback times of electricity generating power plants.” Energy 52 (2013): 210-221.

See also the IPCC’s lifecycle carbon intensities at Table A.II.4 here:

http://srren.ipcc-wg3.de/report/IPCC_SRREN_Annex_II.pdf

If an efficient process is developed to use the waste heat to produce synthetic or biofuels, then fuels from nuclear could be cheap. But it would need to be located next to a 1GW plant and would increase the total footprint significantly – no doubt next to a rail line would be the only practical location.

It would compete with industrial solar thermal especially if the process is designed to use heat from an intermittent source.

Conventional nuclear’s highly pressurized water does not get hot enough to split water, but the closed cycle in a molten salt or metals mix can. This saves the 2/3rds wasted into the conversion for electricity (in the steam cycle). Molten fuels closed cycle is inherently safer and far more efficienct, thus the only problem for widespread deployment (such as by railroads) is public opposition and BAU.

Biofuels could be used (but it would require extensive amounts of land just) to power heavy equipment. In the case for operating strategic equipment, the very low EROEI could be justified.

It may be cheaper to employ CCS and coal liquification to continue with the steel and concrete structures once natural gas and oil become depleted, but then again, I have no idea which of these options would be the least expensive in the long run, because the unlimited power from closed cycle nuclear (such as LFTR or PRISM) is plagued with fear, biofuels are limited to just barely being able to power themselves (low eroei) and a rather large percentage of coal would have to be used to liquify itself and another rather large percent for CCS.

Already existing renewable capacity will probably not be enough to provide for the basic needs (of everyone) let alone to do all of the above.

Willem,

Not to degrade this thread but coal fly ash is the biggest source of solid waste in the world.  I don’t think we will have any trouble finding any.  I am not advocating 100% RE anyway, coal is not going away whether we like it or not which I think was the point of the article.

An evaluation of material and energy inputs required for ANY source is not an attack! Wind has a purpose but it’s not capable of powering full blown planetary civilizations… as long as they require massive sums of concrete and steel. All the renewables and nuclear have advantages which must be worked together if we are to beat the excess CO2 thing. 

If much of the diesel engines can be replaced with electric, less land could be used (or so I thought). That’s probably how most transpo will have to go.

Billions of gallons every day ! Yea, I was under estimating the amount of necessary industrial fuel, especially after considering global growth.

Michael,

Thanks for the link on the lifecycle CO2 emissions.  Perhaps it is relevant to the post as a stand-in for life-cycle fossil fuel consumption.

However, regarding this claim, “Wind energy’s lifecycle impact is a fraction of all fossil-fired energy sources, and significantly lower than almost all non-emitting resources, including nuclear power.”

I think you have relied on the generic summary data, rather than selecting the data which was more appropriate to this post, from within the underlying  journal paper for nuclear, which said this:

“While small relative to coal, the difference between nuclear power life cycle GHG emissions constructed in an electric system dominated by nuclear (or renewables) and a system dominated by coal can be fairly large (in the range of 4 to 22 g CO2 -eq/kWh compared to 30 to 110 g CO2-eq/kWh, respectively). “

Since this post discusses a world without fossil fuel, the appropriate analysis should not assume the nuclear cycle uses uranium which has been processed using coal and gas fired electricity, via gaseous diffusion enrichments plants as was assumed in some of the CO2 estimates; (diffusion plants would never be built today, and are being replaced with centrifuges).  Further, uranium enrichment is a form of self-consumption, such as pumping water or blowing cooling air in a CSP plant.  So in this case, nuclear power would have a similar or better life cycle emissions as wind power (a range of 3.0 to 45 g CO2eq/kWh is given in the corresponding wind power report).

Additionally (and even more relevant to this thread), this 2005 paper from the University of California at Berkeley finds that nuclear power plants use an order of magnitude less steel than wind farms of the same average output.

I believe its relavent because (after searching) it makes concrete stronger, thus less fossil fuels required to build a wind turbine (or any other concrete structure). Some even compare it to “Roman concrete” (which still exists today)!

According to the EIA  (EIA_eth), in 2012, the US produced 13 bilion gallons of ethanol, and (EIA_diesel) about 1 billion gallons of biodiesel.  Using 42 gallons per barrel, and assuming ethanol has 67% of the energy in oil, this corresponds to 0.23 billion barrel of oil equiv.  Our total oil consumption was 6.8 billion barrels, so biofuel was 3.4%.

The oil consumption was about half gasoline (e.g. cars), and half diesel (e.g. heavy trucks, ships, trains, and airplanes).  So just replacing the gasoline with batteries only gets us to 7% biofuel.

Note that fermenting corn starch is about the worst way to make biofuel.  If we choose a cellulosic biofuel method, such as gasifying the biomass, then making Fischer-Tropsch diesel, methanol, or bio-methane we could probably get triple the fuel yield per acre (and we could use a variety of non-food biomass feedstocks).  That gets use to about 10% of the current oil use, which is just about equal to the fuel use for aviation.  So we could replace all oil, if all land vehicles used batteries, hydrogen, or ammonia, and only aviation used biofuel.

If we used sustainable hydrogen (from renewable or nuclear power) to make fuel from the CO2 produced in the biomass gasifier, we would triple the biofuel output again.  This would bring us to 30% of current US oil use; which would be adequate with some combination of efficiency improvements, electrification, or hydrogen/ammonia substitution.

Keep in mind that the US is sparsely populated compared to Europe and Japan, hence our per capita biofuel production can be higher.

We need to get off fossil use quickly not immediately. So fossil transportation, ag and mining fuels will need to be used for the foreseeable future. However we can eliminate the low hanging Co2 emissions such as coal much sooner because we have practical if more expensive alternatives such as renewables and nuclear. The next step is to convert as many cars and light trucks to EV’s as possible. Consumer reports just named Tesla Model S its “best overall” car of 2014 and the following notes Tesla’s potential for storage to balance variable sources of power generation. With the planning of Tesla’s mega battery factory it may became very competitive. ” Morgan Stanley calculates that the roughly 40,000 units of Tesla cars on U.S. roads contain 3.3 GW of storage capacity. equal to 0.3 percent of U.S. electrical production capacity and 14 percent of total U.S. grid storage including pumped hydro. By 2028, the firm estimates Tesla’s 3.9 million units in North America will have an energy storage capacity of 237 GW (and 384 GW globally), equal to 22 percent of today’s U.S. production capacity and nearly 10 times larger than the entirety of U.S. grid storage that exists today.”

Thanks. I found the Pdf from google…

http://festkoerper-kernphysik.de/Weissbach_EROI_preprint.pdf

They explain the math but still, probably going to take me a while to learn it.

Apologies. I was thinking first wood, then steel, then that future stuff.

Robert,

I like your articles.  You write clearly and are generally well-informed on the issues you write about.  You appear to value objectivity and facts, and don’t appear to have any particular ax to grind.  However, I don’t think this is one of your better efforts.  If I were your editor I’d have bounced it back to you with notes and a general comment that “you can do better!”.  I’m not your editor, of course, but here are some notes anyway.  

You get off to a strong start, citing specific figures from the USGS on the material requirements of wind turbines.  “Oh, good!” I think, “Looks like he’s going to be quantitative”.  But then a statement that is at best misleading, in the context of the article’s theme: “However I will note at the outset that the requirement for fiberglass means that a wind turbine cannot currently be made without the extraction of oil and natural gas, because fiberglass is without exception produced from petrochemicals.“

Blaaattt!  The resins used to make fiberglass are made from feedstocks that are currently derived from oil and natural gas, but only because those are the cheapest sources.  Any so-called “petrochemical” can be synthesized, starting from CO2, water, and electricity.  The electricity and water produce hydrogen, and hydrogen and CO2 can be reacted to make synthesis gas — a mix of hydrogen and carbon monoxide.  From synthesis gas, you can get to just about any organic chemical your heart desires.  And in fact, a good fraction of the petrochemicals that are produced do already start from synthesis gas.  It’s just that the synthesis gas they start with is made by partial combustion and steam reforming of natural gas.  That’s cheaper and easier than making it from CO2 and hydrogen.  But the complexity of the many steps needed to make most petrochemicals and the energy losses incurred along the way mean that the front end cost of the synthesis gas is a relatively minor factor in the end product cost. 

What that boils down to is that plastics and petrochemicals are about the last reasons anyone should be invoking for why we can’t do without oil and natural gas.  The petrochemical industry would weather the transition to an all-renewable economy with barely a hiccup. 

Now, when it comes to the diesel fuel needed to run all that heavy mining equipment, or the bunker oil (not diesel) used to fuel most large tanker ships, matters are more complicated.  Diesel fuel, like any other petrochemical, can be made starting from synthesis gas.  There are several well-known pathways for doing so.  But even at $100 to $150 per barrel, diesel is a lot cheaper than epoxy resin or the latest petroleum-based pesticide.  So the cost of feedstock is a more significant issue.  But it’s still “only” a matter of economics, not a fundamental technical issue.

If one could show that the energy produced by a wind turbine, over its lifetime, is insufficient to produce the synthetic fuels needed to produce the steel, concrete, and other resources that go into building it, then one would indeed have made a case that wind turbines can’t be made without fossil fuels.  But you haven’t shown that.  You quickly exit the world of quantified values, and descend into the usual murk of “large”, “very large”, and “enormous”.  Useless!

In fact, while I’m not especially an advocate for wind power as an adequate solution for our energy needs, I have to side with its advocates on this issue.  The best EROEI studies do seem to establish that wind turbines are a sound energy investment.  I’m not suffiently familiar with the details of those studies to know if they accounted for the higher energy cost of synthetic fuels over fossil fuels, but even if they didn’t, I doubt that the additional costs would be enough to tip the balance.  

There’s even one issue on which the favorable EROEI studies are overly conservative: the lifetime of the wind turbine.  I believe that most studies assume 20 years.  That’s both too high and too low, in my opinion.  Too high, because current generation wind turbines with mechanical gearboxes may wear out sooner than that.  But too low, in that the overwheming bulk of the “energy in” is for the tower.  With very modest maintenance, there’s no reason that a tower couldn’t last for centuries.  The wind turbines themselves can be removed and remanufactured for very low energy input.  It’s not yet done, AFAIK, but that’s because the turbinnes are mostly too new to need that treatment.

You wrap up by writing, “Now, none of this is to argue against wind turbines, it is simply arguing against over-promising what can be achieved. <..>”  Now, there you have a point I can certainly endorse.  I just wish you had been a bit more rigorous in building a case for it.

Roger

With all due respect you critize the article in a certain way and then proceed down the exact same path

“Any so-called “petrochemical” can be synthesized, starting from CO2, water, and electricity.”

In theory this is correct. In practice though we have very few example. A prime example is various isotopes of butanol which can be produced via fermentation pathways but have yet to displace the petrochem derived cousins. What Robert is highlighting is the incredible difficulty of getting of various forms of fossil fuels while we have a multitude of studies saying that 100% renewables is possible that do not even consider the basics of what is written here. (Oh and ethylene would be the chemical that I would bench mark the petrochemical industry on. https://www.irena.org/DocumentDownloads/Publications/IRENA-ETSAP%20Tech%20Brief%20I13%20Production_of_Bio-ethylene.pdf )

You and your commentors make wonderful points. I could go on for hours on this, but will suffer you less.

First, there is a great 140 year history to modern steel and Minnesota. “Taconite” has a wikipedia page. Development of consistent feedstock (taconite pellets) was worked on for many decades with great urgency by skilled scientists. And high grade “iron ore” is created using huge electro magnets. There is high quality steel and there is melted dirt. In short, no you can’t make those turbine structures without far more energy than even considered in this article.

Second, if you want to elevate a wind turbine in the Great Plains you might want to build a barn under it with all that construction material. Old barns had huge vertical axis ventillation turbines to cool the hay loft and livestock. A barn roof is quite an airfoil giving more energy to less turbine. I’ve been trying to figure out how they built that stuff for 40 years.

Third, I’m very impressed with wood laminates. And fourth, rock makes concrete go further; but good luck finding labor.

We can’t abandon wind energy. But we have a right to question the current wind direction.

Well, the question how to replace “fossil fuels” / carbon emissions from non-energy related industry processes is a very exiting one. 

It’s a pitty that you went from “Is it possible?” to “Lets look how we do things today”. 
Your title should be called: “We don’t build wind turbines without fossil fuels today”

————

Here’s the fun you missed by not exploring things:
Cement without carbon dioxide emissions: (feasable)
http://phys.org/news/2012-04-solar-thermal-cement-carbon-dioxide.html

Or

Multi MW wind turbines can also be build using modern wodden towers: (Reality)
http://www.timbertower.de/en/

When you write that article, please research the subject well. There are things like “biocoke” in developement. As far as I know it’s based on the hydrothermal carbonization process. It’s not simply char coal. Hard to find alot of information in English though.

Lots of work happening around the world, something the article you linked to seems painfully unaware / ignorant of. Would be sad to see you write a similar piece. 

http://www.csiro.au/Organisation-Structure/Flagships/Minerals-Down-Under...

http://onlinelibrary.wiley.com/doi/10.1002/cite.201100094/abstract

Some kind of project by nippon steel (unfortunatly used in a palm oil farm ):
http://www.asiabiomass.jp/english/topics/1112_01.html

The key point that I meant to make was essentially the same as that made by Thomas Gerke — that there is a disconnect between the article’s title, “Can You Make a Wind Turbine Without Fossil Fuels”, the article’s content, and the sentence just before the final paragraph, “In conclusion we obviously cannot build wind turbines on a large scale without fossil fuels.”  

As Thomas says, “you went from “Is it possible?” to “Lets look how we do things today”.  You’ve made it clear that we currently use a lot of fossil fuel to make wind turbines.   No argument about about that.  But to go from there to concluding that “we obviously cannot build wind turbines on a large scale without fossil fuels” is leap unjustified by anything you’ve written in the article.  To buy that conclusion, we’d have to accept the premise that the way we do things today is the only way they can possibly be done. 

Still speaking as your friendly hypothetical editor, there are two ways you could go to fix the article.  One is to change the title and rewrite the offending “In conclusion” sentence.  Take it in the direction of “these are the issues we will have to resolve before we can completely eliminate depencence on fossil fuels”.  I think that’s pretty much what you intended anyway, and it’s perfectly valid.

The other way you could go would be to stick by your “not possible” guns and make a serious attempt to prove that case.  That would be an extremely significant accomplishment, if you could pull it off. But you’d need to quantify all the inputs, accounting for the possibilities of fuel synthesis, hydrogen-based reduction of iron ore, and alternatives to conventional concrete.  You’d neet to show that the energy economics just don’t work.  That might be difficult, as I suspect it’s not true.  

Regarding fuel synthesis, you need to be careful with that “science fiction” label.  Some serious studies comissioned DOE / NREL concluded that electricity at 3 cents / kWhr could produce synthetic gasoline and diesel competetive with oil at $50 / barrel.  The studies I recall reading were maybe five  years back, and they may have underestimated the costs.  But they were based on off-the-shelf equipment and well-known processes.  I don’t think they would have been all that far off the mark.  In any case, the issues are economic, not technical.  Your statement that it will require “generations of engineers” to get it to work is over the top.

Well you’re right that I didn’t quantify the things I was writing about — but I wasn’t claiming to prove anything.  Just describing a pathway that would have to be ruled out (shown unworkable) before claiming that building wind turbines without fossil fuels is impossible.

You’re also right that ethelyne is more often the favored feedstock for synthesis of petrochemicals.  But there’s not always enough available in natural gas to supply the chemical plant.  In that case, I believe the usual practice is to reform methane into synthesis gas and from that, produce ethylene.

Wooden structures a football field high and wide plus enormous pressures lasting as long as steel towers and composite blades… call me a pessimest. I look forward to whatever comes after steel.

When I searched, I see mostly “bio” which means like “all” the forests or whatever at the large scales needed to replace diesel. Excuse my exaggeration (???) but I’m sure the biofuels approach might not suffice unless just for select industrial activities (such as wind turbines?).

I hear that closed cycle nuclear has high enough temps to make clean liquid fuels, so I found this (here at TEC) from a google search.

http://theenergycollective.com/barrybrook/172766/zero-emissions-fuel-transportation

It’s not necessary to get the excess carbon from the air as it can be taken from the ocean (and probably more urgent to do so). Here’s another link about nuclear ammonia.

http://theenergycollective.com/barrybrook/66539/nuclear-ammonia-sustainable-nuclear-renaissance-s-killer-app

You should inform yourself abit more about the technical properties of wooden structures. Using wood for tower construction is in many ways superiour to using steel. Not just from an ecological point of view. 

For example building a 100m high steel tower for wind turbines would simply be too expensive. That’s why mainly hybrid towers (steel / concrete) are build.

Cement process is doable perhaps but not realistic given current technology. You are talking about the electroylsis of limestone; high temperatures and interesting solutions needed. Considering the issues with iron ore electroylsis (and that there are similar sucessful processes for other metals), this is a long shot. You should have said so.