The Ergosphere
Monday, January 04, 2010

Revisiting Green Freedom

A discussion at Futurepundit which wound its way around to hydrocarbons produced with nuclear energy produced this comment, which really merits its own post...

I went over the Green Freedom overview again.  It's not specific about power and efficiency, but the figures given are no cause for optimism:  $4.60/gallon at the pump (page 8).  The investment of $9.6 billion for 18,400 bbl/day of gasoline is a cost of more than $500k/bbl/day, compared to $100k/bbl/day for tar sands [correction:  ~60k/bbl/day for tar sands, $100k for coal-to-liquids].

The hypothetical plant produces 5000 tonne/day of MeOH and reforms it to gasoline.  The HHV of 5000 tonnes of MeOH is about 114 TJ, while the LHV of 18.4 kbbl of gasoline is about 94 TJ (I am not sure such a high efficiency is realistic).  The daily generation of a 1.3 GWe nuclear plant is about 112 TJ, so the author's numbers appear to be off by a substantial fraction; they must be missing something, like the energy required for CO2 capture or losses in electrolysis and methanol synthesis.  The electrical figures they claim on page 6 are 55 kJ/mole just for CO2 recovery (after the credit for the co-produced hydrogen).  The overall electric energy demand is 410 kJ/mol CO2, so the power consumption for just that segment is 790 MW.  Each mole of CO2 requires 3 moles of H2 (CO2 + 3 H2 -> CH3OH + H2O) of which only 1 mole is co-produced, so working backwards from their 355 kJ/mol credit an additional 710 kJe/mol CO2 is required for another 1.37 GW.  The total electric power required is 2.16 GW, or roughly 1.5-2 Gen III nuclear reactors, not one.

It makes a heck of a lot of sense to compare the energy requirements and capital expense against alternatives, such as PHEVs.  18,400 bbl/day (773,000 gal) at 35 MPG is 27 million miles per day.  Putting 2.16 GW into PHEVs at 250 Wh/mi is about 210 million miles per day.

Suppose for a moment that we need to build and power a fleet of 10 million vehicles which drive 40 miles per day each.  These can either be Chevy Volts at 250 Wh/mi or next-gen Chevy Aveos at 35 MPG.  Fueling the Aveos would require 11.4 million gallons/day or 14.8 "Green Freedom" plants at $9.6 billion apiece, total capital cost $142 billion/year.  Charging the Volts would require 4.17 GWe or perhaps 4 AP-1000's at maybe $3.5 billion apiece, total $14 billion.  Building the Volts might cost an extra $8000 per vehicle (which will come down) or $80 billion/year, total cost $94 billion/year at the beginning and falling to perhaps half that over time.  Residual value of batteries is an unknown, residual value of the vehicles might be a lot higher due to the long life of electrical systems.

That's the comparison against other ways of making vehicle fuel.  How does it compare against other ways of reducing carbon emissions?  Using nuclear power to replace coal and NG so that NG can displace petroleum (a nuclear Pickens plan) is just as effective for GHG reduction.

4.17 GWe of nuclear power displacing coal at 346 g/kWh is 34.6 thousand fewer tonnes of CO2 per day; if it displaces NG instead at 206 g/kWh, it reduces emissions by 20.6 thousand tonnes/day.  5000 tonnes of MeOH contains 1875 tonnes of carbon, which would form 6900 tonnes of CO2.  Even on what should be its best point, "Green Freedom" falls short by a factor of 3 against diverting fuel to NGVs.

"Green Freedom" appears to be aimed at perpetuating the market for petroleum.  It isn't competitive until oil is around $150/bbl and the entire downstream infrastructure would still be built around hydrocarbons.  If you want to make the USA free of oil imports, nuclear-electric is much cheaper than nuclear-hydrocarbon.

Good post EP. As is so often the case, a simple back of the envelope calculation can show the folly of some of these ideas.

"Green Freedom" appears to be aimed at perpetuating the market for petroleum.

I quite agree and think the same could also be said for E10 and even E85.

As you have pointed out in several posts from some years back, while you can convert almost any carbonaceous feedstock into synthetic petroleum, but much of the original energy is lost in doing these multi step conversions, or lots of supplemental energy input is needed.

For this plan, it would be better to simply use the straight MeOH as fuel, or make DME, but even so, it's still better to use the electricity directly.

I think the reason why we see these sorts of plans cropping up is not to explicitly preserve the petroleum market, but to be able to sell into it.

If you can produce, it, you can sell it, but creating an MeOH, DME, CNG or electric transport economy requires modifying vehicles etc, which leaves the producer in a chicken and egg situation.

I agree that our collective efforts are better spent on petroleum alternatives, not alternative petroleum. Let's hope the government doesn't subsidise this this one and distort the already awful economics even further.
The politicians want desperately to tell people that they won't have to replace their existing vehicles -- that there are sufficient liquid fuels that can burn in today's ICEs with little or no modification. The business community and the media have largely got the message, and know they can propose all manner of outlandish things and get support.

They are grasping at a dizzying array of straws. More oil in the Gulf, the Arctic, Iraq, wherever. Corn ethanol. Liquids from coal. Oil shale. There are hardly any ideas too outlandish, if they purport to produce something that can be used where gasoline/diesel is used today.
Indeed, the idea of a wholesale system change is something they can't control, but would get blamed for if things go wrong.

Electrics appear to be the only alternatives that people (and politicians) want, and they are the furthest away from mass production.

As has happened in the past, real innovation and change can and will occur, despite the best efforts of governments to control it.
I think the assumption is that the nuclear plant and the liquid fuel plant would be co-located, such that the 60 % or so of the thermal energy that isn't converted into electricity could be used as low-grade process heat for many of the pathways in the liquid fuel refinery. To evaluate how realistic that is we would need to know what many of the process temperatures are, and how that compares to the outlet temperature off the steam turbines at the nuke plant.
The diagram on the page numbered 2 (page 4 of the PDF) has nuclear heat as an input to the water electrolysis, but not the CO2 capture process or any of the chemical synthesis stages.  The electrolysis of steam rather than liquid water reduces the required energy input substantially by eliminating losses in conversion to electricity, but I am skeptical that it would go so far as to reduce the power input to the scale of an AP-1000 reactor.  The energy requirements for CO2 capture are listed on page 6 of the PDF.

The major process-heat requirements are probably in the region of 50-100°C for the CO2 purification, as hot as possible for electrolysis.  The efficiency impact of removing 100°C steam is substantial, but not overwhelming.

I think the political ass-covering tendency argues that Green Freedom will never be built.  Laying out billions of dollars for a first-of-a-kind plant that produces gasoline for $4.60/gallon is the kind of thing that would bring back the ghost of William Proxmire to bestow a Golden Fleece award.  Governments, companies and individuals can buy PHEVs and EVs in lots from thousands and hundreds down to single units, but they add up.  By the time anyone suggests this boondoggle seriously, there will be all kinds of people with no need or desire for gasoline saying "Forget that, just get over to the dealer and buy one of these."  The real impact of the proposal is in well-poisoning in the early market for electric propulsion, which is right here and now.

After looking at your link on Molten Carbonate Fuel Cells in our discussions about coal-water fuel on TOD, it seems to me that applying the CO2 turbine to a the MCFC would be a good option. Not open cycle, so more heat exchangers needed but certainly small and beautiful.

Having said that, maybe you set up your coal plant as a straight CO2 turbine. Unless the DCFC can get a real world efficiency up into the 60's, the CO2 system seems a beautifully simple alternative to steam.
If you look at the Cooper presentation, the DCFC can achieve efficiencies around 80%.  IMHO, that can be summarized as "Fucking impressive".
No doubt that 80% is awesome, and you had posted previously (a couple of years ago, I think), about the DCFC, saying that it should be the subject of a major R&D effort. What I don't understand, with such a promising technology, is why the coal industry isn't backing this in a big way.

They are spending lots of their (and government) dollars on sequestration, and, as afar as I can see, not funding this.

It looks like DCFC is still some way of utility scale production, while the CO2 turbine seems to be closer to large scale deployment.

Either way, there are lots of potential improvements for coal, and I just don't understand why the industry isn't getting behind them in a big way.

When the electric cars come along, we'll need lots more electricity, and coal is the cheapest way to get it, but they have a lot of PR work to do make the public want them to continue business- something like this would do this trick - and reduce their CO2 along the way, with or without sequestration.
US electric generation from coal is currently down about 12% year on year.  The US market for electricity is largely mature, so the effect of large increases in efficiency would be to slash the size of the fuel market over and above the effects from decreased generation.  It's not hard to see why the coal industry would be less than enthusiastic about doing this.

There are also the twin issues of alternative-fuel competition and Jevons' paradox.  The DCFC (like most fuel cells in general) does not require large scale to achieve high efficiency, so it can be placed close to load centers... or hard-to-transport fuel supplies.  If efficiency is doubled, fuel costs can also double without changing the bottom line, while smaller plant size reduces transport costs for diffuse fuel supplies.  This is the sort of thing which could put biofuels (straw, stover, wood chips) onto a much more competitive footing compared to coal, further eroding coal's sales and bottom line.

The industry lobbies aren't stupid.  Just as the petroleum industry got rid of PNGV (a severe and near-term threat) and replaced it with Freedom Car (not even competitive when running on renewables), Big Coal knows what side its bread is buttered on.  You can't expect to see them promote anything that weakens them relative to their competition, existing or potential.
Couldn't agree more with you on this
"you can't expect to see them promote anything that weakens them relative to their competition, existing or potential."

Where I was coming from is that I see their main future competition being new nuclear, and that this would answer their critics on CO2. NO other mainstream industry has a new technology that can halve CO2 emissions.

Agreed that it would favour distributed load centres, which big coal may not like, but I think they would adapt to that pretty quickly.

Here in British Columbia, which exports lots of coal, a recent policy change, from our conservative government, is that any new coal fired electrical project must have full CO2 sequestration, so coal/electric is out of business here. Would not be surprised to see California and a few others start to go this route too.

In the words of Jared Diamond, in his book collapse, they are starting to lose their "social license to operate". Nuclear lost that in the 70's and is only now about to get it back.

An advanced technology like DCFC's seems to me the best way for coal to throw away the image of smoke belching stacks, etc, and re-invent itself for the 21st century.

I don't doubt that you are correct in your analysis of their stance, I just think that it is not a good long term position.
Coal's future, if it has one, could be as a general supply of chemical feedstocks via polygeneration.  Rentech is going that direction, but I think there's too much emphasis on F-T liquids which will neither be economical nor meet GHG restrictions.

Your advocacy of electrification of personal transportation and all of ground transportation for that matter is clear to everyone. But I think you never discuss or even mention the disadvantages. So I will do that here a little bit.
I think the most serious disadvantage is the need for a huge additional infrastructure. This is firstly the electrical wire that goes from the power station to the point of consumption e.g. where the battery is charged. Then this is the battery. It is heavy and very expensive. It contains a lot of hard-to-get metals. As do the wire btw. Actually the battery may be avoided altogether by pulling a wire over the highways so cars can draw current from it like electric trains.
The ability to go where you want, which is the purpose of personal transport, is essentially lost. Liquid fuel has huge advantages because of ease of storage and distribution. This is why we are using it because we have access to natural liquid fuel in the form of oil which can be refined into fuel relatively easily. They can be made from other sources as well, but not as easy anymore. Now this is the problem that we have to solve - how to cheaply make liquids from other, preferably renewable sources!

black ice
Huge additional infrastructure?  One major point of using electricity as opposed to hydrogen (or even CNG) is that the infrastructure is already built and has ample spare capacity for large parts of the day.

The "wire... to the point of consumption" for PHEVs like the Volt is a 110 V 15 A outlet and an extension cord.  I priced a 50 foot 12 gauge cord at about $35 the other day; shorter lengths are cheaper.  A system for a "new" fuel which already reaches 65% of the possible market without trying is doing pretty well.

The metals aren't hard to get.  Lead, zinc, and lithium are all in ample supply.  Lithium in particular is extremely cheap.  I'm told that Li-ion requires about 80 grams of metal per kWh; at current Li2CO3 prices of ~$5200/ton, the metallic lithium costs less than 0.3¢/gram (around 22¢/kWh).  Lithium carbonate could be ten times current prices and have only a minimal effect on Li-based battery costs.

I'm all for electrifying highways.  I think we should replace pavement with rails at the same time, to provide an electrical return path and reduce maintenance costs while also eliminating the need for drivers to guide vehicles some of the time.  This would be a huge plus for safety.  Vehicles would use rubber tires when they left the rail network.

I know you're trying to play advocatus diaboli, but I don't see how electric cars eliminate the ability to "go where you want".  PHEVs in particular can electrify most mileage with no range restrictions.  Electrified highways or Better Place-style battery swaps electrify most long-range trips as well.

Last, I'd like to see exactly how to make cheap, renewable liquid fuels.  Between the hidden subsidies from fossil fuels in the current system, the low efficiency of schemes like Choren, and the rather limited primary productivity of plants compared to our current demands, I am skeptical that they can ever compete.
I am not trying to play anything. What I meant with the additional infrastructure is that you have to have a decent power line coming to your place which might be a problem if you live in the middle of nowhere. I know that the US have a great electrical infrastructure which, however, is certainly not true for most of the world. As more and more people decide to charge their vehicles soon a point will be reached when the existing infrastructure just can't handle that. Liquid fuel allows you to live and work in a situation where there is no huge power cable nearby.
Alright, the power line and the battery are not problems that cannot be solved. It is a matter of philosophy. The point of BtL is to use the residues that are left from crops that we grow for eating. Let's say one consumes 2 kg of corn a day. This leaves maybe up to 20 kg of stalks, which are harvested together with the crop. No separate harvest or dedicated growing is required. Efficiencies of up to 60% can be achieved in BtL, i.e. 4 kg of dry biomass is needed for 1 kg of hydrocarbons. This way up to 5 kg of fuel is produced essentially as a byproduct. The residue is returned to the fields as fertilizer; only the nitrogen is lost in the thermochemical conversion process, the rest of nutrients remain. Regarding Choren, I personally think that their scheme is not very efficient, but that is another story.
I drive 50 km a day, and my current old car with a standard 100 HP carburetor engine uses 8 L per 100 km (city cycle), that is 4 L a day, or 3 kg of hydrocarbons a day. I would need 12 kg of dry crop residues for that. But in the future efficiency will improve, and the automakers have already announced plans for very efficient automobile engines. In a recent GCC article they claimed that standard 100 HP engines will be supercharged very efficient 1.1 - 1.2 L gasoline or diesel engines and use 3.6 - 4.2 L of diesel/gasoline per 100 km. This halves the amount of crop residues that I need to 6 kg. From this amount it is possible to obtain no more than about 10 kWh of electricity. For an electric car about 8 kWh (data for Tesla's Roadster) are needed to drive 50 km. This is about the same efficiency.
So this is a question of philosophy - whether we extract more and more precious metals for ever more powerful cables, batteries, electrical powertrains, and nuclear plants, or we convert the residues from food production that would otherwise rot in the field in a form that can burned in existing comparatively cheap and increasingly efficient heat engines.
"Last, I'd like to see exactly how to make cheap, renewable liquid fuels."
The plants have to be rather small and decentralized. They have to be near food processing facilities to simplify logistics. The produced hydrocarbon mixture is sent to a centralized refinery for processing. The actual production process is as low-tech as possible. It is a whole new industry, but closely integrated with existing farming and petrochemical industries.
"The metals aren't hard to get. Lead, zinc, and lithium are all in ample supply. Lithium in particular is extremely cheap."
You can't be serious with this statement. Lithium in particular is not only rare, but also scattered with few high concentration ores. The global reserves are estimated at only 35 million tons. Nickel and lead have the same occurrence, albeit they are concentrated in sulfide ores and are thus easier to extract. And do not forget that the electric drivetrain needs a lot more extra pure copper and aluminum for engines and cables than an ice drivetrain. These metals are mined in harsh conditions in places such as Canada, Siberia, or Africa.
Wouldn't it make more sense to instead manufacture hydrocarbon fuel from local renewable sources?
True, metal (cobalt) catalysts are needed for hydrocarbon production, but arguably they can be recycled easier than batteries.
"you have to have a decent power line coming to your place which might be a problem if you live in the middle of nowhere."

How many people live in the middle of nowhere?  By definition, not many.  People living off-grid can increase their energy production enough to supply a vehicle, go on-grid, stay with chemical fuels or some combination of 1 and 3 (PHEV charged with excess solar/wind).  There will be some amount of petroleum available for many years, and it doesn't matter which segments switch off it first.  Electrify urban and suburban vehicles and you've got most of that problem licked (and several others too).

"As more and more people decide to charge their vehicles soon a point will be reached when the existing infrastructure just can't handle that."

You could say the same about everyone having big air conditioners, but the grid built out to handle that.  800-watt plasma TVs?  It built out to handle that too.  I think history argues against you rather convincingly.

"Let's say one consumes 2 kg of corn a day. This leaves maybe up to 20 kg of stalks, which are harvested together with the crop."

No, the production of stover is roughly equal to the production of maize.

"Efficiencies of up to 60% can be achieved in BtL, i.e. 4 kg of dry biomass is needed for 1 kg of hydrocarbons."

That's news to me; figures I've been seeing are closer to 45%.  But let's use 60%.  A US corn harvest of 12 billion bushels (300 million metric tons) would yield an equal amount of stover.  300 mmMT stover would yield 75 mmMT of hydrocarbons by your claim.  At a density of 0.75, that's 1e8 m³ or 1e11 liters; on the order of 25 billion gallons.  In 2008, the USA consumed 137 billion gallons of gasoline.  Even by your numbers, crop byproducts cannot form more than a small fraction of any solution to the petroleum-depletion problem.

"Lithium in particular is not only rare, but also scattered with few high concentration ores."

Lithium is not rare, and at today's concentration it is a negligible part of battery cost.  Today's Li2CO3 cost is about 0.27¢/g of metal.  At 80 g/kWh, this is about 22¢/kWh; you could multiply this by 100 before it became comparable to the battery cost.

The Great Salt Lake alone is estimated to contain 520,000 tons of lithium.  If the entire US vehicle fleet was electrified with 100 kWh of batteries each, that would require 8 kg Li per vehicle.  That's 125 vehicles per ton, or 65 million vehicles from Great Salt Lake deposits alone (roughly 400 million Volt-sized batteries).  The pegmatites in N. Carolina are estimated to be good for another 2.6 million tons of lithium.  Salton Sea geothermal brines, 16000 tons per annum.  Hectorites have apparently not even been explored for reserves yet.

On top of this we have lead for things like Firefly and lead-carbon, zinc for zinc-air, nickel for sodium nickel chloride, etc.  We are not running out of material for batteries.

"Wouldn't it make more sense to instead manufacture hydrocarbon fuel from local renewable sources"

In a word, no.  Such resources cannot replace more than a very small fraction of petroleum, and using them for hydrocarbon fuels means foregoing uses such as carbon sequestration.
"That's news to me; figures I've been seeing are closer to 45%. But let's use 60%."

45% efficiency figures are for schemes like Choren's. This is due to gasification technology employed by them which is essentially entrained flow gasification with oxygen. The inherent inefficiencies stem from need to separate oxygen from air, high make gas exit temperatures, and the fact that there is no use for synthesis reactor tail gas other than to generate electricity. This scheme, however, is well adaptable for scaleup. Higher efficiencies can be obtained by gasification with external heating, such as Range Fuels technology (which is the same as Rentech's I think). 60% is readily achievable; the theoretical efficiency is 83% (this does not include electricity for operation) with external heating. Essentially, 4 kg dry biomass yields 1 kg hydrocarbons at 60% thermal efficiency.
But the efficiency of a technology matters little. What matters more is the total number of work hours needed to obtain a unit of energy, or in other words, will this technology improve the lives of people or not. This is what matters most.

"A US corn harvest of 12 billion bushels (300 million metric tons) would yield an equal amount of stover. 300 mmMT stover would yield 75 mmMT of hydrocarbons by your claim. At a density of 0.75, that's 1e8 m³ or 1e11 liters; on the order of 25 billion gallons. In 2008, the USA consumed 137 billion gallons of gasoline."

25 billion gallons - that is 18% from consumption, and this is absolutely huge! Almost one 5th! And this is only corn, we are not counting others. You could get as much as 50% of gasoline consumption covered by crop residues!

"using them for hydrocarbon fuels means foregoing uses such as carbon sequestration.""

Thermochemical conversion of biomass will invariably yield some char residue that will be returned to the fields which is essentially carbon sequestration.
Post a Comment

<< Home
Talk largely about energy and work, but also politics and other random thoughts

Mail Engineer-Poet

(If you're mailing a question, is it already in the FAQ?)

Important links

The Reference Library

Blogchild of

Armed and Dangerous

Blogparent of


The best prospect for our energy future:
Flibe Energy

January 1990 / February 2004 / March 2004 / June 2004 / July 2004 / August 2004 / September 2004 / October 2004 / November 2004 / December 2004 / January 2005 / February 2005 / March 2005 / April 2005 / May 2005 / June 2005 / July 2005 / August 2005 / September 2005 / October 2005 / November 2005 / December 2005 / January 2006 / February 2006 / March 2006 / April 2006 / May 2006 / June 2006 / July 2006 / August 2006 / September 2006 / October 2006 / November 2006 / December 2006 / January 2007 / February 2007 / March 2007 / April 2007 / December 2007 / January 2008 / May 2008 / June 2008 / August 2008 / October 2008 / November 2008 / December 2008 / February 2009 / March 2009 / April 2009 / May 2009 / June 2009 / July 2009 / August 2009 / September 2009 / October 2009 / November 2009 / December 2009 / January 2010 / April 2010 / May 2010 / June 2010 / July 2010 / August 2010 / September 2010 / October 2010 / November 2010 / December 2010 / January 2011 / February 2011 / March 2011 / April 2011 / May 2011 / July 2011 / August 2011 / September 2011 / October 2011 / April 2013 / November 2013 / December 2013 / January 2014 / February 2014 / March 2014 / April 2014 / July 2014 / August 2014 / September 2014 / October 2014 / November 2014 / February 2015 / April 2015 / October 2015 / March 2016 / April 2016 / May 2016 / June 2016 / July 2016 / November 2016 / December 2016 / February 2017 / May 2017 / June 2017 / September 2017 / October 2017 / November 2017 / March 2018 / May 2018 / June 2018 / October 2018 / December 2018 / January 2019 / March 2019 / June 2019 / October 2019 / November 2019 / March 2020 / June 2020 / December 2020 / March 2021 / April 2021 / May 2021 / July 2021 / January 2022 / February 2022 /

Powered by Blogger

RSS feed

Visits since 2006/05/11: