Keith, cc Greg and list Few inserts below.
On Dec 20, 2013, at 11:07 PM, Keith Henson <[email protected]> wrote: > On Fri, Dec 20, 2013 at 3:19 PM, Ronal W. Larson > <[email protected]> wrote: >> List cc Keith and Greg >> <snipping where no replying needed> >> 3. I am pretty sure that Keith is one of the world experts on this solar >> satellite topic. He certainly has had a long history of various >> space-oriented activities. > > There are many people more knowledgeable than I am on the subtopics. > Jordin Kare, for example, knows much more about laser propulsion. But > I have put the whole thing into an economic model and made minor > contributions here and there. [RWL3: I have looked up Dr. Kare’s new company (see http://lasermotive.com/ ) and am impressed by its various successes. There could be a role in agroforestry for seeding. > >> 4. See also two responses below. <another snip> >> RWL1. Readers will find that Keith’s approach is quite expensive (many >> trillions of $) and not likely ready soon. > > That's not in my writings on the topic. The economic model may not be > right, but it shows that the venture needs only $60 billion to become > profitable. That a bit over half the largest energy project now going > and only twice what China put into building Three Gorges Dam. > > As for "soon", it looks like the first power from space will take > about 6 years, break even slightly short of 8 years and 500% ROI in > ten years. Fast ramp up takes it to replacing the energy from fossil > fuels in 22 years. The power companies have to spend trillions on > replacement power plants anyway, this is just a cheap way to build > carbon free sustainable power. Of course it will never be ready > unless it is started, and for that to happen, it needs to be > recognized as a practical engineering project. > > That's going to take some effort, including psychological, acceptance > that there can be a positive, energy rich future. I *think* there are > solutions to the identified problems, but there may be a showstopper > not yet found..So beat on it folks. [RWL1’: I hope you are right. But most of this is not (yet) “Geoengineering”. So far all mitigation. > >> The above site shows a new lower >> cost way to put hardware in space. My view is that today's renewables can >> do the job at an acceptable cost - > > I don't think this is the case. Gail Tverberg, widely known as "Gail > the Actuary" on The Oil Drum blog has this article out. > > http://theenergycollective.com/gail-tverberg/266116/oil-prices-lead-hard-financial-limits > > Couple of months ago at a conference in Baltimore I pinned Gail down > and she gave $30-50/bbl oil as an acceptable range for energy cost. > Synthetic oil can be made for that cost from electric power of 1-2 > cents per kWh. That means power satellites can cost up to $1600/kW > and lift cost to GEO can be no more than $100/kg, one percent of > current cost for communication satellites, but well under the > theoretical physics limits. > > But there is no possibility I know of for getting power from ground PV > or wind down to 1-2 cents per kWh. For PV, consider > http://htyp.org/File:Solar_PV_Experience.jpg The lower limit for PV > is around 60 cents per watt or $600/kW. That's a good number till you > multiply it by 4-5 to get the cost for full time power. When you use > an optimistic 4, the number is $2400/kW. The rough formula to get > cents per kWh is to divide by 80,000 which gives you 3 cents. That's > about twice as high as is needed for cheap synthetic oil and that's > after truly heroic installation of ground PV, decades into the future. [RWL1”: I am familiar with Ms. Tverberg and this experience curve. You’ll find disagreement on the lower limit for future PV costs. But this is (mostly) off this list's areas of interest. I say mostly, because the SRM and CDR approaches will have similar curves, and I have seen none. It would be great to have predictions for the right starting points and slopes (that for wind is about half as steep). > >> but I wish Keith luck if he can do the >> fossil fuel replacement job cheaper. I concur on his statements about >> nuclear - which I believe has no or small connection to geoengineering. >> Keith has previously proposed a way to make a fuel starting with CO2 and his >> low cost electricity. Again not a “Geo” topic -but maybe someone can offer >> other approaches on either the CDR or fossil replacement tasks? > > There is a direct connection. A process that can make cheap synthetic > oil from CO2 out of the air can pump the cheap oil back into empty oil > fields. It stayed there for geological times, no reason it would not > be a good way to sequester carbon. If 500 cubic km of CO2 (~100 ppm) > were stored underground and it blew out, it would be hard to breathe > for a long way down wind. See notes here > http://www.theoildrum.com/node/5485 BTW, bio char is a much better > idea than anything involving CO2 that could blow out. [RWL: Now we are on list topics. I will pass on the “blowout” issue, but think the BECCS folks on this list would not concur it likely. The “oil drum” cite gives a lot more on this topic from yourself that some may wish to look into. >> >> What was the >> reason the Japanese dropped their program? >> >> I don't know, but it really doesn't matter. The program they were >> working on would not lead to displacing fossil fuels. The >> Skylon/laser propulsion/power satellite approach *might*. >> >> I calculated how much energy it would take to capture and safely >> sequester 100 ppm of CO2. Have you run this calculation? >> >> >> [RWL: The first answer is that biochar doesn’t require ANY energy - as >> pyrolysis is exothermic. But assuming Keith wants to know how energy and >> char work together, I can say they are NOT partners; more of one means less >> of the other (biochar is a partner with soil improvement). But if half of >> the initial carbon produces energy (and released CO2), then 100 ppm of CO2 >> requires about 400 Gt C to be put in the ground (we have had other dialog >> on this number). The energy content of the other 400 Gt C is valued at >> about 30 GJ/tonne C. (of course not all useful). Thus the theoretical >> available energy is about 12,000 E18 Joules. > > Using pyrolysis gas to make biochar is a terrible waste when it could > go to making valuable liquid synthetic fuel. If energy from power > sats got down into the 1-2 cents per kWh range, it would be worth > using it to make biochar, and you would have *much* fewer design > problems on the processing units. [RWL””: Making char and “valuable liquid synthetic fuel” is being done - as you suggest - without a pyrolysis gas phase. Apparently good economics. See www.coolplanet.com . I hope you can expand on how low-cost electricity could help with making biochar. For most production, electricity used is small. In almost all large scale biochar operations are likely to produce their own electricity. > >> Hopefully, we can get started soon enough that we need less than 100 ppm. >> Hopefully there will be a suite of CDR approaches, that will be using PV, >> wind, hydro, geothermal (and some non-biochar biomass) >> >> What is your own calculation on “how much energy it would take”? (I >> presume all of an opposite sign?) > > 300 TW-years to make 100 ppm into synthetic oil and pump it back into > the depleted oil fields. [RWL: To convert each others' energy numbers, 1 TW-year is (1E12 Joules/second)*8766 hours*3600 seconds/hr = 31.55 E18 Joules, so 300 TW-years is getting close to 10 E21 Joules, whereas I had (above) 12 E21. The difference is in sign; your approach requiring that amount. I was releasing a bit more energy from the pyrolysis processes, as we both were moving 100 ppm. If biochar could achieve the transfer in 50 years, the annual average release would be 240 Exajoules, about half of today’s consumption, greatly (totally?) helping wind, solar and other renewables move off of fossils. Your approach would add about 50% to the total consumption, without touching liquid fuels. I suggest that liquid fuels might be a good choice for your proposed conversion process, but remind you that the American Physical Society has estimated collection costs (via DAC) of atmospheric CO2 is many hundreds of dollars per tonne CO2. Nowhere near as much cost for biochar collection and processing. > > 22 years into the power satellite project, the production to date > would have been 15 TW and the rate two TW/year of new plant. Continue > to build for another 7.5 years or more and in about ten additional > years you can put all the extra CO2 back in the ground. > > Or, if it is less expensive, you can use plants to collect the CO2 and > process that into biochar and the gas into synthetic oil. [RWL: Exactly. I think the sign on the energy contributions indicates which will be less costly to get both char and liquids. Photosynthesis is great because the main inputs (CO2 and sunlight) are free. Water and some nutrients might have a cost. Certainly costs in planting and harvesting. > > Lots of options with oceans of low cost energy. [RWL: Not enough options (so good luck on the satellite option) . The word “oceans” needs to be used carefully on this list. Thanks for continuing the dialog - I conclude there are satellite possibilities with mitigation, but haven’t yet seen much connection to geoengineering. Ron > > Keith > <snipped a short amount not needed for above> -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/geoengineering. For more options, visit https://groups.google.com/groups/opt_out.
