On Fri, Dec 20, 2013 at 3:19 PM, Ronal W. Larson <[email protected]> wrote: > List cc Keith and Greg > > 1. This is #3/3 in a string today - all with some relationship to the > MacDougall article). Not sure of the etiquette here as Keith was only > addressing Greg and myself. But Greg responded to the full list and I > think/hope Keith would like that I do the same.
No problem. I was just trying not to be presumptuous and/or off topic. > Keith has talked of his > proposed low-cost electricity approach earlier on this list. > > 2. As background, readers interested in Keith’s electricity production > views should look at material at > https://docs.google.com/file/d/1PHkFACumTHyfMPOfIDhAY46vPe_mt8zNmy3i2ZsOnHgqZqpGuMpSh3JaJsCO/edit > I also found a video covering the same. > > 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. > 4. See also two responses below. > > > On Dec 20, 2013, at 11:13 AM, Keith Henson <[email protected]> wrote: > > On Fri, Dec 20, 2013 at 8:20 AM, Ronal W. Larson > <[email protected]> wrote: > > Keith cc Greg > > I appreciate your enthusiasm for the solar satellite approach, but I have > my hands more than full with CDR (and specifically biochar). > > > What you really need is a way to turn off the current flow of CO2 into > the atmosphere. *Then* biochar or other ways to lower the CO2 have a > chance to work. But that's not going to happen as long as people need > energy to stay alive unless there is a way to replace the energy from > fossil fuels. It's the reason Hansen and the rest of them have > recognized nuclear energy. That will work if you are willing to put > up with a meltdown a year. > > > 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. >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. > 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. > > 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. > 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. 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. Lots of options with oceans of low cost energy. Keith > Ron > > > (The next addressed today to Greg and myself, with one response each > from Greg and myself) > > > > On Dec 20, 2013, at 12:05 AM, Keith Henson <[email protected]> wrote: > > Would you be interested in an engineering proposal to end the use of > fossil fuels? > > Warning, it does so by substituting a cheaper energy source. > > Keith Henson > > On Thu, Dec 19, 2013 at 10:33 AM, Greg Rau <[email protected]> wrote: > > Delayed response from me also. Just saw a brief review of this paper in my > > > <snipped - to save space; I think all repeated earlier today> > -- 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. 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