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Bickel and Lane (still at #70) say:
Sixth, Robock states, “…Bickel and Lane ignore the effects of ocean acidification from continued CO2 emissions, dismissing this as a lost cause. …” Actually our paper does discuss ocean acidification as a harmful effect of CO2 emissions [and] … the uncertainties concerning both its consequences and the prospects for remediation.
Well, the report says “its relevance to [climate engineering] remains unclear”, after citing work suggesting the CO2 already up there might be enough to do for the coral reefs anyway. That’s dismissing it as a lost cause, all right.
(By the way, alarming as Cao and Caldeira  is, I fail to see how you could fairly summarize it as showing “The CO2 already in the atmosphere might cause enough acidification to destroy all or most of the existing reefs”?)
Our paper, does not … discuss it further for the same reason that it also omits discussion of possible defects in the regulation of the global banking system.
This odd comparison underlines your dismissal of acidification as irrelevant. You discuss SRM as an option to counter the threat of global warming, the bulk of which is caused by CO2 emissions, which also cause ocean acidification, another potentially major threat that can be limited by limiting emissions but not by SRM. The relevance of ocean acidification to assessing these policy options should be as obvious as the irrelevance of banking regulations.
SRM neither reduces the costs of these problems nor raises them. Other measures are called for, and the analysis that we were invited to do centered on SRM.
If ocean acidification is a major threat that needs to be addressed in its own right, doesn’t that affect the cost/benefit of GHG controls (emission cuts) relative to SRM? GHG controls could kill two birds (warming, acidification) with one stone. SRM could not, but would have to be supplemented with more dubious engineering fixes, at additional cost and risk, for the ocean.
… with only a single exception, every scenario reported in our paper envisions the use of SRM in conjunction with a GHG control regime.
But the use of SRM to keep temperatures down would tend to reduce the perceived urgency of limiting CO2 concentrations, and a policy mix with a major SRM component would probably have a smaller GHG control component than without SRM, allowing the acidification problem to grow. In general, as the AMS policy statement puts it,
The possibility of quick and seemingly inexpensive geoengineering fixes could distract the public and policy makers from critically needed efforts to reduce greenhouse gas emissions and build society’s capacity to deal with unavoidable climate impacts. Developing any new capacity, including geoengineering, requires resources that will possibly be drawn from more productive uses.
I’d think a qualitative discussion acknowledging these concerns would be in place even if the state of knowledge does not permit costs and benefits to be quantified.
I find it fascinating that the only comment about using engineering in space to solve this rather than a fairly large planetary intervention in the atmosphere (with unknown and unknowable secondary consequences), simply disagreed without giving ANY cause for the disagreement.
I am trying to imagine how that works… except that perhaps people here are over-focused on the solutions proposed in the original post and the most recent comments relating to those, and did not notice the suggestion.
If you have CATS you can put mirrors in space. It doesn’t cost that much if you have Cheap Access To Space. If you have that you can put solar power satellites in space EASILY. You don’t have to burn coal for power any more. You also gain access to the resources of the entire solar system, which is a boon to the species beyond measure. You can use the mirrors to cool, or warm, the planet as required by the phase of the solar climate we are in. Shutting down the coal plants reduces the CO2 loading.
Simon Donner had the answer to 101 a few years ago. Basically we may still have reefs under current conditions, but not the carbonate corals that we now have (at least for a little while).
PS: This is called the indirect, or second order, blog-whoring effect. Linking to someone who links to you.
BJ_Chippindale 19 August 2009 at 2:11 PM
Regarding solar power collection from Earth orbit, I guess I’m missing the train when it comes to understanding why we’d raise the bar so high as to install our equipment in space as opposed to letting it continue to sit on the ground.
On the terrestrial side we do have inconveniences of day/night, clouds, and dust. On the other hand, we have the benefit of possessing solar power collection systems having the excellent virtue of existence, beyond imagination and prototyping, solidly grounded (sorry!) in reality and already being deployed.
Up in space our bad habits have accompanied us from the instant we began lofting hardware into orbit, 50 years and tens of thousands of fragments ago, meaning that any really sizable objects constructed in LEO or NEO will likely end up riddled with holes, at the same time liberating yet more fragments to contend with. Accepting for a moment that we can engineer around the Swiss cheese problem, there’s next the matter of conveying energy to the ground with a reasonable degree of efficiency, so far seemingly only addressed with artists concepts showing hypothetical hole-free antennas, etc. Meanwhile, “CATS” is proving far less tractable now that our initial carbon nanotube euphoria is wearing off.
(perhaps if we only had -enough- junk orbiting the planet we could shade ourselves, at the cost of never being able to leave the planet?)
Again, on the ground side we have stuff that works, now, many avoided billions of dollars worth of distractions closer to being useful.
All the same, cheap access to space would be a wonderful thing…
Doug Bostrom, there is also the rather significant issue of radiation in orbit which cuts solar cell life considerably. And that’s in the unlikely event of cheap lift capacity.
If you have CATS you can put mirrors in space. It doesn’t cost that much if you have Cheap Access To Space
Get back to us when we have cheap access to space …
The day-night and clouds thing is pretty important when you start talking about baseload power. Which you can do with solar.
The CATS thing wouldn’t be so expensive if we hadn’t killed it so often, the last X-33 with all the major components constructed and better than 90% completion for example. It doesn’t need carbon nanotubes in a space-elevator, just a reasonable amount of re-use. There are viable methods and development is punked out because there is not any collective corporate will to do it in the USA.
I agree that LEO is a pretty nasty place. It poses no real problem to either the mirrors or the SPS. Satellite power wouldn’t be in LEO so the junk is not a large problem. The mirror need not be that substantial. Swiss-cheese effects don’t prevent it from working.
All that is required is CATS.
CATS isn’t even complicated engineering anymore. The hard part is to give it the priority it deserves. Do that ONE thing and the other problems are very easily solved, and we’ve certainly spent more on Banksters than it would cost to actually finish the job.
CATS isn’t even complicated engineering anymore.
This would explain the X-33 component failures during test.
Rather than wait for some magic-wand technology to become available to transport yet another magic-wand technology in low earth orbit thereby allowing us to finally, decades from now, maybe do some good if nothing fundamentally unsolvable by then-existent engineering capabilities, why not simply solve the problem with technology available or within site, today?
Not to mention run-on sentences :)
BJ_Chippindale- cheap access to space would be really nifty! However, if you think that it is easier to convince the government, and the taxpaying public, that this concept is viable before they all accept the reality of global warming, peak oil, the ongoing destruction of ocean biota, and overpopulation, then I suggest that you try to revive the L5 Society as a viable separate entity and get really concerned about Chemtrails (Google it).
I have witnessed sleeping CATS, when threatened by a dog, levitate straight up into a tree, but it was only five feet, or so, vertical.
BJ_Chippindale 19 August 2009 at 5:50 PM
I guess I’m stuck with my dial on “disagree”, at least as regards orbital solar power collection. Inspired by your post, I did a quick skim of what might contribute to making this easier than when it was first proposed and later when I actually read about it for the first time. I don’t see any “eureka” material.
Engineering-wise, space access is and always will be relatively complicated compared to walking around at the bottom of the gravity well. In absolute terms, it’s extremely complicated, involving enough single points of failure in the launch phase to make any sane engineer sweat every launch. It’s become fairly obvious over the past five decades that there’s a nearly ineradicable and relatively large residual rate of failure in launch systems that will become quite expensive if and when the number of launches is scaled up. Every care and caution along with lavish expenditure are exercised in the design, construction and operation of launch vehicles yet failures remain a routine occurrence.
Meanwhile, the Echo balloon system is not a very useful model for what we’re discussing. Assuming the necessary materials for a multi-kilometer size collector system could be realized from where they are now (largely in our imaginations) deployment of a collector array sounds easy in concept. Yet think about previous attempts at dynamic structures of even the simplest types. Remember the space tether system designed to exploit electric fields in orbit? That was basically an adaptation of a spin-cast fishing reel adapted for space, very simple, seemingly very predictable and fool-proof, and it failed. In the case of power collection systems we’re speaking of dynamic structures many kilometers in size, essentially impossible to test until orbited.
Then we come to the necessary transmitters and antennas. I see cited efficiency numbers from early experiments in the mid 80% range, but I suspect those refer to the efficiency of transmission of power actually emitted from the antenna as opposed to the overall efficiency of the transmission system, particularly including the active electronics in the transmitter. I don’t know of any existing microwave power amplifiers wth an efficiency of 90%, though perhaps I’m wrong. Meanwhile, the transmission antenna is another kilometer-sized structure. The transmitters themselves would not be amenable to structural artistry such as inflation, etc. and would necessarily be massive, particularly expensive to orbit. As well, we don’t actually know how to build 500MW microwave transmitters for deployment down here, let alone in the space environment with its cooling challenges etc.
Earthside, if I understand the geometry correctly, in order for the space-side collection system to be continuously exposed to sunlight as well as being oriented for reasonable performance without continuous attitude adjustments, there will need to be multiple receiver sites, with a means provided for handoff while leaving grid performance constant.
These are just the most obvious difficulties, to me anyway. As some wag said, it’s the unknown unknowns that really are a b___h, and of those I’m sure we’ll find a multitude.
Space based solar power collection involves inventing many huge new problems as well as continuing our waltz with some very old ones we’ve not yet solved.
Meanwhile, down here, we already have everything we need to collect solar energy, today. Doing so will be easier yet if the unfathomable billions needed to attempt space systems in pursuit of the same objective are not expended that way.
Perhaps the easiest and cheapest low tech “geo-engineering” solution is simply to ensure as many roofs as possible that don’t have solar panels on them are white. Doesn’t really substitute for reducing emissions or sequestering carbon via biochar, but it may buy us some time.
Ways to baseload solar:
1 don’t do it right away. An initial large chunk of solar energy can provide peak daytime power.
2. CAES (compressed air energy storage)
3. Thermal storage for concentrating solar power (CSP) or thermophotovoltaic or thermoelectric conversion devices
4. various passive solar and residential solar heating applications – thermal storage.
5. Combine CSP with geothermal and biofuels to boost thermal to electrical conversion efficiency and levelive power output.
6. Electrolytic hydrogen production, use in fuel cells or combine with biofuels to convert to methane to feed into existing natural gas infrastructure, put fuel cells in buildings to convert natural gas into electricity and use waste heat
7. use wind and hydroelectric, adjust hydroelectric output to balance variations in wind and solar, and use excess peak solar for desalination and water pumping, and CO2 sequestration or biofuel processing
8. Allow electricity consumption patterns to evolve.
9. Transcontinental HVDC
I want to defend BJ_Chippendale here… perhaps it is true that CATS is impossible within our lifetime, but the glittering prize is to place solar power in a location where there is 24/7 constant sunshine. Meaning baseload solar power, without the need of 5x (conservatively) nameplate overcapacity plus double-up storage.
Plenty of engineering challenges… Ray of course sees the problem of radiation for photovoltaics. For concentrating solar, the biggest challenge I see is the radiator needed to provide the cold end of the cycle — it will have to be big. But hey, if nuclear fusion is worth researching, why wouldn’t this be?
The solar satellite power stations might or might not be a good idea. But they would definitely take many years to deploy, and we just don’t have the time. If we don’t do a lot in the next 5-10 years, human civilization is doomed.
Re coral reefs (#103),
Eli, for a rabbit, you can be pretty depressing sometimes. :)
The review article Simon Donner referenced (and B&L maybe should have) takes into account the double whammy from global warming and acidification, and considers three coral-reef scenarios over the next century, with stabilization at 380ppm, 450-500ppm and >500ppm respectively. It doesn’t sound to me quite as bleak as your conclusion:
If conditions were stabilized at the present [CO2]atm of 380 ppm, … coral reefs will continue to change but will remain coral dominated and carbonate accreting in most areas of their current distribution. (Hoegh-Guldberg et al. 2007, p. 1740)
The question to Bickel & Lane was about “all or most existing reefs” being “destroyed” by “acidification” from “the CO2 already in the atmosphere”.
If I read correctly, the Cao & Caldeira paper they cite predicts that with stabilization at 380ppm 62% of coral reefs would experience aragonite saturation below the pre-industrial level of 3.5, affecting their calcification ability and long-term stability. At 450ppm, 92%. They predict reef-dissolving undersaturation in parts of the Southern Ocean at 450ppm, but not yet at 400ppm.
My layman’s take would be that there could still be a whopper of a policy-relevant difference between present CO2 concentrations, a low-emissions scenario, and hell in a handbasket.
B. J. Chippindale says, “CATS isn’t even complicated engineering anymore.”
I say “Bullshit!” Jeebus, dude, have you ever looked into what goes into launching a satellite, getting it into position and making it work once it gets there? Do you think this is just about launching frigging Estes rockets?
Patrick 027, don’t forget ocean thermal energy conversion. It bridges the intermittency by using natural heat storage in sea water, which otherwise is a big no-no.
Another thing worth not forgetting is that this isn’t only about electricity. Agriculture needs fertilizer, currently produced with fossil fuel energy, which will run out and/or become “climatologically un-burnable”. One could use the daytime/sunny weather overcapacity of solar to power fertilizer (and other bulk substances of high energy content, like aluminium) factories.
But hey, if nuclear fusion is worth researching, why wouldn’t this be?
I don’t think it’s not worth researching. BJ claims it’s “easy engineering, today”, which is false. It’s something that might, after a lot of research, be doable with difficult engineering quite far in the future.
“Cats isn’t complicated engineering anymore”?! Meow…
Martin Vermeer 20 August 2009 at 8:01 AM
“One could use the daytime/sunny weather overcapacity of solar to power fertilizer (and other bulk substances of high energy content, like aluminium) factories.”
That’s a marvelous idea, and there are so many others like it available requiring very little adjustment to exploit. Some amateur in Europe recently suggested “over-cooling” frozen food storage facilities with surplus wind energy being poured into the grid during off-hours; his idea was explored, numerated and is now being used to store energy in a strangely counterintuitive way. Frozen foods warehouses gobble electricity; by supercooling them their electrical load can be shed for long periods during daytime.
RE #75, Patrick, another thing I thought about re economics is that according to the social science framework I use, I consider all the dimenions of the human condition (the environmental, biological, social (of which economics is a part), cultural, and psychological) to be analytic distinctions, not concrete distinctions, and each dimension completely interpenetrates all the others and the whole — which is why everything seems economic.
Everything about the human condition is also cultural; everything is also environmental, psychological, etc. No one dimension determines the others, but rather impacts them. It’s sort of more an ecological view than linear determinist view. But it’s not like a concrete system with distinct components, although the analytic dimensions do have distinct properties that cannot be explained by or reduced to the other dimensions. Just as biology cannot be reduced to or explained by chemistry or physics.
Perhaps in the past (but I don’t know when, since now some are saying even early horticulturalists altered the climate thru extensive slash & burn), human behavior did not so extensively impact the environment. But since that is clearly not the case today, then we can say the the cultural, social (incl economics, but also power, and other social sub-dimensions), and psychological interpenetrate and impact the environmental dimension.
I’m just wondering what social (econ, power, kin, friends, social connections, social status, social structural), cultural (ideology, technology, knowledge, beliefs, values, etc), psyhchological (motives/emotions, cognitive content and processes), environmental (as in we’re faced with global warming, etc), and biological (e.g., the stomach) impacts lead some people to come up with fantastic and potentially dangerous or costly geo-engineering schemes, while seeming to ignore our potential to greatly reduce our GHGs through energy/resource conservation/efficiency and alternative energy. I’m not necessarily against such schemes, but only thinking let’s do all we can or make sure we’re doing all we can, while contemplating geo-engineering.
Let’s not use geo-engineering the way hydrogen fuel cell cars from futuristic fantasy land were used to derail a real, working, and immediate solution of electric cars in California.
Much, much simplier to make and bury biochar.
Rather lo-tech, that.
” This means that the path they propose would lead directly to geoengineering, even just to test it,”
I disagree. The basic physics is well-known. The specific result is somewhat chaotic, but fortunately, with SRM there’s no rush. Models and small-scale tests and a decade. After all, it’s mostly side-effects that we’d be testing for. A little chaos can kill a lot of people.
I like Martin’s point about using solar in energy-intensive applications, rather than baseload.
What about electrolysis to produce hydrogen? Biofuel refining? A lot of things don’t need a 24/7 cycle.
Geoengineering is the new strategy for avoiding/delaying emissions reductions, advocated most strongly (and with fewest caveats) by those in think tanks and organizations most closely associated with climate denialism:
“The new climate denialism is all about trying to make the continued burning of fossils fuels seem acceptable, even after the public has come to understand the overwhelming scientific consensus that climate change is real. That’s why denialists present geoengineering as an alternative to emissions reductions, and couch their arguments in tones of reluctant realism.
One of the earliest political calls for geoengineering was Gregory Benford’s essay Climate Controls, written for the Reason Foundation (you can find out more about their links to the Carbon Lobby and their role in climate denialism here). Benford was explicit that he saw geoengineering as a way to avoid reducing CO2 emissions:
“Instead of draconian cutbacks in greenhouse-gas emissions, there may very well be fairly simple ways–even easy ones–to fix our dilemma. …take seriously the concept of “geoengineering,” of consciously altering atmospheric chemistry and conditions, of mitigating the effects of greenhouse gases rather than simply calling for their reduction or outright prohibition.”
Benford is far from alone. One of the major proponents of geoengineering is the American Enterprise Institute. AEI has a long history of working to deny the scientific consensus on climate change. They have strong ties to the Carbon Lobby (ExxonMobil CEO Lee Raymond served on the AEI board of trustees, and $1,870,000 from ExxonMobil helped fund their anti-climate work).”
Here’s a layperson’s point of view.
Lomborg et al.’s proposal to inject sulfates into the atmosphere can be characterised as “chemotherapy for the planet”.
Three points about chemotherapy:
It’s a last resort.
Frequently, it does not work.
Frequently, it makes the patient worse.
Feel free to use this as a sound bite.
This thread sounds like Romper Room for physicists. Are you guys really concerned about the climate?
And 121, Lynn Vincentnathan, truly, hydrogen fuel cell cars were silly, but electric cars in California are not really a solution when the realities of electric power generation are considered.
Let me guess: You think electricity from a plug is a fuel; lots of people do. Or, you think MPG has any meaning for an electric car without considering the heat engine needed to make the electricity. Or you think electrons have names on them so solar generated electricity can be claimed at night when the car is recharged. Or you think that there is such a thing as a “mix” of energy sources that respond to a new load. Or you think that power companies choose to run the more expensive of their options when a load is added.
Electric motors have a roll as energy conversion devices in cars, but there is a lot more needed to make this a substantial solution.
On top of it all, I would point out that money is a bit short, both in California and the USA. After the cash gusher conquers the recession, there is good reason to think there will be very little money for climate solutions. (Read the recent Warren Buffet letter.)
David #122, if you can make it cheap enough. You have to work with billions of tons of material spread all through the atmosphere, efficiently and cheaply. I honestly doubt that’s less of a challenge than launching into/manufacturing 10^8 tons of coherent hi-tech structures in a zero-g environment :-)
Jim, you sound like an arrogant jerk.
Your opening sentece in 127 does that.
Do you think electrons from renewable sources are ONLY sunlight ones? Do you think that you work 100% of the daylight hours and nobody has thought that you aren’t actually USING your car while you’re at work (few desks accommodate integral carparking indoors…)
And when you BURN something, do you think it gets HOTTER? So isn’t that one (really quite major) difference between an ICE (hot burny block of metal that uses SOME of that hot burny gas to do work) and an electric car (where the motion of electrons produces force and only electrical losses are expressed as heat, )?
On top of it all, money is a bit short only because it is being hoarded by the rich people who are really quite terrified of becoming poor people. Same happened in the great depression of the US: the rich lived, if anything, in a world more kinglike than they had managed before, since the poor may have less to lose but each loss has a greater effect on their life.
Rich guy: I cannot afford five houses!
Poor guy: I cannot afford rent.
RichardC “I disagree. The basic physics is well-known. The specific result is somewhat chaotic, but fortunately, with SRM there’s no rush. Models and small-scale tests and a decade.”
I point you to the tests of iron seeding of algal blooms.
Worked fine in tests.
Models said it was a goer.
A bigger test flunked: iron wasn’t the least abundant requirement for life.
Re Lynn (121) and Jim (127),
Electric cars have quite some potential in the long run, also without thinking the things that Jim (most likely wrongly) accuses Lynn of. It’s much more efficient to power a vehicle by electricity than by an ICE. Of course the eventual climate effect depends on what is used to generate the electricity, but I’ve understood that even when coal is used for that purpose, an electric vehicle gets in about the same ballpark as a conventional car (in terms of total CO2 emissions per km). The more gas turbines, or better yet, renewables are used to produce the electricity, the better the electric vehicle is compared to the ICE. For a future where renewables are expected to become more and important in electricity generation, electric cars can serve an important role in balancing supply and demand (with not a little help from smart grids) and in decreasing CO2 emissions resulting from traffic. Please don’t reply by guessing what I think. (sorry for the off topic comment)
A. Steffen (125), Just an aside: Killing an idea just because it (also) comes from people you don’t like because of non sequitur characteristics — ‘no geoengineering because Mr. Ugly over there is suggesting it’ — is just as bad a process. There are plenty of substantive reasons for limiting geoengineering to go around.
Geoengineering ideas are quite a bit less than half-baked. To argue that they represent a realistic solution that obviates the need for CO2 reduction is either irresponsible or disingenuous. You pick.
A guess is not an accusation.
Why is it much more efficient to power a vehicle by electricity? That efficiency is entirely dependent on the spinning heat engine that actually is linked to the car by electricity. Yes, some are better than others, but the thing that counts is what will be cranked up in response to the car load, not all the stuff that is already running. No, renewables are not close to existing with capacity that puts them in that category. Whatever they are, they will be used without the existence of the electric car and there is no way they can respond.
And yes, CO2 is less with spinning gas turbines, than with coal fired generation of whatever type. Maybe if the price of natural gas stays low we can afford to use more natural gas. Futures traders do not seem to expect that. We can do a lot better with natural gas than just to run turbines with it, combined cycle or single stage turbines.
When money grows on trees, renewables might come up to the job.
When sensible regulators start thinking, (re in California) hydro can do far more about load balancing than the trivial little bit that the utilities would like us to think about.
Yes, the grid can be an important part of a future infrastructure that makes energy sense. If it services a distributed generation network, things begin to make sense.
I dare not guess, so how about telling how electric cars reduce CO2 emissions resulting from traffic? CO2 is still dependent on the energy used by the car, and it will come from a CO2 source somewhere in the global system.
And 129 Mark, those who talk about power from space vehicles, CATS or not, belong in the physics playpen. This has popped up over the years in the space business, but the process of relaying the power to earth has not the slightest grain of sense. Do these folks know that a low earth orbit satellite is in the shadow about half the time. It goes around in about 90 minutes. And there is no conceivable microwave antenna that could collimate the downlinked energy, and microwave power conversion is miserably inefficient. No, radar peak effective radiated power is hardly any energy on the power scale of things. Of course for the playpen crowd, we could use superconducting wires and built slip rings around the earth to couple in the electric power. Sorry for the mean jokes, but sometimes there is a need for harsh criticism.
At 126 Greg,
Your prescribed chemotherapy for the earth is premature, as is the run of global “engineering” nonsense being spouted here.
For some constructive discussion see comments at the IEEE Spectrum site:
Ray, to geoengineering as < half-baked and irresponsible solutions, fair point. But I would offer that the various C02 reduction ideas, ingenuously offered or otherwise, are at least as problematic. They require a large number of human beings to agree with each other and change their behavior on a global scale. How baked is that expectation? — Walter
Jim Bullis #134: criticism, harsh or otherwise, is welcome only if it is informed. Surely you are aware that powersats are supposed to be geostationary?
It has been demonstrated to work at good efficiencies (90%-plus). The collimation works too, do the numbers. The receiving rectenna is large, but lets sunlight through and is no worse than the myriad high-voltage lines criss-crossing our countryside today. Many of which it may replace one day.
Martin Vermeer (128) — Biochar goes in the ground, not the atmosphere. :-)
With decent growing conditions, 2 hectares would produce about one tonne of biochar per year. One able worker could probably, in their otherwise spare time, do about ten tonnes of biochar per year. So to be a complete solutioin, need one billion farmers and 20 billion hectares. The first is available, the second might not be.
136 Martin Vermeer,
Geostationary means that the altitude is 34,000 miles. I am guessing about the wavelength (Lambda) you have in mind.
Collimation gradually stops around 2 x D^2 / Lambda, D being the aperture dimension. Lambda at x-band (10Ghz) is about an inch. So for a 100 ft dish as an example, collimation goes out to about 40 miles. Easily, spherical spreading loss will govern the situation at 34,000 miles. And that is a lot of loss, even for a huge capture area receiving antenna.
I arbitrarily picked 100 ft diameter for the space antenna; keeping the right dimensional shape at larger diameters might be difficult.
I will look at your link to check, but this seems right as a quick response.
Martin Vermeer 21 August 2009 at 2:45 PM
I’ll wager some imaginary dollars that while 90% of the juice going into the antenna and crossing free space to another antenna can be recovered, nothing close to 90% of energy entering the complete system gets to the other side. TWT amplifiers are roughly 40-60% efficient at converting electrical energy to microwaves, solid state amplifiers currently 30-40%. The gently sloping part of the curve for obtaining easy gains in efficiency has already been traversed. Both techniques are remarkable achievements but seem unacceptably inefficient for the purpose of sending hard-won juice down to Earth. More, all of the dissipation must be dealt with via radiators.
As promised I checked the link you provided.
30 kW over 1 mile at 84% efficiency has supposedly been demonstrated, for an unspecified time duration. Not enough details are provided at the linked Wikipedia page to establish confidence in this report, but ok.
Now scale this to 34,000 miles and a power level of meaningful magnitude.
Then look into the cost of launching a very large satellite into geosync orbit.
Okay, okay. I might be completely wrong, but the guys at the Fox Valley EV Association (that converts ICE cars to EV) told me even if the electricity is from coal burning, the EV emissions are about two-thirds of an ICE car and easier to control at point-source — AND EVs are much cheaper to drive and maintain.
In the mid-90s when I presented the idea of EVs at our church environmental committee meeting to our guest ComEd guy (ComEd was then 75% nuke, 25% coal), he got excited and told us one of their biggest problems was that electricity demand was so high during the day, but low at night, and that IF a significant # of people could get EVs and plug them in at night, ComEd could cut their electricity rate substantially.
And, as I alway say (as I alluded to above in #121), we need to “greatly reduce our GHGs through energy/resource conservation/efficiency and alternative energy.” That means driving less, moving closer to work, running multiple errands, carpooling, offset driving cars by taking public transportation, cycling, walking, etc. So if we could reduce our driving, say, by one-forth, slap a few solar panels on our roofs or car tops or get parking facilities to do so (the FVEVA guys said solar is a clean source (meaning smooth electricity into the batteries, or something), put up a some superquiet mini-wind generators in our yards or wherever feasible and allowable, etc., we might be able to herald in an EV age without too much additional stress or strain on the grid.
EVs are just one solution among many many others. I haven’t written off hydrogen fuel cells or certain biofuels as playing their parts. Not sure, but maybe bring back a few horse and buggies ?? — then the manure could be made into biofuel.
I guess it’s just a guy-thing (or perhaps Western Civilization man thing) to look for a silver bullet solution.
BTW, Jim Bullis’s Miastrada idea looks intreguing.
130 Mark said, “I point you to the tests of iron seeding of algal blooms. Worked fine in tests. Models said it was a goer. A bigger test flunked: iron wasn’t the least abundant requirement for life.”
Exactly. A cheap, small-scale test in geoengineering. Perhaps the next test should be using low clouds in the arctic to “replace” ice as it melts? Albedo maintenance seems a reasonable test. It would be cheap and answer a lot of questions too.
Or maybe there’s another source closer than geosync that can replace burning fossil fuel, reversing the trend now making ocean pH change worse:
“… Here we report observations that clearly contradict the common assumption about symmetric aurora: intense spots are seen at dawn in the Northern summer Hemisphere, and at dusk in the Southern winter Hemisphere. The asymmetry is interpreted in terms of inter-hemispheric currents related to seasons, which have been predicted5, 6 but hitherto had not been seen….”
Trees to Power Their own Wildfire Sensors
By Alex Hutchinson, Published on: December 18, 2008
MIT researchers have discovered that trees carry a (small) charge. Now, green energy takes on new meaning with wildfire sensors powered by the woody plants themselves. Here’s how it works….
… Voltree Power’s big idea started as a rumor on the Internet: If you drive a nail into a tree trunk and another piece of metal into the ground nearby, the claim goes, you can measure a voltage difference between the two. It turned out to be true. Now the startup company is racing to complete prototypes of miniature treepowered forestfire sensors in time for this spring, when it will fieldtest its detection gear during a controlled burn set by the U.S. Forest Service.
Jim Bullis –
You have to consider not just what energy sources are operating at the time of battery/flywheel/whatever recharge, but the net effect – electric vehicles may/can be more efficient in fuel energy to motion, and adding clean energy power any time of day reduces the total day’s worth of fossil fuel consumption, so electric vehicles may make a lot of sense – there is 1. a replacement of petroleum with clean energy + 2. replace clean energy with fossil fuel one time of day in exchange for replacing fossil fuel with clean energy at another time of day (Of course, eventually fossil fuels will be completely phased out, but there are ways to make clean energy into a sufficient baseload power source).
> I arbitrarily picked 100 ft diameter for the space antenna;
The numbers for really proposed powersats are more in the kilometre range, and the rectenna even larger, much larger than beam diameter (a requirement). A very large, modular antenna is no special problem on what will be a very large satellite anyway. Keeping it in shape should not be a problem in the hi-tech era, think adaptive optics.
Doug Bostrom: as a practical data point, your microwave oven does 70% — and there are other losses besides the magnetron. Currently these devices are not being used in a bulk power transmission context and perhaps therefore, high efficiency has not been a design focus.
As an “ad hominem” argument, these things have been documentedly studied for half a century now by reputedly pretty smart people (NASA); don’t you think they had to face the very same, rather obvious objections y’all come up with?
No, it isn’t easy; something worthwhile rarely is.
BTW a historical curiosity: Peter Glaser’s patent:
Lynn Vincentnathan –
I think we generally agree on the tangible things. My point was just that we ultimately do need to compare apples to oranges very often in life, weighed by personally aesthetic value, and economic and moral value, and that, there is some relationship among the different kinds of value – if the economy worked ‘perfectly’ then there might be some constant proportionality of aesthetic to economic value (maybe??), and if all actors were moral, then the free market would tend to maximize moral profit, etc, and if there is some corrective policy, for externalities, etc, that involves a tax or other price signal, in principle the best price signal to use to get the greatest economic benifit would be the external economic cost of that which is being taxed, and the policy we should seek is that where the tax is the moral cost, hence implying a proportionality between economic and moral benifit…
PS another aspect of free markets is that they might ‘solve the equation’ most effectively when the domain is approximately continuous – ie decisions can shift in many small increments – (?).
Ray (133), I think they’re better than half-baked; I would give them an even average of half-baked. Just IMHO. I do NOT think, “…that they represent a realistic solution that obviates the need for CO2 reduction…”
I made a decimal point error in comment #137. A reasonable estimate is 10 tonnes of biochar from 2 hectares. So to make 10 gigatonnes of biochar per year requires but 2 gigahectares of productive land; still a lot.
145 Martin Vermeer,
I need to explain that the studies you describe do not constitute “really proposed powersats.” To be fair to NASA, it looks like they have had nothing to do with recent chatter on this.
It all comes down to chosing a practical course of action. I based my “obvious” objections on an antenna size that I considered difficult and very expensive.
From having been involved in many satellite programs that cost enormous amounts of money I can confidently assure you that the satellite system here discussed would cost many billions of dollars; vastly more than simply laying solar panels out in the desert. The gain in solar production due to being outside the atmosphere is not close to being enough to justify this large cost multiple.
Why not think about more down to earth possibilities?
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