There's certainly no reason to think that much has changed based on this latest call for it:
PV technology has improved considerably since this idea was developed adding to the argument that this source of energy should be revisited. In addition, the economics of the cost of energy have changed. According to Dr. Neville Marzwell and his colleagues at the Jet Propulsion Lab, an SSP system could generate energy at a cost including cost of construction of 60 to 80 cents per kilowatt-hour at the outset. He believes that "in 15 to 25 years we can lower that cost to 7 to 10 cents per kWh." The average cost of residential electricity was 9.86 cents per kWh in the U.S. in 2006.
The problem (as always) is that this doesn't account for the costs of competing energy sources dropping even more. And of course, the notion of building SPS with the existing space transportation infrastructure remains ludicrous. Get the costs of access down (a good idea for a lot of other reasons), and then see if it makes sense. Unfortunately, current space policy (or at least the vast amount of expenditures on space transportation) seems aimed at increasing the cost of access to space.
[Via Ken Silber]
[Early evening update]
Mark Whittington:
Rand's approach is just clearly wrong. There are no market incentives to decrease the cost of space travel, outside the COTS competition.
Nope, none at all. How will we ever do it without the government?
Oh, wait! How about the millions of people who want to take a trip, and can afford to do so if the price comes down? Mark ignores that one, though, because it doesn't require NASA getting billions of dollars, or giving them out for a few flights via COTS, that will do very little to significantly reduce the cost of access.
And once again, there is NO sane reason why SPS should not be continuously investigated at least on par with fusion power. They both hold promise, neither is certain, both should get some actual attention in proving the tech. Fusion of course does, while SPS gets zero to none.
Once the technology is tested and put on the public conciousness, the chances of it being picked up improve and getting it on radar as one of the potential markets to drive high flight rate space transportation would improve.
There should be a clear target for getting a functioning demo out to shake out tech and quantify problems.
I've looked into this a little, on several occasions - and the conclusion seems to be that SSP is never going to be economically viable - because the power can't be sold for enough to amortise the money that building the plants costs - IF one assumes that all the materials are going to be lifted from ground. Unless one assumes Orion vehicles (the real Orion) to lift all those megatons of mass.
The only way to make large space structures viable is to use space materials - which means major space and Moon infrastructure - which has such minor side benefits as, for example, enough iron to plate the USA a metre deep in steel.
Current space policy is, of course, designed by very clever people to make it difficult to impossible for the above to happen. Why? Simple. Because the bureaucrats responsible would be out of a job, and the American Imperium would be over for good.
Unfortunately for those bureaucrats, Americans aren't the only people who have or can get the technology. The lingua franca of the greater Solar System will likely be Chinese - or Hindi.
There may be a few intermediate steps to SPS that make business sense. I talked last week to a man that retired from an electric company a few years back. He mentioned that one of the problems now is getting right of way for power lines from new power plants. It seems that right of way issues are more of a show stopper than permitting new plants in some areas.
Microwave transmission and rectenna towers might be feasible to get around this issue in some areas. The towers would be large and expensive, just possibly less so than power lines and right of way easements in certain areas.
If that actually happens, power relay satelites become more feasible with ground infrastructure in place.
If those two things happen, SPS could be brought much closer to financial feasibility.
>> PV technology has improved considerably since this idea was developed adding to the argument that this source of energy should be revisited.
Transmission costs matter also.
If improved PV can be located closer to the end point user transmission costs and transmission infrastructure will be avoided, even if efficiency is somewhat reduced.
I fear a major SSPS effort would end up like the satellite telephone industry, a supposed "killer-app" that crashes badly when a less expensive superior terrestrial solution is found.
What they said, especially Bill.
Ground based PV is already starting to look pretty attractive and costs are going to come down further. Even in somewhere with the sun level of Seattle or the UK, Solar makes sense for domestic supplies. Especially if we also have some battery/capacitor breakthroughs.
I don't think there really is an energy crisis providing we invest the right technologies; nuclear, solar, hydrogen.
Global Warning arguments aside, as Harry Harrison remarked in The Stainless Steel Rat Saves the World - burning precious hydrocarbons is dumb.
We might have a bit of trouble getting through the environmental compliance regs. I hear those MWs like water vapor...
Geez, Rand, you spend so much time making fun of Mark I'm beginning to think you like him.
I hate to sound like a "split the difference" kind of guy, but what about upper stratosphere-based PV power stations? Granted, working on them wouldn't help the effort to reduce access to orbit, but it has the advantages of getting above most of the atmosphere and all the clouds that would block ground-based stations, and of reducing a lot of the attenuation that a geosychronous satellite would have beaming the power back. There is a lot of technology to work out, of course, keeping the station aloft and on station would be difficult, but surely it's an effort worth the money, at least to investigate. I believe I read lately where the US Air Force is concerned about our lack of ability to take advantage of the space between lower atmosphere and low orbit. Seems like there could be some synergy between any USAF work and solar power entrepreneurs in that space, working in the "Sorta-Kinda High Frontier".
Again, why, if anyone mentions SPS people start talking about "major efforts" and "power stations" and major structures in space and economic sense?
The technology has not been proven anywhere near enough to make any informed judgements about economic feasibility of such. What needs to be done is technology maturation and shakeout. A pilot program or whatever.
It would serve two good purposes a) getting problems quantified so that we CAN start talking about feasibility of larger-scale implementations, or if it obviously wont work just forget it b) putting the concept on the public conciousness
Ground based solar can advance in small steps. People are much more willing to take risks on $10M or $100M investments than on $100B investments. SSPS requires enormous facilities, built (at least initially) at enormous cost. The ground competition (and not just ground solar) is going to advance much faster.
One thing that may be contributing to the sense that terrestrial solar power is becoming more useful is the LED lights that require so much less power. I've seen two recent small-scale applications (standalone walkway lighting and an alarm system sign for a house) that really show a shift there, but that may be a false lead due to our other electrical needs (air conditioning, etc) not changing their appetites that much.
On the stratospheric front, it loses due to the multi-hour night. SSP can brag about very low downtime (
continuing previous, not sure why it got clipped.
less than 10 percent, even on days of maximum eclipse, for geosynchronous orbit stations)
(my first version used the less than sign and percent symbol in the text. Would that be a problem?)
"Global Warning arguments aside, as Harry Harrison remarked in The Stainless Steel Rat Saves the World - burning precious hydrocarbons is dumb."
Yea, let's save those precious hydrocarbons for ... wait what are we saving them for? Hmmm ... let's see if we don't use them then they aren't precious anymore, then we can use them but then they'll become precious again ...
See how stupid that argument gets!!! Let's use what we have and develop more options. Geez, let's not be timid.
SPS researchers have been beating their heads against a wall trying to figure out how to compete commercially with other power sources by bringing the cost down to 10 cents per kWh. But of course the most recent development is the military waving their hand and saying, "Hey, we're spending more than $1 per kWh on remote battlefields".
http://spacesolarpower.files.wordpress.com/2007/11/final-sbsp-interim-assessment-release-01.pdf
my first version used the less than sign and percent symbol in the text. Would that be a problem?
If you use a less-than sign, it thinks you're starting an HTML tag, and ignores it (and everything that follows, unless it's a good HTML tag). Either write "less than" or use the HTML code for it, like < (the code is <).
Yea, let's save those precious hydrocarbons for ... wait what are we saving them for? Hmmm ... let's see if we don't use them then they aren't precious anymore, then we can use them but then they'll become precious again ...
A Wikipedia quote:
[quote]For decades one of the great appeals of plastics has been their low price. Yet in recent years the cost of plastics has been rising dramatically. A major cause is the sharply rising cost of petroleum, the raw material that is chemically altered to form commercial plastics.[/quote]
Since we make many of our plastics from petroleum, burning it all up as fuel might not be prudent.
Finding an alternate fuel source for vehicles could lower the cost of plastic increasing everyone's standard of living.
Ethanol is an obvious scam, and using it raises the price of food, but maybe we should keep on looking.
Terrestrial solar powered production of hydrogen (fission powered production, too) and fuel cells are a possible option.
Defense Department applications might very well be viable. I can support that. But mostly with military budgetary dollars plus some funding of the core physics underlying power beaming in the "Science" category.
Just say "No!" to the idea that SSPS can "solve global warming" or rid us of dependence on foreign oil and don't blow smoke about SSPS finally giving us a "killer app" that will demand zillions of units of Earth to LEO launch capability
A couple of us biz types sat down one day and tried to figure out how to close the SPS in LEO business case and we just couldn't do it no matter how low we assumed launch costs could go. But what we could close was lunar SPS by fabricating the PV in situ:
http://ieeexplore.ieee.org/Xplore/login.jsp?url=/iel5/9889/31426/01488252.pdf?arnumber=1488252
What I think is being missed is the "not in my backyard" issue. While it may be cheaper to blanket the desert with solar power plants, that will not be allowed (interestingly enough by the same people that are screaming for those plants). GEO orbit is far enough away that it is in noone's backyard. That may be enough by itself.
Bill,
You can make plastics out of methane, coal or trash crude that is of little use for fuel.
There is no shortage of feedstock for plastics in the long term.
Mike Mealing:
When you guys were trying to close the business case for SSP, did you consider solar thermal rather than PV? Granted, there are moving parts (turbines/generators, working fluid) which can lead to maintenance issues, but that can be localized; the vast majority of the mass of such a satellite would be little more than aluminized Mylar or some other such lightweight reflective material. With a cold sink like the background temperature of space, the Carnot efficiency easily exceeds 99%, even if the hot side is a very moderate 300 Kelvin. So, the efficiency of the system then boils down to the efficiency of the turbine, generator, conversion losses from electricity to microwave and back, and microwave transmission losses.
Let's assume some pessimistic numbers: 100 tonnes for the turbine, generator, antenna, working fluid, radiator, electronics, and structural material for the power plant part (not including the big reflector). Assume a wildly pessimistic 95% loss through the whole system from light received at the reflector to electrical power delivered on the ground. Assume that the reflector is a parabaloid made of aluminum foil (although it could be even thinner than regular household aluminum foil, it gives a baseline mass per unit area) with a thickness of 0.2 mm. Finally assume that the power delivered to ground is 1 Gigawatt.
With those numbers, the amount of light received at the satellite would have to be 20 Gigawatts, and at 1340W.m^-2 that works out to a reflector area of just under 15 million square meters; roughly a dish with a radius of 2180 meters. 15 million square meters of Aluminum foil times 0.2 millimeters thick gives 3 thousand cubic meters, times 2700 kg per cubic meter gives 8100 tonnes of reflector. Total mass of the system then is less than 9000 tonnes, or less than that if the efficiency is greater than the wildly pessimistic 5%.
The space shuttle weighs over 100 tonnes, so a reasonable payload value for a heavy lift launcher can be assumed at 100 tonnes. That means we're looking at 82 launches on a big dumb booster, only one launch of which is the expensive stuff (turbines, generators etc); the rest is just passive reflector.
Terrestrial solar thermal research is huge right now, and in space the efficiencies would go way up; as I mentioned, those numbers are wildly pessimistic. Stirling Energy Systems produced an efficiency of 31.25% power delivered to grid in a test at Sandia earlier this year - and they are using a Stirling engine. At that efficiency, the reflector area would drop to less than 2.5 million square meters, or 1350 tonnes - a total of 15 launches.
Does that help to close the business case?
# You can make plastics out of methane, coal or trash crude that is of little use for fuel. There is no shortage of feedstock for plastics in the long term. #
No argument . . .
But, I was responding to the argument that there was nothing else useful we could do with petroleum except burn it as fuel. Also, I believe that a more complex feedstock requires less energy to convert to plastic than starting with less complex hydrocarbons.
Push come to shove we can make plastics starting with CO2 and H2O and few additives but that takes more energy and greater processing and that equals increased expense.
= = =
Solar thermal is a fast growing industry. Here is a link to a marvelous pilot project being deployed in Israel:
http://enr.construction.com/news/powerIndus/archives/080402.asp
But as terrestrial solar thermal improves, the cost of producing terrestrial electricity shall fall, under-cutting the SSPS business model.
Anyway, if SSPS happens with private financing as the primary funding source, I will certainly wish them the best of luck and be very pleased if it works out.
Requests for massive taxpayer assistance? I am very much less supportive of that.
again and again.. large installations, billions, global warming and so on. All this discussion does nothing but harm for the cause and misses the crux of the matter entirely.
Who here opposes a pilot program funded at say, a few hundred mil a year to validate the SPS technology ?
If you do oppose, justify what makes it worse than ITER ?
Also, I believe that a more complex feedstock requires less energy to convert to plastic than starting with less complex hydrocarbons.
Er, Bill, wouldn't plastic itself be a "more complex feedstock"?
Liberals have been pushing mandatory recycling for decades. Why are you suddenly telling us it's better to use oil?
In the long term, carbonaceous asteroids can provide a pretty good feedstock for plastics.
Who here opposes a pilot program funded at say, a few hundred mil a year to validate the SPS technology ? If you do oppose, justify what makes it worse than ITER ?
Apples and oranges. Nuclear fusion needs to validate the technology; Space Solar Power needs to validate *the economics*. If fusion can be done at all, no decisionmaker doubts that it will be economical. (They're operating on faith.) So, they can justify spending almost anything. On the other hand, no one doubts that it's possible to produce solar power from space, but many people doubt that it can be done affordably so a different type of demonstration is necessary -- a demonstration of economic viability. Cost becomes very important.
with all due respect, mr. Wright, you are wildly overoptimistic about economics of fusion, and you are wildly overoptimistic about technological feasibility, or readyness of space-based solar power.
Plus, when you say "no one doubts" you mean all these people, all dozen of them who actually know about the concept ? Because when i go to a random science professor at the local university and tell him we ought to put a bunch of satellites up there beaming solar power down over microwave he would think im nuts.
If you think only 12 people in the world know about Space Solar Power, you're bound to reach some strange conclusions.
Why would you ask a random scientist what he thinks about "putting up satellites"??? Why would you expect a molecular biologist to know anything about transportation systems?
And why would you ask scientists instead of Members of Congress, venture capitalists, or power company executives? Most scientists are not wealthy.
it seems useless to explain (again) that a Space Solar Power's energy may costs between HUNDREDS to THOUSANDS times the solar energy produced on Earth (send a 10 mT solar panel in Space with a rocket will NEVER cost LESS than send it to an Earth's desert with a truck and that costs can't fall in future) since these useless and crazy research are FUNDED !!! (...and "business is business"...)
You are evading my point, mr. Wright. My point was ( i though clear enough ) that SPS is not a very well known concept. Especially so because its never been tried on the tiniest scale, and there is no plan to do so.
gm:
I agree with you. Lifting tens of millions of tons of machinery from ground to orbit will never be an economically viable source of power - barring such crazy stuff as using nuclear pulsejet Orion to lift it. An approach with a few side effects, I think you will agree.
However, there is an alternative. Lift a few thousand tons to the Moon, and lift another few thousand to orbit - and use Moon materials (and later asteroidal ones) for the build. This approach, incidentally, gives humanity enough living space for quadrillions and literally astronomical amounts of resources, as a bonus.
Hell, Gerard O'Neill said all this in 1984! And he was assuming 1984 technology, too. Check out "High Frontier".
Fletcher,
this approach may be cheaper but never like (simply) deploy the panels in a desert, also, we need more alternative energy NOW while the space/moon energy could be available only in the next 30-50 years
Don't you all get the feeling that those high-flying projects and/or thoughts about solar energy harvesting out in space are not economically (and probably not technologically) feasible? IMHO a down-to-earth system would kill two birds with one stone: our society is built on transportation, but we don't have - or can no longer afford - the fuel to propel us from A to B. So let's dump our gas guzzlers and switch to electric cars as fast as we can (why haven't our politicians adopted such a policy years ago?). Let's take the necessary electric energy from PV panels on our roof (or elsewhere), get the flywheels in our cars up to speed (Rocky Mountain Institute has done some marvelous work on such a vehicle) and drive to work where we can park under solar panel shades and charge up some more. Flywheels are comparatively simple energy storage devices and the more cars use them the more energy we can store - even sell some back into the grid. We could even install a flywheel underground in our backyard for domestic power or feed excess power to the "Neighborhood Flywheel Central"... it may not work in Minnesota, but it may well work in Arizona.
You are evading my point, mr. Wright. My point was ( i though clear enough ) that SPS is not a very well known concept.
If that's true, how do you expect to get hundreds of millions of dollars for a demonstration?
Especially so because its never been tried on the tiniest scale, and there is no plan to do so.
I'm not sure what "it" is, but generating solar power in space has certainly been demonstrated. So has the transmission of electrical power using microwave beams. The two have never been demonstrated together (as far as I know) but no one really doubts that it's possible to put them together. Again, the only question is the cost.
microwave beaming has been demonstrated over short distances, never through tens of miles of different atmosphere layers. currently saying that SPS would work, is a leap of faith. after demonstrating it, real implementation becomes a question of cost. Demos have awesome power.
There are several other things that ought to be demonstrated sooner rather than later : on orbit cryo propellant transfer, ANY type of lunar ISRU, living organisms surviving a six-month martian trip ( say lab mice ) and so on. All of them removing a significant faith barrier from further concepts.
microwave beaming has been demonstrated over short distances, never through tens of miles of different atmosphere layers. currently saying that SPS would work, is a leap of faith.
Huh? There are electronic systems beaming microwaves through tens of miles of atmosphere 24/7.
There are several other things that ought to be demonstrated sooner rather than later : on orbit cryo propellant transfer, ANY type of lunar ISRU, living organisms surviving a six-month martian trip ( say lab mice ) and so on. All of them removing a significant faith barrier from further concepts.
Those sound like good things to do, but I still don't see any comparison to nuclear fusion.
The bottom line for space based power is a cost factor of 2 to 3 times competitive earth based solar power, or equality with other environmentally friendly power production. Why 2 to 3 times? Because the sun shines 1/2 to 1/3 as much if you leave the panel on earth, vs. the cost of launching it into orbit. Maintenance is much cheaper on earth, as well. In addition, I predict we will have high temperature (liquid nitrogen cooled) superconductors spanning the globe for power distribution before we have space based solar power, and the sun is always shining sonewhere on earth.