Dr. Weinstein sent me a post suggesting a unique method for clean energy production in the future. If you’re interested in the energy production aspects of climate as I am, this post is a fun read with some interesting conclusions.
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The Solution to Future Energy Needs and Global Pollution
Leonard Weinstein, Sc.D
April 19, 2009
Introduction:
There are two problems quickly becoming apparent that will have a profound effect on modern civilization. These problems are:
1) Increasing energy costs due to limited availability of fuels
2) Increasing pollution due to increased development and energy use in the world
The problems are highly interdependent. They clearly derive from the burning of fossil fuels, which are finite and in some cases are unable to be obtained in quantities fully able to meet demand.
How we satisfy our present energy needs:
There are two distinct categories of energy needed for modern civilization. The first of these is the energy needed for fixed locations (e.g., homes, businesses). This includes electricity, oil, gas, and solid fuels (e.g., wood, coal) for heating, cooling, lights, motors, etc. The second of these is required for transportation (i.e., cars, trucks, trains, planes, and ships). This is currently mainly liquid fuels (gasoline, fuel oil, alcohol, etc.), but can include compressed or liquefied gases (methane, propane and even Hydrogen). There are some vehicles that use grid electricity for power (trams, and some trains), but these requires a limited fixed travel route over the ground.
The vast majority of the energy needed for fixed locations is derived from fossil fuels, with lesser amounts from hydroelectric and nuclear electric generation. Other sources of power also are available, such as Geo-thermal, wind power and Solar. The main present source of electrical energy production in the world is from coal-fired steam turbo-generators. The large quantities of coal available (including huge reserves) and low mining cost, make it an especially low cost source of power. Coal was even used for many years as the main source for heating. However, the need for individual bulk delivery to homes, the difficult method of fueling the fire (cleaning out ash and shoveling coal), and the dirty smoke led to use of more convenient and cleaner fuels and sources of power. Present homes and businesses now mainly use oil, gas, or electricity for heating, and electricity from power plants for other energy needs (cooling, lights, powering motors, etc.). Natural gas is gaining in popularity due to its increasing availability and relatively clean burning, and also due to the fact that it can be continuously delivered via pipelines.
The energy for transportation is mainly derived from fossil fuels, with the vast majority using oil derivatives (gasoline, kerosene, jet fuel, etc.). Use of bio-fuels such as ethanol, plant oils, and plant-based methanol are increasing in importance, but are still a small fraction of the total fuel used. A major driving factor for fuels for transportation has been cost, and cheap oil has satisfied this need well until recently. The increasing oil consumption of countries that were previously third world (mainly China and India), and limited easily obtained increased oil production (and finite reserves) has put the pressure on obtaining alternate sources of fuel. The huge oil sands deposits located in North America are becoming a major source of oil. Other potential sources including shale oil and synthetic oil made from coal are not yet competitive, but probably will be so in the near future.
The problems with present sources of energy:
Burning fossil fuels produces Carbon Monoxide, Nitrous Oxides, Sulfur Oxides, and particulates (including heavy metal contamination), which all negatively affect the atmosphere to some extent. Carbon Dioxide is also produced in large quantity, but this is not a negative factor as the others are. Burning coal also produces large amounts of waste ash which is difficult to dispose of safely. In addition, the present easily obtainable oil reserves are limited and might not last too much longer. Since oil is the main source of fuel for transportation, this is particularly significant. Alternatives such as synthetic oil based fuels made from coal or other sources are both more expensive, and also will eventually be limited.
The use of renewable fuels such as ethanol, methanol, and biologically produced oils appears to be an attractive solution, but many issues have arisen including the limited amount of land that can be dedicated to production without negatively impacting food production and costs. In addition, recent analysis indicates that converted land (converted from forest or multi-crop activity) may actually produce more pollutants due to the conversion than is reduced in the vehicle by use of the alternate fuel.
Nuclear fission power has its own problems. Licensing and building reactors take a very long time. If the fuel were used directly (non-breeder reactors), the finite Uranium sources would limit the available operation in a relative short time (several decades). Going to breeder reactors can greatly extend this time, but these reactors produce Plutonium, which is very toxic and dangerous. Getting rid of reactor waste products is a major problem. One final problem is due to the need for large quantities of cooling water, which can exacerbate the existing problem of stretched water supplies. If fusion energy were available, it would have some of the same problems as fission power plants, but it is not even available.
While hydroelectric, Geo-thermal, wind and Solar generated power do not have the polluting problems of the previous techniques (but may have other problems) and do not get used up, they are also limited in location, magnitude, and in the case of wind and Solar, are limited in production times. Hydroelectric and Geo-thermal power are very limited in generation capacity. Unless far more practical energy storage and long-range distribution systems are developed, wind and Solar will also remain limited to a small part of energy production.
Some features of ideal solutions to the energy problem:
A source of energy for power for stationary location and a source of fuel for transportation are needed that satisfy the following requirements:
1) A source of energy that is non-polluting of CO, NOx, Sulfur oxides, particles, and that does not have large thermal waste
2) A continuously available source of energy in all weather
3) A source of energy that can be available without long-range transmission needs
4) A source of fuel for transportation that is continuously available
5) A type of fuel that is minimally polluting
6) A type of fuel that can be transported easily
Solutions to the energy and fuel needs:
One solution (and in fact is the only one that has been proposed to meet the energy needs that satisfies all of the requirements stated above) is to make an array of Solar power satellites in Geosynchronous orbit to beam microwave power to receiver areas at numerous locations on the Earth. This solution has been studied in considerable detail, and would be practical if it could be done at low enough cost. Unfortunately, lifting all of the material directly from the Earth would be far too expensive at present costs, and would still be too expensive to be practical even at the projected lower cost of the next several generations of lifters. A possible way to bring the cost into a reasonable level might be use of in-situ obtained material from space. One possible scenario of how that could be done is shown in a later section.
Most transportation means, with the possible exception of aircraft, that also satisfy all of the above limitations, are probably limited to electric motor driven propulsion. Aircraft might still have to use hydrocarbon-based fuels, and are not included in the present proposed solutions. The transportable electric power would either have to use storage batteries, or fuel cell electricity generation. Energy for recharging the batteries would come from the Solar power satellite system. A compact and non-polluting storable form of Hydrogen would be needed for the fuel cells. Reformulating hydrocarbons are thus not considered, since they still use fossil fuels. Possibly the best form of hydrogen storage might be in the form of liquid Ammonia, which has about 1.75 times the volumetric Hydrogen content as liquid Hydrogen, and which can be kept liquid at room temperature and modest pressure. The Ammonia would not be made from natural gas or using electricity from hydrocarbon burning power plants as is presently done, or the pollution would still be a problem. The energy from the Solar power satellites would be used to electrolyze water and purify Nitrogen, and the Hydrogen from the water would be combined with the Nitrogen using the Haber process. The liquid Ammonia could then be shipped by truck or rail, or by pipeline, to the locations where it would be dispensed. Use of a Nickel catalyst has demonstrated over 99.5% conversion of the Ammonia to Hydrogen and Nitrogen in compact reactors. Most of the residue can be easily chemically removed from the exhaust stream to make this a practical source of Hydrogen for the fuel cell.
Cost Effective Solar Power Satellites:
Obtaining power from large solar cell power collectors in GEO and beaming the energy to selected locations on Earth using microwave energy has been extensively studied. This produces no pollutants, and would generate very little thermal waste energy. The technical problems have been extensively examined and do not seem to indicate stoppers. However the present high cost to lift all materials from Earth to GEO prevents this approach from being practical with that approach. If it became possible to make these solar power satellites cost competitive, a significant portion of the electrical power needed on the Earth could be obtained from space. In addition, the power could be directed to many regions otherwise difficult to reach. The present sections suggests a possible way to develop the power satellite capability at a competitive cost if certain assumptions can be demonstrated to be valid.
The first issue to be examined for potential space solar power is the type of power collector and generation system to be used. While solar concentrator based systems could be made very lightweight, and the high intensity used to either illuminate concentrator solar cells, or even make steam for turbo generation, the need for massive waste-heat radiators would lose the mass advantage originally obtained with the concentrators. A very low mass to power radiator concept, practical at very large-scale, is described in an unpublished paper by the present author (but available on request) “Low-Mass Free-Piston Space Radiator”. However, even for that very low mass radiator version, the radiator mass to waste power eliminated would be > 10 kg/kW at the temperature required for solar cells. Since the waste heat is about 2/3 of the total input energy for a reasonably efficient system, this would require a radiator system mass to useful output power ratio of over 20 kg/kW. When the solar concentrators and cells along with the support structure and power converters are included, the ratio is even worse.
There are present prototype versions of solar cells that mass less than 1 kg/kW, and produce about 140 watts effective net output per square meter in space. While the cells are only about 10% efficient, it is the mass to power that is critical, not area of cells needed (space is BIG). These cells would not need separate radiators to remove excess heat while producing electricity! The converters and microwave transmitters needed to send the power to Earth would generate some waste energy and would need radiators, but at a fraction of the total power produced, and at fairly high temperatures, so much smaller versions of the low mass radiators could be used for a far lower total mass. The additional support structures, transmission means, and radiators would probably about triple the mass/kW over the cells alone, so I use a value of 3 kg/kW produced power as possible (about 1/7th the ratio of the concentrator versions).
The greatest driver of the present high cost of space power satellites is the high cost of lifting payload from the Earth’s surface to GEO. Present costs run >$12,000/kg to lift payloads to LEO (and more than double that for Shuttle), and about 3 times this cost to lift payloads from LEO to GEO. This cost of over $48,000/kg to GEO is the limiter for this approach. The next generation of heavy lifter could cut this cost considerable. It would not be unrealistic to assume $3,000/kg to LEO and thus $12,000/kg to GEO as possible in the reasonable future. These optimistic future rates will be used next to estimate how expensive solar cell based power satellites might be able to be made, using Earth to GEO lift.
In order to estimate the cost, it is necessary to make realistic estimates of the mass of power collectors and converters. The cost of assembly, maintenance, and the cost of ground facilities also need to be estimated. The lift cost to GEO using the projected lower cost Earth to space. Heavy lifters (at 3 kg/kW) would thus be about $36/Watt (it would be over $144/Watt with present best technology). The solar cell manufacture cost on Earth might be about $1/Watt in very large quantity, and the ground stations to receive the energy could possibly be made for $1/Watt. The initial design and hardware cost is also assumed to add about $1/Watt for very large systems. The assembly, repair, and operation cost are most difficult to guess, but I am assuming $4/Watt for 20 years of operation. The total of the above is $43/Watt, of which $27/Watt was needed to lift LEO to GEO.
It should be observed that one Watt of continuous delivered power for 20 years yields 175 kW-hrs of total energy. It thus appears that the power cost could be about $.246/kW-hr. This doesn’t include financing cost, and profit. For the present examples, I assume these double the power cost to $.49/kW-hr.
The real advantage of space based solar power would not become convincing unless much lower delivered cost could be achieved. The only realistic probability to accomplish that would be to obtain in-situ materials to make the solar cells and support structures in space, as well as obtain the propellant to put them in GEO. The critical point is to obtain this material and capability at low enough price. The most plausible places to obtain the materials are the poles of Luna and the moons of Mars. There are reasons that I think the best source of materials is the moons of Mars, and for now I am just assuming the larger moon of Mars, Phobos, is selected as the source of the materials.
There are several critical materials needed to make power satellites in GEO from mostly in-situ obtained sources. The one needed in largest quantity would be propellant for orbit transfers. Water is almost certainly the raw material that would be used to make the propellant, and could probably be obtained from under the dust layers of Phobos (see appendix). Energy to obtain the water, and to electrolyze the water and liquefy the oxygen and hydrogen would be needed in large quantity, and would most likely be obtained with fairly large Solar cell arrays (but much smaller than for the power satellites). These could be manufactured on Phobos using power from a smaller array carried up from Earth (bootstrapped).
The second greatest quantity of material needed would be that required for the substrate of the Solar cells. One substrate possibility is a very thin metal foil. The metal (Iron and Nickel) could also probably be obtained from Phobos. Support structures, energy converters, microwave transmitters, and other materials needed for the power satellites may be made from a mix of parts, some of which may be brought up from Earth, and some made in-situ, depending on complexity to make and lift mass trade-off. The quantity of silicon and the trace impurities needed for the outer coat of the large arrays of amorphous multilayer solar cells in the power satellites is far smaller than the quantity of water, substrate material, and structural materials, and could be obtained directly from Earth.
For the following example, a sufficiently large number of Solar power satellites is assumed to be made so that the initial cost of establishing a mining facility on Phobos, and the equipment development costs and factories in space costs are spread over a large number of power satellite systems. The substrates and solar cells would be fabricated at GEO. As in the direct lift example, the mass needed in GEO (not including factories or worker habitats) to produce delivered energy is assumed to be 3 kg/kW.
Costs from previous major space programs, but adjusted to the projected lower lift cost levels expected, were used to make a conservative estimate of costs for a large capacity facility that could be developed, built, and supported over 20 years at Phobos, with the required in-situ mining and shipping capacity. The factories needed to manufacture the cells in GEO would also have to be developed and lifted from Earth to GEO. The cost over a period of 20 years to develop and make the facility, and manufacture and maintain the power satellites is estimated to be $6/Watt. When ground base cost of $1/Watt, and development costs of $1/Watt are added, the total cost comes to $8/Watt. This would result in a cost of power of $.045/kW-hr, and retail $.09/kW-hr. It would be far more reasonable compared to a fully developed system lifted from Earth if this were possible. However, this approach is still associated with large initial technical uncertainty and very high up-front costs.
One or more missions to Phobos would first be needed to assure the practical availability of the water ice and also the availability of Iron and Nickel (as metal or magnetic oxide). A much smaller prototype power system would likely be made first to solve the technical problems and assure there are no unexpected surprises. If continual increased production of power capacity went on, the unit cost would come down even more, since most of the added mass would not be lifted from Earth, and the established bases and factories could be relatively cheaply expanded. These are actually the main reasons that in-situ sources of material are far better in the long run than lifting most of the material from Earth. If a significant fraction of the factories and support structure were made in space using the in-situ obtained material (rather than making them on Earth then lifted), the cost could be even lower, since the limiting main cost is lift from the Earth surface. A delivered power cost comparable to or possibly even lower than present low cost generation should be possible at large enough scale. It seems to me that this approach holds promise to eventually solve Earths energy problems at low cost, and with no pollution.
The conclusion I draw from the estimates is that even assuming lift costs to LEO are reduced to $3,000/kg in the near future, direct lift of material for power satellites would still be too expensive to be practical. Considering the high risk and large required up-front cost, this approach may not be too attractive. However if most of the material is obtained from the moons of Mars, the cost could conceivably come down to a much more acceptable level. The use of in-situ materials also would significantly lower the cost even more as the scale of production increased. The availability of water and raw materials on these moons has to be examined before any significant movement can be made in this direction, Manufacturing solar cells might actually be much easier in space due to the availability of vacuum for vapor deposition on low mass substrates. The largest masses needed for the cells are the substrates and support structures. The remaining large problems are mainly the need to develop in-space mining, large-scale transportation, and manufacturing facilities. The limited transfer times and long transfer distances from Mars to Earth are factors here, but I have developed a concept that may make it far less of a limitation (contact author for details). The appendix makes a case for the use of the moons of Mars as the source of materials and selects Phobos as the preferred source.
Appendix:
Abstract:
The two moons of Mars appear to be captured asteroids with composition similar to class C asteroids found mostly in the outer part of the belt between Mars and Jupiter. The measured average density is less than 2 g/cc for both moons. This seems to imply that there is either a loosely packed rubble pile core, or high void fraction (porosity), or that a high fraction of hydrates and water ice is present in a solid core. A very strong argument can be made that the rubble pile or high porosity core is not a probable configuration, although a loose rubble collection on the surface can occur. It is most likely that the interior of these moons is a solid core with about 50% water ice and hydrates (from the need to match the observed densities). The near surface ice would evaporate this near the Sun, and leave a thick layer of fine dry dust on the surface. Calculations indicate that the rate of vapor diffusion through an overlay of loose dust may limit the ice loss rate sufficiently to allow the core to retain a large fraction of water ice, even over billions of years.
Density of Phobos, Deimos and some asteroids:
Recent space probes orbiting Phobos and Deimos, which are thought (with a high probability) to be carbonaceous chondrite asteroids (class C), were able to determine their mass. Since their size is also known, their density was fairly accurately determined. Phobos which is 26 X 18 km has a density of 1.9 g/cc, and Deimos which is 16 X 10 km is 1.75 g/cc. Combining the measured size of some other asteroids-with recent measurements made either by examining the orbits of small satellites around the asteroid, or made by observing orbit perturbations, have fairly accurately determined the average density of these objects also. Generally, measurements made on carbonaceous chondrite asteroids have resulted in lower densities than expected. For example 253 Mathilde, which is 66 X 48 X 46 km has a density of 1.3 g/cc. 45 Eugenia, which is a class FC, 226 km in diameter, has a density of 1.2 g/cc. Even giant 1 Ceres, also a class C that is 960 X 932 km, and is the largest known asteroid, has a density of only 2.05 g/cc. The most accurate measurement for a Stony (class S) asteroid is for 433 Eros, which is 33 X 15 X 13 km, and which has a density of 2.65 g/cc. The expected density for stony asteroids seems to be close to the expected value for nearly solid stony objects (i.e., 2.5-3 g/cc).
Carbonaceous chondrite asteroids with low density may have a large fraction of water ice:
If the asteroids were formed far enough away from the Sun, it is likely that they would have formed with a large fraction of water ice, with small particles mixed in. If the ice rich objects then were perturbed to be closer to the Sun, but did not come in too close, evaporation would remove volatiles close to the surface, leaving a crust of nonvolatile materials such as dust (including carbon compounds), and possibly some captured rock and metal chunks. The fine powder in the surface crust would act as a vapor diffusion barrier. Calculations made for such objects at the distance of Mars, using a surface texture comparable to sand, indicates that even at a thickness of one km, the surface would prevent the ice from evaporating for several billion years. Finer grained dust would not even have to be that thick to hold the vapor. Assuming that the asteroids solid cores are mostly a solid frozen mixture of dust particles, ice, and hydrates, they would have to be near 50% H2O content to have the a density just below 2 g/cc, and much higher H2O fraction for even lower densities. The presence of water ice and hydrates, along with Iron, Nickel, Carbon, and Silicon would satisfy the material needs for the Solar Power Satellites, and propellant to transport it to GEO.
the Air Vent 
Space based solar is very interesting to me. It ties in nicely with my plans to go into the private space flight industry some day!
This is very interesting. Nice work.
I love this idea! However, rather than mine material at Mars – why not move the material (astroids from between Mars and Jupiter) to a Lagrange point inbetween Earth and the Moon – and set up your manufacturing there.
I would think this would ultimately be much easier to manage.
Sure this is Science Fiction today – but in 20 years we could probably do it.
A small force applied to an astroid over a long period of time will change its orbit.
They are looking at this right now to shift the orbit of astroids which we might find 15 or 20 years out – which could be on a collision course for Earth. The idea is to use the force of gravity itself to change the course of the astroid. Simply place a spaceship very close to the astroid (the heavier the better) – hold it in place and over time (years) – the gravitional force between the bodies will change the course of the astroid.
It would be even faster to find astroids with materials which could be made into fuels, strap some rockets onto the astroid – pointed away from Earth – and anchored to the astroid – then apply a small thrust over a large period of time.
Get the astroid falling toward Earth – and adjust course until you end up stationary at the Lagrange point.
We could pick astroids with all the proper materials to manufacture whatever we need.
Think of the jobs it would create!
Not only would this solve our engergy problems – but why not move all heavy manufacturing off Earth into space.
This would solve a lot of pollution problems.
Just dump all waste into the sun!
Anyway – good idea.
Thank you for giving some important details about energy for an essay.Overall this a good site especially telling about asteroids
Let’s see. I thought this was a good idea when I was in grade school after seeing Goldfinger. However, as I learned later, the reason we hadn’t already built microwave systems like this is “beam spread.” The beam attenuates as it travels through the atmosphere and the resulting area needed to collect the “power” is massive. Only certain desert locations would be suitable–and then only if environmentalists didn’t find it a risk to the Hairy-chested Nut Scratcher.
Then, of course there is the problem of heating the air column through which the beam passes–we have AGW hooey to attend to now. The loss, as heat, also means less power collected at the terminus.
Dr. Weinstein is far too pessimistic about nuclear power. Licensing doesn’t have to take a long time and nuclear power stations can be built inside four years. Also there is sufficient uranium to last hundreds of years, even for thermal reactors. Uranium exploration has been virtually non-existent for years, and the cost of electricity generation is very insensitive to uranium price. Breeder reactors would extend the period virtually indefinitely. See chapter 24 of the book “Sustainable Energy – without the hot air” by David MacKay, freely downloadable at http://www.withouthotair.com/ There are some fascinating facts in the book. For instance 32,000 tons/year of uranium are delivered to the sea by rivers every year.
Dr weinstein should know that thermal reactors, as well as fast breeders, also produce plutonium, which is not particularly dangerous; it just needs handling correctly, and is no more toxic than most metals (who is going to ingest or breathe it anyway?)
Modern reactors produce little waste. It just needs storing safely for a period of several hundred years, by which time it is no more radio-active than the uranium that was mined in the first place.
Water for cooling is no more a problem than for any other steam turbine plant. Large rivers, lakes or the sea are all suitable. After all there are large numbers of nuclear plants in Europe and the only problem so far has been in France in very hot summers when the river flows are reduced and there are maximum limits on allowed river water temperatures. Building them on the coast is no problem.
RickA:
I considered near earth asteroids and even ones further out and could find no candidate with the proper material structure or size that could be practically moved to a better location. If pre processing of the desired material is done before moving it, far less mass has to be moved. It is clear that moving an asteroid is not a good solution in the near future (but may become so as technology advances).
Cbullitt:
The problems of receiver area and air heating have been studied and the problems solved. Areas of 3 or so km diameter would do for GW level receivers, and the energy flux would not be a problem. These could be located in any area outside any city. It could even be located over water areas. The energy flux would be too high to live in continuously, but not too high to pass through (even for birds).
Phillip Bratby:
I also like the nuclear option, and agree it could be made to solve much of the problem, but the ideal start up time will never happen, so very long lead times are needed. Also, the public fear is real and can’t simply be discounted. It is mostly unjustified, but is reality. The thermal waste heat is a problem for all Earth based energy production, but not for space based power, so saying coal plants have the same problem points out that even the large supply of coal has a thermal waste problem even if it did not have other problems.
Hi RickA, Two flies in the Lagrangian ointment: the Lagrangian between the Earth and Moon is almost all the way to the Moon, and it is an unstable Lagrangian, meaning any facility built there would have to be powered and controlled to stop it rolling off the gravity hilltop. The two Lagrangians at 60deg fore and aft the Moon in its orbit are stable. They might be better choices.
Ugh! This is like something a 10 year old boy would dream up. You pat him on the head and say “That’s really cool” and encourage his budding interest in science. But when he grows up, he finds that there are always other considerations and this proposal is no exception.
From a technical standpoint, is such a system possible? I have little doubt it is. But in reality? Not a snowball’s chance in hell. Even if the cost of lifting fabricated materials to orbit was zero this proposed system could never be built and operated. The problems are almost too numerous to keep track of. Here are a few which quickly come to mind:
No Fly Zone: The moment you switched on the system you’d be cooking more birds than Colonel Sanders. Everything flying through the clear air above the receiver stations would be nicely toasted. Aircraft would have to steer well clear of the beam. Even if the people were safe in the aluminum shell the avionics probably wouldn’t be. Accidents still happen, though.
How much power loss would normal clouds cause? How about storm clouds and rain in the beam? How much beam scatter would there be after 22,300 miles and the depth of the atmosphere?
What about sabotage, terrorism or incompetence? What would a microwave beam with that much power do if someone ran it back and forth across a major city? How about a stadium hosting a World Cup or Superbowl game?
There’s already contention for the limited “parking spots” in the geosynchronous orbit over the most populous areas of the globe. Who decides what nations have the rights to orbital slots? Would North Korea or Iran get one? Who would control the beam targeting?
What would happen to every current satellite with a lower orbit? Do they get fried or does the beam get turned off for each predicted passage? In addition to manned missions there are hundreds of scientific and communications satellites. Iridium alone has about 90 in low earth orbit.
For national security reasons, anyone would have to limit how much of their economy relied on this power source. Russia’s anti-satellite program is well known. China’s space prowess is developing rapidly. North Korea might even manage a single shot. To kill one of these birds all you need to do is get a payload into an intersecting orbit, then disperse a cloud of projectiles, such as ball bearings, and let the relative velocity shred the target. For the ultimate billiards shot, one anti-sat device put into the geosync orbit with counter rotation could destroy every one of the power satellites around the globe along with any comm sats in the way.
When it comes to environmental considerations, you can do all the impact studies you want but only the real system in operation will reveal all its problems. Eventually. If using a window air conditioner at home can open a hole in the ozone layer over Antarctica, what kind of amazing problems could something on this scale cause? If, after five or ten years of operation, some unacceptable environmental problem is found, who will bear the cost of shutting down the system?
The only potential power source which could in fact fulfill the ‘feature list’ (and then some) would be nuclear fusion. Funding for fusion research has never been at a level which acknowledged that it truly is the only long term answer to the world’s energy needs.
MikeW:
Numerous studies were made by NASA on Solar power satellites and the only stopper was cost. My approach is the only way I can conceive that overcomes the cost limitation.
The energy flux would only be about 1/3 that of sunlight, and the fact that it is microwave is not the problem you think. The frequency of the microwave oven is deliberately selected to interact with water, and that is how it heats food. The beam would be a different wavelength. Birds would not be affected due to the low energy density. Microwave communication can have energy levels of that magnitude near transmitters. Planes and satellites would also not be damaged passing through. Fusion energy production has not even been solved (and has a waste energy problem). The only issues (after we assure the composition of the moons of Mars) are cost and willingness to make the effort. I agree it is unlikely the effort would be made, since a lot of people are short sighted and not able to think ahead (including our leaders). The terrorist problem is much larger for any nuclear fission or fusion on Earth than it would be for objects in GEO.
Thanks for your response Doc. You make some interesting points. As a lifelong fan of science fiction, I’ll admit that the space power system does have an appeal to me. Still, you have yet to budge me in the slightest from my belief that such a system could never be built in the real world.
I’ll easily concede that a different microwave frequency than that used in ovens would eliminate the majority of any risk to living things. It would certainly be optimal to choose a frequency which best penetrated the atmosphere with its significant water content. I was quite surprised though at your suggested flux level equivalent to only 1/3 of sunlight. This immediately begs a stupid question:
I assume that solar eclipse for the power transmitters in geosynchronous orbit is a non issue, amounting to no more than minutes per year at most. Thus, I’d expect near constant power transmission. In contrast, sunshine is only available for half as much time, with a lesser amount really available for conversion to power. Still, I would think that a good eight hours ought to be available on most days. Since those eight hours would be at three times the power lever of the microwave beam, the total receiver available power would be near equivalent on a per day basis.
Of course, there are always some niggling problems such as receiver conversion efficiency. Silicon solar cells run to about 22 percent efficiency although new zinc-manganese-tellurium ones have broken 40 percent. I have no idea what the microwave to electricity conversion efficiency would be for the chosen frequency. Obviously, the sunlight based system is burdened with the need to provide a power storage system to deal with nighttime and inclement weather. The space based microwave relay has the little matter of perhaps being the most complex, costly, difficult and risky engineering project in all of human history.
Don’t get me wrong, I believe that solar power is an invaluable niche application resource. But no more than that. Counting on solar, or wind for that matter, to supply any significant percent of a power grid’s capacity is criminally reckless and economic suicide.
Something you fail to address is the perversity of complex systems. Even if everything worked perfectly I don’t think you could build the system due to cost. We both know that wouldn’t be the case by a long shot, and as a NASA alum you should certainly be sensitive to this, uh, ‘feature’ of the universe. What was the mood in your group when Hubble’s flaw became known? If I recall correctly, Hubble was originally intended to be put in a far higher and more useful orbit, far beyond any repair mission. So things could have been much worse. Then there was the ill fated Mars Climate Observer followed by the equally ill fated Mars Polar Lander, both killed by likely simple errors.
Even when things stay on Earth they can be a mess. Witness the Airbus 380 design and fabrication management nightmare. The project was supposed to break even after delivering 270 aircraft. After the delays and cost overruns, that figure was increased to 420 units several years ago. The break even point is reported to continue to increase although they no longer will say what it is. By the way, total orders for the A380 stands at only 200.
I continue to believe that fusion power represents the best prospect for an ultimate solution to global energy requirements. What we need is a research pioneer to do to ITER what Craig Venter did to the Human Genome Project. If ITER works as hoped, they expect to have a viable system in 2050 with deployment over the following 30 years. Maybe they should hire a couple of more helpers. Sigh.
Andy Revkin over at NYT Dot Earth had a post on a similar oldie-but-not-goodie idea that was submitted as a white paper to ARPA-E by Marty Hoffert (author of an excellent overview article on energy sources in Science Compass back in 2001) and summarily rejected. And for good reasons. It proposes to use an optical (laser) beam to transport solar energy to the surface. Other than that, it is identical to the idea posted above. I posted a short, optimistic analysis of the laser-linked space-based solar array. It uses numbers from Hoffert’s proposal, which differ from the numbers above. The differences don’t matter much, because its hopeless.
1. Energy delivered to the grid- 1365 W/m^2 in orbit gives 33 kWh/m^2/day energy available. Panel efficiency of 20%, DC to laser light of 60%, thermal derate of 10%, light to DC of 40% at surface, DC to AC of 90%, thermal derate of 10%, gives total conversion efficiency for substation-ready power of 3.5%. This gives about 1.1 kWhr/m^2/day of electrical energy, where area refers to the orbiting solar panel. I didn’t include an 85% transmittance of the atmosphere in the Sahara or some other location that is cloudless 99% of the time.
A fixed panel mounted in Arizona will receive 6.5 kWhr/m^2/day averaged over the year, and almost 8 with a single-axis tracking mount. With 20% panel efficiency, DC to AC of 90%, thermal derate of 10%, a resulting efficiency of 16% gives an average daily output of about 1.05 kWhr/m^2/day for a fixed panel.
The efficiency improvement gained by mounting panels in space is thrown away in the transfer of that energy from orbit to Earth. Until this limitation can be solved, the space based solar approach cannot compete on a cost basis with surface-mounted solar. Compared with fossil fuel, hydro and nuclear its hopelessly overpriced.
2. Assembly time. To achieve a constant 1 TW delivered to the grid on Earth requires about 5.7 TW of solar panels in space. Using your 1.5 kW/kg for panels and support structures gives a total payload weight of 3.8 Tg. A Proton rocket has a payload capacity of 20,000 kg. Getting this material into orbit will require 190,000 launches. Assuming the system is complete before panels need replacing (30 years typical), that would require 6300 launches per year, or about 17 launches per day for 30 years.
3. Costs- The space based solar approach requires two solar panel farms, one to receive sunlight in space and the other to receive laser light projected to the Earth’s surface. The 40% efficient solar converter on Earth assumes use of non-Si technology for high efficiency. Pricing of >$10/W is not unreasonable. A DC-light converter is also required in space at current prices of $50/W, which may drop to $5/W in large quantities. Typical lifetime is 10,000 hours (1 year) unless significantly derated (at least a factor of three). The required 3 TW (beam power) optical transmitter will cost $15T – $45T. Solar panels rated for space use will likely cost at least $5/W(p). Generating 1 TW of output power will require 5.7 TW of panels for a cost of at least $28.5 T. The laser transmitter is a substantial portion of the system cost. A microwave generator will be cheaper, but the efficiency is about the same.
The total electrical energy produced over 30 years by a 1 TW delivery space solar system has a value (at 5 cents/kWhr) of 2.6 x 10^14 kWhr*0.05 = $13T. The total system cost including transport and installation needs to be well below this to make the investment worthwhile.
4. Heat dissipation- With constant exposure to 1365 W/m^2 and conversion efficiency of 20%, nearly 1100 W/m^2 of heat load will be placed on the panels, giving an average panel temperature of 314 K if the receiving surface is designed for high absorption in the visible and high emissivity in the infrared. This will impact panel efficiency and life. Cooling for the DC-to-light converter will be a daunting challenge. A 1 TW grid-delivery power system will need to radiate over 2 TW of heat to space.
5. Transport costs- If somehow space and terrestrial systems did cost the same for materials, and energy production is the same as shown in (1) above, then transport and installation costs will be a major decision-maker. Terrestrial transport costs on average $2/kg in the continental U.S. This is a lot less expensive than $10,000/kg for space-launched material. Transporting 3.8 Tg of material to space will cost $38T. Assuming this takes 30 years to complete gives an annual launch cost of $1.2 T. After 30 years, all the space panels need replacing, so launches will continue.
6. In-situ assembly costs- Unknown.
7. Maintenance costs- Unknown.
But in the end, the first issue, delivered energy from space solar compared with terrestrial solar, is the killer. If you can make cheap, reliable, efficient solar panels for space, you can generate solar electricity far more cheaply by mounting them in a sunny spot on terra firma, even though the sun sets every day.
Chris Y
You make many good points. However, they are generally not valid. It is true that ground based systems in desert areas would be more effective if the storage problem could be overcome. However, one main point of space based systems is that they can beam to almost anywhere on Earth, so the power transmission problem from generation location to use location (across thousands of miles?)is not there. The receivers can be near the city of use. Also they can transmit through almost all clouds and are continuous 24 hr/day 365 day/yr. In fact, the electrical to microwave to electrical energy conversion is very high (higher than you stated) with the beam transmission losses portion very low. However, the main point of my writeup is use of in-situ material from the moons of Mars to bring the cost way down. This would not be a short term effort, but a slow and sustained buildup of capability, with emphasis of developing the materials source capability at the moons of mars. I have much more detail on solving pieces of the problem, and have looked at every issue you stated. This project would be very expensive and take several decades to even start beaming power, but the long term effect would be low cost and environmentally clean power.
One last point: The main cause of temperature effect on life of Solar panels at the temperatures of interest is shock of change, not level (at least at 314K level). Cells that go day to night and on and off with clouds degrade. Continuous operation is much less a problem.
I was going to mention this – very true. Efficiency of an electrical antenna is quite high and not nearly as many conversions would be required. The tradeoff, of course, is that the longer wavelengths translate to larger apertures to acheive the same gain.
Keep in mind, I’m not endorsing this concept as feasible (I don’t know), I just don’t think a comparison to a laser-based system is a legitimate argument for discounting it.
Mark
Mark T:
You hit the nail on the head. It is not a laser based system. The receiver site is a large area with a large number of simple antenna’s. The requirements have been well studied, and the estimated cost is very low. The receiver area would be several km square per GW power (a typical large site for a city), but the ground under antennas (if they are held at a reasonable height) is still usable for many applications, including farming! The energy passing a reasonably efficient antenna array is only a small fraction of the input beam, and a simple wire mesh can block the rest. this entire problem has been studied and solved to death. The only stoppers are cost, and that is the emphasis of my point. The point was made that this would be complicated. It is and would cost trillions, but cost per kw-hr delivered could be brought below any other approach if a large enough system is made (at least hundreds of GW capacity), so a large investment is logical. The problem is who do you know that is logical any more?
I am. 🙂
Mark
“It is and would cost trillions, but cost per kw-hr delivered could be brought below any other approach if a large enough system is made (at least hundreds of GW capacity), so a large investment is logical. The problem is who do you know that is logical any more?”
Hmmmmm – my logic tells me it will be cheaper to waste less and that this can be done with smaller scale incremental investments using here and now technologies appropriate to the diverse environmental and economic conditions on the planet.
Curious said:
It would be much cheaper to waste less and do all of the right things. However that won’t happen in the real world. The present average amount of world wide energy used is several TW and rapidly increasing, and the (world wide) present cost for energy is several trillion dollars per year. My whole point is that eventually there will be a need for alternate energy (which may be several decades away, but it would take a long time to set up the capability, and you can’t wait for the problem to be here before you start), and space bases Solar is a possibility with many advantages. When you realize the size of the need, the problems of power transmission, the pollution or unintended side issues (as happened with dams for hydro), the problems with terrorists, etc, space based Solar looks more and more attractive if the cost can be brought to a reasonable level. Read my entire writeup and rethink your answer.
Lweinstein-
My estimates aren’t any less valid than your estimates.
You are right that a laser-based space solar system is different from a microwave-based space solar system. However, the big problems with space solar are the same for both approaches.
The latest research I’ve seen on power efficiency of TWT’s or Klystrons is in the range of 50% – 60%, but when energy transfer is calculated, the conversion efficiencies are closer to 45%, excluding ancillary equipment (power conditioning, cooling) energy draw. This is actually lower than the laser efficiency hoped for in Hoffert’s proposal.
The rectenna receiver array will certainly be far less expensive than an equal-power solar receiver array. It will also be much more efficient than a solar receiver array. I have seen reports of 80% – 85% efficiency for realistic rectenna designs. The difficult part is to figure out how to get most of the microwave beam generated in geosynchronous orbit onto the rectenna array.
Hoffert also comments on microwave energy transport- “…“Small” (power<a gigawatt) microwave SBSP is hopelessly inefficient. Diffraction physics is built into the laws of the universe and attempts to get around it cost-wise, for example, with “sparse arrays,” invariably generates inefficiencies like “grating lobes.”
Even with these optimistic improvements, the costs are still hopeless. Launch costs alone dwarf the revenues generated over the life of a space based solar system.
20 – With respect I think you should reread my comment and reevaluate your entire approach.
You are proposing a hugely ambitious technological fix in order to meet a problem which is to some extent a red herring. Perhaps take an analagy to household finances – would you think it is wise to pick up a high paying job in a city 150miles away and cram every waking second with activity in order to hold the job down just to finance a lifestyle at home that allows you to throw away 2/3rds of your weekly purchases? How about reducing your losses by half and working from home? Sorry not to have time to expand this properly but IMO lifestyle (in large part) is a question of the balance betweeen required intensity of energy use and production. Your “solution” is only looking at production on the premise that energy consumption has to continue to grow.
Chris Y:
Again you seem to not be reading my initial write up. The size of the receiver is several km, and pointing from GEO to hold that accuracy is not a problem. You also keep repeating the high launch cost. Read my write up. The whole point is to overcome that limitation by using in-situ material from the moons of Mars. As to efficiency, the microwave beaming seems to be heading to somewhat higher efficiencies than you quoted, but if the cost and mass per watt delivered for the sats is low enough, and the process doable, what is the issue? The critical points are kg/kw, cost per kg, and the ability for near continuous local delivery most locations.
Curious said:
You think fossil fuels will last indefinitely? You think energy consumption will not continue to grow? The only very long term alternative to Power sats is nuclear (fission or fusion), and I think it would be great if breeder reactors were used to solve the long term problem. Fusion seems to be a pipe dream (but things change, so it is not out of the question). Non breeder fission can last a good while, but even that is not really long term solution. Breeder reactors have some real and more perceived issues, so may be a hard sell. I am just presenting a real alternative with some different issues, but nuclear or space power sats are the only long term solution, and waiting for shortages would be far more disruptive than planning ahead.
I find these discussions, with out-of-the-box thinking, can be both a learning experience and thought provoking. Such proposals, however, do not mean much in the way of real world application without more details and specifics, and, more importantly, to do the same for the existing technologies. It is a little too easy to hand wave off current technology by pointing to the limitations and problems that exist in order to change the subject to latest and greatest new ideas that are almost always presented without a full review of their limitations and problems.
One of my major concerns with such proposals is that they have apparently not evolved in the free market place of ideas, and, as such, that there is always the temptation and impatience to push them with government subsidies and force. In fact, the more the approach requires direct or even indirect government actions the more chance, in my view, that we will get the application wrong.
Space based solar, I would think would have to viewed in context of past government run space programs and the rate of progress made there. Our US space program was instigated by military use and a space race with the old USSR, none of which had profit motivations. The history of the space shuttle has included a couple of disasters and not really much quantifiable progress.
“Curious said:
You think fossil fuels will last indefinitely? You think energy consumption will not continue to grow?”
I think this is just a typo – but I didn’t say either.
Fossil fuel: There are many people who think that we are around global peak oil production now. Many of their arguments appear to be soundly based and I tend to agree with them. However there has to be recognition of the role national resource and economics plays – I think this is a big problem with your scheme. Who is going to finance it and to whose benefit? I’m based in the UK where our continental shelf production has definitely peaked for oil and gas. Last winter Russia flexed their gas supply muscles over a spat with the Ukraine bringing fossil fuel shortage into sharp focus. Check out theoildrum and many other peak oil sources for detailed commentary. So, no, I definitely do not see fossil fuels lasting indefinitely. I do however see reserves (in years) being dependent on consumption rates – putting aside the economic and political stuff half consumption rate = double reserve life, no?
Energy consumption: IMO our developed world economies are founded on the flow of energy. Hence the mentality is to maintain/increase energy consumption to provide economic growth. On this basis could one argue that we should waste as much as possible in order to create economic activity and indeed this is part of the economic system we have “evolved”. But it does not need to be this way – why does an approx. gross waste of 2/3 of the energy liberated in electricity production and distribution benefit anybody? Energy consumption can be reduced tomorrow simply by turning some switches off and over a 20year programme driven by some motivated scientists, engineers and business people I think our energy consumption could be dramatically reduced. And at much lower capital cost and project risk than the type of approach you are advocating. And with a much faster return.
Lweinstein- you say “Again you seem to not be reading my initial write up. The size of the receiver is several km, and pointing from GEO to hold that accuracy is not a problem.”
Yes, I read your write-up. I never brought up the pointing issue. There are issues of lobe patterns and losses caused thereby. The lifetime of the space-based panels is a serious one, not only because of thermal stress, but also because of radiation. Space-qualified solar panels typically have lifetimes of 10 years, far less than the 25 year warranties provided by reputable solar panel manufacturers used in terrestrial installations. The 30 year life that I assumed for panels in orbit was being very generous.
“You also keep repeating the high launch cost. Read my write up. The whole point is to overcome that limitation by using in-situ material from the moons of Mars.”
I was under the impression that you were exploring the realistic engineering (which always includes costs) possibility of space based solar sometime in the next 20 or 30 years. Advocating for Martian moon mineral mining for raw materials is as sci-fi as Mr. Fusion and puts your proposal out beyond 2100, with unknowable costs.
I’d prefer to spend today’s precious R&D money on lowering the costs of terrestrial solar systems so that subsidies, rebates and tax credits are not needed to make them cost-effective compared with the energy provided by the gargantuan amounts of naturally-occurring fossil and nuclear fuels that we currently enjoy.
As you say, the whole point is to overcome the current hilariously high costs of space-based solar. I’d wager some serious money that terrestrial-based solar and storage will essentially eliminate the need for space-based solar long before space-based solar is cost-effective.
Heck, even Reverend Gore’s proposal to build solar and wind farms in the southwest US and then install hundreds of thousands of miles of underground superconducting transmission cables crisscrossing the country to move that energy to load centers is more cost-effective than space-based solar.
Kenneth Fritsch:
I do not ignore present capabilities and alternatives, I just put another possibility in the list-one with potentially very desirable features. The concept of Solar power Sats has been very well studied and is well represented in scientific literature, but that is not to say there would not be surprises, since it has not been done. Presently our military is considering doing it, and the state of California is considering paying a company to put a trial system in orbit. These would both have unacceptable per kw-hr cost, but are proof of concept systems. I do not say the government has to do it, but the initial investment needed is too large for a private company, so it appears they would have to be involved (unless a group of energy companies gets together to do it). The present problem is large initial investment and later high cost per kw-hr. However, this is due to cost to lift payloads from Earth. If you read my writeup, you see my concept is to minimize lift payload cost, and use a far lower cost delivery of material. Yes it would take a lot of innovative development, but why assume that is not possible? There are a lot of very bright people. I have a lot of additional material on the problems and solution on how to do this. I could enclose info if you desire, but won’t waste my time for generally negative responses. I actually think my method could be done relatively cheap, but that approach would take a long time to put in place. The higher cost would be to speed the process and scale up. Your comments on government development of space is partly correct, but if you look at space science, weather sats, GPS, telecoms, etc., space has paid off big. Generally the technology advances made to do missions, not the missions like shuttle, pay for themselves many time over the total program costs.
Curious said:
I would never disagree that if people were logical, reasonable, and nice that we could cut waste, etc in the 1st world countries. Be real, if people ate less and walked more, health care would cut in half. If we rode bicycles to work and didn’t waste energy otherwise we could cut more than half of energy use. You think either is going to happen because you know it would help? Even if we did these things, the 2nd and 3rd world rising living standard and increasing world population would still cause the increasing need. We still would eventually need alternate energy under the best of conditions. That is a fact.
Chris Y:
You make statements as if you know the answer. It turns out that amorphous type panels (less efficient) are not rapidly degraded in space. 30 year lifetime should be possible. The low efficiency (10% or so) for that type is not an issue if the kg per kw is still low. There are cells already developed that mass about 1 kg per kw of that type. It is the high efficiency cells that degrade faster. I have spent a considerable amount of time looking at the in-situ material issue, and think it is quite doable. The only issues not resolved at all at the present are the detailed material composition on the moons of Mars, and I think it reasonably likely that I know what that is. It would take a lot of detailed development of equipment to do the tasks, but none of it is beyond present technology. The task would be LESS in many ways than making a manned base on our moon. Most of the work in GEO would be tele-operated robotic, and some of the tasks at the moons of Mars also robotic, but with manned presence. I have developed a way that people on the moons of Mars would have simulated gravity, and be shielded from radiation and space debris. I also developed a way to ship material on a daily basis (but with a given load taking years to make the trip). The time scale if we started now and committed 1 trillion dollars total would be about 20 to 30 years to first power, but this is not too different than the proposed manned mission to the surface of Mars. In fact, it would be easier is some ways, and only so costly due to the large scale of activity building the power sats in GEO. The level of output for that level of cost would be several hundred GW. Expanding to several TW would just take a small increase in cost and a lot longer, or a large increase in cost in a fairly short time.
chris y said
September 5, 2009 at 1:48 pm
Are you sure you understand antenna theory? Just asking…
Focusing from geostationary (or maybe just geosynchronous) orbit to a point only several km wide on the ground will present a challenge for just about any wavelength that can penetrate the atmosphere, but that’s a different issue.
Mark
27 – You are arguing that you have “The Solution to Future Energy Needs and Global Pollution”. Do you think this will “just happen because you know it would help?” Or do you think it would take R and D plus policy and investment decisions etc etc?
My point is that your proposal is a poor performer in terms of deliverability, cost and return compared to alternative approaches using real, tangible and current technologies and solutions.
Dr L, since you may have an interest in selling an idea that would require government initiatives, by your own reckoning, I would ask whether you have any profit and loss figures on some of these space missions. How many have been fully funded by private enterprises? And how many pay reasonable use fees to cover the government expenses of providing the service?
Mark T-
Since its most likely going to be a phased-array transmitter (whether microwaves or infrared), there are going to be lots of lobes in the far field down on Earth. They are small but non-zero. With space-based solar, every photon is precious.
Are you suggesting the far-field distribution will be free of side-lobes?
Lweinstein-
Think of what could be accomplished if $1T was put into terrestrial solar. Or new fission power plants. Or $1T into improved insulation/energy efficiency of existing structures. Lets do that and then re-assess space solar in 10 or 20 years.
Sure sidelobes exist, but they do not constitute any legitimate loss.
Mark
Curious said (30):
It would take all of the items you stated. It would be a new start, and have some uncertainty. Since when do we stop doing new things? I think a small start to find problems and solve them would proceed a big investment, so no big loss if it turns out bad. It is just an alternative. I do think breeder fission is probably a more straight forward choice. Ground based solar and wind are limited unless 1)cheap room temperature superconductors become available, and 2) a super cheap energy storage method becomes available. I think space power sats are more likely than 1 & 2.The question of acceptance of breeder reactors is less certain. No other choices are long enough range for permanent solution. It is also amazing to me that you know it is a poor choice compared to, well give me the list of alternates?
Kenneth Fritsch (31):
First I am not trying to sell anything. I am compelled to try to solve problems. I have many other ideas just made because I saw a problem. Most are probably not going anywhere. That is just who I am. I would prefer if government stayed out of most activities, but that is not always practical in the beginning of new technology. I think you need to look at the current group of commercial space activity (commercial flights to space, plans for hotels in space, commercial launch, commercial sats, etc.). Once the military and government paid the cost to develop airplanes. Airmail was the initial killer ap that pushed technology forward. Now individuals fly cheap private aircraft, and commercial flies people in large scale. There is always a costly and inefficient start in new technology, and some efforts needed government to start the process, but as problems are solved technology becomes cheaper and better(example-electronics). What I suggest is not a PROJECT with a short life and one off, it is a start on a path. Initial cost and success will look bad, but unless a surprise stops the effort, it could get to the useful point.
Chris Y (32):
Do you mean a $T like the amount just pushed down a rabbit hole by our government. No amount of money would make current ground based efforts for energy independence cheap and good except nuclear (and electric cars), which I do suggest as an alternative to my idea. I just give another alternative, which I think could do even better, but is less certain. As to insulation, and other efficiency ideas, the problem is not mainly the US power wasted, it is growing needs for the rest of the world, which will impact us in the end no matter how we conserve, unless we become energy independent. Also every photon is not precious. We just need to receive the required amount, and some losses are going to happen.
Dr L, I appreciate the time and effort you have taken to respond to all the comments and questions. You appear well acquainted with the technology of collecting solar energy and transporting it. I will make efforts in the future to get up to speed on this subject.
Just to make clear my purpose for commenting on the space programs record in transporting materials is that, as you have said, a major part of your idea’s success depends on development of an economical system of transporting heavy payloads or many lighter ones into space. I would think in the logical evolution of these things space transport will progress based on other areas of need and uses that can be profitable enterprises, i.e. discovering more efficient means of transporting material into space will not be developed primarily to implement your idea.
Without a handoff to profit making enterprises I do not see rapid developments being made in the space programs vis a vis payload transport. Governments do rather serendipitously come up with concepts that are later fully exploited by profit seeking businesses, but the longer the government retains control over these enterprises the slower they develop – if they develop at all.
Your idea at this point additionally faces the severe handicap of needing 30 years to start paying off and starting with huge initial expenditures. That is a very long time for a government to look ahead – think about the impending problems with SS and Medicare and the lack of attention and funding that receives and also think about the heavy debt loads that have been recently incurred by our government in the name of warding off an immediate (so they say) and impending crisis. I think a trillion dollars expended today with a 7% rate of return has a 30 year future value of 8 trillion dollars. Of course if you could make the case that the alternative was that the government was going to collect that much money, i.e. remove it from the pool for investment in profitable enterprises and waste it anyway, i.e. have a negative rate of return, you might be onto something. You would just need to convince some politicians that they are now wasting an awful lot of taxpayers’ money.
34 – very quick reply.
For example –
re: ground based pv – invetigate solar Solyndra. Nice product, here and now, solves some issues with PV esp. mounting, european contract signed, using a $0.5bn loan gtee.
re: ground based solar thermal – investigate cost benefit for domestic and industrial use.
re: transport – compare US car fleet avg. consumption to european. compare cost benefit performance of walking and cycling in urban areas to infrastructure related projects. investigate and understand travel behaviour.
re: efficiency – investigate combined heat and power and trigen vs. simple thermal plants, investigate efficiency gains and paybacks available from overhaul of hydro schemes, investigate cost benenfit case of improved thermal insulation, investigate benefits of intelligent energy management systems, investigate closed loop product cycles.
re: policy – investigate (limited) european success with land use planning and transport policy to reduce fossil fuel based travel needs.
re: finance – Kenneth has pretty much covered it. In the UK all we have in the bank is debt yet our politicians are keenly promoting a hugely costly high speed rail plan to link north and south. Ok it would be nice to have etc. but what we need are many unglamourous incremental improvements around the country improving capacity and service levels. The big projects are always easy to push on the “progress” agenda when infact they can be the opposite.
etc etc etc
Curious said (36):
It so happens that I have developed a ground based solar thermal energy production approach (heat, not electrical). It is only practical where reasonable Solar intensity is available. My approach for that would be small individual systems for single homes, or small groups. However that is not a solution for electrical generation. I also have a patent for a Solar water still able to make homes nearly independent of separate water supplies. I am in the process of developing that idea. Efficiency, and other approaches are all good. However, the world will eventually need a large scale electrical power generation source and not a long time away. The problem will start to occur in our life times or our childrens. The only solutions in sight are nuclear or Solar power sats, and if we wait for the problems to be on us before we start doing something, there will be a large gap of BAD times. The immediate need for starting to address the energy problem is more urgent than seems to be understood.
Immediacy is one of the major problems with your “Solution to Future Energy Needs and Global Pollution”. But let’s agree to disagree? – good luck with your proposal. C
Curious said:
I think you are reading more into my comment on immediacy than I said. I said the need to starting to address the problem, not the need to jump in and do the construction. It takes a long time to study choices, make decisions and develop technology.
Not when there are proven and available solutions:
http://www.worldwatch.org/node/6225
Click to access securingpower0708.pdf
Directing policy and investment towards these type of projects will have a much faster and more tangible return than feasibility studies of mining on Mars.
Curious said:
CHP is not new and is already being used widely. I never said to not get the most out of what we have, only look down the road a bit more when that runs out of steam. Eventually we have to get away from sequestered energy sources (oil, coal, gas). You seem to have an either or mentality. All approaches have to be examined.
“CHP is not new and is already being used widely.”
From the first link in 40:
*****
All told, U.S. waste-energy recycling is contributing about 10,000 megawatts of electric power to the national total each year, according to the latest available data. Yet, according to a recent study for the U.S. Environmental Protection Agency, more than 10 times that amount could be generated in 19 different U.S. industries just by recycling wasted heat. Most of it would be electricity replacing electric power currently purchased from coal- or natural gas-burning utilities. To put that potential in a broader perspective, we should note that waste-energy recycling of the kind we have been describing is a form of combined heat and power (CHP), which includes the even larger potential to be achieved by exploiting the waste heat emitted by electric power plants (see page 37). The heat from power plants can’t be used to generate electricity because it is too low in temperature, but if the generation is moved to local production in the places where low-temperature heat could be used for heating homes and buildings, the largest single drain on U.S. primary energy could be largely eliminated. Data for CHP don’t always separate out local-production CHP from high-temperature waste-stream recycling, but it is noteworthy that while the United States uses relatively little of either, both forms are now widely used in some other countries. One reason Arcelor Mittal was receptive to energy recycling in Indiana was that this technology is now widely used in northern Europe and Japan, where Mittal has other operations. Denmark now generates over 50 percent of its electricity by waste-energy recycling or CHP; Finland gets 40 percent, and Russia gets over 30 percent. U.S. industries have barely scratched the surface. The 14 steel plants recycling waste heat or flare gas, for example, constitute only 2 percent of the plants in the U.S. steel industry.
*****
“You seem to have an either or mentality”
Not at all – I just think your suggested approach is completely misguided. The UK situation as reported by Poyry is that industrial CHP could contribute the equivalent of approx 8 nuclear plants. We already have industrial scale implementation of the technology. Despite this at one of the prime candidate sites we will be building a 2GW CCGT plant using imported NG. IMO if we put our energies into realising these type of opportunities, rather than creating antigravity so we can mine the moons of other planets, we’d all benefit from a dramatically improved energy supply system whilst we make a transition to the post fossil era.
Please read the links in full, do some research and reconsider your position re: “The Solution to Future Energy Needs and Global Pollution”.
Or agree to differ?
Here is another article on Space Solar power. The point of that one is it is doable, but present plans are probably too expensive. My approach addresses that issue.
http://e360.yale.edu/content/feature.msp?id=2184
Dr Lweinstein’s article appears to merge to separate ideas into one. Whilst Solar Power Satellites of the type he outlines may be feasable, building them from distant moons is currently fanciful and will likely remain so for the next few centuries.
Clearly, Solar Power Satellites would be best built on earth and lifted into orbit. Dr Lweinstein limits his thinking to the current, self imposed, boundaries on ‘lifting’ technology. I remember reading about the development – back in the 1950’s – of launching nuclear-powered space craft. I remember reading this method of propulsion could lift a vehicle the size and weight of an ocean liner into space through a series of controlled atomic explosions during accent.
If this technology were developed and a launch pad built far away from any human habitation (on an island in the middle of the pacific ocean, for example), it might provide a far more realistic and achievable method of getting the necessary heavy ironware up into space… with a minimised impact if things go wrong. Such lifts could be unmanned and the lighter, more expensive, components taken up by more conventionally fuelled lifting vehicles. If we have the technology within our grasp, why not seek to use it?
“If we have the technology within our grasp, why not seek to use it?”
Ladders and roofs come to mind
Peter S:
Since you do not know the economics of using “distant moons”, and are going by your gut feelings that it seems too fanciful, you come to a conclusion that I could clearly refute. The Orion nuclear put-put lifter would still be incapable of lifting the required mass at a level and cost even if it were available. The mass needed in GEO for 1 TW power, using my numbers, would be several million tons. The ability to move that level of mass from the moons comes from the fact that the gravity well from those moons to GEO is small and the needed material is probably there. I did state that missions to verify the presence of the required materials is needed before commiting to that plan.
An interesting posting, but I think you are being too pessimistic about the other sources of energy that we already have available. There are a lot of presently working and profitable or nearly profitable sources of energy without resorting to new gadgets on orbit.
http://chiefio.wordpress.com/2009/03/20/there-is-no-energy-shortage/
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