the talk today will be in essentially three parts the first is just generic assessment of energy sources and how you might go about that we’ll discuss where our energy comes from today which you may already have some idea about we’ll have a quick rundown of some of the proposed alternate alternate energy sources that you may have heard of and also take a look at some of the barriers that any new energy source might encounter as we might or might not have tried to implement it solar energy from space if you haven’t heard of it before I’m gonna describe what it is how it works what the barriers to its adoption might be how it compares with other energy sources also during the course of the talk if you have any questions please just stick your hand up there and I encourage us to be interactive in this discussion finally we’ll conclude and we’ll say come up with an assessment as to whether solar energy from space is a source of energy that deserves further investigation so where does our energy come from today it’s probably no surprised that most of our energy comes from non-renewable sources fossil fuels if you look at the top row here the the four there make up the vast majority of the energy we consume this plot shows you from 1971 through 2011 what the production of various energy sources has been this comes from the International Energy Agency a report they do annually this one is from last year if you want to look at this in a slightly different way you can see it broken out from the whole and about 85 percent of the energy is non-renewable you can see natural gas coal and oil represent a huge portion nuclear even though it’s been around for many decades still about 5% and this is for the entire world biofuels and waste is about 10% and then the others are are almost negligible I’ll I’ll go in a moment into a broader breakdown of that tiny portion a couple considerations so as we mentioned about 85% of our current energy supply is drawn from exhaustible sources whether you think they’re going to run out in ten years or 100 years or 200 years the fact is there’s a finite supply it is gonna run out one way to represent this is what’s been called the matchstick plot and this image comes from another blog that you owe it to yourself to check out the do the math blog which is written by Tom Murphy a professor at the University of California San Diego and he points out that it’s only been the last few hundred years and he’s not the only one to observe this graphic as his but the idea has been around for some time prior to the usage and leveraging of fossil fuels pretty much people burned wood and they used muscle power to get things done to plow the fields and build the pyramids and what have you we have what you might think of as a single matchstick in the form of all these fossil fuels that we’re using now once they’re gone they’re not going to come back for a long time so it took many thousands hundreds of thousands millions of years for them to form and they are certainly not going to be regenerated as quickly as we consume them so we have to come up with something once they’re out left we are in a situation where we certainly would have to change our lifestyles consume a lot less energy and there’s actually a whole parallel discussion one thing that we’ve enjoyed in the last hundred couple hundred years is this linear increase in the consumption of energy and it has created a mentality that growth doesn’t really have a limit it can just kind of continue linearly forever and of course that’s not true either because once again we’re starting from finite resources kind of a whole different discussion but certainly something worth realizing and then if you have read Phil’s blog and I think he even posted something about this just in the last week or so climate change is a concern for a lot of us despite some columnist writings recently calling this into question whether it’s settled science or not consensus is that climate change is real that has have anthropogenic origins and we it would behoove us to do something about it all right so let’s break down that tiny little sliver of the renewable and clean energy a little bit more so this is about 15% of the total and this is a little bit different this is the consumption rather than the production side but for our discussion they’re essentially equivalent the huge brown wedge you see the biomass and heat the majority of that is people

using their wood-burning stoves for heat and cooking so that is that is not high-tech you can see that the proportions of everything else is diminishing Li small you’ve probably heard a lot and seen a lot about photovoltaics perhaps even on your way here today maybe even at your house do you have photovoltaics but you can see they represent a very minuscule amount of our existing energy sources today so it’s a little sobering to look at this when you think of what portion of energy we consume is use it once and then it’s gone I guess another interesting thing to think about is these conventional sources the oil natural gas and coal are really solar energy that’s just been stored for us over time so the the Sun of course is the the closest thing in our solar system we have to a infinite source of energy and it’s not actually infinite so what are some other possible future energy sources people have been doing research and artificial photosynthesis for quite some time with kind of varying results breeder reactors are a form of nuclear energy that help dispense with proliferation issues and radioactive waste storage issues they’re certainly being investigated they do use fuel which is also finite fusion energy we’ve been doing fusion research for coming up on over 60 years I think methane hydrates are found on the seafloor there another carbon-based source of energy also finite also would contribute to greenhouse gases and climate change solar energy from space which also is gone by the name of space solar power solar power satellites power set space basically power it has a lot of different names but the concept is the same and then there’s there’s others that I’m not mentioning here but these are some of the major classes so we might say askable well how do we compare these and I’m gonna go back to my friend Tom Murphy’s blog he posts on his blog is largely about energy issues and he has come up with his own subjective rating scale and created this alternative energy matrix to take a stab at comparing these and one thing you probably know if you’ve read his blog or you should know and looking at this is he has a penchant towards solar energy which is perhaps one of the reasons that it comes out on top although he fully discloses that and he he recognizes that the way he created this matrix is he took ten criteria abundance difficulty intermittency demonstrated electricity heat transport acceptance backyard and efficiency and applied a subjective rating one of three subjective ratings or in the case of deuterium deuterium fusion one of four subjective ratings to try to come up with a quantitative assessment so if it gets a green box that’s a positive score and you get +1 point if it’s the yellow box it’s kind of middle and you get zero points if you get a red box it’s minus one and sum up all the boxes and you come up with this relative score so one thing that you may find interesting is a conventional fishing which even though it only amounts to 5% of the world’s energy he’s scoring only at a two versus the Solar ones which score much higher so again a lot of limitations here this is subjective but it helps you think a little bit about what are the considerations that we want to have in mind when we’re examining these alternative energy sources now you say well Oh question certainly abundance which just means if you use that how much can you use before you run out so if you look at the like tidal energy there’s only a couple places you could implement that so that’s not especially abundant if you’re in the Rocky Mountains it’s not going to be your best source of energy similarly for like geothermal if you’re not near a geothermal then the difficulty is how much effort you have to put into actually getting the energy intermittency which is actually pretty important consideration because currently there is no means of grid scale energy storage and this is a huge issue because with the increase in the alternative the wind and solar if the sun’s not shining you don’t if it’s nighttime you don’t have solar if it’s not windy you don’t have wind and if you don’t have a good way to store the energy that means you’re back to your 85 percent your fossil fuels so so the intermittency is pretty pretty important factor demonstrated pretty self-explanatory electricity whether it’s a source that is suitable for generating electricity heat whether you would use it for heating transport whether it could be used in a liquid fuel for transportation acceptance whether the public would say I don’t know if I’m really into having that next to my my house backyard if you could do it on a small scale so you can put solar panels on your house you’re not going to put a fishing reactor in your house

hopefully and then the efficiency which actually turns and in my mind is something that while interesting doesn’t really tell that much of the story so you’ll notice and actually I think I’ve discussed this in charter too that he doesn’t really have anything that directly relates to an economic consideration here and later I’m going to show you some information from the the US Energy Information Agency that does have that to to apply kind of that consideration so the top one you probably saw he has a solar photovoltaics PV is just photovoltaics that’s your solar panel you’re probably familiar with he has that on a scale of a five if you look at the conventional sources oil natural gas and coal they of course do very well which is one of the reasons they comprise eighty five percent of our current and consumption so what I did and and this is this is my assessment not Tom Murphy’s I said I so if I use his criteria and the same scale and I apply that to solar power satellites solar energy from space well with the score B and I think it’s probably also a one or two it’s probably in the same neighborhood as your fusion and you’re kind of non demonstrated more futuristic energy sources and obviously in space you can have all the sunlight you want the difficulty of it would be that accessing to space I’m going to go into more depth on this later one of the biggest selling points is unlike ground solar it’s not intermittent there has been some research and development on it it’s great for electricity the heat and transport you could do if you use the electricity the acceptance the whenever I talk about solar power satellites the first thing people invariably ask is well isn’t gonna isn’t it gonna fry birds and it turns out that there’s there’s a couple answers to that question but really probably not and then you would have to do it on a scale where it’s not suitable for doing in your backyard and the efficiency is comparable to to ground solar other factors that Tom or anybody else might use in comparing alternative sources of energy is weighting these factors differently so in the matrix I showed you all of the considerations were weighted the same not necessarily appropriate dispatched ability is the ability to get that energy to a place that you want when you want it usually you have a power plant that’s sitting there and if you need the power you better be hooked up to the grid that the power plants hooked up to or somewhere where you can use it it’s hard you you wouldn’t take your nuclear plant and move it from Iowa to Maine for some reason probably for the futuristic ones when you develop them much like the space program of the 1960s we got a lot of technological dividends where while you’re trying to solve the challenging problem of going to the moon we developed a lot of technology that then found a home elsewhere and improved our lives in other ways that we might not have expected so certainly some of these are better suited to that’s than others and then a huge one is the economic attractiveness and there’s many many factors under this I’m just gonna hit the two of the big ones the payback period how long does it take for you to make back all the money that you spent to develop the system the operating expenses you have to buy fuel for every day or in the case of the solar panel or you’re just getting the sunlight for free return on investment so there’s there’s a lot of factors in there that is probably also a presentation unto itself so let’s talk about question yeah definitely true I suppose that could fall under difficulty but certainly that that is its own consideration like do you need to have and I guess maybe a little bit of the backyard too because like with the solar panels you can buy at Home Depot and stick in your backyard no infrastructure requirement the fish and reactor fish and reactor you obviously need the grid to get it to your house so so that is a big consideration that also ties into the expense as well so yes sir certainly we’re something to consider so for any new energy source I’ve boiled it down to three potential barriers and this is by no means all comprehensive but I think it’s a good place to start particularly in examining these things from a skeptical point of view so the first one is physical is the proposed energy source consistent with the laws of physics if it’s not you should be very skeptical technology does the technology to actually implement this source of energy exists or are you looking at a huge campaign to develop new technology and then finally back on the economics if it’s wonderful but it’s going to be extraordinarily expensive there has to be someone who’s willing to pay for it is probably not ever gonna get off the

ground let’s go into a little bit more depth on each of these three barriers so you’re probably familiar with the laws of thermodynamics first law thermodynamics involves the principle of conservation of energy you cannot create or destroy the energy this has often been succinctly summed up as you can’t win you’re not going to get more out than you put in second law thermodynamics put succinctly you can’t break even if you do any kind of conversion you’re gonna lose energy you can’t have any any conversion that is a hundred percent efficient so good good way to think of it you can’t win you can’t break you in couple sources that fail the physics test you may be familiar with some of these any perpetual motion machines or overunity devices we you know and of course if you have a working prototype it’s a different story but nobody has a working prototype so these guys have been around for a long time and they have various injunctions their own and judgments from the government organized government government organizations against them but they they persist and they are they don’t own any power companies ColdFusion some of you may remember 1989 the Utah State ColdFusion flap and there is still a community and now it’s called low energy nuclear reactions and it it persists it’s another case where whatever I find one of these folks not talking to say all right so when are we gonna hear about the Revenge of ColdFusion and we have yet to see it so it’s always a month or a year away and then there’s zero point energy which is a real quantum mechanical phenomenon but the ability for us to get usable energy out of it is dubious at best so some sources that fail the physics test does the technology exist as you might imagine there are a lot of organizations whose very livelihoods in existence depend on technology and they’ve come up with a rating scale for this so the simplest question is has anything been done previously now I know Scott knows working with NASA there is something called the technology readiness level of being of the existence of many engineers and there’s a lot of different versions of it but they’re all essentially trying to convey the same thing which is how ready is the technology for prime time like how much it’s really how much is gonna cost if I’m gonna spend a million bucks but the TRL is only three I shouldn’t expect to have a satellite in space at the end of the project so taking it from the bottom the level one would be this basic technology research the it doesn’t break the laws of physics but there’s been no technology development whatsoever next level next series of levels up would be proving that it’s feasible developing that technology doing some sort of demonstration with it then developing the systems and subsystems that would go into that operational system and in the case of a space context you’re launching it and operating in space so DoD uses this a lot of organizations use this if you can assign a technology readiness level to something you have a better idea of how far along it is and of course this is also something that’s very subjective and people argue about a lot of weird scalability come something might work on a small scale simply not scale properly where would that leave them yeah that’s a really good point and that is something where some things will not work at all in a small scale but they’ll work great on a large scale or vice versa so that’s that’s an excellent point I’d mention that here but certainly and that actually is a factor for solar power satellites as well economically feasible is it competitive with existing energy prices pretty key question or if it is not competitive with existing energy prices does it offer some sort of compelling advantage that we’re going to talk a little bit about what that compelling advantage might be so let’s start probably most of you paid an electric bill in the last month does anybody know how much you’re paying in cents per kilowatt hour anybody just pay it online you don’t even look at it 10 cents 10 cents ish and yet any other that’s pretty good so it’s I guess so probably some of you have Pepco and some of you have Dominion so I know I’m paying about 10 cents a kilowatt or maybe it’s like nine and a half or something like that but yeah but $0.10 kilowatt hour pretty pretty close for for estimate so the this these figures except for the bottom row here are again from the International Energy International Energy Agency the average for us read dense residential the cost this is not the cost to generate but the cost that you pay is about 12 cents a kilowatt hour so so in that range if you’re in industry and you’re buying hundreds of thousands of kilowatt hours a month you get a break average there is six and a half I’m six point seven you probably know

that in the United States we pay a lot less for energy than other countries all around the world I’ve just taken a couple different examples Denmark they pay close to 40 cents a kilowatt hour Japan a country that has very limited natural resources pays close to 30 cents an hour and then there is a special case that you may not have thought that much about and that is remote US military out outpost fortunately at this point we’re almost done with our our various wars but while in Afghanistan I would speak to some of my friends who are deployed and it works again energy to them sometimes it’s not just the fuel convoy that you has to avoid the roadside bombs and the insurgent attacks but it goes to the main Ford Operating Base and then to get to the combat outpost maybe it takes a helicopter trip or a chain of helicopter trips and by the time you get that fuel to where it’s actually going to be used they generator to power the communications equipment you’ve spent a tremendous amount of money not to mention the lives that you’ve risked and the equipment that you’ve risked and there have unsurprisingly been a lot of government and DoD reports on this and their report is that they’re spending close to in some cases $10 a kilowatt hour which sounds insane to us but that’s just what it costs because it’s very difficult to get energy to some places and there are other countries like you could imagine like a remote island would also be a very difficult place to get energy to so so there are some cases where people are paying a tremendous amount of energy much more than we would pay on our pepco or dominion Virginia bill okay so probably in the last week no question yeah you had the Residential’s for the for other countries do you know what the Industrial it’s in the same table I didn’t put them here in general the Industrial is cheaper there are a few countries where Industrial is actually more expensive and I guess that’s based on kind of the tax structure but but in general the Industrial tends to be about 60 to 70% of the residential okay and the reason I ask is mostly because generally a lot of our energy policies corporate they’re looking very closely at you know their rate relative to other industrial competitors absolutely yeah yeah I know in in Mexico and their power is actually a little bit cheaper than ours in the residential side I think it’s like 9 cents a kilowatt-hour national average and they’re their industries pay a little bit more than that aap I think I want to say they pay like 12 so but yeah it’s very easy to find this resource online and it’s got a whole table for many countries not all of them but certainly a lot of them all right so probably in the last week some of you have filled up your car with gas do you remember how much you paid per gallon 330 okay okay so I’m thinking you’re you’re probably getting regular the same resource list the prices for unleaded premium and these these figures are from 2013 so I know there are some fluctuations of seasonal fluctuations so in the US if you’re getting the unleaded premium their averages reported at just under 380 you like electricity elsewhere in the world people pay a lot more for energy in Turkey it’s $10 a gallon Netherlands $9 a gallon Japan over $6 a gallon and again this remote military outpost and they’re usually using JPA which is and it’s similar to gasoline it has about 10 percent higher energy content per gallon but the electricity they’re getting is from burning JP ape so the cost of moving that fuel can be enormous so certainly if you went up to Exxon any tanks at 400 ollars again you’re probably somewhere else but but they don’t have a lot of options out there okay so we’ve talked about assessment of kind of generic energy sources among it now we’re gonna discuss with you space littler power does anybody know what space flow powers or think they know what it is one two three four okay so most people five so most people have not heard of it or don’t know what it is you want to tell me what it is launch satellites with the photovoltaics and beam down microwaves and catch them and giant retina farms and see if you can get them to tell you how many saw equivalents what the energy level will be excellent succinct explanation I think it’s actually very similar to what the young man early earlier stated so yeah so essentially uh super if you’re copping ham you don’t get credit collection of solar energy in space and it’s wireless transmission for use on earth alright let’s talk a little bit about the history this idea to my knowledge first appears in an Isaac Asimov story from 1941 called reason about some robots that are controlling this solar solar power station in orbit

and it develops a consciousness of its own and it’s actually really interesting story it’s a short story so it’s quick read but you’ll enjoy it the concept is outlined by Peter Glaser widely considered to be the the father of this idea in science magazine in 1968 there was a demonstration that NASA did in 1975 where they actually had a big microwave beam over about a mile and they collected it with about 80 percent efficiency during the energy crisis of the 1970s the Department of Energy and NASA spent about 20 million that and it’s about 50 million in inflation-adjusted dollars studying this concept the context of that time was very interesting because we had just been to the moon and a lot of engineers figured they could do it anything they wanted and we had this energy crisis where there was suddenly this panic about like wow there is a threat to our way of living the way we run our energy we really need to figure out how we can get from under the thumb of these opec countries so there was a lot of a lot of effort put into this and studies North American company The Boeing Company Raytheon all did very extensive studies certainly to date the most in-depth detailed rigorous studies that have been done on solar power satellites energy crisis ended peels out I’m just going to stick with oil don’t you worry about anything else so since that time NASA and other organizations around the world the International Academy of astronautics Union of radio scientists international various organizations have put together studies that the DoD has put together studies there’s a famous one in 2008 where they did a study look at this and in general the conclusion of these studies has been that this is something you can do but that it would be fairly expensive what’s happening now with solar power satellites they’re actually about half a dozen companies that are pursuing the development of solar power satellites with kind of varying degrees of credibility there’s a company Silurian in California that actually has a contract with Pacific Gas & Electric to supply energy from solar power satellites before 2020 Japan and China currently spend on the order of 20 million dollars a year doing research related to solar power satellites the US government does not currently have any research programs and people often say well part of this is because energy falls under the Department of Energy but space doesn’t they don’t do anything in space and NASA’s mission is really exploration so why would they do anything related to energy so how would it work where you’ve heard the explanation let’s use this graphic to kind of get a better sense of exactly how it might work and before I explain this you should be aware and I’m gonna show you a lot of different concepts in a minute that there have been dozens and dozens of different ideas about how this could be done and this is just kind of one example that shows you so so you got the the Sun here if it’s daytime you don’t need to bother with any satellites you just stick your solar panel outside or you’re good to go this particular configuration has big concentrating reflectors that redirect the light onto the photovoltaics it’s converted from direct current the output of the photovoltaics to a microwave signal comes out of a large antenna and this satellite would most likely be in geosynchronous orbit so that it would appear to be over the same spot on the earth constantly beam is sent down to a large receiving with retinas and those converted back into the electricity that you would put into the grid so functionally the concept is fairly straightforward I’ll just I have a number of different designs and and it’s generated tons of space art so you can see many different variants on the one that I showed you in the previous chart some people have proposed using lasers instead of microwaves just using reflectors and you see over over the past several decades there have been many many different concepts so what does this satellite actually have to do I mean basically just has to do two things has to collect the energy and it has to give that energy to the ground so the collection could be done with a photovoltaics that’s what’s usually posited you could use some kind of big heat engine a solar thermal sort of approach some people say this makes more sense because photovoltaics are bounded by the chocolate kisser limit which says that you can never have 100% photovoltaic this solar thermal the heat engine isn’t bound by that limit so theoretically it could be more efficient you could actually have a laser and use the sunlight as a pump on the lasing material and generally laser beam that way to get the energy down you could use the microwave approach like we’ve been discussing or you could use a laser the

downside of the laser a couple downsizes laser but one downside is the laser is not going to go through clouds as well as the microwave was is going to the microwaves whether you have the worst monsoon ever if you’re below two-and-a-half gigahertz that energy beam is getting through 24 hours a day all the time you could also just put a big reflector up in space right and just use that as a mirror who knows what that might do to the the wildlife get a little confused about what time of day it is but that’s been proposed as well and there some a number of different scales as well for the rest of our discussion today I’m gonna focus on the photovoltaic and microwave combination just because that’s the one that has gotten the most attention and makes it a little less complicated to discuss the alternatives so what are the advantages of doing this why would you want to go through the difficulty and expense of doing this rather than just just having your solar panel on the ground I think it’s one way to start with that do say well the advantages certainly enjoyed are the same as with ground solar you don’t have the greenhouse gases other than during the manufacturing of production which you have for pretty much on any kind of alternative doesn’t require fuel that’s pretty huge and this is really more a dig at nuclear energy but doesn’t produce any radioactive waste so so that’s a certainly a benefit one of the compelling benefits is it’s never cloudy in space it’s never nighttime in space if you’re in geosynchronous orbit or more accurately 97 plus percent of the year it is not nighttime there was a brief period around the equinoxes when the satellite would be eclipsed at local midnight for something like 40 minutes so you could plan around that much like you have any any power plan that’s taken down periodically for maintenance but it’s effectively 24/7 all year round there’s a lot more solar light in space because it’s not being attenuated through the atmosphere when you’re on the ground so more energy all the time it becomes what’s called a base load power source so if you have a coal plant or a nuclear plant that thing is just gonna keep running as long as you keep putting fuel in it it’s it’s essentially always there and that industry really likes this kind of plant because it provides base load energy you can count on it to be there it’s not like you’re wind and solar where it’s like oh sorry it’s been cloudy for a week or we’re in the doldrums no wind so so that you can use this as a base load source and it is also having the benefits of a lot of the renewable sources as kind of novel if you have this satellite in space you could either beam it to a single receiving station or you could beam it to receiving stations that would be on a pretty large portion of the earth one satellite could conceivably reach Seattle and places in South America just because you could redirect the being this gives you a big advantage where if the grid in one place just happened your plant went down or it’s not windy or it’s not sunny I just move the beam over there you put the energy in there and once that’s resolved you can send it back to wherever usually would be it gives you an opportunity to fill in where energy is needed the most if we actually went through the trouble to develop this you would need to put a lot of massive space and in doing that you would probably have to have launches something on the order of almost every day depending on how the approach was taken if you were launching every day instead of maybe once a month or I guess around the world we have launches with some frequency but but the demand for launch is comparatively is is pretty low but if there was a known that you’re gonna have a launch every day or maybe even more frequently suddenly you have the opportunity of scale to the launch industry and the cost of launch potentially could be reduced dramatically if you launch the cost reduce the launch costs dramatically maybe you also enable new industry is like cheaper space tourism or extraterrestrial resource exploitation so you mean a lunch per day while the infrastructure while this is being built or a launch per day forever that sounds like rather a lot yeah so you would have to put a lot of math since we actually it’s a good segue into Mike’s next slide here in almost every concept you have to put a pretty large amount of mass in space and that’s gonna require a lot of launches once you’ve assembled the satellite you don’t have to do launches anymore other than what you might have to do for maintenance although some people say yeah you know you get your robots up there and you can just have them fix stuff and you use stuff from the moon so you don’t have to bring anything else from the earth and some some people say you should start building this from extraterrestrial materials and not launch all this stuff from Earth get your asteroids or your lunar material and build it that way and certainly I mean again that’s not

against the laws of physics but we haven’t built anything yet from extraterrestrial materials really so that kind of makes makes it even more into the realm of science fiction which not to say impossible but certainly farther farther down the road so yeah so this this is a big issue having to put all this mass and space so all these launches you’d have to do the power transmission we’ve talked about the microwave beam radio wave beam people associate microwaves with the Box in their kitchen that cooks their chicken so their first thought maybe that’s gonna cook the birds that are flying by is this gonna interfere with my bluetooth with my Wi-Fi is it going to with this beam flying down or what what if an airplane flies suit or satellite goes through it and these are good questions it turns out that the way you design the system gives you some latitude you can either have a large collection area with a low power density beam kind of makes sense or you can have a small collection area with a high power intensity beam and this is something really that the engineering requirements would dictate like if you’re in the military base case you probably don’t have acres and acres or you can put this huge collection thing so you would need to have something small it’s a a high-intensity but it’s a trade-off and you could you could kind of push it either way we’re already in a situation where if you look at nuclear power plants they have good perimeter security you can’t fly into commercial airline over a nuclear power plan you probably wouldn’t fly a commercial airliner over one of these rectina farms where you’re collecting all the energy for a space so and then the costs definitely this has been a common theme in a lot of the studies and can’t you can’t really deny it this is this is something that would be expensive doing almost anything in space is expensive so how does it fare against our three barriers that we outlined earlier so it depends what you’re asking the the coverage of a single satellite would be large but it would not be able to provide power unless it was staggeringly enormous provide the entire power for the United States you probably wouldn’t want to do that anyway because then that would be kind of like a single point of failure and if the satellite went down nobody’s like to beyond so that would probably make a lot of people unhappy you would definitely not want to just build one of these you it would make more I mean you would have to decide what the size is that is most appropriate trying to build them you could think of like a hydroelectric power dam right like we don’t dam every little creek and Brook because it just doesn’t make sense we build stuff like the Hoover Dam or the Grand Coulee dream Dam where it’s an enormous thing and it takes a lot of money to build that but once you’ve built that you’ve essentially got low cost power for the life of the dam which may be many many decades so the similar case would be with these solar power satellites where they would have to be pretty large to justify building one and you actually need them to be pretty big for the physics on the microwave beam to work because it’s the antennas aren’t big enough the beam starts to spread out but you definitely wouldn’t want to just have one that would be your single point of failure many of them you would need a lot oh yeah now you I mean so geosynchronous orbit has a lot of communication satellites in it and you would want to probably use geosynchronous orbit in almost every case to do this although a lot of people think that other orbits make a lot more sense the amount of energy that fall if you took at Geo singer sort of if you took a kilometer wide swath the amount of sunlight that falls on that and one day is more than what we consume in a year so certainly the capacity there is there if we can put satellites and all that spot to collect it so so this is again you’re tapping into your effectively unlimited energy source the Sun without having to worry about being on the dark side of the planet or being under cloud cover so so the capacity is there and the question of how many satellites it would take depends on how much what the capacity of any individual satellite is some people say should be at least one or two gigawatts 5 gigawatts 10 gigawatts our the world’s consumption is something like 16 terawatts so these are huge huge numbers but there’s nothing like the the sunlight is there the more satellites you have the more material you have to put in space if you can get down to the point where the cost of putting things in space is almost what the energy cost is it becomes very small but that only happens if you’re doing it very frequently how far away is this from being space-based weaponry is this a dual use technology great question very question even if it’s not intended that way can it be interpreted that way then suddenly somebody else wants to weaponize yeah yeah a great question the

microwave ones would be extraordinarily difficult to weaponize the laser ones are kind of iffy because with a laser beam you’re gonna have a higher power density and you the question you should ask yourself is okay if the Chinese are gonna do this am i comfortable with them stationing over Hawaii or somewhere a geosynchronous satellite with a five gigawatt laser and it’s not just you it’s whether the Department of Defense is comfortable with that right so this is people and there’s there’s certainly trade-offs people advocate for laser because they say oh you won’t have any of the radio interference that you would have with microwave but now you have this higher power density in this potential political dimension that would be sort of hard to negotiate the microwave case it would be very difficult to use a microwave solar power satellite as a weapon the laser one definitely has a closer pathway to that didn’t wily coyote try so uh so yeah I mean that is certainly a factor and and these pros and cons I certainly don’t intend to be completely comprehensive it’s kind of the major ones that people thought yeah so in and focusing on this the photo will take microwave one weaponization is essentially impossible so let’s go back and look at our barriers physical technological economical how does solar power satellites compare with these physics no problem the energy beam that wireless power is consistent with Maxwell’s equations pointing vector helmoltz wave equation we’re not creating energy from nothing no problem does the technology exist there have been a lot of demonstrations of segments of the technology we have not just the NASA demonstration in the 70s people have been doing wireless power beaming all over the place for decades so this is something else that a lot of people just aren’t aware of but wireless power has a very rich history it’s been described by will Brown of famous electro engineer is ready for use when it’s needed so it’s fairly mature technology there have been cases where even hardware that would go in a solar power satellite has been prototypes on a small scale and photovoltaics also have been around for really long time so that’s a very mature technology so each of the segments that you would need to make a system like this enjoys a lot of maturity however it’s not been put together into a meaningful end-to-end demonstration so you can’t really say that it’s been demonstrated the economics okay so all the words make a big point of talking about the economics it’s tricky because we don’t have a demonstration system we don’t really have a true data point we can look at and say this is how much it costed how can we compare it with existing sources and alternatives there is a quantity called the levelized cost of energy that is commonly used for comparing different sources of energy it is expressed in cents per kilowatt hour or some unit of cost and some unit of energy question becomes can we construct at least a simplified expression that would give us an idea of what the levelized cost of energy would be for solar power satellites factors we might consider the things that go into making the the dollar part the the top part of that that fraction the cost of launch as we’ve been discussing it depends on how many launches you’re doing how much the satellites weigh cost of the actual satellite design of production the materials operation and maintenance cost the receiving station whether there’s any government incentives to do something like this Germany has enjoyed a lot more solar power than you would expect because of government incentives then the bottom of the fraction the amount of energy that would be delivered that depends on how long the satellites up there if you put it up there and it’s good for five years it’s not very long if it’s good for 50 years you’re getting 10 times as much energy how big the satellite is besides the receiving station the end-to-end efficiency of the system so if we take just kind of a few of the factors that are likely to have the largest weight we can put them into an expression that depends only on four things on the top on the cost side the cost of launch we always have heard that that is going to be a big factor in whether this is feasible or not the cost of the satellite and then the hardest to understand perhaps of the quantity is is this power per unit mass and that’s just how much power you could expect to get on the ground per kilogram that you have to put in space you want this number to be huge if you can get 10,000 watts per kilogram that would be great and then the lifetime of the system how long is it be up there so you see that the kilograms cancel out from the top and bottom of this fraction and you’re left with the cents per kilowatt-hour that

figure that is a little bit more accessible since we see it each month on our electrical bills so what I did is I said alright let’s look at four cases because we don’t know necessarily exactly what numbers we should put into this expression let’s look at what we can do today if I go out and buy a lunch today how much is it gonna cost for per unit kilogram if I try to buy a satellite today what is it likely to cost per unit kilogram how long do satellites last nowadays and then there’s some recent research that gives us that watts per unit kilogram and you’ll see the numbers I’ve use for that now we can assume look at what if they’re just modest improvements what if kind of not necessarily Moore’s law but just better than what we have now then you can assume more aggressive case maybe this the we really put a focus research effort into something and we get get more improvements and then you say what if we get revolutionary nothing that’s defies laws of physics or something that’s without precedent but very large improvements so I’ve tabulated here the results for putting in different values and you can plug in your own things into this form is very very simple formula if you want and you can see with today’s using today’s demonstrated values and this admittedly simplified expression expression that neglects a lot of factors that you would want to consider when you’re doing a very detailed serious analysis of this you end up at about 16 dollars a kilowatt hour which is you’re not going to pay on your your Pepco or your Dominion bill however that’s not that far off from what DoD is paying in remote places that are difficult to get electricity to in a case to the kind of incremental improvements or closer than the two orders of magnitude out we were with the the first one we’re still 10 times as much as we’d like to be but it’s not that far out if we assume this these aggressive improve improvements this concentrated effort you get down to about seven cents a kilowatt hour and then if you assume the revolutionary ones you’re too cheap demeter almost right with what they used to say about the nuclear energy the nuclear industry let me go into a little bit more depth just about the numbers in cases 1 & 4 so that you get a sense that I didn’t just pull these out of the air the service life in years 20 years so it is routine in the communication satellite industry for satellites to last 15 to 25 years there have been satellites that have lasted in an excess of 30 years so in case one where I say 20 sounds like a long time but it’s actually reasonably conservative and 35 is not insane that is that is something that we’ve seen the cost of launch if you go to space exploration technologies website today and look at their cost per kilogram for a launch if you get their largest rocket there our Falcon 9 that’s about twenty five hundred dollars per kilogram this is the one where if you’re doing it every day and you say I’m gonna buy a thousand of these you should be able to get the cost down if you look at the energy to get into orbit and you just cost that out it’s less than $10 to get to orbit in terms of energy costs so a hundred is ten times that absolute lower bound so that’s also not insane that’s Tullio so you would have to have the in space transportation as well and yeah and that and that’s one of the simple simplifications of the model is to uh to get it down to four factors that’s one thing that was was discarded so you certainly would have to do that however if you use electric propulsion and you got these huge photovoltaics it’s not gonna be that difficult to go from Leo to a deal question what are the major factors that affect service life just like how much well so once you’re in space and you’re working you have radiation that affects your electronics and you have a finite amount of fuel because right now it is difficult or impossible to refuel your spacecraft and even in geosynchronous orbit for this orbits we use nowadays for communication satellites you have to consume fuel on about a monthly basis basis per station keeping to compensate for the effects of the Sun and the moon there is an orbit called a geosynchronous Laplace plane orbit which does not require fuel because it’s slightly inclined and you actually wouldn’t need station-keeping fuel for that but it would that your microwave beam would have to steer I think like plus or minus five degrees or something like that so that’s that’s one thing that technically knowledgeable people ask about of it Oh what’s the station keeping requirements for this and if you use this particular orbit it would be essentially nothing so the cost for the space segment the kind of rule of thumb nowadays is about ten thousand dollars a kilogram for a any any given satellite the cost per kilogram of your widescreen TV is on the order of 50 dollars so if your mass producing the elements double that is not insane the mass specific power is kind of the most interesting case until

and I could try to blow my own horn too much here until some research I did I don’t think there was actually a figure for our that came that had an empirical basis there had been estimates that would be between four kilograms or four watts per kilogram and 40 watts per kilogram and I actually have have built hardware that demonstrated it was actually six six watts per kilogram so but that’s that has actually been demonstrated looking at the 200 you say well what’s what’s the basis for that you can buy today thin film solar panels that are a thousand watts per kilogram so that admittedly does not include the DC to microwave conversion that you need to do but that’s not again insane so even case four which is revolutionary these are not made-up numbers they they have they have a basis and then the two and three are kind of in between there so I get so I my sense is that the cost of launch will be higher because you’re going to Geo and the cost that’s basically lower because a lot of what you’re doing is just this it’s not it’s not all the guts of the real big you know real important saddle satellite is really yeah well and the way you would build this is you would try to make it as modular as possible where you could generate most of the components on an assembly line and just churn them out and assemble these pieces in space some people say they could be self assembling a lot of this like definitely gets them to things that have not been demonstrated very much but but but none of this is is taken from with no basis whatsoever alright so I told you a little less than an hour ago that I was going to show you some cost numbers these are from the US Energy Information Administration these are their estimates for the levelized cost of energy for plants that would go into service in 2017 so they take a huge survey look at existing plants they look at resources and trends and they try to figure out what the cost to generate the electricity so this is not what you pay this is what it costs that power company to make it what that would be in 2017 so the cheapest thing probably unsurprising to those who follow this stuff is natural gas natural gas advanced combined cycle about six and a half and they also account for inflation a year so that’s why that might be seem a little bit higher on 2017 everything will probably be more expensive then you can see they go in kind of a ascending order of costs with the exception of this group of four cases at the bottom which are the ones from the previous chart and pretty much like you would expect the case is three and and four are the ones that really start to be price competitive now you’ll notice I don’t account for things like the operation of maintenance or the transmission you can also see that those contributions are actually quite small compared to the levelized capital costs so the the one that is of most interest probably is that variable operating and maintenance which includes the fuel so in the cases where you have something like a coal plant that about a third of the cost is due to the the fuel so Tom Murphy really likes the solar solar does not very cost competitive according to Energy Information very sensitive to that capacity factor definitely true yeah and that’s the putting solar and wind in places where there’s a lot of wind all the time and there’s a lot of absolutely true absolutely true yeah and actually that’s that’s probably column I should draw some attention to it so this capacity factor tells you how often that plant was running so so I’m assuming the solar power satellite is running for ninety percent which is similar to the nuclear plant at ninety but the solar PV and the solar thermal twenty five twenty percent that’s because you’re not only like for a couple hours during middle of the day do you get like the full power right and that reduces the capacity factor if you could increase that you would certainly reduce your level iced cost of energy all right about the fuel so one thing we can do is we can express the cost of the fuel based on a direct energy conversion from the kilowatt hours so kilowatt hour is an expression of of energy much like joules you can have in a given quantity of fuel fixed amount energy if we just assume there’s a hundred percent which again we can’t because it would disobey the second law of thermodynamics we can make a conversion between the cost of a gallon of gasoline or jp8 to the kilowatt hour cost and what I’ve done is I’ve pointed out where these different solar power satellite cases would be so the sixteen dollars a kilowatt hour case one still more expensive than the $400 a gallon for JP eight that the DoD is paying case two is definitely closer

case three is competitive and then our too cheap to meter would be way up the chart there alright so where does this leave us I told you at the beginning that we’ve got this one match this fossil fuel that we’ve got now that no matter when you think it’s gonna run run out it will run out should we be using part of our match on solar power satellites how do we do against the three barriers with the solar power satellites well physical no problem but then again everything for a perpetual motion and Joe Newman does pretty well against physical technological we’ve said the pieces are there but they haven’t been demonstrated in an end-to-end system the economical depending on the assumptions you put into the model you can see there’s a huge range between $16 a kilowatt hour and less than a cent a kilowatt hour so what does this mean well at the risk of sounding like a stereotypical researcher to definitively address the technological and economical barriers more research is required so but but it is true I want to put this in perspective relative to one prominent alternative that you’re familiar with them that I’ve already mentioned once in this presentation and that is fusion so you may know that there is a joke in the fusion community and I guess people who follow a fusion and that is that few unit has been ten years away for about sixty years how much have we spent on fusion in the last sixty years we’ve spent about thirty billion dollars in inflation-adjusted inflation-adjusted dollars on fusion between 1953 and 2012 and in 2012 we spent 700 million not quite a billion dollars but certainly a sizeable sizable amount of money in that same period we spent less than one one thousandth of that amount on solar power satellites now I’ll remind you for fusion nobody is trying to build a fusion power plan right now if you look at eater and Europe and any of the research we’ve done National Ignition facility these are all experimental so nobody is at the point where they’re trying to build an operational fusion power plant they are still doing research you could say if we are going to be serious about this all-of-the-above energy strategy that you’ve heard where will you use things that are kind of known quantities but we’re also pursuing these high risk high payoff situations like fusion probably makes more sense to do additional research into space solar power now I’m not saying we should develop space solar power I’m saying that the research should be done to clarify exactly how realistic of a source it is since it does see like there’s a range in some places where I would work in some places where it certainly would not work once that match though I’ve been describing is gone it may be too late thank you for listening I’m just curious because you kept referring to the cost of getting energy to remove military operations so with this space now with the microwave receivers be fairly mobile and something where the the satellite can change its sayin fairly quickly yeah so the the req tenor receiver is amazingly simple it’s essentially there’s a lot of ways you could do it but it’s essentially like a wire and a Schottky diode and you would still have to have like a collection Network but it’s incredibly robust it’s not very heavy it can be packed up quite small now one thing that I should mention about the military case is that they need more than just energy at a military base you can have all energy you want but if you don’t have food you don’t have water you don’t have ammo you’re not really a military base and you can’t send those things in with a microwave beam so the not dead right yet so so I think it’s important I’ve talked a lot about the military case but I don’t want to give you any illusions there’s probably not a really awesome way to like completely get rid of logistical deliveries to military bases so a lot of people have kind of especially advocates of solar power satellites have seized on to this military gave some say Oh DoD has lots of money they pay inflated prices for everything they can develop solar power satellites but it doesn’t actually solve all of the problems like you could reduce the the amount of fuel you have to deliver but you’re not gonna like this is not a magical solution to supplying military bases if that’s the case then like one of the things one of the perigee for backyards like could you have like your own personal receiver or is it probably not the the reason for that is with the the way the microwave beam works so so you know light and microwaves are all part of the electromagnetic spectrum the only difference is the wavelength

I guess that enters the energy in it if you use these microwave wavelengths the two-and-a-half gigahertz they give you the advantage of being able to get to the atmosphere and the cloud and the rain you have to have a large transfer and when I say large and Fred say yeah five-point-eight occurs twice the frequency you need a kilometer diameter transmitting antenna in space and probably a five kilometer receiving station which also is not going to fit very well on your Combat Outpost so putting something in your backyard either is not going to work very well or you’re going to have to worry again about this energy density problem where maybe you can get this like millimeter wave wave being that you can direct to people’s houses but there’s gonna be a lot of energy in that beam area how like what kind of urban density with that necessarily how much energy would that be so the footprint of the beam and that energy in the beam are actually independent to a large extent you have to have even if you’re just trying to get down ten watts for at the frequency at the five point eight gigahertz to get to to close that link to have that link and not be in the noise to get the the 90% kind of beam coupling that you would probably want for this sort of system you need that size now once you have that you could put the five or 10 gigawatts through there and what would happen is the energy density in the center of the beam would be a lot higher at the risk of getting a little technical here so the the transmit energy profile on the antenna and space would be approximately a Gaussian distribution and the reason for is just because it avoids the side lobes you’re not like sending energy off into places that you don’t want and kind of commensurately the energy density in the center of the receiving station would be the highest but what level that is this is contingent on how much total energy you’re trying to get down one thing that people also typically ask about is so how do we know this energy beam isn’t go wandering around the countryside and that’s actually effectively been solved or it’s been demonstrated I should say if you have a pilot beam as you certainly would want to in the center of your receiver that sends a signal up to the satellite and it uses the face from that pilot signal to direct the beam so unless the satellite is receiving that pilot signal it’s not going to send the energy it would totally disperse and this has been demonstrated a number of occasions there’s a colleague of mine Anu buchaiah from the University Coby in Japan who has demonstrated this with like a little microwave powered Rover and he has a phased array and the rover sends out of pilots ago and as it drives around the microwave beam just follows it around it if you turn it off the energy spreads out so that’s the problem that people are often worried about that has actually already been addressed one of the explored potential problems as we said there’s no clouds in space but there is space weather so thinking of the worst case scenario I guess it was sometime in the night mid 19th century there was a devastating yeah event or even something from about 25 years ago Quebec Power Grid we’re off of course being exposed in geosynchronous orbit this bait up craft would be a scourge yeah knowing that is that is definitely a concern one thing that is less of a concern I’ll just mention it because it’s kind of in a similar vein is people are worried a lot about space debris but space debris is primarily a problem in low-earth orbit not in geosynchronous orbit dealing with the the possibility of a solar storm is is a very real consideration I don’t think people know exactly what the magnitude of such things could be like the 19th century case you talked about seems like it’s probably worse than anything we’ve seen since and when you design communications and other satellites now you put in measures to try to deal depending on what your mission length requirements are to make yourself resilient to solar activity and sometimes people will safe the satellites they know there’s a solar storm coming and that might be something you would have to do where you would have to take it offline and like position it in a particular way that would make it more likely to survive or you would have to design it to be robust and that’s I think that’s part of the research that I’m advocating shouldn’t be done leave nature but the fact that our guys were supposed to disappear about 30 years ago and they just kept making him better better better and memory so things last

year that actually helped wondering that that’s not eventually an issue with what you’re talking about particularly if you become edited with me all right yeah no certainly that is a an issue like I mean so this also brings in you may have read the innovators dilemma and be familiar with Moore’s law and how how things get better and better like you could get to a case where maybe we get really good at like the ground storage of the electricity and having this low the if you only have sunlight for a couple hours a day and you can build it up you can store up like a month’s source of electricity if you could do that cheaply like the case for doing something like this certainly is lessened because you’re addressing one of the main shortcomings of the alternatives so yeah I mean this is definitely that is something you have to weigh in the fact is that for large-scale energy like it has to be able at some point to be able to compete on cost except for in these like weird situations like the military or if you have a remote research station or an island or something so so yeah you would have to be able to get there eventually and I agree that it’s not clear whether that path exists or not it may or it may not does the levelized cost of energy account for any kind of externality like pollution it depends on which formulation you use so some of the levelized cost of energy expressions have like 20 different terms in them and researchers kind of make up their own I don’t know exactly what they did what the Energy Information Agency did for each of those cases so but certainly you if you applied some cost factor like you could say like I for whatever amount of tons of carbon you emit you should increase the cost by X amount so I don’t know if that’s done you certainly could include that I don’t you saw in the solar power satellite when I only have four terms so that’s clearly not included in that alright thank you very much

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