"The beam from a power satellite is under 0.3 kW/m^2. Sunlight is around a kW/m^2."
then why would we use this instead of just using solar power? They must be using Republican math to try to justify this corporate welfare.
Do you mean that math in the replies where Henson said:
Addressing the economics, electricity is a commodity, especially base load power. Market goes to the lowest cost producers. Power satellites are cheaper than ground solar in close to the ratio of their utilization (i.e., fraction of the year they are selling power). Ground solar plants sell power about 20% of the time, vs space-based upwards of 90%.
Now if you have an issue with his 20% and 90% numbers then feel free to present your own analysis that refutes those numbers.
I have in issue with his ignoring launch costs. When launch cost are not more than 4.5 (0.9 / 0.2, his numbers) times the cost of the actual solar equipment then power satellites will be cheaper. Ignoring transmission costs and assuming solar systems on orbit have the same life as on roof.
Elon Musk ranted amusingly about space-solar power a few years ago in an interview [youtube.com] with Popular Mechanics, saying, "I wish I could stab that bloody thing through the heart." However, speaking off the cuff, he used a less favorable space/ground ratio than the L5 proposal. I'd be interested to hear what he thinks of this plan, especially as SpaceX is on the verge of proving its new reusable boosters, which would be a great enabler for the launch cost aspect.
Musk, i.e., SpaceX is correct to be down on power satellites. His stated reason, low efficiency from sunlight to electric power is bogus though. Efficiency isn't a concern, cost is. Think about it. What would be lower efficiency than sunlight to hydro power? But hydro power is the cheapest kind of electricity we have.
Using what amounts to V2, or Saturn V technology (at the most), I think SpaceX will get a full ten to one reduction on the cost of cargo to GEO. But as I put in another post, that's not c
Why focus on commercial baseload power? The cost to the military or other organizations to provide power in remote hostile locations is orders of magnitude higher than $0.03/Kwh. Isn't your best bet to fill that demand? Competing with coal seems a fool's errand when you can compete with diesel fuel humped over 3000km in tankers, forwarded to advanced basis in Afghanistan on Humvees, and burned in inefficient generators. The costs there are more like on the order of $30/Kwh. Building a reception grid for 10K
Lots of people have thought long and hard about military and other niche markets. The physics (and economics) is so against you that even the really smart guys have not figured out how to makehttp://interviews.slashdot.org/story/15/08/26/1644228/interviews-l5-society-cofounder-keith-henson-answers-your-questions# it work. If you can make a case for it, please do. You will be the first.
If you know of a case which is convincing, please point me to it.
In simple terms, microwaves that will get through the atmosphere can't be focused tight enough to deliver the small blocks of power needed for military and niche markets. Lasers will deliver small blocks of power, but are blocked by clouds. The scale/frequency problem is in one of the graphs here:
Well... That's not ENTIRELY true, you'd need a Rectenna of about 1000m in diameter, for reasonably high efficiency, but it could be considerably smaller in many cases and still be valuable, nor is that size necessarily prohibitive. This is all assuming only GEO, the divergence for lower orbits is MUCH less, so it becomes a balancing act between costs and limitations on the ground vs potentially needing more satellites and/or taking some time to reorient the ones you have.
Its not a perfect system by any mean
"Time is money and money can't buy you love and I love your outfit"
- T.H.U.N.D.E.R. #1
If it is 1/3 the power of the sun... (Score:2, Interesting)
"The beam from a power satellite is under 0.3 kW/m^2. Sunlight is around a kW/m^2."
then why would we use this instead of just using solar power? They must be using Republican math to try to justify this corporate welfare.
Re: (Score:4, Insightful)
"The beam from a power satellite is under 0.3 kW/m^2. Sunlight is around a kW/m^2."
then why would we use this instead of just using solar power? They must be using Republican math to try to justify this corporate welfare.
Do you mean that math in the replies where Henson said:
Addressing the economics, electricity is a commodity, especially base load power. Market goes to the lowest cost producers. Power satellites are cheaper than ground solar in close to the ratio of their utilization (i.e., fraction of the year they are selling power). Ground solar plants sell power about 20% of the time, vs space-based upwards of 90%.
Now if you have an issue with his 20% and 90% numbers then feel free to present your own analysis that refutes those numbers.
Re: (Score:2)
I have in issue with his ignoring launch costs. When launch cost are not more than 4.5 (0.9 / 0.2, his numbers) times the cost of the actual solar equipment then power satellites will be cheaper. Ignoring transmission costs and assuming solar systems on orbit have the same life as on roof.
Re: (Score:2)
Elon Musk ranted amusingly about space-solar power a few years ago in an interview [youtube.com] with Popular Mechanics, saying, "I wish I could stab that bloody thing through the heart." However, speaking off the cuff, he used a less favorable space/ground ratio than the L5 proposal. I'd be interested to hear what he thinks of this plan, especially as SpaceX is on the verge of proving its new reusable boosters, which would be a great enabler for the launch cost aspect.
Re: (Score:2)
Musk, i.e., SpaceX is correct to be down on power satellites. His stated reason, low efficiency from sunlight to electric power is bogus though. Efficiency isn't a concern, cost is. Think about it. What would be lower efficiency than sunlight to hydro power? But hydro power is the cheapest kind of electricity we have.
Using what amounts to V2, or Saturn V technology (at the most), I think SpaceX will get a full ten to one reduction on the cost of cargo to GEO. But as I put in another post, that's not c
Re: (Score:3)
Why focus on commercial baseload power? The cost to the military or other organizations to provide power in remote hostile locations is orders of magnitude higher than $0.03/Kwh. Isn't your best bet to fill that demand? Competing with coal seems a fool's errand when you can compete with diesel fuel humped over 3000km in tankers, forwarded to advanced basis in Afghanistan on Humvees, and burned in inefficient generators. The costs there are more like on the order of $30/Kwh. Building a reception grid for 10K
Re: (Score:1)
Lots of people have thought long and hard about military and other niche markets. The physics (and economics) is so against you that even the really smart guys have not figured out how to makehttp://interviews.slashdot.org/story/15/08/26/1644228/interviews-l5-society-cofounder-keith-henson-answers-your-questions# it work. If you can make a case for it, please do. You will be the first.
Re:If it is 1/3 the power of the sun... (Score:2)
Well, I don't really expect you to tutor me in these numbers, but I've heard the case made pretty convincingly. What in the numbers doesn't work?
Re: (Score:1)
If you know of a case which is convincing, please point me to it.
In simple terms, microwaves that will get through the atmosphere can't be focused tight enough to deliver the small blocks of power needed for military and niche markets. Lasers will deliver small blocks of power, but are blocked by clouds. The scale/frequency problem is in one of the graphs here:
http://www.sspi.gatech.edu/aia... [gatech.edu]
$145,000/kW translates into $1.80 per kWh.
Re: (Score:2)
Well... That's not ENTIRELY true, you'd need a Rectenna of about 1000m in diameter, for reasonably high efficiency, but it could be considerably smaller in many cases and still be valuable, nor is that size necessarily prohibitive. This is all assuming only GEO, the divergence for lower orbits is MUCH less, so it becomes a balancing act between costs and limitations on the ground vs potentially needing more satellites and/or taking some time to reorient the ones you have.
Its not a perfect system by any mean