Arstechnica talked with William Maness and Philip Owen of PowerSat about Space Based Solar Power

[bananas]

and has a two-part article about their approach.
Part 1: http://arstechnica.com/science/news/2009/07/will-the-stars-align-for-space-based-solar-power.ars
Part 2: http://arstechnica.com/science/news/2009/07/running-the-numbers-on-space-based-solar.ars
PowerSat FAQ: http://www.powersat.com/faq.html

[Greyskye]

1. That answered a number of questions that I had about space based pwr

Thanks for posting.

[PHIMG]

2. Ok, let me get this right.

It's too hard to build super conducting long distance powerlines from the high solar isolation deserts in the SW to population centers BUT

It's feasable to LIFT solar panels up into orbit (at like what 1 million per pound lifted?), convert the electricity to microwaves (incurring a loss) and then converting it back to electricity (another loss.)

B.S.! This solar plan is a fantasy of people who want to make money chasing this pipe dream and techies who have watched too much Deep Space 9.

The government needs to build the electricity super highways needed to bring clean power to population centers. It also needs to build a massive national CSP w/storage solar park in the Mojave. And we should massively overbuild this federal solar park so we can have enough excess capacity to run machines to suck CO2 out of the atmosphere, and while we are at it use it to create biofuels that the Pentagon can run on.

[Statistical]

3. One point: Solar Isolation = 25x greater in orbit.

In orbit a panel will generate 25x more power per 24 hours than a panel at a spot on the earth with the highest solar isolation.

The combination of constant peak sunlight, no reductions due to atmosphere, and a constant 24 hours of generation per day mean a panel generates far more than it does on the earth.

Even with a 50% loss due to microwave transmission a panel still does generate about 12x as much power.

Even more useful is the fact that the power in constant for 24 hours meaning solar could replace baseline generation (coal & nuclear).

Lifting to space is the only difficult part but with research we can bring the costs down.

Should it be our only focus of research? No but it should be considered.

Powersat is at least being realistic. Largest cost is lifting cost so getting weigh down is the goal or more importantly get more MW per ton.

Traditional PV panels are about 0.1 MW per ton. Powersat is looking at thin membrane PV and inflatable structures (NASA has done a lot of research on this) to get 1.7 MW per ton.

ION engines can be used to slowly (over 6-8 months) moving the sat from low orbit to high GEO instead of carrying large amount of fuel to maneuver the sat.

So they are at least realistic and concentrating designs on optimizing the lifting weight issue.

[PHIMG]

6. Ok good point about isolation in orbit

But ... there are cheaper ways to do this that don't require burning up millions of tons of toxic rocket fuel into the atmosphere:

1. Electricity super highways (super conducting if needed) -- the government needs to build these and build them now to take wind power from the plains and CSP from the SW to the population centers.

2. Concentrated Solar with Thermal Storage. This will generate power 24/7 even when its cloudy for several days. Why is it never mentioned, why do people keep saying that solar can't do baseload? Build the solar field and the thermal storage system big enough and you wind up with a rated capacity that is 24-7.

When you couple these two technologies and scale up #2 drastically you've solved the energy problem and you don't have expensive shit up in orbit that is vulnerable to solar flares, space junk, repairs and maintenance cycles that require rock launches, etc.

What we need, and I think what we'll wind up with eventually, is a nationalized solar farm. Let the federal government sell production from it on the wholesale market to recoup the public funds.

Here is the smart way to do it:

1. Build a train line into the middle of biggest expanse of open terrain in the dessert for raw materials to come in on trains.

2. Build a factory in the center that makes the parts for the solar field from the raw materials (this project should be vertically integrated like the Ford River Rouge plant was.)

3. Use a highly automated assembly line process (using robots from the auto industry mounted to vehicles) to install the solar collector fields. Use collectors with tall enough legs so the topography isn't a problems so you don't have to tear up everything and destroy the desert ecosystem.

4. Do this build out for 20 or 30 years building an ever-growing super-massive solar field that is brought online in stages. The field grows outward from the factory. At the end of it we should have a field that is a multiple of what we need currently for electricity. The idea is to use the vertical integration, the automation and the 30 year build to create such a huge economy of scale that you wind up with a super low cost per gigawatt and you have way more capacity then the country would need for 5-100 years of growth.

5. When the plant is producing too much electricity use the excess to produce biofuels needed for plastics, fertilizers, legacy transportation, etc, and/or to suck out carbon dioxide form the atmosphere and trap it into hydrates to bury underground.

[Statistical]

7. Agreed however everything has a cost.

Concentrated Solar with Thermal Storage. This will generate power 24/7 even when its cloudy for several days. Why is it never mentioned, why do people keep saying that solar can't do baseload? Build the solar field and the thermal storage system big enough and you've got a rate capacity that can be 24-7.

baseload via thermal storage nearly doubles the cost of solar. Plus to handle baseload in the winter you need an array nearly 2x as large.

So you theoretically could handle 100% of baseload 24/7 365 with solar but you would need a solar arry 4x as large and the cost per kwh would be 4x as high. Given that solar already costs nearly double nuclear or coal that is a cost 8x as high.

Many consumers will not be happy to see their electric bill go from $100 per month in the summer to $800.

Given unlimited resources or a massive (90%) drop in the cost per watt sure you can do everything with solar.

Today with cost per MW of capacity at around $5 million ($5 billion per Gigawatt) and limited resources it might be better to think smart rather than brute force.

[PHIMG]

8. Ok where are the cost estimates for lifting a gigawatt of solar panels?

NASA can't even get a replacement for the space shuttle together. You'll never convince me that building a solar plant IN SPACE would be more economical and feasable than doing a massively huge solar plant using the techniques I've laid out. This is just people who love sci-fi dreaming. Or maybe its just another, lets kick the can down the road like hydrogen and biofuels (rather then building out electric intrastructure for battery electrics.)

Even in smallish installations of 500 to 900 megawatts, solar has reached grid parity (just ask PG&E)... so you are quoting outdated figures. Note that figures for coal and nuke are subsidized and and exclusdes externalities such as asthma, etc. If you build a massive solar park the way I suggest you could get the cost per gigawatt way lower than coal. Btw if nuclear is so cheap to build out where are all the new nuclear power plants. Oh right Wall Street won't finance them because they are a horrible return on capital.

I can't believe anyone can argue that space-based power is more viable then massively scaled CSP. This is insane.

[Statistical]

11. Nobody is talking about using the shuttle.

The shuttle is the most expensive lift system devised on a per lb basis devised. Even Saturn rockets from the 50s launched cargo as a cheaper rate.

The advantage of the shuttle is flexibility not economy.

I would love to see an article where PG&E indicates solar has reached cost parity for baseline loads without subsidies.
It would make my day but I doubt it is true.

Solar has reach parity for peaking loads which are often paid 4x-5x baseline rates.

So solar is competing against natural gas peaking stations not nuclear & coal baselines.

I am not saying build them tomorrow but it is interesting to look at and I think would be worth spending a couple hundred million to develop a small scale test platform. We spend more than that in a day in Iraq.

[PHIMG]

13. You are comparing apples to oranges.

I'd like to know where you are getting your figures from. Most anti-solar people compare the cost-per-watt of a 15kw roof mounted system using PV panels against a 1GW coal or nuke plant and say this is a valid comparison. Economies of scale is what is pushing solar into competition with coal and nuke.

PG&E has a contract for ground based 1.3GW, 500GW, and 900GW and this space based fantasy (if it ever gets up.)

In this credit market I doubt that the space based project will ever get off the ground, even with the power purchase agreement form PG&E, and just wait for the community-based NIMBY uproar when they try to site the ground based collector. "My child's playground is only 2 miles from this collector!"

My money is on CSP built at a massive unprecedented scale using public funds once global warming is RED ALERT crisis.

[Statistical]

17. 900 GW? That is larger than entire US power grid.

Not sure where you are getting these numbers from. You are off by a factor of 1000.

http://www.inhabitat.com/2008/04/10/mojave-desert-solar-power-fields/

PG&E has contracts to purchase up TO 900 MW of solar capacity. Only 100 MW is confirmed. The 900 MW deal is valued at $5 billion. Like I said around $5B per GW.

Even 900 MW is less than 1 nuclear power plant (1000 MW). Why? because utilization factor on nuclear power plant is 90%. Utilization on solar power plant is less than 30% due to solar isolation (only 4-7 hours of peak sunlight per day vs 23.5 operating hours per day on a power plant).

http://www.pge.com/about/news/mediarelations/newsreleases/q2_2008/080401.shtml

The first of these solar power plants, sized at 100 MW in Ivanpah, California, could be operating as early as 2011 and is expected to produce 246,000 megawatt hours of renewable electricity per year. BrightSource will build and place in commercial operation each of its plants as quickly as permitting and infrastructure allow.

100 MW * 24 hrs * 365 = 876,00 MWH @ 100% utilization. PG&E project based on solar isolation that the plant will produce 246,000 MWH. 246,000 / 876,000 = 28%.

So even at $5B per GW it doesn't tell the whole story.

1 GW nuclear power plant = 7884 GWH of electrical generation per year at 90% uptime.
1 GW solar thermal plant = 2628 GWH of electrical generation per year at 30% utilization (7 hours solar isolation).

So it would take 3x 1 GW solar plants (@ $5 Billion each) to replace a single nuclear power plant ($4B) in terms of raw generation.

When you factor in reduced efficiency if you need to scale plant to replace nuclear during winter months (40% of peak output) or to store enough thermal energy (with associated 30% losses) to generate power at night it would take 12 solar plants (at $5B each) to replace a single nuclear power plant ($4B each) and be able to provide for baseline energy (24/7/365 stable output).

It simply is not cost effective. You are trying to force a round peg into a square hole. It is the same reason that nautral gas peaking plants haven't replaced coal or nuclear.

Nobody is trying to use solar to provide for baseline energy. It is being used to replace high cost peak energy demands.
Peaking plants generally charge 4x to 5x as much as baseline plants to provide the peak needed to cover energy requirements. the higher price per KWH means that solar is competitive at those prices.

However peak usage is only about 15% of daily demand. That is the "low hanging fruit" to move past that would require solar to achieve a whole new level in efficiencies.

Try to find a single solar plant anywhere in the world that cost less than $5B per GW ($5M per MW).

[PHIMG]

19. Pretty clearly meant 1.1GW, 900MW, and 500MW

And the value of the deal is the value of all the energy being produced from the installations over the 20 year contract, not the price to build.

PG&E is also building it's own Solar plants.

Lets see how many MW PG&E is buying in terrestrial before they buy 1 megawatt from space-based, and I still want to know how they are going to get the collectors past NIMBY.

[bananas]

27. NIMBY won't be much of a problem.

Most people are comfortable with microwave ovens, cellphones, wifi, tv, and radio.
The big question is whether they can do this economically or not,
we'll find out for sure in a few years when they try to put one up.

[PHIMG]

28. LOL....

ok! :)

[bananas]

15. Solar thermal (CSP) is MUCH cheaper than nuclear

Solar PV is more expensive, but is coming down. By the time a new nuclear plant would come online, it will be cheaper to buy PV off the shelf.

[Statistical]

18. Show some numbers it simply is not true.

Most solar thermal runs about $4 - $5 million per MW capacity.

Solar isolation of 7 provides 30% utilization.
Most nuclear power plants have an uptime of 90% (some newer ones are pushing 94%).

So 1 GW of nuclear power is approximately equal to 3 GW of solar power.
Solar is roughly 3x the cost of nuclear in terms of total life cycle.

Nobody on the planet is building solar to replace baseline energy.
Nobody. Anywhere. Peaking power runs 4x to 5x higher than baseline on per kwh basis.
Power companies can save a ton by using solar power to replace peaking costs.

Baseline is a whole factor more efficient.
Prove me wrong. Find a deal announced that is 100MW or more with a price less than $500 million. Google is your friend.

China, Dubai, California, Australia all the peak solar places on the planet. Nobody has managed to produce a plant at a cost of less than $4 million / MW in capacity.

Here is just one to get you started

Nevada Solar One
http://en.wikipedia.org/wiki/Nevada_Solar_One
64MW
$266 million build cost
cost per MW = $4.15
Generation 134,000 MWH / year
Utilization: 23%

I am interested in space based solar because at approximately $1 per watt solar becomes cheaper than nuclear. I don't mean cheaper to build or cheaper to operate but cheaper over the entire lifecycle. I am not sure $1per watt solar is possible on earth however given that daily solar isolation in space is 25x higher if we can get cost of space based solar down to "only" $25/watt it is cheaper than any form of power on the planet.

If you can build/deploy/generate from one sat @ <=$25/watt you could do it for 100, or 1000 power sats.

[kristopher]

20. Pssst...

http://www.gosolarpowerforhomes.com/solar-power-for-homes/go-solar-power-for-homes-glossary-of-terms-i-to-l

Insolation = Shorthand term for ‘incident solar radiation’, insolation refers to either direct or diffuse sunlight. The solar power density incident on a surface of stated area and orientation, usually expressed as Watts per square meter or Btu per square foot per hour. Not to be confused with ‘insulation.’


I'll let bananas address the rest.

[Statistical]

22. Did you have a point?

By taking the peak capacity of the plant * insolation * 365 days * uptime = generation in kwh, mwh, gwh

The point is unlike a convetional powerplant which runs 24 hours per day a solar power plant will only get 4-7 hours of peak sunlight equivelent per day.
It doesn't matter how that is spread out it simply matters that a solar panel or solar heater will only output 4x to 7x it nameplate rating in one day (assumming 100% uptime).

Nuclear power plants have an annual uptime of 90% - 95% giving them 21.6 to 22.8 hours per day. Coal is a little lower with 80%-85% uptime annually.

At best the uptime (also called "capacity factor") of a solar power plant is going to be 7/24 = 30%.
In reality some downtime will occur during the day so most large scale solar power plants have a capacity factor that is slightly lower (25%-28% is normal).

30% capacity factor vs 90% capacity factor means any way you want to slice it a 1 GW solar powerplant located at the highest solar insolation in the US will generate substantially less that a nuclear power plant or coal power plant.
Solar plant 1GW * 7hrs/ day (insolation) * 365 = 2555 GWH annually
Nuclear/coal power plant 1GW * 24 * 0.90 (uptime) * 365 = 8760 GWH annually.
Same nameplate rating but a conventional powerplant generates 3x the power.

Until you put a solar panel in orbit you will never get more than solar insolation of 7. Moving to a space based platform allows a massive jump in power and that jump in power combined with the constant output allows solar power to fulfill base load requirements.



Doon't trust me..... Check the numbers yourself.

http://www.pge.com/about/news/mediarelations/newsreleas...

The first of these solar power plants, sized at 100 MW in Ivanpah, California, could be operating as early as 2011 and is expected to produce 246,000 megawatt hours of renewable electricity per year. BrightSource will build and place in commercial operation each of its plants as quickly as permitting and infrastructure allow.

So the plant has a nameplate rating of 100 MW however it only generates 246,000 MWH in one year.

Nameplate * insolation * 365 = power generated.
100 MW * insolation * 365 = 246,000 MWH
insolation = 6.7 (slightly less than the theoretical max of 7.2 for the area likely due to estimated downtime and inefficiencies).

A conventional 100MW powerplant running 22 hours day would generate 100 MW * 22 * 365 = 803,000 MWH or about 3x as much.

[kristopher]

23. Yes I had a point

You were using the wrong word.

Would you prefer that no one help you identify obvious errors in your writings? There are plenty of other points that could be made regarding your arguments, but as I said, that's a discussion you're having with bananas and I'm sure bananas is well prepared to respond with specifics.

[bananas]

25. I don't always have time to follow up.

Thanks! :hi:

edit to add: I don't even have time to read all the posts!

[bananas]

24. here you go

Two studies and two recent news articles.

According to the Cooper report published last month (pdf):

THE ECONOMICS OF NUCLEAR REACTORS: RENAISSANCE OR RELAPSE?

<snip>

FINDINGS
Within the past year, estimates of the cost of nuclear power from a new generation of
reactors have ranged from a low of 8.4 cents per kilowatt hour (kWh) to a high of 30 cents. This
paper tackles the debate over the cost of building new nuclear reactors, with the key findings as
follows:
• The initial cost projections put out early in today’s so-called “nuclear renaissance” were about
one-third of what one would have expected, based on the nuclear reactors completed in the
1990s.
• The most recent cost projections for new nuclear reactors are, on average, over four times as
high as the initial “nuclear renaissance” projections.
• There are numerous options available to meet the need for electricity in a carbon-constrained
environment that are superior to building nuclear reactors. Indeed, nuclear reactors are the worst
option from the point of view of the consumer and society.
• The low carbon sources that are less costly than nuclear include efficiency, cogeneration,
biomass, geothermal, wind, solar thermal and natural gas. Solar photovoltaics that are presently
more costly than nuclear reactors are projected to decline dramatically in price in the next
decade. Fossil fuels with carbon capture and storage, which are not presently available, are
projected to be somewhat more costly than nuclear reactors.
• Numerous studies by Wall Street and independent energy analysts estimate efficiency and
renewable costs at an average of 6 cents per kilowatt hour, while the cost of electricity from
nuclear reactors is estimated in the range of 12 to 20 cents per kWh.
• The additional cost of building 100 new nuclear reactors, instead of pursuing a least cost
efficiency-renewable strategy, would be in the range of $1.9-$4.4 trillion over the life the
reactors.
Whether the burden falls on ratepayers (in electricity bills) or taxpayers (in large subsidies),
incurring excess costs of that magnitude would be a substantial burden on the national economy and
add immensely to the cost of electricity and the cost of reducing carbon emissions.

<snip>

The Severance report from January this year estimates nuclear at 25-30 cents/kwh:

http://climateprogress.org/2009/01/05/study-cost-risks-new-nuclear-power-plants/">Exclusive analysis, Part 1: The staggering cost of new nuclear power

A new study puts the generation costs for power from new nuclear plants at from 25 to 30 cents per kilowatt-hour — triple current U.S. electricity rates!

This staggering price is far higher than the cost of a variety of carbon-free renewable power sources available today — and ten times the cost of energy efficiency (see “Is 450 ppm possible? Part 5: Old coal’s out, can’t wait for new nukes, so what do we do NOW?“).

The new study, Business Risks and Costs of New Nuclear Power, is one of the most detailed cost analyses publically available on the current generation of nuclear power plants being considered in this country. It is by a leading expert in power plant costs, Craig A. Severance. A practicing CPA, Severance is co-author of The Economics of Nuclear and Coal Power (Praeger 1976), and former Assistant to the Chairman and to Commerce Counsel, Iowa State Commerce Commission.

<snip>

These studies are being validated in the real world.

Here's a Reuters Business Wire article from a week ago:

http://www.reuters.com/article/pressRelease/idUS142854+07-Jul-2009+BW20090707">Cooper: Escalating Nuclear Reactor Costs Seen in Major Reversals for Industry on Wall Street and in Texas, Canada
Tue Jul 7, 2009 10:30am EDT

Ratings Warning From Moody`s Followed by Mothballing of New Reactor Plans in
Texas and Ontario; Developments in Line with Cooper Report from June Projecting
Trillions in Excess Costs for Nuclear, Compared to Combination of Renewables and
More Efficiency.

WASHINGTON--(Business Wire)--
Three major developments in the nuclear power industry in late June underscore
the key findings of the "The Economics of Nuclear Reactors," a report released
on June 18, 2009 by economist Dr. Mark Cooper, a senior fellow for economic
analysis at the Institute for Energy and the Environment at Vermont Law School.
The Cooper report finds that it would cost $1.9 trillion to $4.1 trillion more
over the life of 100 new nuclear reactors than it would to generate the same
electricity from a combination of more energy efficiency and renewables.

Available online at
http://www.vermontlaw.edu/Academics/Environmental_Law_Center/Institutes_and_Initiatives/Institute_for_Energy_and_the_Environment/New_and_Noteworthy.htm,
the Cooper analysis of over three dozen cost estimates for proposed new nuclear
reactors shows that the projected price tags for the plants have quadrupled
since the start of the industry`s so-called "nuclear renaissance" at the
beginning of this decade - a striking parallel to the eventually seven-fold
increase in reactor costs estimates that doomed the "Great Bandwagon Market" of
the 1960s and 1970s, when half of planned nuclear reactors had to be abandoned
or cancelled due to massive cost overruns.

Cooper said that three late June developments provide new evidence of the
validity of the cost-related concerns documented in his report:

* On June 30, 2009, Exelon cited "economic woes" as a major factor in postponing
for up to 20 years plans to build two nuclear reactors at its site in Victoria,
Texas. (See
http://www.victoriaadvocate.com/news/2009/jun/30/gs_exelon_070109_56587/?business&local-news
for local coverage of the decision.)
* On June 29, 2009, the Government of Ontario announced that it has suspended
the competitive bidding process to procure two replacement nuclear reactors
planned for a Darlington, Ontario site. As the New York Times reported: "Two
years into a $20 billion nuclear upgrade project meant to replace aging reactors
with next-generation technology, the Ontario government postponed the entire
process on Monday, citing excessive cost and uncertainties involving the
ownership status of the sole Canadian bidder … Yesterday`s move is a setback for
the Atomic Energy of Canada Limited, the 57-year-old government-owned
corporation that has built all of Canada`s reactors and could soon be sold off
to a private investor." (See
http://greeninc.blogs.nytimes.com/2009/07/01/ontario-puts-nuclear-expansion-plans-on-ice/.)

* On June 23, 2009, Moody`s Investor Services issued a report titled "New
Nuclear Generation: Ratings Pressure Increasing." The summary to the report
included the following: "Moody's is considering "taking a more negative view for
those issuers seeking to build new nuclear power plants … Rationale is premised
on a material increase in business and operating risk … most utilities now
seeking to build nuclear generation do not appear to be adjusting their
financial policies, a credit negative. First federal approvals are at least two
years away, and economic, political and policy equations could easily change
before then …" Cooper pointed out that even though Moody`s concludes that
reactors might be financially viable once operating, the barriers to actual
permitting and affordable construction may make it impossible to reach the
operational new-plant phase. See the report summary at
http://www.alacrastore.com/storecontent/moodys/PBC_117883 and a related news
story at
http://money.cnn.com/news/newsfeeds/articles/djf500/200906250936DOWJONESDJONLINE000658_FORTUNE5.htm.

Institute for Energy and the Environment at Vermont Law School, South Royalton,
VT.
Ailis Aaron Wolf, [phone]
[e-mail]

Copyright Business Wire 2009

And just today at Climate Progress:

Nuclear Bombshell: $26 Billion cost — $10,800 per kilowatt! — killed Ontario nuclear bid

We knew new nukes were absurdly expensive (see “Areva has acknowledged that the cost of a new reactor today would be as much as 6 billion euros, or $8 billion, double the price offered to the Finns.”). Now we know they are literally unaffordable.

Our friend and fellow blogger, Tyler Hamilton — who actually has a real job as senior energy reporter for the Toronto Star — published this stunning news in Canada’s largest daily newspaper:

The Ontario government put its nuclear power plans on hold last month because the bid from Atomic Energy of Canada Ltd., the only “compliant” one received, was more than three times higher than what the province expected to pay, the Star has learned.

Sources close to the bidding, one involved directly in one of the bids, said that adding two next-generation Candu reactors at Darlington generating station would have cost around $26 billion.

It means a single project would have wiped out the province’s nuclear-power expansion budget for the next 20 years, leaving no money for at least two more multibillion-dollar refurbishment projects.

“It’s shockingly high,” said Wesley Stevens, an energy analyst at Navigant Consulting in Toronto.

So nuclear bombshells have now been dropped on Canada, Finland, Turkey (see “Turkey’s only bidder for first nuclear plant offers a price of 21 cents per kilowatt-hour“) and this country (see “What do you get when you buy a nuke? You get a lot of delays and rate increases….”).

Now you may be saying, wait a minute, Joe, hasn’t Areva said it would deliver a single plant for $8 billion, so that should work out to a Walmart-style $16 billion price, rather than AECL’s Tiffany-style offer. Hamilton has more juicy details:

<snip>

[tinrobot]

4. Beaming microwaves from space...

Do we really know what the environmental impact of beaming a few GW through the atmosphere will do?

[OKIsItJustMe]

5. "The experts" assure us it will be relatively benign

http://en.wikipedia.org/wiki/Space-based_solar_power#Myths

…

The long-term effects of beaming power through the ionosphere in the form of microwaves has yet to be studied, but nothing has been suggested which might lead to any significant effect.

…

[PHIMG]

9. How about when a pice of space junk knocks it off alignment

And a school yard full of kids gets microwaved?

Nothing could go wrong!

Sci-fi geeks get boners over space based power, everyone else sees it for the fantasy it is.

[Statistical]

10. The beam has low intensity per sq meter.

Unless the "kids" are couple square miles large they can't absorb enough microwaves to be hamrful.

The beam is powerful but very very very big meaningful the beam focused on one person is negligible.

Think of it as the difference between a firehose and a raincloud.
They both delivery same amount of water per second. The firehose is painful because it is concentrated.
The rain cloud delivers the same amount of water over a large area, dozens of square miles. So the amount falling on one person isn't enough to be painful.

[PHIMG]

12. Yes, I'm sure that people are going to accept that!

Oh this isn't a SPACE DEATH RAY.... it's harmless. Right! We've had 1 major nuke accident and people are still freaked out over it and you can't even get a new reactor in at an existing installation and there are still groups actively trying to get installations like Bessy Davis and Indian Point decommissioned.

Sorry i'm not buying it, if the economics don't prevent this then the NIMBY would. And the author of the article acts like it is the solution because you can have multiple receivers to get around bad long distance power distribution.

Modern power = no risk, no pollution, no fuel, no carbon.

Space based power = FAIL.

[pscot]

14. If the beam is that diffuse

aren't you going to need a vast array of collectors to gather it in and re-concentrate it into useful energy? Obviously I'm missing something, because this makes no sense at all.

[Statistical]

16. Yeah the collector is vast. However it is little more than a grid...

of metal wires on top of 30ft poles. Imagine poles arranged in a grid 30ft tall and 100 yards apart. Now run wire between the poles.

It could be "built" on top of existing farmland or grazing grasslands.

<3 minutes and pretty good overview
http://www.youtube.com/watch?v=4TYhYrnKd5Y

[bananas]

26. It could also be placed over solar farms since it lets 90% of sunlight through. nt

[NNadir]

21. Works great!!!!!!!! That's why the Pioneer, Voyager, Cassini, and Galileo missions

were all solar powered, using solar powered oars for renewable propulsion.

What?

They weren't?

You mean their were ignorant anti-science thugs, including TV hosts whose radiation paranoia tried to destroy these instruments before they were used?

Who knew?

Good thing too...

The crash of the Apollo 13 aircraft which contained, (gasp) Plutonium, and crashed into the Pacifici Ocean wiped out all of Hawaii, New Guinea, Australia, and the strange aliens residing at the bottom of the Marianas trench.

It was a great tragedy, comparable to the huge disaster at Three Mile Island that wiped out the city of Harrisburg, PA, killing everyone in it, and like the disaster at Chernobyl that wiped out the city of Kiev.

In my ethics one of the higher purposes of humanity is to extend vision which as some - not me maybe, but guys like Frank Tipler - argue is the purpose of the universe.

I actually believe that Voyager, Pioneer, Cassini and Galileo were worthwhile missions and that the opponents of these missions were insufferably stupid people with their heads up their asses.

I would say the same for New Horizons.