Backyard Aquaponics
A place to discuss aquaponics

I have not found a great deal of attention given to space-based solar power when considering renewable resources and sustainable futures. Space-based solar (SBS) is solar collection from space--collecting the extra energy that passes the Earth--and either re-directing it as RF back down to Earth (to unpopulated locations) or converting it to some other space-based application with economic return.

In order to fully understand the scope of such a project, here are a few facts about the energy situation.

Global power consumption: ~15 Terawatts (15,000,000,000,000 Watts)

Global power from the Sun (as received by the Earth): ~180 Petawatts (180,000,000,000,000,000,000 Watts); much of this drives the weather (wind, rain, fog, etc.), and the rest is reflected into space

Total Solar Output: ~380 Yottawatts (380,000,000,000,000,000,000,000,000 Watts)

Placing a satellite into geosynchronous orbit above Earth would require a very high area to amount to realistic power collection. On the surface of Earth, there is only about a kW per square meter (kW/m2) solar maximum during the day at about 30 degrees latitude. Our distance from the sun is 93,000,000 miles, so the Sun's output is greatly diffused by the time it gets to Earth. This type of project becomes much more practical by placing a satellite closer to the sun, where the energy density increases proportionally to the distance from the source. By far, this seems more practical than nuclear power (fission or fusion), fossil fuels, or any other combustion-based fuels.

We should all be aware of the dangers and problems of nuclear power (waste, weapons, accidents, costs, etc.). I am not convinced that fusion-on-Earth will be any better than fission power. As with the start of any new technologies, there are always many mistakes until a safe system is developed. Fusion promises to yield more power than humans will ever need in the near future--which to me translates to larger disasters than any other in human history. What's more, is that we already have fusion power--at the perfectly safe distance of 93 Million Miles away.

I think it's a bit of a dream scheme though really.. Number one thing, we have to get used to living with a lot less energy consumption, there is no other option... The cheap oil age is almost over and when it is, we can never have that wasteful energy surplus again, it's gone.

Here's a break down of potential costs of sticking the equipment up in space, "when" we have the technology.



Could something like that ever actually make it to an energy neutral stage? Could it make as much energy as what it rook to get the thing manufactured and then up into space?

On the other hand, perhaps one could mine the moon or capture an asteroid. A moon-based magnetic launcher would toss the materials into location fairly easily once we deal with the "minor" issue of construction there. This could be a step toward moving some humanity into space for actual colonization. On the other hand it is hard to imagine that we could damage earth enough to make it less hospitable than the next best place in the solar system.

I do agree that a much more frugal lifestyle might work better. Reducing our power use by a factor of two or even ten seems possible. Still, I'd like to see some deep thought into our goals for spending this inheritance we have received of oil, natural services, etc. It would really be a shame for humanity to disappear or our civilization collapse because we are not wise enough to figure out a plan before forced to do so. It seems to me that we are acting like kids with a huge inheritance, spending it thoughtlessly in a wild party. Whoohoo!

Just happend to be reading about problems with space travel this morrning from Wiki

Mabey next year

I think the answer is less people.
Cheap oil and the Green Revolution provided heaps of food (grain crops),through industrialised agriculture.http ://en.wikipedia.org/wiki/Green_Revolution
Unfortunately all the extra food it created a population explosion.
and the food production is unsustainable and relies totally on cheap oil.
http://www.harpers.org/archive/2004/02/0079915

The solution may be what happened in Cuba when the soviets Union collapsed and cheap oil stopped flowing
They converted to organic agriculture and fed the population from small urban farms.

This is the future
http://www.youtube.com/watch?v=jRz34Dee7XY

As much as I am a believer that we should be pushing to develop a sustainable space based industry solar collection to supply even a portion of the energy requirements of the world is a long way off.
To make it feasible you need to be manufacturing outside our gravity well.
Rf transmission is not exactly the most efficient method of energy transferal either, perhaps in the long run a "space elevator" may incorporate power conductors.

However since in the last 40 years we have made little inroads into this direction I cant see much hope for fast development.

Short term if we want to reduce carbon emission we have too look at what is available now. One nuclear plant would replace the 4 stages of Muja power station (~800MW) which is one of the biggest polluters in Australia. Stage A+B were brought back online temporary during that gas crisis in 2007, and are currently being refurnished to be brought back online this year.

A 1000MW nuclear power station produces approximately 30 tonnes of waste a year from what I have been to find. I personally think Sweden and the other countries that are building storage facilities 500-1000m underground have the best interim solution.
Long term if we survive the stored waste is likely to be reusable in new currently theoretical designs.

While its an entirely different debate the world really needs a 0 population increase policy until such time as new resources ie from space are available.

Yeah, love what they have done in Cuba, that country is an example to us all of us, on what IS possible..

They would have the most doctors per capita of any other country, if other countries didn't entice them away... And free medical.. Free medical for everyone...... Michael Moores film Sicko was a real eye opener...

Sustainable, urban agriculture, where farmers are held in high respect within the community? Yeah..... Communities that are connected intimately to their food production? Bring it on....

The bigger picture:

Provided that the U.S. consumes 20 billion barrels per day of oil and Austrailia about 1 million, an unsecured and and volatile resource, wishful thinking really lies in the hopes of a peaceful future. Tensions between India and China have been increasing as China continues to acquire more Asian resources and raising the prices of its own exports. Parenthetically, another result is the spike in value of Australian coal and iron ore exports. When the resources of fossil fuels diminishes, then the cost to send Space Based Solar Power (SBSP) satellites in space will be trivial, but the cost of potential outbreaks of war (and/or famine) would dramatically hinder such an endeavor. To refer to this as a "dream scheme" is to damn ourselves to a third-world future. Using less power is good in the short term. That choice should not be the vanguard of our obligations, only a subtitle to the bigger need--investment in sustainable energy.

Fusion research has topped several billion dollars. It has achieved little in return. It's a crap-shoot at best. Even if it does work, will it truly be the answer--better than fission power? The Sun is still burning, and we can confidently expect it to keep burning over another thousand year period. WE HAVE FUSION. It's in the middle of our solar system.

So, let's assume the initial R&D project costs US$100 Billion dollars. It's a return that would be limitless. The energy it collects could ultimately fuel itself--self-sustaining energy collection. The Apollo missions were custom built--first of their kind. The missions were not geared toward improving efficiency--a select number of missions, each with very specific scientific (and defense-oriented) goals. It was in no way streamlined, as the production of a Ford F-150 is on the assembly line.

We'd need to figure out how many watts it would take to get that thing into orbit. Figuring out how many dollars it would take seems like an arbitrary metric.

I hate when people ask that question about PV in general because they never seem to ask it of nukes, or coal power plants.

My 18 year old PVs seem to still put out plenty of power. I'd need to get out an amp meter to get an actual number. Even if power generated dropped by 25% or whatever it's still producing.

From the NASA Space Shuttle FAQ
http://www.nasa.gov/centers/kennedy/abo ... e_faq.html

Q. How much does it cost to launch a Space Shuttle?
A. The average cost to launch a Space Shuttle is about $450 million per mission.

Q. How much fuel for a space shuttle launch?
A. Each of the two Solid Rocket Boosters on the Space Shuttle carries more than one million pounds of solid propellant. The Space Shuttle's large External Tank is loaded with more than 500,000 gallons of super-cold liquid oxygen and liquid hydrogen, which are mixed and burned together to form the fuel for the orbiter's three main rocket engines.

Q. What types of propellants are used in the Shuttle? How much do they weigh?
A. At liftoff, an orbiter and External Tank carry 835,958 gallons of the principle liquid propellants: hydrogen, oxygen, hydrazine, monomethylhydrazine, and nitrogen tetroxide. The total weight is 1,607,185 pounds.

Q. How much does the Space Shuttle cost?
A. The Space Shuttle Endeavour, the orbiter built to replace the Space Shuttle Challenger, cost approximately $1.7 billion

From wiki
http://en.wikipedia.org/wiki/Space_shuttle

Total launch weight of Discovery: ~4.5 million pounds

The current cost of a kilowatt, let's say, is about 6 cents. To pay for a SBSP satellite, we would need to collect about $2.5 billion dollars of energy. Or about 41,670,000,000 Watts per mission.

To collect that much energy from GEO would require about 29,800,000 square meters of surface area, assuming 1.4kW per square meter.

Moving closer to the sun would yield a much higher energy density. Those numbers coming soon.

From the following lecture
http://www.ess.uci.edu/~yu/class/ess55/ ... energy.pdf

L = 3.9E26 W from sun

Solar Constant (S) = L/(4pi*d^2)
Earth: Distance from sun: 1.496E8 km
Venus: Distance from sun: 1.082E8 km

So, at the distance of Venus, the solar constant (S) = 2.65 kW/m2

Good idea but who is going to pay for the extension lead

So the original quote was for a 4 GW set up. Not sure what that means exactly. 4 GW per hour? What is a GW exactly. Does the 41,670,000,000 Watts mentioned above translate to 41 what? Terra Watts???

There have been many claims that M.M. film was very biased excluding some pretty critical facts. As an example - from wiki:

Black market healthcare:
The difficulty in gaining access to certain medicines and treatments has led to healthcare playing an increasing role in Cuba's burgeoning black market economy, sometimes termed "sociolismo". According to former leading Cuban neurosurgeon and dissident Dr Hilda Molina, "The doctors in the hospitals are charging patients under the table for better or quicker service." Prices for out-of-surgery X-rays have been quoted at $50 to $60.[53] Such "under-the-table payments" reportedly date back to the 1970s, when Cubans used gifts and tips in order to get health benefits. The harsh economic downturn known as the "Special Period" in the 1990s aggravated these payments. The advent of the "dollar economy", a temporary legalization of the dollar which led some Cubans to receive dollars from their relatives outside of Cuba, meant that a class of Cubans were able to obtain medications and health services that would not be available to them otherwise.[54]

I'm not trying to start a big HC debate....just saying...