Comments on: The Swarm http://blog.greens.org.nz/2007/12/26/the-swarm/ hopping along the corridors of power Fri, 21 Nov 2008 17:18:20 +0000 http://wordpress.org/?v=2.3.3 By: Trevor29 http://blog.greens.org.nz/2007/12/26/the-swarm/#comment-36736 Trevor29 Fri, 25 Jan 2008 22:40:50 +0000 http://blog.greens.org.nz/2007/12/26/the-swarm/#comment-36736 Statkraft haven't yet reached an economic system in their development, so I can only point you to the links above and to Google. It doesn't need a hydro dam, just a supply of fresh water flowing into a sea. It is not harvesting kinetic energy, from the flow of the water. Instead it is harvesting the energy required when water is removed from a salt solution (as when the water evaporates off the surface of the seas) - think of the sea water sucking the fresh water into it. However without a dam or equivalent storage, you are looking at a "run-of-river" generation model, i.e. baseload power or intermittant generation rather than power when you want it. I expect smaller installations won't be as economical as larger installations because there seems to be a significant amount of maintenance involved. Trevor Statkraft haven’t yet reached an economic system in their development, so I can only point you to the links above and to Google. It doesn’t need a hydro dam, just a supply of fresh water flowing into a sea. It is not harvesting kinetic energy, from the flow of the water. Instead it is harvesting the energy required when water is removed from a salt solution (as when the water evaporates off the surface of the seas) - think of the sea water sucking the fresh water into it. However without a dam or equivalent storage, you are looking at a “run-of-river” generation model, i.e. baseload power or intermittant generation rather than power when you want it. I expect smaller installations won’t be as economical as larger installations because there seems to be a significant amount of maintenance involved.

Trevor

]]> By: Kevyn http://blog.greens.org.nz/2007/12/26/the-swarm/#comment-36728 Kevyn Fri, 25 Jan 2008 13:56:31 +0000 http://blog.greens.org.nz/2007/12/26/the-swarm/#comment-36728 Trevor, Can it be scaled down to efficiently harvest the tailrace energy from any hydro dam? Trevor, Can it be scaled down to efficiently harvest the tailrace energy from any hydro dam?

]]> By: Trevor29 http://blog.greens.org.nz/2007/12/26/the-swarm/#comment-36724 Trevor29 Fri, 25 Jan 2008 11:41:55 +0000 http://blog.greens.org.nz/2007/12/26/the-swarm/#comment-36724 An Osmotic Power station using the waters from the Manapouri tailrace could generate 500MegaWatts, or around 3000 GigaWatt-Hours per annum - comparable to Benmore, and about 60% of the output of the existing Manapouri generators. And the best thing is that this is despatchable power, since it would run at the same time as the existing generators - when the power was needed. Unfortunately it is likely to be too expensive (for now) and the technology is perhaps 7-10 years away. Trevor. An Osmotic Power station using the waters from the Manapouri tailrace could generate 500MegaWatts, or around 3000 GigaWatt-Hours per annum - comparable to Benmore, and about 60% of the output of the existing Manapouri generators. And the best thing is that this is despatchable power, since it would run at the same time as the existing generators - when the power was needed.

Unfortunately it is likely to be too expensive (for now) and the technology is perhaps 7-10 years away.

Trevor.

]]> By: Trevor29 http://blog.greens.org.nz/2007/12/26/the-swarm/#comment-36146 Trevor29 Sat, 12 Jan 2008 22:27:34 +0000 http://blog.greens.org.nz/2007/12/26/the-swarm/#comment-36146 It is interesting that Osmotic Power didn't even get a mention in the EECA's 2006 status report (the 2007 report isn't available) http://www.eeca.govt.nz/eeca-library/renewable-energy/report/renewable-energy-industry-status-report-06.pdf nor did it get a mention under marine power resources http://www.eeca.govt.nz/renewable-energy/marine.html You can't even apply for funding for Osmotic Power development under the Marine Energy Fund because this is restricted to devices that "converts wave or tidal stream energy into electricity", although to be fair, this fund is for deployment rather that initial development. Given that the theoretical potential of the energy available from this resource in New Zealand is around 3 GigaWatts, equivalent to 2 or 3 nuclear power stations, it is a little disappointing that it hasn't shown up on the EECA radar. Trevor PS: The equivalent head of water pressure is of the order of 220 metres, or 21.5 atmospheres. http://dbhs.wvusd.k12.ca.us/webdocs/Solutions/Osmosis-Equation.html Another site gives 27.8 atmospheres and the convenient value of 0.77 kiloWatt-Hours per cubic metre: http://urila.tripod.com/desalination.htm (The difference in values from these two sites is largely or wholely due to taking different sea water salt concentrations.) It is interesting that Osmotic Power didn’t even get a mention in the EECA’s 2006 status report (the 2007 report isn’t available)
http://www.eeca.govt.nz/eeca-library/renewable-energy/report/renewable -energy-industry-status-report-06.pdf

nor did it get a mention under marine power resources
http://www.eeca.govt.nz/renewable-energy/marine.html

You can’t even apply for funding for Osmotic Power development under the Marine Energy Fund because this is restricted to devices that “converts wave or tidal stream energy into electricity”, although to be fair, this fund is for deployment rather that initial development.

Given that the theoretical potential of the energy available from this resource in New Zealand is around 3 GigaWatts, equivalent to 2 or 3 nuclear power stations, it is a little disappointing that it hasn’t shown up on the EECA radar.

Trevor

PS: The equivalent head of water pressure is of the order of 220 metres, or 21.5 atmospheres.

http://dbhs.wvusd.k12.ca.us/webdocs/Solutions/Osmosis-Equation.html

Another site gives 27.8 atmospheres and the convenient value of 0.77 kiloWatt-Hours per cubic metre:
http://urila.tripod.com/desalination.htm

(The difference in values from these two sites is largely or wholely due to taking different sea water salt concentrations.)

]]> By: Trevor29 http://blog.greens.org.nz/2007/12/26/the-swarm/#comment-36138 Trevor29 Sat, 12 Jan 2008 12:21:37 +0000 http://blog.greens.org.nz/2007/12/26/the-swarm/#comment-36138 Here is another wierd source of energy - fresh water, or more specifically osmotic pressure. A Norwegian company seems to be one of the leaders... http://www.statkraft.com/pub/innovation/teknologiutvikling_i_statkraft/saltkraft/hva_er_osmose.asp http://ec.europa.eu/research/energy/pdf/other_res05_aaberg.pdf Given the number of rivers that we have flowing into the sea, this has to be a significant possible resource for New Zealand, with the benefit of continuous power production, night and day, if the water is flowing. They estimate the resource in Norway is 25,000 GigaWatt-Hours per annum. Trevor. Here is another wierd source of energy - fresh water, or more specifically osmotic pressure. A Norwegian company seems to be one of the leaders…
http://www.statkraft.com/pub/innovation/teknologiutvikling_i_statkraft  /saltkraft/hva_er_osmose.asp

http://ec.europa.eu/research/energy/pdf/other_res05_aaberg.pdf
Given the number of rivers that we have flowing into the sea, this has to be a significant possible resource for New Zealand, with the benefit of continuous power production, night and day, if the water is flowing. They estimate the resource in Norway is 25,000 GigaWatt-Hours per annum.

Trevor.

]]> By: Kevyn http://blog.greens.org.nz/2007/12/26/the-swarm/#comment-36125 Kevyn Sat, 12 Jan 2008 03:00:24 +0000 http://blog.greens.org.nz/2007/12/26/the-swarm/#comment-36125 BJ, Frankly, I'd rather be nailed to a wall than be lost in space listening to "Never fear Nick Smith is here". Actually, this is the down to Earth technology I was referring too. http://www.solarwall.com/home/whatsnew.aspx http://www.solarwall.com/home/data/Image/CaseImages/Ford%20Motor%20Company.pdf BJ,

Frankly, I’d rather be nailed to a wall than be lost in space listening to “Never fear Nick Smith is here”.

Actually, this is the down to Earth technology I was referring too.
http://www.solarwall.com/home/whatsnew.aspx
http://www.solarwall.com/home/data/Image/CaseImages/Ford%20Motor%20Com pany.pdf

]]> By: Trevor29 http://blog.greens.org.nz/2007/12/26/the-swarm/#comment-36115 Trevor29 Fri, 11 Jan 2008 22:10:10 +0000 http://blog.greens.org.nz/2007/12/26/the-swarm/#comment-36115 The efficiency of eletrolying water to hydrogen isn't horribly bad. One company is achieving more than 75% and getting close to doing this at power densities of 1 Ampere per square cm. However the efficiencies going the other way are worse. Remember that energy is never destroyed. Low efficiencies normally mean heat is generated instead, so if that heat is useful, then the effective efficiency isn't as bad. This means that if you can use the waste heat from your hygrogen fuel cell to heat your buildings or your hot water, the net losses aren't horrible. Of course, if you can use the hydrogen as it is, then the conversion efficiencies of fuel cells or engines don't enter the picture. Heat for cooking and industrial processes come to mind, but New Zealand already manufactures hydrogen for use in ammonia manufacture and the oil refinery. Trevor. The efficiency of eletrolying water to hydrogen isn’t horribly bad. One company is achieving more than 75% and getting close to doing this at power densities of 1 Ampere per square cm. However the efficiencies going the other way are worse.

Remember that energy is never destroyed. Low efficiencies normally mean heat is generated instead, so if that heat is useful, then the effective efficiency isn’t as bad. This means that if you can use the waste heat from your hygrogen fuel cell to heat your buildings or your hot water, the net losses aren’t horrible.

Of course, if you can use the hydrogen as it is, then the conversion efficiencies of fuel cells or engines don’t enter the picture. Heat for cooking and industrial processes come to mind, but New Zealand already manufactures hydrogen for use in ammonia manufacture and the oil refinery.

Trevor.

]]> By: Trevor29 http://blog.greens.org.nz/2007/12/26/the-swarm/#comment-36114 Trevor29 Fri, 11 Jan 2008 22:02:34 +0000 http://blog.greens.org.nz/2007/12/26/the-swarm/#comment-36114 One idea that was believed to be feasible right now was a set of solar power satellites in low earth orbit, each equipped with a pair of high power infra-red lasers. The laser frequency (colour) would be tuned to one absorbed by water molecules in the air. Relatively standard aircraft would have laser targets on top, near the tail (similar to the American Air Force's AWAC planes in appearance) which simply heat up when hit by the laser beam. This heat then drives jet engines mounted on the tail. The plane takes off and lands using its conventional engines and then when it gets high enough, it calls up the satellite and the satellite hits its target with the laser. The extra jets start working and the pilot shuts down or backs off the conventional engines, saving most of the fuel. The lasers would be focussed on the height of the plane, so if they miss, the beam that hits the ground is defocussed, and largely absorbed by the water in the atmosphere below the plane (remember the plane is flying at 30,000 feet or higher, above most of the atmosphere) and of course the beam is sweeping a large area of ground (at >500 miles per hour). These are passive safeguards so no significant injuries would occur to anyone illuminated by the beam. However there would be active safeguards as well, so the beams would be shut down automatically if they aren't directed onto the plane's target. I expect that the plane would carry enough fuel so it isn't reliant on the lasers to get to a safe landing site - even for a Trans-Atlantic crossing. For a long flight, the aircraft would need to be switched between satellites. This would also largely solve the problem of a satellite moving into the earth's shadow for a while. Sounds scary, and impractical but it isn't as far fetched as it seems and doesn't require new technology such as nano-tubes. Trevor. One idea that was believed to be feasible right now was a set of solar power satellites in low earth orbit, each equipped with a pair of high power infra-red lasers. The laser frequency (colour) would be tuned to one absorbed by water molecules in the air. Relatively standard aircraft would have laser targets on top, near the tail (similar to the American Air Force’s AWAC planes in appearance) which simply heat up when hit by the laser beam. This heat then drives jet engines mounted on the tail. The plane takes off and lands using its conventional engines and then when it gets high enough, it calls up the satellite and the satellite hits its target with the laser. The extra jets start working and the pilot shuts down or backs off the conventional engines, saving most of the fuel. The lasers would be focussed on the height of the plane, so if they miss, the beam that hits the ground is defocussed, and largely absorbed by the water in the atmosphere below the plane (remember the plane is flying at 30,000 feet or higher, above most of the atmosphere) and of course the beam is sweeping a large area of ground (at >500 miles per hour). These are passive safeguards so no significant injuries would occur to anyone illuminated by the beam. However there would be active safeguards as well, so the beams would be shut down automatically if they aren’t directed onto the plane’s target. I expect that the plane would carry enough fuel so it isn’t reliant on the lasers to get to a safe landing site - even for a Trans-Atlantic crossing. For a long flight, the aircraft would need to be switched between satellites. This would also largely solve the problem of a satellite moving into the earth’s shadow for a while.

Sounds scary, and impractical but it isn’t as far fetched as it seems and doesn’t require new technology such as nano-tubes.

Trevor.

]]> By: bjchip http://blog.greens.org.nz/2007/12/26/the-swarm/#comment-36105 bjchip Fri, 11 Jan 2008 13:12:40 +0000 http://blog.greens.org.nz/2007/12/26/the-swarm/#comment-36105 24 hour a day sun. Solar intensity greatly increased. No need to clean the dust off. Easy transmission to remote sites and sites that seldom get ANY sun. -------------------- Side benefit... after working out the construction problems of large arrays and mirrors in space we also get the ability to alter the solar insolation of the entire planet, access to every rock in the asteroid belt and colonies in space. The human species leaves the planet. Try to do that while you're nailed to your wall. BJ 24 hour a day sun.

Solar intensity greatly increased.

No need to clean the dust off.

Easy transmission to remote sites and sites that seldom get ANY sun.

——————–

Side benefit… after working out the construction problems of large arrays and mirrors in space we also get the ability to alter the solar insolation of the entire planet, access to every rock in the asteroid belt and colonies in space.

The human species leaves the planet.

Try to do that while you’re nailed to your wall.

BJ

]]> By: Kevyn http://blog.greens.org.nz/2007/12/26/the-swarm/#comment-36103 Kevyn Fri, 11 Jan 2008 12:56:32 +0000 http://blog.greens.org.nz/2007/12/26/the-swarm/#comment-36103 Er, why put something in space when you could just stick something on your wall and get the same nett effect? Perchance because Dr Who is "sexier" than Bob the Builder? http://www.thegreenpowergroup.org/solarthermal.cfm?loc=us Er, why put something in space when you could just stick something on your wall and get the same nett effect? Perchance because Dr Who is “sexier” than Bob the Builder?

http://www.thegreenpowergroup.org/solarthermal.cfm?loc=us

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