Comments for NASA Funding Satellite That Would Beam Solar Power Down to Earth at http://www.ecogeek.org , comment 1 to 17 out of 17 comments http://www.ecogeek.org Thu, 23 May 2013 07:29:13 +0100 FeedCreator 1.7.3 http://www.ecogeek.org/solar-power/3745-nasa-funding-satellite-that-would-beam-solar-power#comment-46832 The devil is always in the details, details they haven't looked at yet. Launch costs are huge, and I didn't see any mention of assembly costs. It's also easy to draw a nice beam of energy that connects the satellite to the receiver but no real antenna works that way. All have sidelobes. Further, there's no such thing as a receiving antenna that is 100% efficient, so along with the energy the antenna receives there's the question of dealing with the energy it doesn't, i.e. the energy that is just heating up the receiving site. There's issues of spacecraft stability to prevent the beam from wandering off the receiver and cooking the local critters (or humans). One BIG detail is that is one awfully big target for space junk. A target that can't be moved. So you hit one mirror with some piece of junk, and the junk becomes thousands of little pieces still moving at close to orbital speeds and what's in front of all those pieces? The rest of the mirrors. Basically it becomes a giant, hypervelocity scattergun. NASA should spend its seed money elsewhere. - Bob Thu, 14 Jun 2012 15:41:06 +0100 http://www.ecogeek.org/solar-power/3745-nasa-funding-satellite-that-would-beam-solar-power#comment-46795 I know it's just in the early stages but this looks so ridiculously promising. This makes my day just a bit better after learning republicans are trying to repeal mercury limit laws. I really hope energy corporations could see the potential behind projects like these and start investing. - Robert Mon, 11 Jun 2012 15:35:38 +0100 http://www.ecogeek.org/solar-power/3745-nasa-funding-satellite-that-would-beam-solar-power#comment-46408 If you go through the design of a power satellite, such as was done here: http://www.sspi.gatech.edu/aiaa-2009-0462_ssp_alternatives_potter.pdf you get numbers around a dollar a kWh. Clearly a non starter. Another approach is to set the cost of power at some number such as two cents (about half the price of power from burning coal) and see what has to be adjusted for the project to hit the goal. The main thing is the cost of lifting millions of tons of parts to geosynchronous orbit. That has to come down to around $100/kg for power satellites to meet the price target. (Or the mass per kW has to be very low.) That seems to be possible, but not with chemical rockets, the performance isn't good enough and the payload fraction is too small. But air breathing flight till you run out of air and laser heated hydrogen beyond that looks like it will achieve the target price. http://www.theoildrum.com/node/7898 The low transport cost will grow out of using the early power satellites to power propulsion lasers. - Keith Henson Wed, 25 Apr 2012 20:15:40 +0100 http://www.ecogeek.org/solar-power/3745-nasa-funding-satellite-that-would-beam-solar-power#comment-46407 It's not for EARTH, it's for SPACE! A central power station for satellites!!!!! - Gareth Field Wed, 25 Apr 2012 19:51:25 +0100 http://www.ecogeek.org/solar-power/3745-nasa-funding-satellite-that-would-beam-solar-power#comment-46404 I don't like the sound of microwave beams, either! Another article from Physorg, [u]Space-Based-Solar Power Coming to California[/u], introduces a company working on beaming radio waves to earth via a solar collecting satellite. "In Solaren's proposal, solar power satellites would be positioned in stationary orbit about 22,000 miles above the equator. The satellites - whose arrays of mirrors could be several miles across - would collect the sun's rays on photoelectric cells and convert them into radio waves. ... Because the radio beam is spread out over a wide area, it would not be dangerous to people, airplanes, or wildlife." It goes on to say: "Japan's space agency, JAXA, has recently begun testing a space-based solar array that beams energy to Earth in the form of microwaves. If the tests are successful, the agency plans to launch an array of satellites that would transmit power to a 1.8-mile-wide receiving station, which would generate enough electricity to power about half a million homes." I imagine they're desperate to come up with an alternative to nuclear. I hope it doesn't create another disaster for them! - Harriet Wed, 25 Apr 2012 16:03:57 +0100 http://www.ecogeek.org/solar-power/3745-nasa-funding-satellite-that-would-beam-solar-power#comment-46380 Just how orbital solar power would work has been worked out in pretty fine detail. In most proposals the satelite would be in geosynchronos orbit and would bream microwaves of an intensity that aren't dangerous enough to be used as a weapon to a receiver on earth. The efficiency of beaming microwaves and converting them back to electricity should be over 80%. There would be brief periods when the satellite would be in the earth's shadow, but it would be possible for another satellite to take up the slack. The drawback is cost. Even though solar cells in space might produce seven times as much energy as ones in a cloudy location on earth, we currently can't even build a satellite solar power system that can compete with ground based solar and other generating capacity, let alone build it and launch it into high orbit. Orbital solar power needs lower satellite construction costs, lower launch costs, and/or the the use of raw materials in space to be cost effective. But there is a market for improved solar power systems for satellites, so people will continue working on improvements in this area. - Ron Sat, 21 Apr 2012 05:03:32 +0100 http://www.ecogeek.org/solar-power/3745-nasa-funding-satellite-that-would-beam-solar-power#comment-46374 I always thought this was one of those crazy ideas for the far future, but i'd be open to persuasion if the inventor could give us some further details: Has it been costed out? What's the cost per installed megawatt at today's launching costs? How are they going to steer the beam safely to the ground reciever and avoid cooking anyone? How does the ground station work, and how efficient will the conversion procees be? How will the ground station remain in line-of-sight as the world rotates? If it's geostationary won't there be dead-time? Will it need multiple ground stations? If all this has been worked out then the proposal will be much more noteworthy. - Magnus Fri, 20 Apr 2012 08:27:02 +0100 http://www.ecogeek.org/solar-power/3745-nasa-funding-satellite-that-would-beam-solar-power#comment-46366 These devices represent a NET increase in the amount of energy being released in the earth's atmosphere. If enough of these devices were in operation, the effect could be very significant. The only way to counterbalance the effect would be to remove the equivalent number humans from the planet necessary to counterbalance the effect. I am guessing you would need to process several thousand humans a day to keep things manageable. - nathan Thu, 19 Apr 2012 23:58:43 +0100 http://www.ecogeek.org/solar-power/3745-nasa-funding-satellite-that-would-beam-solar-power#comment-46359 [i]"The satellite could feasibly send a constant stream of microwaves because of its position -- possibly thousands of megawatts worth. That constant stream of unlimited energy would utlimately make any upfront costs totally negligible and could bring a huge leap in amount of renewable energy fed to the grid. Truly, this is the stuff that clean tech dreams are made of.[/i]" This kind of language is extremely silly. A set of mirrors and PV cells would produce a finite amount of energy over their life time. If you this energy into the cost (which in spite of relative 'light' components could be immense since they have to be lifted out of a deep gravity well) you get a cost per kWh just like any other technology. Maybe the author is getting excited about avoiding the intermittency issues of earth based renewable energy, but any time someone talks about 'unlimited' energy you know that they are living in a fantasy world. - Roger Brown Thu, 19 Apr 2012 20:23:31 +0100 http://www.ecogeek.org/solar-power/3745-nasa-funding-satellite-that-would-beam-solar-power#comment-46354 in concept it would seem that a roaming satelite could harness a greater concentration of the suns energy maybe up to 10-100 times the power of a earth solar receptor also if it rotates with the sun it could absorb the suns energy 24 hours a day seems pretty awesome to me - erik Thu, 19 Apr 2012 11:52:30 +0100 http://www.ecogeek.org/solar-power/3745-nasa-funding-satellite-that-would-beam-solar-power#comment-46346 Satellites have been converting solar energy into microwaves and beaming them down to earth for a long time and we have been gradually improving this process. But we are quite definitely, absolutely, not near a point where it is cost effective to generate electricity from these microwave transmissions. Building better and cheaper methods of solar powering satellites is a good idea and there is a market for it, but getting solar energy from space is not currently economically viable, and it will be quite some time before there is any chance of it being viable. - Ron Wed, 18 Apr 2012 21:43:30 +0100 http://www.ecogeek.org/solar-power/3745-nasa-funding-satellite-that-would-beam-solar-power#comment-46345 Since we would be beaming additional energy into our atmosphere (that we would not normally have obtained from the sun), would there be concerns about climate change? Seems this would be counter-productive... - curious observer Wed, 18 Apr 2012 12:08:34 +0100 http://www.ecogeek.org/solar-power/3745-nasa-funding-satellite-that-would-beam-solar-power#comment-46342 What is global warming: To much heat from the sun captured by earth greenhouse effect. And what is this project? [b]Harvest more energy from the sun, and beam it to earth [/b] >:( [i]Nasa wants to coock us?[/i] :P - Tom34 Wed, 18 Apr 2012 08:38:25 +0100 http://www.ecogeek.org/solar-power/3745-nasa-funding-satellite-that-would-beam-solar-power#comment-46338 Can imagine a company like Verizon charging a separate "service fee" to keep my cell phone battery "fully charged". - Ml Tma Tue, 17 Apr 2012 23:12:11 +0100 http://www.ecogeek.org/solar-power/3745-nasa-funding-satellite-that-would-beam-solar-power#comment-46337 The design is brilliant however any microwave transmission that is concentrated is a weapon, any microwave transmission that is not a weapon would have too large of a collection area. - Ipad41001 Tue, 17 Apr 2012 23:03:50 +0100 http://www.ecogeek.org/solar-power/3745-nasa-funding-satellite-that-would-beam-solar-power#comment-46336 We could get it from the SUN... - me Tue, 17 Apr 2012 20:31:17 +0100 http://www.ecogeek.org/solar-power/3745-nasa-funding-satellite-that-would-beam-solar-power#comment-46335 Sim City already did this! - Jim Tue, 17 Apr 2012 17:10:33 +0100