Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!henry From: henry@utzoo.UUCP (Henry Spencer) Newsgroups: net.followup Subject: Re: Alternate Energy & Microwaves Message-ID: <4196@utzoo.UUCP> Date: Thu, 9-Aug-84 20:45:47 EDT Article-I.D.: utzoo.4196 Posted: Thu Aug 9 20:45:47 1984 Date-Received: Thu, 9-Aug-84 20:45:47 EDT References: <565@hou2h.UUCP> Organization: U of Toronto Zoology Lines: 23 >> Microwaves have been proposed for power transmissions, but whenever I think >> of microwaves carrying enough energy to actually be useful, I keep on seeing >> all these birds, airliners, etc. flying through the beam and getting cooked. Airliners are no problem; they have metal skins, which reflect microwaves quite well. The beam intensities are too low to have any gross effects on birds, although there is some concern about long-term low-level effects on them. This is actually the most (!) serious known problem. > The proposed SunSat (SPS, whatever) uWave beams carry less energy (even in > the center of the beam!) than full sunlight; their advantage is that they > irradiate the rectenna (RECtifying anTENNA, as I recall) 24 hrs/day and are > unblocked by clouds... They have another big advantage: microwave-to-electricity conversion can be quite efficient (70-80%), whereas converting sunlight to electricity is dismally inefficient (15% is good for solar cells). Of course, the power satellite itself probably uses solar cells, but it is out in space, where (a) the sun shines 24 hours/day, and (b) the waste heat does not go into Earth's biosphere. -- Henry Spencer @ U of Toronto Zoology {allegra,ihnp4,linus,decvax}!utzoo!henry