Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!linus!decvax!tektronix!hplabs!sri-unix!KING@KESTREL From: KING%KESTREL@sri-unix.UUCP Newsgroups: net.space Subject: Light Antennae Message-ID: <12222@sri-arpa.UUCP> Date: Wed, 8-Aug-84 16:47:00 EDT Article-I.D.: sri-arpa.12222 Posted: Wed Aug 8 16:47:00 1984 Date-Received: Fri, 10-Aug-84 08:14:52 EDT Lines: 43 From: Richard M. KingI don't see why storage should be considered impractical, since it is already being done on a large scale. We could, for example, only use hydro at night or on cloudy days, doubling or more the amount you get from a given river. (Less power is used at night than during the day.) The fact that an electric car would usually never need to be recharged (A roof+hood area of 3-4 square meters gives about 2KW at noon; if the car has a duty cycle <10%, and most do, it would never taste an electric outlet!) might make them a winner finally. Solar shingles would be a real possibility. (Note that converting sunlight to electricity and using resistance heat is more efficient than most solar collectors, if you believe the 75-80% figure. Also, the efficiency of a thermal collector falls proportionally to the insolation (virtually nil on a cloudy day), and this wouldn't. An article in Technology Review of about 1 1/2 years ago gave about 3-4 cents/KWH as the cost of the home storage unit (Flywheel, Kevlar, ball bearings, permanent magnet motor/generator, evacuated) and approx 10 cents/ KWH for the collectors. (This is from memory; correct me if I'm wrong.) With the cells so cheap and efficient we can afford to provide enough to power our load on cloudy days! To summarize, the major uses of energy can adapt well to this source: ground transport electric cars with receiver roof domestic thermal (600 degree cast iron stores 20 KBTU/cu. ft; you need a 4 foot cube to heat a house for 48 hours) electrical (flywheels, batteries, whatever!) commercial easier than domestic; less happens at night heavy industry store the product! (Seriously, we would need twice as much (say) aluminum smelting capacity to meet America's need as we do now (assuming existing plants run at night - do they?) but the major cost of Aluminum is the electricity. These comments were jotted down very quickly - pardon any inaccuracies. -------