Path: utzoo!attcan!uunet!shelby!apple!rutgers!mcnc!ncsuvx!news From: ghhart@eos.ncsu.edu (GREGORY HUGHES HART) Newsgroups: ba.transportation,ca.environment,sci.electronics Subject: Re: Fuel efficiency Message-ID: <1990Sep27.185524.21413@ncsuvx.ncsu.edu> Date: 27 Sep 90 18:55:24 GMT References: <38776@ucbvax.BERKELEY.EDU> <70019@sgi.sgi.com> <8220@ptolemy.arc.nasa.gov> <34284@cup.portal.com> <38826@ucbvax.BERKELEY.EDU> Sender: news@ncsuvx.ncsu.edu (USENET News System) Reply-To: ghhart@eos.ncsu.edu (GREGORY HUGHES HART) Organization: North Carolina State University Lines: 40 In article <38826@ucbvax.BERKELEY.EDU>, cameron@janus.Berkeley.EDU (Mike Williamson) writes: > >The power from the sun, even at the god awful conversion rate of 10% (or > >whatever solar cells happen to have currently) is much better than > >burning fossil fuels. > > Just so's people get an idea of how much power we're talking about currently, > there's about (extremely roughly) 1 kilowatt per square meter during the sunny > hours in the middle of the day (provided there's no clouds - but even with > some clouds a decent amount of power gets through). At the nominal efficiency > of 10% this is about 100 watts/sqare meter. Three people live at my house, > and our average daily useage is about 10 kilowatt-hours. (PG&E rates are > about 10 cents a kWh so this is about a dollar a day). > > So, to generate that power, given 5 hours of solar collection, takes about > 2 kW, which at 10% efficiencies is 20 square meters - less than the surface > area of our roof. > > The spatial dimensions are right, but panel efficiencies and panel and system > costs are still prohibitive, unless you build a house away from PG&E lines > (which a lot of people do in remote areas of the state). So let's work on > cost and efficiency! Rah! Go bears! Anyway, just some rough figures to > stimulate some thought about the rough state of the technology. No criticisms > should be directed at this because I am disclaiming all this as super-approx- > imate and I am not trying to push anything down anyone's throat, I'm simply > posting this for those who have no idea how much (to lowest order) power and > cost is involved. > > Respectfully yours, > > Mike Hasn't there been some advancement in solar cells recently by using something (germanium-something) instead of silicon, with an efficiency of much more than 10% (25-30%?) Anyone know the latest?