Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!ucsd!ucbvax!janus.Berkeley.EDU!cameron From: cameron@janus.Berkeley.EDU (Mike Williamson) Newsgroups: ba.transportation,ca.environment,sci.electronics Subject: Re: Fuel efficiency Message-ID: <38826@ucbvax.BERKELEY.EDU> Date: 27 Sep 90 08:04:04 GMT References: <38776@ucbvax.BERKELEY.EDU> <70019@sgi.sgi.com> <8220@ptolemy.arc.nasa.gov> <34284@cup.portal.com> Sender: usenet@ucbvax.BERKELEY.EDU Reply-To: cameron@janus.Berkeley.EDUIn article <34284@cup.portal.com> Ordania-DM@cup.portal.com (Charles K Hughes) writes: Lines: 29 >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