> On Dec 1, 2020, at 4:29 PM, jim--- via EV <[email protected]> wrote: > Bill, you better check your math. It would take a lot more than "a few > square kilometers of solar panels put up to supply the entire world’s energy > needs". In very rough numbers, a square kilometer of fairly high conversion > rate solar panels is about 250 MegaWatts for roughly a quarter of the day
…and I accuse other people of being innumerate, while blathering on from memory of having worked out numbers myself a long time ago. I suspect that my use of “a few” meaning “not all of New Mexico or Algeria” may be the source of the disagreement here. So… Right now, we’re using about 18tW of energy total, of which 2.5tW are currently electrical, and much of the remainder is inefficiency from petrochemical processes. Do we agree on these numbers? I just pulled them from public governmental reports. So, let’s be generous and say that it would be 10tW if it were 100% electrical. Your figures of 250mW/k^2 x six hours per day seem to be uncontroversial, which means (hand-waving about storage and peak-shaving and so forth), we get 62.5mW per k^2. Which puts us at 40,000 km^2 if we were to ignore or shut down all other sources of power (hydroelectric, wind, etc.) which clearly wouldn’t be necessary. Note that this is FOUR TIMES more pessimistic than David J.C. MacKay was… He said 10,000km^2, and other analyses are saying that he was pessimistic by a further factor of two: https://energypost.eu/10000-sq-km-of-solar-in-the-sahara-could-provide-all-the-worlds-energy-needs/ But, to proceed with your numbers, the uninhabited portion of New Mexico (to pick a sunny US state arbitrarily) is 319,000 km^2, of which we could use 12%. The uninhabited portion of Algeria (to pick a sunny African country arbitrarily) is 2,381,000 km^2, of which we could use 1.6%. The uninhabited portion of Australia (to pick a sunny Oceanic country arbitrarily) is 7,692,000 km^2, of which we could use half a percent. These are not big portions of otherwise unused land. Cost figures for large solar farms seem to be in the range of USD 42M / km^2, which means a total cost of about USD 1.7T, or about three months worth of fossil fuel subsidy at current rates. So, very cheap by comparison with the amount of money we’re flushing down the toilet to keep ICE junkers on the road. Do those numbers all seem reasonable to you? -Bill -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 833 bytes Desc: Message signed with OpenPGP URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20201201/d3cdcddc/attachment.sig> _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub ARCHIVE: http://www.evdl.org/archive/index.html INFO: http://lists.evdl.org/listinfo.cgi/ev-evdl.org Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
