This topic is at least as appropriate as the number of ml in a mug of beer in the UK.
On Mon, Oct 26, 2009 at 12:16 AM, Martin Vlietstra <vliets...@btinternet.com > wrote: > May I make two points: > > > > 1) A discussion about the pros and cons of renewable energy against > fossil fuels and nuclear fuels is not appropriate for this forum. > > 2) The entire discussion has not put a cost on the effects of > pollution and of climate warming that might be caused by using fossil fuels > or nuclear processes as part of the energy costing equation. > > > > While I believe the latter point to be important, this is not the place to > discuss it. Without discussing it, the first point becomes meaningless. > > > ------------------------------ > > *From:* owner-u...@colostate.edu [mailto:owner-u...@colostate.edu] *On > Behalf Of *John M. Steele > *Sent:* 26 October 2009 00:14 > *To:* U.S. Metric Association > *Subject:* [USMA:46069] Re: Treatise on renewable energy > > > > I accept your efficiency of 20% as a ballpark or typical figure for ICE; I > don't accept it as an absolute maximum. With a variety of techniques, I > think high twenties or even low thirties are achievable, 40 % is NOT > achievable. > > > > At the sweet spot on the engine map, spark ignited engines can operate > above 30% and compression ignited engines near 40%; the problem is the range > of operating conditions and the time spent well off optimum. > > > > Several techniques are being used today to improve this: > > *Higher number of gears in transmissions to ensure more time at optimum > rpm/torque, > > *Engine off at idle and fast restart with hybrid technolgy > > *Regenerative braking (linked with engine off) > > *Hybrid technology so the ICE can be sized closer to cruise power > requirements, and acceleration being supplemented by the electric motor. > > *Direct injection and ultra-lean operation of spark ignited engines can > make efficiency approach diesel (but a lot of extra NOx control is > required). > > > > These will somewhat raise the bar for electric vehicle competition. Range > is not the only area where electric vehicle falls short. The second big > stumbling block is "refueling" time. An ICE with liquid fuel can be refueled > in perhaps 5 minutes and drive another 300-600 miles. A battery operated > vehicle has substantial downtime for recharging. This is acceptable in a > commuter vehicle with a limited drive cycle per day, but is not acceptable > for a car or truck used for long haul driving. > > > > The third uncertainty is battery life, in terms of number of recharges. > > > > There may well be a role for electric vehicles and it could ultimately > replace ICE, but I think this will go VERY slowly. > > > > My point about cheap energy was that we need liquid fuel for > transportation, and with cheap electricity, we may have options for making > that fuel (not from petroleum) that are not currently being looked at. > > --- On *Sun, 10/25/09, Edgar Warf <edgar.w...@gmail.com>* wrote: > > > From: Edgar Warf <edgar.w...@gmail.com> > Subject: [USMA:46067] Re: Treatise on renewable energy > To: "U.S. Metric Association" <usma@colostate.edu> > Date: Sunday, October 25, 2009, 7:02 PM > > John, > > > > I posted this earlier in a separate conversation with someone else, > but I'll *"cut and paste"* some of it here for convenience. > > > > Burning oil for transportation (specifically commuting) is insanity, but I > don't fault prior generations for the development of the internal combustion > engine (ICE), as it has been a stepping stone to get us to where we are > now. The reality of the ICE is that it's a marvel of engineering, and > successive iterations of this machine, over that last 100 years or so, have > evolved it beyond anything the original designers imagined. > > > > Conversely, the weakness of the EV has never been the electric motor. > That's been around for as long as the ICE (mid to late 19th century), but > didn't really come to the fore until the early 20th century. > > > > Rather, the *Achilles heel* of the EV has been (electrical) energy > storage, and with first generation EVs (possibly second generation), we > shouldn't expect much in terms of range initially. As for performance, > ergonomics, and amenities, the EV will (or has) matched that of ICE autos. > > The appeal of *gasoline* (or any fossil fuel) is that it has a very high > *specific > energy* of approximately *47 MJ/kg*. Granted, *the efficiency of an ICE*, > regardless of vehicle type (Prius, Hummer, Malibu, etc.) *is at most 20%*- > delivered as torque to the wheels. > > So, this knocks the *"effective"* specific energy (of an ICE automobile) > down to *9.5 MJ/kg*. That's a little better, but the best electrical > storage medium available today, as you alluded to, (batteries, > ultracapacitors, superconducting magnetic energy storage, etc.) has a > specific energy on the order of 2 to 3 MJ/kg...at most. > > The good news is that some head-turning developments will be announced very > soon (late 2009 into 2010) that will improve that number (MJ/kg), and put > the EV within striking distance of the performance offered an ICE auto using > petroleum. > > So, in no way do I downplay the significance of oil, natural gas, or coal. > > > > With the advent of the EV (supplanting a large portion of transportation > for commuting purposes), I still see oil's role in agriculture, > construction, textiles, plastics, etc. The only difference is that a very > large percentage of oil consumption will be diverted to electrical > consumption, significantly reducing overall oil usage and extending the life > of those reserves even further beyond the 400 years of oil (the Bakken oil > field in the Dakotas or the Canadian oil sands) or the 300+ years of coal > mentioned before. > > > > The only thing I have issue with is the oft-repeated comment about oil's > (or coal's, or natural gas's, or to a lesser extent, uranium's) impending > decline, when that simply isn't true. > > > > Also, if I understood your closing comment correctly, I agree that the > refining or processing of petroleum-based products (gasoline, diesel, > biofuels, etc.) is virtually impossible (in *large-scale refinery > quantities* available today) without the electrically-driven machinery > needed to make these products. > > > > The loss of oil (which is becoming highly unlikely because of new > exploration, coupled with the dawning of algae-derived fuel) would not > necessarily sentence us to a pre-industrial age...because of nuclear > power...or coal-fired generation...or natural gas-fired generation, or > hydroelectric, etc. > > > > In other words, we have options. > > Regards, > Edgar > > On Sun, Oct 25, 2009 at 4:41 AM, John M. Steele < > jmsteele9...@sbcglobal.net<http://us.mc824.mail.yahoo.com/mc/compose?to=jmsteele9...@sbcglobal.net>> > wrote: > > I largely agree with your remarks about electric generation. > > > > However, in my view, liquid, chemical fuel to power the transportation > fleet is an equal underpinning of modern society. Even with vast excessive > supplies of electricity from nuclear power, batteries can not propel our > transportation fleet. Only a fraction of transportation needs can be met by > electrified rail (either third rail or overhead wire). > > > > Large , cheap supplies of electricity may enable some reactions to make > liquid fuel that would otherwise be impractical. > > > > > >
