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: [email protected] [mailto:[email protected]] 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 <[email protected]> wrote: From: Edgar Warf <[email protected]> Subject: [USMA:46067] Re: Treatise on renewable energy To: "U.S. Metric Association" <[email protected]> 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 <[email protected] <http://us.mc824.mail.yahoo.com/mc/[email protected]> > 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.
