You forgot to mention, that the production of hydrogen is an enery sink, i. e. for the production of 1 kW of Hydrogen enery you need 1,5 kW of traditional (nuclear, fossil, sun) energy.
You better use that energy directly. Reinhard Henning "Keith Addison" <[EMAIL PROTECTED]> schrieb: > Forward from the stoves list at Crest. > > >Delivered-To: mailing list [EMAIL PROTECTED] > >From: "Tom Reed" <[EMAIL PROTECTED]> > >Subject: Hydrogen Economy greatly overrated, biomass underrated... > >Date: Sat, 21 Sep 2002 14:18:03 -0600 > >Organization: BEF > > > >Dear All Biomassers: > > > >The message below from my good friend Tom Milne, Bob Evans and all > >anouncing a new report on hydrogen needs to be put in context. > >Speaking as a fuel scientist, I hope I may be permitted a personal > >diatribe in this forum. If you are emotionally convinced that > >hydrogen is the world's best fuel, and wish to stay convinced, > >delete this message. . > > ~~~~~~~~~ > >HYDROGEN has been known and used since the early part of the 19th > >century. It is easy to make in the laboratory from iron and HCL or > >by electrolysis. > > > >Hydrogen is unique amongst the elements with outstandingly good and > >bad properties. > > > >As a fuel it has the highest Mass Energy Density of any fuel by a > >large margin, so liquid hydrogen isn't too bad a fuel if you can > >afford the cost and keep it well insulated. As a gas it also has a > >very low Volume energy density (same as CO, 1/3 that of methane). > >It is an important component of synthesis gas (CO + H2) and producer > >gas (CO + H2 + N2). > > > >Hydrogen also has a flame velocity (2.83 m/s in air compared to .5 > >m/s for methane, propane etc.). For this reason it is a difficult > >automotive fuel, since stoichiometric combustion produces "hydrogen > >knock". However, it has the widest flamability limits so can be > >burned very lean for better efficiency. > > > >Another hydrogen problem I haven't heard discussed is that it > >contracts chemically 1/3 on burning according to > > > >H2 + 1/2 O2 [1.5 moles or voumes] ===> H2O [1 mole] > > > >by contrast, methane gets full value, since CH4 + 2 O2 [3 moles] > >===> CO2 + 2 H2O [3moles] > > > >~~~~~~~ > >Hydrogen is an important chemical for converting vegetable oils to > >margarine etc. and is widely used in large chemical plants. > >Electrolysis of water to make hydrogen is only 72% efficient (due to > >high overvoltage), and conversion of heat to electricity is > >typically 30% efficient, so electrolysis is 18% base efficiency. > >Hydrogen can be made from methane and hydrocarbons using steam > >reforming and the water gas shift reaction - probably 80% efficient. > > > >So for 150 years pure hydrogen was only used by quartz workers. > >However, many gases, including our producer gas, can contain large > >fractions of hydrogen - 18% in our current producer gas at CPC. > > > >~~~~~~~~ > >So how has hydrogen risen so high in research circles as a target fuel? > > > >It all started with "The Hydrogen Economy" about 1970. At that time > >we were naively told that nuclear electric power would be too cheap > >to meter in a short time (Ha!). But you can't run a car on > >electricity so we would still need a "fuel tank". Since power had > >no cost, hydrogen from water would have no cost! Voila. I remember > >hearing these arguments at the first "Hydrogen Economy" conference > >held appropriately at the Playboy Club in Miami about 1974. > > > >We have since become disenchanted with the nuclear energy side of > >this argument, but dreamers still talk of hydrogen combustion being > >"non polluting" and therefore the ultimate fuel. > > > >Today's cars are amazingly clean compared to those of the smoggy > >''70s, so they are relatively "non polluting" in the atmospheric > >sense. However our current fossil fuels do increase atmospheric CO2 > >levels so can be considered "polluting" from a global warming > >perspective. Don't worry, the oil will be gone soon at the present > >rate of usage/wastage. > > > >For a REALISTIC view on hydrogen, check out.. > >http://www.nrel.gov/ncpv/hotline/pdf/hydrogen_economy.pdf > > > >Your Skeptical Fuel Scientist, TOM REED > >BEF GASWORKS > > > >----- Original Message ----- > >From: "Milne, Thomas" [EMAIL PROTECTED]> > >To: "Milne, Thomas" [EMAIL PROTECTED]>; [EMAIL PROTECTED]>; > >[EMAIL PROTECTED]>; [EMAIL PROTECTED]> > >Sent: Friday, May 24, 2002 12:36 PM > >Subject: GAS-L: RE: Biomass to Hydrogen Report Web Address > > > > > > > > > > > > -----Original Message----- > > > > From: Milne, Thomas > > > > Sent: Friday, May 24, 2002 11:27 AM > > > > To: <mailto:'[EMAIL PROTECTED]'>'[EMAIL PROTECTED]'; > ><mailto:'[EMAIL PROTECTED]'>'[EMAIL PROTECTED]'; > ><mailto:'[EMAIL PROTECTED]'>'[EMAIL PROTECTED]'; > > > > <mailto:'[EMAIL PROTECTED]'>'[EMAIL PROTECTED]' > > > > Subject: FW: Biomass to Hydrogen Report Web Address > > > > > > > > Interested parties may access our recent IEA report, "Hydrogen from > > > > Biomass--State of the Art and Research Challenges", at the WEB address > > > > listed below. The authors would welcome corrections or additions to > > > > references, as a supplement for Year 2002 is planned. > > > > > > > > Tom Milne, Carolyn Elam and > > > > Robert Evans. > > > > > > > > > > > > -----Original Message----- > > > > From: Elam, Carolyn > > > > Sent: Thursday, February 28, 2002 11:10 AM > > > > To: Milne, Thomas > > > > Subject: Biomass to Hydrogen Report Web Address > > > > > > > > http://www.eren.doe.gov/hydrogen/iea/pdfs/hydrogen_biomass.pdf > > > > Biofuels at Journey to Forever > http://journeytoforever.org/biofuel.html > Biofuel at WebConX > http://www.webconx.dns2go.com/2000/biofuel/biofuel.htm > List messages are archived at the Info-Archive at NNYTech: > http://archive.nnytech.net/ > To unsubscribe from this group, send an email to: > [EMAIL PROTECTED] > > > > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/ > > > -- bagani GbR, Reinhard Henning, Rothkreuz 11, D-88138 Weissensberg, Germany Tel: ++49 8389 984129, Fax: 984128, e-mail: [EMAIL PROTECTED] internet: www.bagani.de ------------------------ Yahoo! Groups Sponsor ---------------------~--> Plan to Sell a Home? http://us.click.yahoo.com/J2SnNA/y.lEAA/ySSFAA/9bTolB/TM ---------------------------------------------------------------------~-> Biofuels at Journey to Forever http://journeytoforever.org/biofuel.html Biofuel at WebConX http://www.webconx.dns2go.com/2000/biofuel/biofuel.htm List messages are archived at the Info-Archive at NNYTech: http://archive.nnytech.net/ To unsubscribe from this group, send an email to: [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
