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[HailMan06]

How much biomass would be needed to produce enough hydrogen to replace our FF demand?

[PhillipS]

How much biomass would be needed to produce enough hydrogen to replace our FF demand?

 

Here is the figure from the paper's abstract:

 

 

 

What immediately struck me is that in addition to xylose the reaction consumes 5 molecules of H2O and produces 5 molecules of CO2 for every 10 molecules of H2.  Phrased another way, to produce 1 metric ton (1,000 kg) of H2 with this reaction consumes 7.5 tons of xylose and 4.5 tons of water, and produces 11 tons of CO2 as waste.  If the biomass source is 30% xylose (the highest figure given in the article) then producing 1 ton of H2 requires 25 tons of biomass feedstock.  Which, of course, takes fuel to grow, harvest, and transport to the converter.

 

Compare this reaction to that of electrolysis of water with electricity from PV or wind.  2H2O => 2H2 + O2.  Producing 1 ton of H2 requires 9 tons of H2O and the 'waste'  from the reaction is 8 tons of O2.  No C02 or other GHG whatsoever.

 

I'm skeptical that this new process will make it through commercialization - but I've been wrong many times before.

[HailMan06]

Here is the figure from the paper's abstract:

What immediately struck me is that in addition to xylose the reaction consumes 5 molecules of H2O and produces 5 molecules of CO2 for every 10 molecules of H2. Phrased another way, to produce 1 metric ton (1,000 kg) of H2 with this reaction consumes 7.5 tons of xylose and 4.5 tons of water, and produces 11 tons of CO2 as waste. If the biomass source is 30% xylose (the highest figure given in the article) then producing 1 ton of H2 requires 25 tons of biomass feedstock. Which, of course, takes fuel to grow, harvest, and transport to the converter.

Compare this reaction to that of electrolysis of water with electricity from PV or wind. 2H2O => 2H2 + O2. Producing 1 ton of H2 requires 9 tons of H2O and the 'waste' from the reaction is 8 tons of O2. No C02 or other GHG whatsoever.

I'm skeptical that this new process will make it through commercialization - but I've been wrong many times before.

Totally agree with your cynicism. On my phone so I can't post a link but according to wikipedia the 30% figure is the higher range, mainly coming from birch. Most other plants have a xylose concentration of ~12%, much lower than what this article would lead one to believe. I just feel like if were to go down this path would be consuming a ridiculus amount of plant matter to get all of this hydrogen. Also what will happen to all the plant waste that would be produced from such a process? Will it just disappear, never to be burned or decompose thus releasing GHG's? I just see too many holes in this solution to seriously replace FF anytime soon.

[AvantHiatus]

Well, that's the opposite reaction you would expect to a key issue such as Global Warming/Climate Change. It appears money will win the day once again and the world will continue on a rather unecessary path. In my opinion, fossil fuel independence has been possible since the 20th century but has not been implemented on a large scale.

 

1.) Solutions such as hydrogen harvesting are not economically viable and require too much investment.

 

2.) Alternative fuel sources such as electricity require the burning of fossil fuels, albeit to a lesser degree than our current energy structure.

 

3.) Corporate agendas and political lobbyists who keep the market focused on fossil fuel consumption through limiting new laws and technologies that damage the fossil fuel industry.

[PottercountyWXobserver]

Why can't we just keep the electrolysis method produced by renewable energy? No CO2 waste period! It is either electrolysis method, or electric vehicles fueled with renewable energy.