Re: How will air travel work in a green solar economy?

Wed, 09 Jul 2014 17:18:24 -0700 



________________________________
 From: meekerdb <[email protected]>
To: [email protected] 
Sent: Wednesday, July 9, 2014 4:42 PM
Subject: Re: How will air travel work in a green solar economy?
 


On 7/9/2014 11:19 AM, 'Chris de Morsella' via Everything List wrote:


>
>
>
>Liquid hydrogen is hard to make and store (it needs to be liquefied to near 
>absolute zero -- an energy intensive process all by itself); the volumetric 
>density of liquid hydrogen is not all that impressive either. Liquid hydrogen 
>is also aggressive chemically and causes metal tank walls to become brittle 
>over time. Biofuels seem superior
>>Yeah, hydrogen can be no more than an energy delivery medium.  It's not a 
>>primary power source.  As a delivery medium it sucks.  

Hydrogen is an energy carrier; it is not an energy source (unless we are 
talking about fusion of course), but even then ultimately no energy is created 
or destroyed, only transformed.

>>But biofuels, which are primary (solar) energy source, are
      extremely inefficient.  Corn to alcohol barely exceeds one on the
      EROI.  Maybe some genetic engineered algae will do a lot better
      but I doubt they will come close to wind, hydro, and solar-thermal
      or even photovoltaic technology.

I completely agree with you here. Corn ethanol actually has a negative EROI 
according to many studies I have seen. The only reason we have a corn ethanol 
sector at all is because of the political power of the Big Ag. It has been a 
huge drain of resources that could have been better spent instead developing 
other energy harvesting infrastructures such as wind/solar.

The kind of biofuels that I think may have a future role to play are the (often 
genetically modified) algae biofuels, especially those that can be produced in 
brackish or salty water) I have researched these -- and they still have 
production issues -- principally trouble harvesting (squeezing) the oils out of 
the biomass without gunking up the processors), but the potential yields per 
hectare make even palm oil yields look small by comparison. It is these kinds 
of algae based biofuels that may -- IMO -- play a role in supplying aviation 
fuel.
The main advantage being that the existing infrastructure and stock of jet 
aircraft can be used with little or no modification.
But, to be clear there is no magic bullet or panacea in energy matters. It will 
be hard work and the EROI will be less than the EROI we get from pumping 
petroleum out of the ground (while it lasts)
Cheers,
Chris 

Brent



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