Saturday, January 11, 2014

Some comments on Sustainable Energy - Without the Hot Air


Some comments on Sustainable Energy - Without the Hot Air
an online and printed book by David JC MacKay
free online at: http://withouthotair.com/

per request from Ruben commenting at http://thearchdruidreport.blogspot.com
http://thearchdruidreport.blogspot.com/2014/01/2030-is-new-2012.html?showComment=1389407037467#c873603237916407394

my original reply at:
http://thearchdruidreport.blogspot.com/2014/01/2030-is-new-2012.html?showComment=1389392387066#c6081143698827059776

Below I've expanded a tiny bit, but generally a cut and paste of a reply to "Will" claiming that Without the Hot Air finds non-fossil energy sources "adequate".

Sustainable Energy - Without the Hot Air is well written and informative, and I recommend it to all interested in sustainability.  Especially since the online version is free, one has very little excuse not to read it.  The premise of MacKay's work - that we must get sustainable, and must be realistic about it - is a breath of fresh air in the storm of metaphorical "hot air" that surrounds the issue of sustainability.

Even though it is written specifically for the UK, one can generalize the process as MacKay goes through the alternatives in enough detail to convey the magnitude of the problems and needed scale of the solutions.  One finds cause for both alarm and some optimism.  However, non-technical issues of politics and economics are not covered in detail, because those are out of his control and expertise.  The gist one can takes home from this is: there is a lot that humanity technically could do to become sustainable, though it would be economically costly and require lifestyle changes, but the even bigger question is will humanity choose to do them?

Adding up current energy consumption and the technical possibilities for sustainable energy sources shows that the UK can almost meet current energy with non-fossil fuel sources.

But as MacKay explains here:
http://www.withouthotair.com/c18/page_103.shtml
" … in calculating our production stack we threw all economic, social and environmental constraints to the wind."

(and note the production stack shown is slightly smaller than the current consumption stack, indicating that some lifestyle changes are inevitable.)

The rest of that chapter he looks at other estimates, and at the politics - and things don't look so rosy. Yes, PV can power the world, if we all had the willpower to accept peak oil… and that we ought to and can do something, and decided to make the massive investments and changes in lifestyle needed. But most people are like Tony Blair - one moment claiming the utmost urgency, but then when asked about not flying to the Barbados for holiday, he dismissed that idea as "a bit impractical actually".
http://www.withouthotair.com/c29/page_230.shtml


Thoughout the book, MacKay keeps telling us he doesn't care which alternatives we choose, just that we must be honest and that the chosen alternatives "must add up!"

My only quibble is that, for nuclear power, MacKay was (in 2009) still buying the line that a Gigawatt coal or nuclear plant cost a billion pounds (roughly a billion Euro, or 1 Euro/watt).
http://www.withouthotair.com/c27/page_211.shtml

Unfortunately, the current nuclear industry, among several incompetencies it has shown, has not been good at cost-effectiveness, and regardless of one's technological leanings pro or con, is becoming irrelevant from a cost perspective.
The EPR (European Pressurized Reactor) going up in Finland, 1600 MWe, was initially 3.7 Billion Euro, but as of 2012, costs are now estimated at 8 Billion Euro.
http://en.wikipedia.org/wiki/European_Pressurized_Reactor#Progress

8 Billion Euro / 1.6 GWe = 5 Euro/We.
In Germany that could build 2+ GWp of photovoltaics (PV), with no fuel costs, and no radioactive waste disposal issue. If PV module costs come down to 50 cents/Wp, and balance-of-systems (BOS) went that low, 20% capacity factor PV would be way way cheaper than "advanced" nukes.

Here's a nice brochure from E.ON on why they decommissioned the Stade nuclear power plant - it was no longer economical.  This was back in 2003, before anyone heard of Fukushima (March 2011).

http://www.eon.com/content/dam/eon-content-pool/eon/company-asset-finder/asset-profiles/stade-power-plant/kernkraft-decommissioning_Stade_en.pdf

So, even though MacKay's book is a tiny bit dated, it's still well worth a look, if you want a nice dose of reality.

====
Not really germane, but I'll leave this in and expand some, since energy storage is quite useful for many renewables to cover the intermittency of PV and wind for example.

Will gave a link to:
http://www.smh.com.au/technology/sci-tech/new-lowcost-highenergy-batteries-could-be-powered-by-rhubarb-plants-20140109-30iok.html
That in turn refers to the abstract in Nature
http://www.nature.com/nature/journal/v505/n7482/full/nature12909.html

In typical sensationalistic press, a bit of rhubarb can save us all.
But as reading MacKay should warn us - we need to make sure this will really add up.

The use of electrochemically active organic compounds would be nice in that they are not limited by rare elements.  The 9,10-anthraquinone-2,7-disulphonic acid used by the group at Harvard, as well as the bromine "redox" (reduction/oxidation) couple (e.g. able to take up and give off electrons), are not rare.  Carbon, hydrogen, oxygen, sulfur and bromine are fairly common.

While the base compound, 9,10-anthraquinone, can be found in many plants, hence the rhubarb picture in the press, one must be careful of claims that bio-based solutions will actually work.  (c.f. corn ethanol and it's EROEI).

A quick web search "anthaquinone content of rhubarb" found this:
http://journal.chemistrycentral.com/content/pdf/1752-153X-7-170.pdf
The focus of this work is the total anthaquinones content in the rhubarb for Oriental medicine, noting that the Chinese Pharmacopoeia specifies not less that 1.5% total anthaquinones.  First one wonders how easy it is to convert these various anthaquinones to the desired one.  Then one learns there is great variability in content, depending of species and more critically, elevation. At the highest elevations, like the Tibetan plateau, plants contain more, up to 6%, because they increase the glucose, etc. content of their sap to survive cold temperatures, and the glucose binds with the anthaquinones which then bioaccumulate.  My take is that rather than fight the Chinese for a limited supply of Tibetan rhubarb to make flow batteries, we'd just synthesis the pure stuff from anthracene (coal tar) or from benzene and phthalic anhydride.  So - the "adding up" of this looks a bit questionable.

Flow batteries are nice for large scale storage, since the amount of electricity one stores is determined by the quantity of the liquid electrolytes one has, and storage tanks are typically much cheaper than battery electrodes.
http://en.wikipedia.org/wiki/Flow_battery

This anthraquinone based flow battery is interesting (due to the non-rarity and cheapness of the chemicals - at least until coal runs out) , though it requires a proton exchange membrane (if I interpret the fuzzy graphic right). Probably not great energy density due to the molecular size. Definitely be checking my mailbox for this issue of Nature in a few days.


Some guys at Stanford have recently developed a membrane-less Lithium Polysulfide flow battery.
https://www6.slac.stanford.edu/news/2013-04-24-polysulfide-flowbattery.aspx


I would suppose this would be much more energy dense (fewer atoms per stored electron), as well as avoiding the issues of a membrane that tends to foul over time.  

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