Comments on: 100 percent renewables in 139 countries

By: Dénes CSALA

Dénes CSALA — Thu, 24 Aug 2017 01:09:54 +0000

Hi Craig – excellent sum-up there! Wow, I’m amazed at the comments in the global social media sphere on this. So many self-proclaimed “experts”. My 2 cents is that this entire debate is derailed and potentially puts dangerous smoke around openly discussing energy – and here I fully agree with what you say above. This is not about the technical possibility – we are already there. The most important is get people recognize the value in these roadmaps. To start generating the sort of discussion that kicks in motion the more behemoth and slow-moving socio-technical systems: societal and political will. https://theconversation.com/100-renewable-by-2050-the-technology-already-exists-to-make-it-happen-82925

By: heinbloed

heinbloed — Thu, 10 Dec 2015 18:00:00 +0000

Here another study just around in the news showing how a decentralized 100% RE power supply in Germany could be done:

http://www.acatech.de/flexibilitaetskonzepte-2050

Reported in the ZEIT today:

http://www.zeit.de/wirtschaft/2015-12/energiewende-erfolg

By: S. Herb

S. Herb — Thu, 10 Dec 2015 14:05:02 +0000

Thank you Math. More specifically I see in the .xlsx table 2 for utility PV,
Maximum Technical Potential for Installed Utility PV : 464 MW
Amount Needed from optimization: 904 MW, or 194.8% of assumed maximum
This certainly deserves a comment from the authors. I assume that the costs are for the Needed value. It’s not yet clear to me whether the costs include capital items such as electrolysers, H2 to fuel conversion, H2 storage and turbine generators, etc., and financing thereof. The execution does seem to be still very primitive compared to the Fraunhofer ISE work.

By: Math Geurts

Math Geurts — Thu, 10 Dec 2015 08:56:04 +0000

It is a blame for Stanford!

see: http://web.stanford.edu/group/efmh/jacobson/Articles/I/WWS-50-USState-plans.html

in xlsx-spreadsheets, table 2, it is shown that Germany is not able to power itself with water, wind in solar, even in 2050.

By: S. Herb

S. Herb — Wed, 09 Dec 2015 22:15:25 +0000

two more (short) notes:
1. German End-Use Energy TWh/a = 2260 (Jacobson) / 1790 (ISE 85%) => Jacobson is 26% larger (maybe because ISE assumes thorough energy use reduction for buildings)

2. For asking whether Jacobson’s scenario is realistic, the 1080 GW installed PV which it derives must be a good place to start (as noted in previous post this number doesn’t appear explicitly in the report but must be pretty close to this value)

By: Math Geurts

Math Geurts — Wed, 09 Dec 2015 21:27:48 +0000

100% clean and renewable wind, water, and sunlight (WWS) all-sector energy roadmaps for 139 countries of the world (summary paper)(xlsx-spreadsheets)

By: S. Herb

S. Herb — Wed, 09 Dec 2015 19:33:00 +0000

The 139 nation report seems to be a preliminary document, and, not surprisingly, has little
information per country. Using the numbers for Germany from table 3:

‘End-Use Energy’ = 258 GW (presumably averaged over year => 2,260 TWh/a )

‘Fraction of End-use E provided by residential PV’ = 5,72%

‘Fraction of End-use E provided by utility PV’ = 51.2%

From table 4, installed residential PV = 100 GW, listed as 90% of max. available.
We conclude that 100 GW installed provides 0.0572*258 = 14,76 GW, so the PV capacity
factor used is 14.76/100 = 15%. No number is given for installed utility PV. Assuming the
same capacity factor (although utility solar should be somewhat more efficient) we get
258 GW * 0.51/ 0.15 = 877 GW installed (!!!!). Including also the commercial solar category,
the total installed solar is 1081 GW. This is to be compared with about 170 GW in the Fraunhofer
85% scenario. What is happening ??

My conclusion, without any special knowledge, is that the Jacobson ‘optimization’ had limits set
for maximum installed wind and rooftop/commercial solar, and that all excess demand was tipped
into the ‘utility PV’ category. The ‘excess’ capacity presumably generates electricity which is being converted to hydrogen for transport and electricity generation and heat in ground fields, both inefficient processes, which is the problem becoming evident in the Fraunhofer 90% scenario. A
further note is that the Jacobson paper assumes no bio-energy contribution, so this must also be made up by solar.

Jacobson’s group is doing some good work, but my impression is that their publicity outruns their results. The ‘100% everything is great’ conclusion appears to apply to the world as a whole, but not necessarily to each piece of it. The detailed result for the USA looks much better – there one is dealing with a much larger grid with a range of climate zones, etc. so that things average out better.

This will undoubtedly be a continuing story.