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February 06, 2006


Jason C.

Hey Fraser:
I've been impressed with the depth of coverage of energy technology on your blog. I've been reading about Hydrogenics and like the idea of producing hydrogen from clean energy sources. A lot of potential for them. I would even invest, but they have about 95 million shares outstanding and they're way off from reaching close to that in annual revenue.

I just published a post about the retail "price" of utility electricity vs installation price of solar on my blog. I would appreciate any insights if you have the time.

Nice blog!!!

Jason C.



As someone who's totally in favor of renewable energy, especially wind energy since it generates huge revenue here in Denmark, I must say I am not i favor of hydrogen as storage. I my opinion, hydrogen storage is *only* interesting for small islands. The huge energy loss (65 - 80%!) means that 3-4 times as many wind turbines are needed.

Btw, the losses indicated above assume highly efficient fuel cells are developed and sold, which does not seem likely at the moment.

Pretty much all other solutions are better.

First and foremost, we should strive to use wind energy directly, when and where it's available. That calls for a degree of flexible consumption (e.g. iron ore melting plants running in periods of strong wind). Secondly, investment in large (DC) power lines would enable us to move electricity from places of excess production to places lacking power. Such power lines improve the economy of electrical grids even without renewable energy. Only as the last resort should electricity be stored. My suggestion is to use plug-in-hybrids as storage. Make no mistake about it, the storage capacity of plug-in-hybrids will be massive, compared to fluctuations renewable electricity production.

Another thing about renewable energy, particular wind power:
With the possible exception of Denmark and Northern Germany, all other regions in the world can easily start building wind farms, full galore, without reaching the limit of their respective grids anytime soon. My guess is that plug-in-hybrids may well start rolling in the streets before then.

I think linking renewable energy with the hydrogen/fuel cell myth, while comforting for some, only hurts renewable in the long run, simply because it is an inferior solution.

Luckily, this blog presents hundreds of viable alternatives :-)

Sorry, if I seem harsch in my critique of hydrogen, but that's how I feel.


Jim from The Energy Blog

Thomas - I am not going to defend hydrogen, I just try to provide information on what technology is available in as an objective way as I can. I do agree with you that most experts don't see a problem with the intermittency of wind power until it is over 20% of grid capacity. If you can find a way to utilize all the power as it is generated, all the better.


I think it's only best that you stay as neutral as possible, and leave the harsh language to us cranks ;-)

I have a whole vision played out of how at least 80% renewable energy could be achieved in 25-30 years. Only thing is, it's quite complex and involved, and I don't have a presentable version on paper yet. But my previous post gives you the highly condensed highligts:

1) Increase flexibility of consumption
2) Distribute across large distances (because the larger the are, the smaller fluctuations ensue)
3) Use vehicles for storage, because they need to store the energy anyway.

I never meant to offend, I guess I'm just too passionate about this subject.

Keep up the good work!



"There are other energy storage solutions that have been used for wind power such as flow batteries and compressed air energy storage (CAES). It seems to me that the advantage of hydrogen generation is that it is the most developed technology, not necessarily the most energy efficient."

I think that is a good insight, Jim. Storing energy as H2 via electrolysis and then back to electricity via fuel cells is a pretty inefficient process. Assuming 70% efficiency for electrolysis and 50% efficiency for fuel cells (that's pretty generous for today's fuel cells but future cells could be better than that so we'll go with 50% as an in between number), you only get 35% of the electricity you put in back out as usable electricity.

In other words, as Thomas points out, you need about 3 times as many wind turbines as you would need if you were using the wind directly. Now of course, you can't always use the wind directly - that's why you need energy storage in the first place I would hope (i.e. I hope you are not wasting 2/3rds of you energy by making H2 when you don't have to) - but there are other more efficient energy storage alternatives as you mentioned - flow batteries and CAES or Pumped Hydro where geologically possible. According to the figures in your Vandadium Redox Flow Batteries post, round-trip efficiency for energy storage in VRBs is 70-78% - i.e. twice as good as storage as H2!

I'm certainly excited to see owners and operators of wind farms starting to couple them with energy storage to help overcome the intermitency of wind power, whatever technology they chose for storage. However, I hope that they are not ignoring better alternatives, simply because the hype over hydrogen is louder and is drowning out more viable alternatives. That would simply be a shame...


I'm with Jesse all the way. Redox flow cells will blow hydrogen out of the water once they're improved. Hydrogen is a stopgap at best, in the transition from fossil power to renewable power.


Of course, if you intend on basing our electricity supply on a single wind turbine (say on an island), wind intermittency is not to be underestimated. But mostly, it is vastly overestimated.

If you wish to learn more about integration of wind energy into the grid, I recommend taking a look the report made by the European Wind Energy Association: www.ewea.org. The report can be found on the front page. Although not totally impartial, they are probably the foremost experts on the subject.

Quite often wind energy is blamed for the total uncertaincy of balancing power on a grid. On page 63 of the report they stipulate that uncertainty of power demand and output from conventional power plants combined, on a 4-hour lead time basis is around 2.5%. The corresponding uncertainty of wind energy is 4% (based on 10% wind energy production). Combining the two gives a total uncertainty of 4.72%, i.e. less than twice the uncertainty of a grid with no wind energy at all.

The trick is, as I have stated in previous posts, to share renewable energy over areas as large as possible to smooth out local differences.

Or, if the uncertainty of production from wind turbines is 4%, build 4% more turbines and run them at 96% capacity. That leaves a buffer of the remaining 4% (I am aware that will not cover all situations). Output from wind farms can easily be turned down (se page 48 in the report).

In fact, in many cases it is probably cheaper to build excess wind capacity to remove the problem of shortage and just not run at full speed at high winds, than having complex storage facilities with questionable efficiencies.

If not, it is nice to know they exist! :-)



hi guys
I've found this really interesting video podcast's feed about hydrogen as energy source and related Hydrogen Olympics:




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