Re: [Pen-l] smart grid question

[Gar Lipow <gar.lipow@xxxxxxxxx>]

On 6/9/09, Shane Mage <shmage@xxxxxxxxxxxx> wrote:
>
> On Jun 9, 2009, at 11:57 AM, Gar Lipow wrote:
>> ....But if we are going to produce 60% or more of our electricity
>> from variable >> sources like wind and sun, a smart grid is a necessity. Without a
>> smart grid (and for that matter without long distance transmission)
>> you need unacceptably expensive levels of storage...
>
> Why should that be so?  Storage is a very simple matter--
> electrolytically produced hydrogen can be stored at every place
> electricity is generated and used to release that electricity via a
> fuel cell whenever needed.  Once mass production of the needed
> components has been achieved the costs would be very reasonable and
> surely much less than the capital costs and transmission losses from
> long-distance transmission.


Not so simple a breakthrough.   The most likely candidates for cheap
fuel cells burn hydrogen with 70% or less efficiency. (And we don't
even know how to make these cheaply.) Given that the best we can do in
efficiency of electrolysis (85% in practice) that ends up less than
60% round trip efficiency.  That means that electricity losses itself
add 4 cents per kWh to storing electricity via hydrogen. And that does
not include nontrivial costs of actual storing hydrogen.  And I'm not
sure that even these low grade can be made that cheap just through
mass production.

Now it is possible to build fuel cells with 80% to 95% efficiency. But
this kind of fuel cell requires extremely expensive materials and
fabrication techniques. Definitely not just a question of gaining
economies of scale via mass production. We don't know how to produce
high efficiency fuel cells cheaply in any quantity. And note that the
95% efficiency is much harder to reach than the 80%. So even then
electricity alone adds 2.5 cents per kWh cost, and again there are
nontrivial, storage, O&M and capital costs.

With today's technology hydrogen storage (including not just
electricity, but capita,physical hydrogen storage, and O&M) adds 6
cents per kWh assuming mass production lowers the price of fuel cells
to $250 per KW.  And I'm not as sure as hydrogen heads that the
technology is mature enough that mass production will lower costs this
much.  Highly efficient fuel cells made for a similar costs would
still add 4 to 5 cents per kWh. We can build a smart grid and long
distance transmission for a lot less than that.
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