[LINK] Renewable energy 'simply WON'T WORK'

Michael mike at bystander.net
Wed Nov 26 10:37:01 AEDT 2014

On 26 November 2014 at 09:14, Karl Auer <kauer at biplane.com.au> wrote:

> On Wed, 2014-11-26 at 08:49 +1100, Tom Worthington wrote:
> > says, it is difficult to use solar or wind power for on-demand power as
> > the sun does not shine, and the wind does not blow, on demand
> I'd like to see more study of small and large scale energy *storage*,
> since the obvious way to smooth demand vs supply mismatches is to store
> energy when you have a surplus and release it when you have a deficit.
> I'm not suggesting that all of these are actually useful for storing
> (say) solar overproduction, but things like:
> - lifting a weight
> - tensing a spring
> - pumping water up hill
> - dumping energy into heating or cooling
> - battery storage (small local and large centralised)
> - spinning a flywheel
> - dumping energy into ongoing but not time critical tasks
>   (compute tasks like rendering or physical tasks like filling a tank)
> ...and of course the synergy between electrical cars and their potential
> use (sorry) for energy storage when they are not being driven.

Pumping water uphill is already widely used in utility scale hydro. You
lose some efficiency by doing the extra conversions, but if the power was
going to waste anyway, why not? Drawbacks are the need for appropriate
geography. The volumes are such that any sort of manmade storage is just a
drop in the bucket (boom, boom).
Spinning flywheels are widely used in data centres to handle the load
between power failure and when a diesel generator gets up to speed. They
can provide a smoothing of bursty power supplies, but so can just adding
more distributed generation (like wind or solar panels). They also fail
Dumping energy into heating is the principle behind the utility scale solar
thermal plants that use molten sodium for storage. It works out a bit
costlier than coal, but several are in operation around the world.
- dumping energy into non-time critical tasks is formally called demand
management, and it is big already and growing. In Victoria there is a
program to link smart meters with domestic air-con to allow them to be
throttled back on peak days, in exchange for permanently cheaper power.
- don't know much about lifting weights or springs, but similar to the
stored hydro, you need big stuff to make a dent. Also, compressed air fits
in this.
- distributed battery storage is nearly ready. It currently delivers power
at an all in cost of 40c-50c per kWh. My grid bill is 30c p/kWh plus
connection fee, so it isn't stupidly expensive. For users who have worked
hard at conservation so they use little power, making the $1 per day
connection fee a big part of their bill, it is likely to be worth doing in
the next year or two, or maybe now.
- centralised battery storage has some economies of scale, but probably not
as much as you would expect, but suffers from having to be all things to
all people. That is, if I am careful with my power use, I could live with a
local solar/battery system, because I would not run the Air con, clothes
dryer, dishwasher and oven all at once (massive concurrent load), but
utilities build to cover peaks of thoughtless consumption so need to
over-engineer to an absurd degree. Even so, they are already doing some
local grid projects in various places.

My engineering friend who is particularly interested in renewables reckons
solar+local battery will likely be cheaper than today's power prices for
Aussie consumers by 2020. He notes there is good reason to believe we will
see the power companies up the connection charges and lower the kWh fees
before then to combat this.

Michael Skeggs
Disclosure: I'm a director of BMRenew, a renewable energy co-op in the Blue

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