The article points out why using solids could be an advance: it works
regardless of geography. Water only works when you have the terrain to
build an upper and lower reservior to pump in between. In addition water
requires acres and acres of land mass for both reservior to contain the
potential energy. Also as Russell pointed out you have to account for
nature in terms of evaporation and rainfall.

The real competion is batteries. I'm trying to figure out why the cost/kWh
of storage is so high on the concrete. At $10-20 USD per kWh it's a winner.
At $150-200, it's not as it's cheaper to build and deliver batteries in
large scales at that price point.

But just the stability of the storage and the fact that it can be
co-located with renewable plants anywhere makes it worth taking a look.

BAJ

On Fri, Oct 05, 2018 at 11:43:10AM +0100, David C Brown wrote:
> Better done with water than solids.   Mature technology and 80/100 effici=
ent
>=20
> On Thu, 4 Oct 2018, 13:46 Denny Esterline, <desterline@gmail.com> wrote:
>=20
> > This doesn't pass the smell test for me. Really choking on the idea of =
85%
> > round-trip efficiency.
> > Electricity in -> control losses -> motor losses -> gearing losses ->
> > winch/cable/pulley losses -> mass lifted.
> > Mass lowered-> winch/cable/pulley losses -> gearing losses -> generator
> > losses -> grid tie conversion losses.
> > Not to mention all the things the system has to do when it's not
> > raising/lowering mass, e.g. empty hook return.
> > Feel free to apply your own numbers for any of those loss points, but e=
ven
> > optimistic numbers
> > quickly exceed the claimed numbers.
> >
> >
> > Still an interesting idea though. :-)
> >
> >
> >
> > On Thu, Oct 4, 2018 at 3:34 AM RussellMc <apptechnz@gmail.com> wrote:
> >
> > > Concrete weights stacked to store energy and destacked to provide out=
put.
> > > It works (of course) but will have difficulty being cost competitive =
with
> > > other storage technologies.
> > >
> > >
> > >
> > >
> > https://qz.com/1355672/stacking-concrete-blocks-is-a-surprisingly-effic=
ient-way-to-store-energy/
> > >
> > > Claimed end to end efficiency is around 85%.
> > > LiIon efficiency said to be around 90%. (Actual figure depends on met=
hods
> > > of charge/discharge).
> > >
> > > ________________________________
> > >
> > > A "train" (or multiple units) on a track with cable connection may al=
low
> > > improved ease of charge/discharge.
> > > Energy storable per mass is less per distance moved due to non-vertic=
al
> > > track, but can make use of long slopes.
> > > The excessively enthused could move 'wagons' sideways at top and bott=
om
> > to
> > > increase capacity.
> > >
> > > A single looped cable would allow multiple 'wagons' to be pulled up o=
r to
> > > descend using existing chair-lift type coupling/decoupling.
> > >
> > > Masses & heights involved are "somewhat daunting"
> > >
> > > 1 kWh =3D 3,600,000 watt-seconds
> > > ~=3D 360,000 kg.m  (100% efficiency)  =3D eg
> > > 360 tonne x 1m
> > > 36 t x 10m
> > > 3.6t x 100m
> > > 360 kg x 100 x 10m
> > > 36 kg x 1000 x 10m
> > > ...
> > >
> > >
> > >
> > > Russell
> > > --
> > > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
> > > View/change your membership options at
> > > http://mailman.mit.edu/mailman/listinfo/piclist
> > >
> > --
> > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
> > View/change your membership options at
> > http://mailman.mit.edu/mailman/listinfo/piclist
> >
> --=20
> http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist

--=20
Byron A. Jeff
Associate Professor: Department of Computer Science and Information Technol=
ogy
College of Information and Mathematical Sciences
Clayton State University
http://faculty.clayton.edu/bjeff
--=20
http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
.