But that's exactly my point. There aren't lakes everywhere. There isn't hilly terrain everywhere. The article pointed out that hydro storage has only been implemented in a few opportune places. This system can be built anywhere and everywhere without geographic limitations. Essentially anywhere you can put a parking lot, this storage system can be deployed. The best land for large scale solar installations is desert. Where exactly can one find a couple of well placed lakes in the desert? BAJ On Fri, Oct 05, 2018 at 03:12:42PM +0100, David C Brown wrote: > Having worked with Dinorwic in North Wales I may be a little biased, but > we had excellent results using it as spinning reserve. >=20 > That system, like Festoniog, use existing lakes so there is no land cost. > And lack of rainfall will never be a problem on the Welsh mountains ???? >=20 >=20 > On Fri, 5 Oct 2018, 14:34 Byron Jeff, wrote: >=20 > > 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 wate= r > > 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 win= ner. > > 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 > > efficient > > > > > > On Thu, 4 Oct 2018, 13:46 Denny Esterline, wro= te: > > > > > > > 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 -> gener= ator > > > > 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, b= ut > > even > > > > optimistic numbers > > > > quickly exceed the claimed numbers. > > > > > > > > > > > > Still an interesting idea though. :-) > > > > > > > > > > > > > > > > On Thu, Oct 4, 2018 at 3:34 AM RussellMc wrot= e: > > > > > > > > > Concrete weights stacked to store energy and destacked to provide > > output. > > > > > It works (of course) but will have difficulty being cost competit= ive > > 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 > > methods > > > > > of charge/discharge). > > > > > > > > > > ________________________________ > > > > > > > > > > A "train" (or multiple units) on a track with cable connection ma= y > > allow > > > > > improved ease of charge/discharge. > > > > > Energy storable per mass is less per distance moved due to > > non-vertical > > > > > track, but can make use of long slopes. > > > > > The excessively enthused could move 'wagons' sideways at top and > > bottom > > > > to > > > > > increase capacity. > > > > > > > > > > A single looped cable would allow multiple 'wagons' to be pulled = up > > or 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 > > > > > > > -- > > > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > > > View/change your membership options at > > > http://mailman.mit.edu/mailman/listinfo/piclist > > > > -- > > Byron A. Jeff > > Associate Professor: Department of Computer Science and Information > > Technology > > College of Information and Mathematical Sciences > > Clayton State University > > http://faculty.clayton.edu/bjeff > > -- > > 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 .