An interesting idea for energy storage.

[RustyLugNut]

Used with solar heat, it allows storage for an indefinite amount of time to be released at a later date.

Storage advance may boost solar thermal energy potential | News and Research Communications | Oregon State University

[RustyLugNut]

Originally Posted by Old Tele man

Sounds like the "old" sodium atomic reactor approach.

This is not heat being stored in a molten sodium pool. It is strontium carbonate being dissociated by heat into strontium oxide and carbon dioxide. The two components are kept separated until they are recombined to produce heat. That heat is used to drive hot air turbines and steam turbines.

It is much like dissociating water into hydrogen and oxygen and storing them until they can be recombined and the energy derived. However, the strontium carbonate heat dissociation shows much higher efficiency within the cycle than does electrolysis of water.

[ksa8907]

Why not just punp water into a tower then use a hydro-generator to get on demand electricity?

Not very portable but far less complex.

[RustyLugNut]

Originally Posted by ksa8907

Why not just punp water into a tower then use a hydro-generator to get on demand electricity?

Not very portable but far less complex.

Though proven and practical, hydro storage of excess power would require massive towers to be effective, or leverage an existing high reservoir.

Though the idea is still embryonic, thermo-chemical storage would need nothing more than storage tanks and reaction chambers. Also, the arid geographies where sunlight concentrators would be most effective usually lack large amounts of usable water.

[JRMichler]

Originally Posted by ksa8907

Why not just punp water into a tower then use a hydro-generator to get on demand electricity?

Not very portable but far less complex.

Time to do the math. An energy storage system big enough to seriously interest a utility should store 1 GW for 10 hours, or 10 GWH.

10 GWH = 10,000 MWH = 10,000,000 KWH.
1 KWH = 1.34 hp-hr.
1 hp-hr = 33,000 ft-lbs/min X 60 min/hr = 1,980,000 ft-lbs.
1 KWH = 1.34 X 1,980,000 = 2,654,000 ft-lbs.
10 GWH = 10,000,000 X 2,654,000 = 2.65E13 ft-lbs.
Assume two storage ponds, the high one 1000 feet above the low one.
2.65E13 ft-lbs / 1000 ft = 2.65E10 lbs of water.
2.65E10 lbs / 62.4 lbs/ft3 = 4.25E8 cubic feet of water.
4.25E8 cubic feet / 43,560 square feet per acre = 9750 acre-feet of water.
If each pond is 20 feet deep, the surface area will be 9750 / 20 = 490 acres.

If the high storage is only 100 feet above the low storage, you need 10 times as much water. That's why there are so few pumped storage systems. You need to cut the top off a mountain to hold enough water, and that does not come cheap.

[Randy]

The math on the strontium carbonate storage goes like this (assuming I didn't mess it up):
The SrCO3 -> SrO + CO2 reaction takes 235 kJ/mol.
SrCO3 has a molar mass of 148 g/mol.
So it can absorb 1.6 MJ/kg. Pumping water is only 9.8 J/kg per meter height, so it takes 500x more water in the 1000ft lift example. For comparison, burning coal is ~25 MJ/kg.
To store 10 GWH or 36,000 GJ, you'd need about 22,500 metric tons of SrCO3. Also you'd generate 6 ML or 1.3 million gallons of liquefied CO2. That's a lot, but still in the range of large silos.

The SrCO3 doesn't start decomposing until 1500 C, so this would take a big solar concentration factor to be efficient. It's doable for commercial-size concentrated solar plants though.

[IamIan]

In laboratory tests, one concern arose when the energy storage capacity of the process declined after 45 heating and cooling cycles, due to some changes in the underlying materials. Further research will be needed to identify ways to reprocess the materials or significantly extend the number of cycles that could be performed before any reprocessing was needed, AuYeung said.

45 cycles seriously needs to be improved .. or none of the other performance numbers matter.

[ksa8907]

Originally Posted by JRMichler

Time to do the math. An energy storage system big enough to seriously interest a utility should store 1 GW for 10 hours, or 10 GWH.

Without knowing much behind the chemistry, storing that much energy sounds a hell of a lot like a pipe dream. Maybe one day...

With water storage i was thinking more about living off-grid.

[Hersbird]

Originally Posted by ksa8907

Why not just punp water into a tower then use a hydro-generator to get on demand electricity?

Not very portable but far less complex.

Even better, us the solar power from the sun to heat and evaporate ocean water into clouds. Then float the clouds up to 1000 miles inland or more where they release the moisture and form lakes and rivers. Then as the water flows back to the ocean you can put hydro generating plants that capture that energy. 2000 year old solar power right there.

[Xist]

So... build magnifying glasses on water sources?