Alphabet looking to solve energy storage with project Malta

[Greg S]

The search for energy storage solutions has grown to an immense scale in search of preventing wasted energy. Google's parent company Alphabet has a prototype system that they are looking to expand over the coming years to provide a sustainable and cost effective method of storing energy at grid level.

Project Malta is an idea from Alphabet's X skunkworks division, which is also the same research lab that initially delved into autonomous vehicles. Malta is based on a simple property of thermodynamics. When hot and cold air meet, a convection current is formed due to the difference in densities between warm and cool air.

By storing large amounts of hot and cold substances in storage containers, the heated and cooled air can be released to drive a turbine. In this case, Alphabet researchers are using salt to store heat and antifreeze to act as a large refrigerator.

A fairly obvious short coming of this system is that energy can only be stored for as long as there is a difference in temperature between the two storage containers. This means that energy can only be stored for several hours unless heavy insulation is used, which can extend the storage time to a few days.

Alphabet has declined to share how much a fully installed system may cost, but it could "be several times cheaper than lithium-ion batteries and other existing grid-scale storage technologies," according to Raj Apte, head engineer of the project.

It is possible that Malta may never see commercial application, but it is much more promising than the many research efforts to develop higher capacity batteries with better energy densities since there are no known roadblocks in the way of an already proven concept.

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https://www.techspot.com/news/70368-alphabet-looking-solve-energy-storage-project-malta.html

 

[namesrejected]

I would think using tanks with highly compressed air, and tanks with a vacuum pulled on them would achieve the same effect, but gain you longivity of storage. You also would be using air, so a leak would not be harmful to the enviroment unlike antifreeze.

Also, a single pump could at the same time pull the vacuum on one tank and pressure the other. The same pump could be used to spin generator.

 

[Kotters]

This seems like a needless complication of existing technologies to achieve the same purpose. But I guess we'll see where it goes.

 

[peas]

I would think using tanks with highly compressed air, and tanks with a vacuum pulled on them would achieve the same effect, but gain you longivity of storage. You also would be using air, so a leak would not be harmful to the enviroment unlike antifreeze.

Also, a single pump could at the same time pull the vacuum on one tank and pressure the other. The same pump could be used to spin generator.

They probably would've used compressed air if it provided the energy density they need. There's a practical upper limit to the psi in a large container (see the photo at the top of the page for scale), thus an upper limit to the energy density of compressed air.

Most likely the salt/antifreeze compounds can store many times the energy density of compressed air.

 

[namesrejected]

They probably would've used compressed air if it provided the energy density they need. There's a practical upper limit to the psi in a large container (see the photo at the top of the page for scale), thus an upper limit to the energy density of compressed air.

Most likely the salt/antifreeze compounds can store many times the energy density of compressed air.

I understand that ( why an air impact wrench uses a lot of cfm of air, and a small lithium battery could run a impact wrench of similar torque for an hour or 2. ) Im sure that is the issue.

 

[mbrowne5061]

They aren't using compressed air for two reasons:
The first is that such systems already exist, and they only way they work on an economic scale is by being sunk to bottom of deep pools of water to help contain the highly pressurized air.
The second is that any given thermodynamic cycle is more efficient than any compressed air cycle. If you get to 30% efficiency with compressed air, you're doing pretty good. Compressing air generates heat, and this heat cannot be effectively or efficiently captured in a productive way. If you are anywhere near 30% efficiency with nearly any external combustion thermodynamic cycle (Rankine, Stirling, Carnot, etc), you're doing pretty poorly. Carnot gets up to around 60% pretty easily.

The only thing new about this is that Alphabet is doing it. The DOE has been providing loans and grants to explorer thermodynamic (and other mechanical-based) storage options for decades.