Energy

"World's first working thermal battery" promises cheap, eco-friendly, grid-scalable energy storage

"World's first working thermal...
CCT SEO Serge Bondarenko (left) and  COO Graham Warburton (right) with the Thermal Energy Device (TED)
CCT SEO Serge Bondarenko (left) and  COO Graham Warburton (right) with the Thermal Energy Device (TED)
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CCT CEO Serge Bondarenko, with his back to us, introduces the thermal energy battery to South Australia's Minisher for Energy and Mining, the hon. Dan van Holst Pellekaan and a group of onlookers at the CCT public launch last week
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CCT CEO Serge Bondarenko, with his back to us, introduces the thermal energy battery to South Australia's Minisher for Energy and Mining, the hon. Dan van Holst Pellekaan and a group of onlookers at the CCT public launch last week
CCT SEO Serge Bondarenko (left) and  COO Graham Warburton (right) with the Thermal Energy Device (TED)
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CCT SEO Serge Bondarenko (left) and  COO Graham Warburton (right) with the Thermal Energy Device (TED)

South Australia has recently put the world's biggest lithium battery into operation – but perhaps it should've waited. A local startup says it's built the world's first working thermal battery, a device with a lifetime of at least 20 years that can store six times more energy than lithium-ion batteries per volume, for 60-80 percent of the price.

Climate Change Technologies, also known as CCT Energy Storage, has launched its TED (Thermal Energy Device) with a set of remarkable claims. TED is a modular energy storage unit that accepts any kind of electricity – solar, wind, fossil fuel-generated or straight off the grid – and uses it to heat up and melt silicon in a heavily insulated chamber. Whenever that energy is required, it's pulled out with a heat engine. A standard TED box holds 1.2 megawatt-hours of energy, with all input and output electronics on board, and fits easily into a 20-ft (6-m) container.

Here are some of CCT's banner claims about the TED: For a given size volume, it can store more than 12 times more energy than a lead-acid battery, and several times more than lithium-ion solutions. Installations can scale from 5-kilowatt applications out to a virtually unlimited size. Hundreds of megawatts of instantly accessible, easily controllable power should be no problem – all you need to do is add more units, plug-and-play style. In the case of an outage, each TED device can remain active for about 48 hours.

It can also charge and discharge at the same time, and there are only three moving parts per box, so maintenance is almost negligible. Where lithium-ion and other batteries degrade over time, perhaps dropping to 80 percent capacity in some 5,000 cycles or so, the TED system has shown no signs of degrading after 3,000 cycles of service on the test bench, and CCT's CEO Serge Bondarenko tells us over the phone that the company expects its units to last at least 20 years.

"Molten silicon just doesn't degrade like lithium does," says Bondarenko. "That's a chemical process, ours is simply phase-change with heat. In fact, it appears silicon even gets better at storing heat after each cycle. And if you do need to decommission a TED device, it's 100 percent recyclable. It simply doesn't create the environmental problems that lithium does."

Importantly for any large scale usage, it's cost competitive – Bondarenko projects it'll cost some 60-80 percent of the price you'd pay for an equivalent lithium-ion solution like Tesla's Powerpacks, while taking up a smaller footprint on the ground. TED can easily be adapted for earthquake-prone environments by installing it on a quake-proof platform, but in the event of a serious issue, Bondarenko tells us "we just turn it off, and it cools down until it's ready to go again. It's very safe." Mind you, since the melting point of silicon is more than 1,400° C (2,550° F), it's not something you'll want dribbling out on the ground.

CCT has signed an initial deal to provide TED devices to Stillmark Telecommunications, as well as a reciprocal manufacturing agreement with MIBA group, which will have exclusive rights to manufacture and sell the technology through Denmark, Sweden and the Netherlands, with negotiations ongoing about adding other European countries to that list. Manufacture is set to begin this quarter, and Bondarenko says once the devices have been proven commercially, the company plans to ramp up rapidly and be ready to build 100-megawatt-plus installations within a couple of years.

Obviously, this seems like great news for the renewable energy sector. Wind, solar, tidal and other renewable energy technologies can be very effective at generating a lot of power, but only when it's available rather than on demand. Grid-level energy storage solutions could store energy up during the solar peak of the midday heat, then return that power to the grid during peak load times in the evening when the sun's not shining, making renewables a truly 24-hour energy source.

Could the system's huge energy density also scale downward to power electric vehicles? "No," says Bondarenko, "it's too big. The container, the insulation, the heat engine, it needs to be a certain size to realize its density benefits. But we can certainly charge electric vehicles, and we have been in discussions with some manufacturers of large electric ferry boats that could charge the battery up at the dock and use it to power their ferries."

If things pan out the way CCT believes they should, this cheap, high-density thermal battery, powered by abundant elements and totally recyclable, could be a key technology in helping move the world toward a clean energy future.

Source: CCT Technologies

24 comments
Kaido Tiigisoon
It's not important how much a storage device can store. It's important how much it can recover. In this scale, one can hope to get back at best somewhere around 50% of the stored energy maximum. This is due to fact, that energy is recovered through heat engine. One place, where I can actually see the benefit of this device is flattening the demand curve for heat in conventional power stations. The biggest waste of energy happens in transitioning from one working regime to another and that could be mitigated by storing heat in place where the actual heat is generated. That instead of going through Heat>Electricity>Heat (in storage)>Electricity transformation cycle. For wind and solar, battery storage is still the best option.
JimFox
First true "breakthrough" battery technology. Kudos to CCT, also for such rapid commercialisation. Kaido's comment may have merit but I doubt an efficiency of only 50%.
Chris Coles
"In the case of an outage, each TED device can remain active for about 48 hours." So what they are describing is a system designed to deliver all the stored energy over a 48 hour period, or, they are saying that the insulation of the stored molten silicon can only keep the system viable for a maximum of 48 hours. This is a concept that requires further innovation input to get at further improvements.
andy68
There was no mention of what the heat engine is. Most heat engines, like internal combustion engines, are notoriously inefficient, and the over-all efficiency of the device is likely to be less than that of a battery
Guy Macher
How little we understand chemistry is evident in the statement--"In fact, it appears silicon even gets better at storing heat after each cycle." Anyone got a theory? Perhaps the silicon is getting purer in each cycle?
thk
For grid-level energy storage, sodium-ion battery is more viable than lithium-ion.
paul314
"estimate" and "project" are not really words that utility-scale investors like to hear when considering a device that no one has yet put into operation. I bet they're lining up to be the third or fourth to buy an installation.
piperTom
It's too big/heavy for a car? Sure, but what about a home (or small/medium apartment blg)? Then the efficiency issue noted by other commenters can be addressed - at least in winter - by using the "waste" heat within the home. Besides the obvious use with home solar, it will always allow for less infrastructure in "the grid" and better reliability.
Nobody
We need more information. A lot of materials can store heat but the conversion to electricity is the key. Using the term heat engine is pretty vague. There is also no mention of how the heat is originally stored by melting the silicon. Electric heating elements?
JimFox
Heat engine efficiencies are hard to define, it seems. The Carnot cycle is theoretically most efficient but impossible in practice; the subject is beyond my understanding but how does HE efficiency affect operation of this storage system? That it offers advantages of cost, reliability, recycling & safety likely outweighs other considerations?