Energy

"Melting choc chip" blocks could stack up as grid-scale energy storage

"Melting choc chip" blocks cou...
MGA Thermal blocks can store energy in the form of heat, potentially on the grid scale
MGA Thermal blocks can store energy in the form of heat, potentially on the grid scale
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MGA Thermal blocks can store energy in the form of heat, potentially on the grid scale
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MGA Thermal blocks can store energy in the form of heat, potentially on the grid scale
MGA Thermal blocks store energy inside particles that melt like chocolate chips in a muffin
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MGA Thermal blocks store energy inside particles that melt like chocolate chips in a muffin
MGA Thermal blocks can be stacked
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MGA Thermal blocks are made from inexpensive materials and are easily scalable by just stacking more
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Engineers from the University of Newcastle have come up with a surprisingly simple new energy storage system, built around blocks that store thermal energy like melted chocolate chips in a muffin. The team says they’re efficient, scalable, safe, inexpensive, and can be used in existing coal-fired power plants.

Renewable energy is a key component of any plan to reduce our impact on the planet, but storage remains a major hurdle to making these systems viable. Recent solutions include Tesla’s huge lithium-ion batteries, or storing energy in unconventional forms like molten salt or silicon, heavy rail cars on steep inclines, and huge blocks suspended in mineshafts or stacked in towers.

And now the list has a new entry – Miscibility Gaps Alloy (MGA) blocks. Measuring just 30 x 20 x 16 cm (11.8 x 7.9 x 6.3 in), these bricks are made of materials with high thermal conductivity, so they can easily be heated up to store energy and cooled to release it again as needed.

To do this effectively, the blocks are made of two main components. There’s a solid matrix that holds it all together in the brick shape, and embedded throughout that are particles that melt. The team describes the design as similar to a chocolate chip muffin.

“Imagine the matrix is the cake component, which holds everything in shape when heated and rapidly distributes that heat,” says Mark Copus, an engineer on the project. “The other particles, represented by the choc chips, melt and store thermal energy through the solid to liquid change phase.”

MGA Thermal blocks store energy inside particles that melt like chocolate chips in a muffin
MGA Thermal blocks store energy inside particles that melt like chocolate chips in a muffin

The idea is that these MGA blocks could be heated up using excess energy from renewable sources during peak output times, and store it for when demand spikes. Or they could be stacked up inside other power plants, to help recycle waste heat back into the system.

The thermal energy they release can be used to superheat water into steam to run turbines, without having to burn coal. That means the MGA blocks could be retrofitted into retired or retiring coal-fired power plants, to smooth out the transition to renewable energy. As a bonus, that also removes the need to build new facilities or decommission old ones and doesn’t require an upgrade to the grid infrastructure.

“Emissions from coal-fired power plants account for the single largest source of greenhouse gases that cause global warming,” says Professor Erich Kisi, co-founder of MGA Thermal. “Transitioning coal-fired power plants is a win-win to deliver clean baseload power, while also helping to prevent job loss from power plant closures.”

MGA Thermal blocks can be stacked
MGA Thermal blocks are made from inexpensive materials and are easily scalable by just stacking more

The team says that the MGA blocks have a range of other advantages. The system is easily scalable by just adding extra blocks, potentially storing up to thousands of megawatt hours, and they’re made from inexpensive and abundant materials, so they apparently cost 10 percent of the price of a lithium battery of the same size, while reportedly still outputting the same amount of energy. Those materials are also non-toxic and bring no risk of exploding or leaking harmful chemicals.

MGA Thermal is establishing a manufacturing plant in New South Wales to scale production of the blocks to commercial levels and has partnered with Swiss company E2S Power AG to begin designing systems to repurpose European coal-fired power plants to use the new blocks.

The blocks are described in more detail in the video below.

Explainer video MGA Thermal

Source: University of Newcastle

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15 comments
paleochocolate
So the excess energy is used to warm up these blocks that in turn produce steam power that makes more excess energy?
Chris Coles
Yes, I do understand that they are dealing with the thermal dynamics of a storage system using phase change as the storage mechanism . . . within the blocks themselves. However, there is no mention of where, or for that matter, how . . . to store these blocks, and the insulation requirements, nor for that matter the heat retention dynamics of the blocks themselves. We should have had much more information made available in this report, such as a link to the science. Much more info needed.
Bob Stuart
Chris, I think it is clear that the blocks are built to readily gain or lose heat. The normal standards would apply to keeping them insulated to retain heat. The number I'd like to see is the phase change temperature. It is a bit misleading to compare the cost to batteries, though. Batteries put out electricity, the highest form of energy - these may be medium - temperature heat, one of the lowest forms, which would be mostly lost on the way to becoming electricity.
riczero-b
Paleochocolate, it's about supply and demand - the system takes the energy when it's abundant and timeshifts it to when it's scarce.
Bob g
I think it would be useful to state the storage time period envisaged. This project sounds like a short term maintenance period aid for a self contained power station. It would not be so critical on thermal conductivity with the brake-pad type make up of the bricks if it was for longer term storage.
john Wordley
reminds me of the electric storage heaters sold in the UK in the 60's. basically a block of cast iron heated electrically until it glowed cherry red during off peak hours and encased in a highly insulated shell to release the energy during the day. need to see more detail about the total system design as to how this integrates into the grid
Simon Redford
Its what is not being said here that worries me! What isn't being said is how do you charge the Phase Change Material (PCM) blocks with 'renewable' energy? I suspect the answer is that you use excess renewable electricity as seems to be implied in the video. So 100% renewable electricity charges a PCM version of the storage heater which then releases heat to create steam to make electricity on demand with best performance around 30%, but some is lost in storage, so I'd bet no more than 25% comes back as electricity! Give me a battery or a big weight in a mineshaft any day. Clever part is getting high thermal conductivity in a PCM material.
BlueOak
“... surprisingly simple new energy storage system,”. Uh, no. Phase change energy storage as a concept has been around for several decades.
skierpage
At first I thought this system is a way for cold plants to store heat until wind and solar aren't producing, which would obviously be no help to emissions. But if the blocks are heated with renewable electricity, so many issues remain: can the blocks be put inside existing boilers at thermal plants? If not, how much does the new thermal loop to pump supercritical steam through the blocks cost? How are they heated up, and how will that electrical system withstand super hot steam? Are these blocks better than molten salt thermal storage?

"but storage remains a major hurdle to making [renewable energy] systems viable". Solar and wind are already viable! They're the majority of new generation because they're cheap and quick. Maybe Michael Irving meant storage is needed to reach 100% RE.
idearat
I hope their engineering is better than their explaining. It appears, but is not said in so many words, that it's a phase change material embedded a thermally conductive matrix that is strong and holds its shape. Great, now you don't need vats of liquid salt or similar since it is its own container.
Then they throw in coal plants not using any fossil fuels. They are starting with a decommissioned coal plant. That makes some sense since it's already connected to the grid. So rather than the plant sending power out to the grid, it's taking it in and somehow turning that into heat to store in the blocks when there's "excess" energy available. Then in a manner similar to how a coal plant operates it uses the blocks to heat water to turn the turbines to generate electricity.
There are some claims about the cost, size, and energy storage capacity compared to a lithium battery. What I'd be interested in is the efficiency of the cycle, power into the plant compared to power out. I'd be surprised if *that* was the same as batteries.
The bonus might be in the cost to convert a functioning or retired coal plant to a usable energy storage facility. A lower efficiency might be offset, for a time, by the reduced initial outlay of converting a coal plant vs building a new Tesla battery facility. We don't see that info here, we just see a happy baby touching the block to show us it's safe.