Thermal energy storage is one of the hot technologies of the
energy transition. In today's video, we're gonna see a take on
this from MGA Thermal, who I visited a few months ago when I
was in Newcastle and I got a tour of a new pilot facility
that they're in the process of putting together, I found out
about the technology, the manufacturing process and
applications and their scale up plans.
I'm Rosie Barnes, welcome to Engineering with Rosie. So yeah,
thermal energy storage is a bit of a hot topic these days, you
can store heat energy in a huge range of materials from water to
gravel, and a lot of things in between. New versions of this
tech pop up in the media pretty regularly. For example, there's
been a Finnish sand battery getting a lot of attention
recently, and on this channel, I've covered them our energy
storage company Stiesdal who are using gravel to store heat and
seasonal thermal energy storage projects in Canada and
Scandinavia that simply use large pits of water. Basically,
any material that you can heat up can be used for thermal
energy storage. But ideally it will be a cheap and abundant
material that can store a lot of heat in a small space without
causing too many problems as the material is heated and cooled
repeatedly. The topic of today's video is an Australian startup
company called MGA Thermal who have a new material that they're
using to store thermal energy that takes a lot of the pros are
not that many of the cons that I just mentioned. The MGA stands
for miscibility gap alloy. And that's their key innovation that
came out of research from the University of Newcastle about 10
years ago. Since then, they've been working on the
commercialization of that innovation. And now they're just
about to start ramping up production. Their product is a
solid brick with metal alloy distributed throughout in such a
way as the metal alloy becomes molten, but the brick itself
stays solid. So it's supposed to be kind of the best of both
worlds between a molten metal that can hold a lot of thermal
energy in a small space and a solid brick that's easily
contained and doesn't cause a lot of problems with thermal
expansion. I visited MGA's pilot manufacturing facility a few
months ago and got a tour from Arden Jarrett, their business
development manager. And then I spoke to their co founder and
CTO Alex Post separately online since he wasn't available the
day that I was in Newcastle, unfortunately. So first, let's
ask Arden to show us MGA's thermal bricks and tell us what
the miscibility gap alloy is and how it works.
We make these blocks and they're called miscibility gap alloys,
which essentially means that there's two materials that will
never mix. It's like oil and water no matter how much you
shake them up, they're not going to mix up. The two materials are
graphite and a metal alloy. We describe it like a choc chip
muffin, if you heat up a choc chip muffin, the cake, it stays
solid while the chocolate goes through a phase change and it
melts while you heat it up. So our blocks are pretty much the
same in that the graphite is a matrix which holds the aluminium
alloy particles in place. And while that's melting, the
particles go through a phase change, and it stores more
energy through a thing called latent heat.
So all those light spots, that's aluminium alloy, and that's
what's going to melt and this matrix is some graphite, that's
the cake and then the aluminium is the chocolate chips.
There is a special ingredient in there.
I assume you're not gonna reveal it.. How does the technology
work? And what makes it different from other thermal
energy storage.
Our core invention is a composite material, which is
designed to store thermal energy. There are a lot of
different thermal energy storage alternatives on the market,
which are generally based around repurposing existing materials
like graphite, concrete, silica, existing material properties.
Whereas we've gone back to first principles and said, you know,
what are the criteria that make a good material for thermal
energy storage? Let's try and design a material that fills
that purpose. And that's the heart of our technology.
And so what are those criteria then?
So yeah, safety, capacity, cost effectiveness and
sustainability. Safety is a big one, you have to look at events
where you have a rupture of the thermal energy storage material
where it's exposed to atmosphere, energy density, you
have to be able to contain a lot of energy in a very small space,
which intrinsically is hard to do safely, because fuel can
combust. We've seen batteries igniting, it's just hard to
store a lot of energy in a small volume by definition.
How does it work?
You have material changing from one form into another. You have
a solid turning into a liquid, there's actually quite a lot of
energy associated with that transition. Takes a lot of
energy to melt something when it freezes, you can get that energy
back. So it's a good way of storing a lot of energy. The
trouble with that is it's very hard to use that energy. And to
handle that material in a safe way. It means you've got to
handle something when it's solid, but also when it's
liquid. So it's hard to design infrastructure to contain that.
In our case, we're looking at liquid metal liquid aluminium
specifically will eat into almost any material that you
want to contain it in. It's very hard to contain liquid
aluminium, you have to be very, very careful with it. From a
safety perspective. liquid metal at 700 degrees is obviously
quite dangerous. And you also have to cope with quite a big
volume change the same as water freezing into ice. There's a big
change in volume associated with that phase change which means if
you make a vessel to contain your liquid aluminium when it
freezes, it could crack that container because of
differential thermal expansion because of a volume change with
that phase change. So we've tried to address all of those
issues by making a composite, a solid block of graphite. And
within that block, we have small particles of aluminium. So
individual grains, which are completely isolated from one
another, contained within this graphite block. And that means
that from a large scale perspective, it's always just a
solid block, because those grains are all completely
enclosed. But from the perspective of energy storage
capacity, you're still melting that aluminium and storing all
that energy, you just don't have to worry about all of the
difficulties of handling it.
So then you've got these blocks, what are you going to do with
them?
So there are a host of different ways that you could use
technology like this waste process heat pumps, or direct
electric heating through resistive heaters. The initial
market that we're targeting is electric input. So yeah, we use
electricity to power resistive heaters, which heat up our
blocks, there is a lot of electricity available, which is
very, very variable, the market that we're trying to target is
to firm up that variable input from the grid or from a behind
the meter solar farm to heat up our blocks electrically. And
then to use that to provide a firm supply of either process
heat for an industry or electricity to dispatch back
onto the grid. So it's electric heating of our blocks, we heat
them up to about 750 degrees when they're fully charged. So
all of that aluminium that's contained in our blocks is fully
liquid at that stage, it melts down at 660, then we use that to
heat up a flow of inert gas, which circulates across our
bricks in a enclosed insulated container, and then can be
delivered to any process that we want downstream.
And you said the duration was 10 hours. Is that right?
Yeah, that's right. So we can store for longer than that. But
the pilot that we're performing at the moment is designed to
provide half a MW of steam for a continuous 10 hour period.
And can you just tell me, what are some example applications
that would need that kind of steam?
You know, there are a whole bunch of industrial processes
that require steam though, like paper manufacturing, dairy, and
quite often at the moment, the energy source for that steam is
a gas fired boiler. So obviously, you know, people are
trying to replace that to decarbonize. But they don't have
a firm supply of that steam. Now installing solar farms to power
an electric boiler and that kind of thing. But they can't run
that when there's no sunlight. So they have to shut down their
entire process at the moment.
And how would you increase the power and the duration.
So to increase the either the power or the duration, we just
add more bricks, which means a larger insulated enclosure as
well, each of our bricks can store a kWh of thermal energy in
terms of dispatching heat, which is what we're demonstrating with
this pilot, we're very, very efficient. First of all, we have
the electric charging part of our process. In most electrical
processes. Heat is your form of losses. So electric heating is
extremely efficient. Because your only loss mechanism is
heat, which is what you're using. We're in the order of 98%
efficient for our charging, we can store it, we lose about 2%
per day of our stored capacity just as thermal losses from the
container and then discharging we're also very efficient,
because we run a gas loop for the steam generation, gas comes
out of our storage, it goes through a heat exchanger which
creates steam, and any heat that is left in that gas after it
goes through that heat exchanger, which isn't
transferred into steam then goes back into our storage in a
closed loop. So roundtrip for heat we're you know, well above
90% efficiency, and converting to electricity is a little bit
harder for thermal storage because you have to run a heat
engine. So for anyone listening who has a background in
thermodynamics, they'd be aware that heat engines have something
called the Carnot efficiency associated with them, which
means you actually have limitations on efficiency
dictated by the laws of physics where you can't convert heat
into electricity at 100%. A typical steam power cycle is in
the order of 30%, maybe 40% efficient at the very large
scale for a power station, which basically dictates our round
trip efficiency if we're producing electricity.
So, round trip efficiency to go from electricity to electricity
is going to be in the 30s%, is that?
In the 30-40% range, yeah.
Okay, so that's obviously like a lot lower than lithium ion
battery, or pumped hydro or most kinds of energy storage that
people are looking at. So what makes your technology attractive
and when would you use it.
Round trip efficiency isn't actually your key concern. If
you have more energy than you know what to do with in the
middle of the day, then as long as you can capture any of that
to use when you need energy, as long as you can do that cost
effectively, then it's worth doing. So what we're really
trying to emphasize is that even though the roundtrip efficiency
is much lower than batteries, the total cost per Joule of
energy that you pay for that firm's renewable energy out of
the back of the storage is still lower than batteries. And that's
because the capital cost of our storage equipment is so low, so
you're getting very, very cheap energy, you're storing it
cheaply, you store the 30% that you can effectively recover, and
then you discharge that.
One of our potential applications is repurposing
thermal power stations into renewable energy storage
facilities. So that means repurposing the turbine and the
grid connectivity and the building itself, taking out the
boiler and anything to do with the coal, putting in a TES
(Thermal Energy Storage) unit with our bricks and reusing the
infrastructure to capture the electricity out on the other
side. So because it's designed to be bulk energy, so the
efficiency comes when it's a really large system. A lot of
our most interested customers are solar PV farms, because
they've spec'd their output for 9am during the day, so it's peak
load shifting, essentially. So if you go you collect a large
amount of electricity during the day, and then use that large
amount at night.
Okay, as electricity, though, they're happy to lose more than
half of it.
They wouldn't have been able to use it anyway. Okay, so they're
completely lost.
When you say it's going to be, you know, much cheaper than
batteries is that based on how much it costs you to make a
brick today, or you've got some assumptions for the future about
how costs are going to come down?
Yes, that's based on the cost of our current manufacturing
capacity, that we can make very, very large quantities of our
bricks quite economically. And because we're using readily
available raw materials, we don't have lithium, we don't
have expensive materials in our bricks, everything that they're
made out of actually is in the top 25 most abundant materials
on the Earth's crust.
What about recyclability? How long would a brick last for and
then what do you do with it at the end of the lifetime?
So we're targeting a usable lifetime for these bricks for 30
years. In reality, we haven't managed to break them yet. We
haven't tested them to 30 years yet, but that is our target for
the lifetime of the bricks at the end of that lifetime, then
we can actually recover the raw materials that make up the
bricks and recycle them back into new bricks, the two
components that we make them out of are very, very happy to exist
purely in isolation of each other. So when we crush them up
and separate them into those raw materials, then we can
essentially recycle them. It's like new feedstocks.
How small can you make it good every time people see like the
large scale energy storage, they're like, oh, I want one of
these in my house.
Okay, so there is a difficulty with having a thermal energy
storage for household use, especially if it's for
electricity. That's because you need this power cycle to convert
the heat into electricity. That is a technology that doesn't yet
exist at the household level, which means if we are to develop
a household level product, it will have to be for heat only.
So that's our initial target, as as you know, crazy as it is the
need is there at the utility scale for technology. So we're
targeting 100 MW plus sized installations of thermal
storage.
Your forward plans, like what scale they're gonna reach and
when?
We're essentially scaling up tenfold, every 12 to 18 months.
So this is going to make over 1000 bricks per day. And so the
next scale up in 18 months after that is looking at 10,000 bricks
per day. And then 100,000 a year after that, things are scaling
really quickly. We've got 20 GWh of interest in the pipeline, and
we're scaling in order to meet that demand.
So thank you for that tour. I need to give a big thanks to MGA
Thermal for allowing me inside to see all their equipment and
how their pilot line is coming together plus some of their
research facilities. And explaining how this all works.
One of the interesting things about this technology is the
scale. It's quite cheap, the materials involved and so you
can imagine that you can make many, many, many MWh or GWh
potentially of energy storage in this way. You can use recycled
materials and you can recycle it again at the end and hopefully,
I mean, according to them at least, this is going to be a
cheaper way to get this like real bulk energy storage, their
scale up plans are quite aggressive. And they've got
quite a lot of projects in the pipeline. So I think this is
going to be a really interesting one to watch over the next few
years and see how it plays out. See how the cost of all the
competing technology end up going to see what kind of
contribution technology like MGA can make within the broader
context of energy storage and you know, renewable electricity
system in general. Thanks a lot to MGA for the tour. And as
always, big thank you to the Engineering with Rosie Patreon
team. If you'd like to join us, there's a link in the
description. And thanks to you all for watching. I'll see you
in the next video!