45 - All about energy from waste with Mark Shatwell (Principal Engineer @ Fichtner)

We're burning on the grate like a barbecue.

Yeah.

OK, the design and maintenance and operational complexity of these plants is just out of this world.

It's probably the only energy-generating technology where people pay you for your fuel?

Wow, we're talking about black bin-bag rubbish here.

MARK SHATWELL: Yes.

This sounds filthy.

Hello, everybody, Quentin here. And this week's episode is a load of rubbish. We're talking energy from waste. And this whole world of how this works is absolutely fascinating. So I hope you enjoy this conversation between me and Mark Shatwell from Fichtner Consulting Engineers.

This guy knows about burning rubbish like nobody else on the planet. It's incredibly complicated, and a key part of our society. So really keen to hear what you think of this one. Check it out and then let us in the comments. Hit Like, Subscribe, and all the good stuff.

[THEME MUSIC]

QUENTIN: Hello, Mark. Thanks for coming on the podcast. You're welcome.

Yes, Thank you. Happy to be here.

Oh, that's very kind.

Look, I guess the first thing to say is, for everyone listening, and for you, I tricked you into this podcast. So we discussed you guys coming on and talking about all the amazing things that Fichtner's working on in the energy sector.

And then basically, we're going to talk about energy from waste, from start to finish. [LAUGHS]

And I know you wanted to talk about loads of other stuff. But this thing is so interesting. And of all the people who know about it, we've got you on, who--

yeah, we'll talk about your background. But you've worked in this sector--

you've been working on energy from waste for a long, long time, and working lots of different projects. So we thought, why not go deep down this rabbit hole with you?

So before we get started, Mark, thanks for coming on. And do you want to just explain who Fichtner is, or what Fichtner is?

Yeah, OK, so Fichtner was founded in 1922. It's a family-owned company in Germany, based in Stuttgart. And then they formed a joint venture with--

our founder was Nick Gamble--

in 1991, in Stockport. And then we've grown from a couple of employees to now 150.

150? And it's a consultancy? Do you guys call yourself consultants?

Yeah, so we're an independent engineering consultancy. And we support the deployment of lots of different energy types, as you mentioned. So I guess we're going to talk about energy from waste. And Fichtner's growth has been built on energy from waste, really, from the mid-1990s onwards. But we also do all types of thermal-power generation, energy storage, hydrogen, carbon capture, biofuels, solar, wind, anything that generates power, really, or stores power.

Awesome. And then, I guess the big reveal is that you used to work with Tim, who's, of course Modo cofounder with me.

MARK SHATWELL: Yeah.

And you guys--

you taught him everything he knows, right?

Well, yeah, I'd like to think so. Yeah. So Tim joined us from university. I interviewed him.

And I can't remember how long he's with us now. But we worked together on the EnviRecover of energy from waste plan, which I understand you guys have been to visit, not too far from here, near Kidderminster.

Awesome. Let's talk about for a second. So what have you been working on before you got to this pinnacle of your career, being on the Modo podcast?

MARK SHATWELL: Yeah.

What's your background, Mark? What you've been working on? And then we're going to go deep into this energy-from-waste thing.

So I'm a mechanical engineer by background, graduated from Imperial College London in 2006, I think it was now, which makes me feel old, especially with guys here. But my career tracks the change in UK power generation, really.

So from university, I joined Parsons Brinckerhoff, which then became part of Balfour Beatty's, now WSP. And I was doing thermodynamic modeling for CCGT in the Middle East. So these were massive--

CCGT being what?

Yeah, Combined Cycle Gas Turbines. So now, the Middle East is looking at hydrogen and solar. But then, it was all about big, gas-fired power stations for power and water, with desalination. And then--

Desalination?

MARK SHATWELL: Yeah.

That--

just be clear, right, that's taking seawater and turning it to water that you can drink?

And that's what they have to do all over the Middle East because there aren't lakes and reservoirs.

Yeah.

Yeah, yeah. So they were doing that by thermal desalination, so by using steam, and effectively boiling the seawater to get pure water out on the other end. So very energy intensive. So that was thermodynamic modeling.

And then the other thing that I was doing was performance testing on coal stations. So I went to Eggborough coal station, now demolished, Rugeley coal station. And we were doing this, called boiler over fire air.

So at the time, they were looking to make coal stations produce less NOx. And we were doing baseline monitoring. So as a graduate, I was sat on top of this air preheater, sweating, getting static shocks off this probe, that I'm literally holding in the flow of the flue gas.

[LAUGHS]

MARK SHATWELL: So, yeah--

MARK SHATWELL: I was thinking, this is a violent university--

There's got to be some rules around that, yeah.

But yeah, so that was the last hurrah of coal generation, really. So I was at PB for a year. And then I joined Siemens Power Generation, in Energy Service Fossil.

And I said this to a colleague the other day, who actually booed me for being in fossil generation--

Boo.

MARK SHATWELL: --fossil generation.

No, not--

actually, just before--

so not at all, right? So our country--

the globe still requires on burning stuff to make electricity. And there's a very complicated mechanical-chemical process, and electrical, of course. And that's the crucial bit. You need the electrical bit on the end.

And this is fascinating. Yes, hopefully, we're not doing it in 50 or 100 years time, hopefully. But that doesn't mean it's not fascinating. It doesn't mean we shouldn't be putting loads of resource into making it better right now.

MARK SHATWELL: Yeah, yeah.

I just wanted to jump in with that.

MARK SHATWELL: Yeah, no, thank you.

We're not the anti-fossil booing lobby, I don't think.

Yeah, so Energy Service Fossil--

so actually, when I initially went back to Rugeley--

Rugeley being a big coal-power station.

Yeah, and so this was built in the 1970s, a lot of them near coal mines, basically, CEGB, so the Central Electricity Generating Board, before it was all privatized. And this plant, when I went back--

so they were putting in flue-gas desulfurization. So that's--

Flue gas is exhaust?

So--

sorry--

MARK SHATWELL: Yeah, so when you burn the gas, it's--

sorry. When you burn the coal, it's the gas that comes off, along with the combustion air. And in coal, depending on where it comes from, you have some sulfur.

Sulfur comes out of sulfur dioxide. And that could mix with water to get acid rain.

But nasty stuff.

MARK SHATWELL: Yeah, yeah. And so they were putting in flue-gas desulfurization, which is where you douse lime. And it reacts with the sulfur dioxide to take it out.

Lime, as in limestone lime--

MARK SHATWELL: Yes, lime--

--not from squeezing limes.

MARK SHATWELL: No, no, no. As in, yeah, quarried limes.

QUENTIN: Quarried limes.

And we'll come back onto this. It'll have to be a discussion.

OK, cool.

But yeah, so they were spending a lot of money on coal. And that was to help them keep running longer. You may remember--

I think it was the last combustion-plant directive--

said that to run above a certain number of hours, you had to have this desulfurization process.

And they were putting in new turbine rotors. And what we were doing was refurbishing one of these 500-megawatt generators to replace. And so I was working there, at Rugeley.

So a lot of money spent. I don't know if they ever recovered it because it didn't run that many years longer, after that.

And then also, at Siemens, so gas--

we said Combined Cycle Gas Turbine. I worked on probably one of the last new-build CCGT plants, which was down in Marchwood, in Southampton, which probably is still running today. Probably one of the most efficient plants, still providing--

What, built after Langage?

Yes, after--

yeah, after Langage, yeah. So there was a Marchwood. And then there was Severnside. And then there is Carrington Trafford.

So this was built in--

well, in the 2000s.

Carrington Trafford? Is that the one--

we're going back now, a long time--

is that the one that won a capacity-market contract yonks ago--

QUENTIN: --and then they just didn't build it. Or they did build--

did they build it in the end.

So there's--

Because there's a load of drama. They got this amazing capacity-market contract when capacity market was just taking off. And then it just got pushed back and back and back.

So there is one that's operating, Carrington. I've been around it. And then they were going to build a second one next to it. And that might be the one that you're thinking.

Still not built?

MARK SHATWELL: Still not built. I don't think ever will be built. They've looked at--

well, they're now looking, I think, to build a hydrogen and battery plant on the same site because we supported them with that planning.

Anyway, this is the problem. There's so much interesting stuff to talk about.

So then I joined Fichtner in 2010. And as I say--

so around that time was PFI. And that led to a lot of councils building energy-from-waste plants.

So they were borrowing this money, essentially, through the government. And it was driven, also, by landfill tax. So landfill tax went up to like 80-odd pounds a ton, which made it uneconomic for the councils to keep landfilling wastes. And so they were looking to build energy-from-waste plants.

So we, as humans, are producing all of this rubbish that was going into landfill. And then they started taxing it much higher. And council said, what on Earth are we going to do with it? And then the boom of energy from waste. Is that right?

Yeah, so probably--

so some of the oldest energy-from-waste plants operating now were built in the mid-'90s. So you've got the Midlands plants. You've got Stoke, Wolverhampton, Dudley, that were built, yeah, mid-'90s. And then probably from 2005 onwards, there was then a big boom, a lot of it pushed by this PFI.

OK.

MARK SHATWELL: So--

well, we'll get into that in a bit, I suppose. But just to, I guess, finish off my career trajectory--

so yeah, a lot of energy from waste from there. But then also biomass. So the renewables obligation meant that quite a few virgin-wood biomass plants were built.

And I also worked with Estover. I think you know the Estover guys. And they built a lot of CHP wood plants. So as well as generating electricity, they were providing heat.

So they were based on industrial sites, one of which was the Macallan whisky distillery. So they were providing steam--

QUENTIN: Oh, yes.

MARK SHATWELL: --for the distilling process.

So yeah, that was the RO, and as I say, energy from waste. And then the next thing was, capacity market came in. And then at the time, the idea was, this was going to build new, secure, dispatchable power.

And a lot of people thought that is going to lead to a new wave of CCGTs.

And so I supported a client that was looking to build two brand-new CCGTs. We specified them. We went into contract negotiation. But then the capacity market has never yet closed high enough to incentivize a new build CCGT.

So they didn't happen. And now I'm still working on a couple--

QUENTIN: That is probably one of the top three elephants in the room, about the whole UK electricity system, in my opinion.

Yeah?

Which is that still, still, the capacity market has not stimulated new-build CCGT.

MARK SHATWELL: No.

All these years afterwards.

Well, we essentially replaced coal and a new build CCGT with gas peakers.

QUENTIN: Yeah.

Oh, we could do a whole episode on the capacity market. Not my favorite thing. Anyway, it's like Marmite, isn't it? Actually, does anyone love the capacity market?

MARK SHATWELL: Gas peakers.

Gas peakers--

MARK SHATWELL: Yeah, yeah. But--

--are obviously a disaster.

There's still hope amongst CCGT developers that this February might be the one. But we'll see.

Well, fingers crossed. What we do need is new cleaner, gas, efficient CCGT plants in this country pretty fast. All right, cool.

And then you've been at Fichtner the last few years, working on a load of different things. Let's talk about energy from waste now. So Energy From Waste, or EfW, this is--

and I'm going to ask some silly questions now just to make sure we know what we're talking about.

This is taking rubbish that would have gone to landfill, so black bin-bag rubbish--

MARK SHATWELL: Black bin bag, yeah.

Pulling it all together, burning it, taking the energy from burning it, and turning that into electricity.

Yes.

QUENTIN: Is that right?

Yes, that's right.

And so these plants, how big are they? Where are they?

OK, so they're everywhere in the UK. You may not notice them. But obviously the bin lorries collect your bin and drive directly to the FW. So you don't want them too far apart

[GASPS]

Really?

Really?

Yeah, there is also some waste that gets bulked, and sent on trains, to different plants. But mainly, they tip directly into a bunker, so a big pit. So they're all over the country, throughout the UK.

The biggest one is in Runcorn. So that takes all of greater Manchester's waste. That actually does take a lot of waste via train because it has a train depot there.

So there's train carriages is full of rubbish from other places, coming through, to be burnt in this place?

MARK SHATWELL: Yeah, yeah.

Wow.

And so that is four lines. And it is about a million tons of waste a year.

That sounds like a really big number. But I can't--

I don't know what that is in black bin bags. I don't know.

Yeah, I don't either, [LAUGHS]

right.

QUENTIN: Obviously, it depends what you put--

it depends what you throw away. But if people are starving, not so much. So--

OK. So Runcorn--

and how many gigawatts--

how many megawatts is that?

So Runcorn's slightly complicated because it also provides heat, because it's on the INEOS site. So INEOS, former ICI, makes lots of--

QUENTIN: Great cycling teams. They make a lot of great cycling teams.

Yeah, they make cycling teams. They've also got a lot of chemicals. So they take quite a lot of heat. Maybe a better example is Ferrybridge.

So Ferrybridge former coal station--

its shut down, but has to energy-from-waste plants built on the cricket pitch and the golf course.

And between them, they're also 1.4 million tons a year, both around 70 megawatts, so 140 megawatts of electricity.

140 megawatts. That's not actually that many megawatts, is there, for so many tons of waste.

It's not that much. So they're not the most electrically-efficient plants. Typically, you're looking at between, depending on the age, 25% to 30% net efficiency.

QUENTIN: Net efficiency?

So if you compare that to CCGT, which can be as high as 60 with the latest gas turbines--

So the most efficient gas plant you can buy at the moment is late '50s, 60% CCGT. What about gas peakers? Where do they sit?

They're around mid-'40s.

Mid-'40s. And then burning energy from waste--

I won't call it burning from rubbish, but that's what it is--

that's in the '20s?

Yeah, yeah. Or it could be up to 30. So Ferrybridge is probably 30, of the newest ones. And they were built by SSE. So they come from a power background. And they push the efficiency.

Nice. And these things run all the time? Are they--

is it 24/7, go, go, go, go, go?

Yeah, absolutely 24/7. They're base load. So--

QUENTIN: Base-load power.

--they are--

yeah. I guess they're displacing--

the more you build, they're displacing some of the gas base load.

QUENTIN: So we're going to talk, in a minute, about what is involved at these plants to make it happen. I'm sure it's very complicated. But before we get there, let's just take it back a step.

So if we--

you and I, Mark, want to build energy-from-waste plant--

let's say we've got a little land somewhere, and a grid connection, and planning permission--

one of the fascinating things about energy from waste I want to get to, is the way the business case works because it's a little bit different from most things.

So if you build a gas plant, what you care about is what's your gas cost, your carbon cost, your CapEx, and then your operational costs, and then how much you make from the electricity. And you're building the plant to make money from electricity. But energy from waste is different, right? How is it different?

So the majority of your revenue comes from the gate fee. So it's probably the only energy-generating technology where people pay you for your fuel.

Wow. So what is a gates fee? That's literally--

So that is, you charge--

so literally, the lorry turns up full of waste. There's a weighbridge when you come in. They weigh the lorry. And when it comes in, it tips into the bunker.

They weigh it when it goes out. And they charge you for every ton of waste that you've tipped in the bunker.

They charge you for--

so OK, so the energy from waste plant charges the lorry for taking the waste.

Disposing the waste, like you would if you put it in a tip or a landfill.

And do you have any idea--

I've put you on the spot here, apologies. But how much per--

what's a gate fee, roughly? Is it tens of thousands, hundreds of pounds, thousands of pounds per lorry?

So there is a huge range, partly because of PFI and now merchant plants. But it can go from 50 pounds, at the low end, to maybe 120 pounds at the top end. And so under PFI, what the council did was, they went to competitive tender. And the companies that wanted to build their energy-from-waste plants bid a gate fee, essentially. And then that contract was set for 20, 25 years.

So a bit like a bidding for a CFD, if you're a wind plant, you'll bid for a gate fee if you want to build energy from waste?

Yeah, but just to that council.

And so the idea is, the gate fee is that it paid back the capital cost of the plant, as well as, obviously, made a profit for the developer.

But then the council would look at it as, well, it's going to cost me this much to landfill it. So then as long as the gate fee is coming in similar, then everybody wins, in a way.

So at some point in time, we decided, as a society, that we didn't want to stick things into landfill anymore, and we wanted to do energy from waste instead.

Yeah.

Interesting. Is it for--

the electricity price, are they locking in long-term PPAs on these prices or are they just taking the market? How does that work?

So I don't work in that much. But yeah, traditionally, they've locked in a PPA. And it's just a flat rate because they're base load. And this is changing. But traditionally, the electricity is a nice-to-have byproduct. The main thing is about burning waste.

So unusually again, for a power plant, almost all energy-waste plants have a bypass around the turbine. So if the turbine trips, you still want the plant to keep running. And even if the turbine is out, you still want to just keep burning the waste because that's what generates the money. And also, because you don't want trucks backing up. And there are penalties if you can't take the waste.

This is fascinating. So whatever happens, that--

is a furnace? Do you call it a furnace?

Yeah.

QUENTIN: That furnace is going, right, you're burning this waste. And then hopefully, ideally, 100% of the time, the turbine is running, and you're generating electricity. But if it's not, you're still going to take that waste because otherwise, the rubbish is going to just keep on coming.

MARK SHATWELL: Yeah.

Let's talk about the plant for a second.

MARK SHATWELL: Mm-hmm.

So I imagine there's a--

what is the plant? There's a big road that comes into it because you're going to need all these lorries. I imagine there's lots of potholes on that road.

And then the lorries tip into something. And then you burn it. And then there's a generator. What's involved?

So there's--

yeah, they come in. They go over the weighbridge, like we said. And then there's a tipping hall. So then that has a series of bays, again, a bit like you might have at your local tip.

The vehicles reverse into the bays and tip into the bunker, which is a big, concrete pit.

How big is a bunker, just to give an idea? It's like a sport--

it's like a football pitch or a sports hall or--

MARK SHATWELL: Yeah--

--are they? Wasn't it?

Obviously, it varies with the size of the plant. But yeah, it could be--

well, Runcorn is probably at least two football pitches. And then they might be 30 to 40 meters from the bottom of the pit to the hopper, which is where you tip the waste. And they might have anything like 12 bays. I think EnviRecover was eight bays.

So, yeah.

Surely, this thing is--

this might be a silly question. Sorry. But if you've got two football pitches in ground coverage, and you're tipping the rubbish off the waste--

sorry--

off the side, from a truck, doesn't it all go at one end? Do you have to move it, or it's like--

move it around a bit?

So the cranes move it. And one of the jobs of the cranes--

so generally, they spend a third of the time feeding the boiler, a third of the time mixing the waste, and the rest of the third of the time, stacking. So what the crane has to do, as they tip, is the crane has dig a trench. And they will just move the waste to the back so you can stack it as a slope. And then as it gets fuller and fuller, you can start to close off bays so that the bunkers are completely full in that area.

Wow. And this is--

again, we're talking about black, bin-bag rubbish, here.

MARK SHATWELL: Yes, yeah.

This sounds filthy.

MARK SHATWELL: Yeah, and it is. And if you look in--

because from the control room, there's a window into the bunker because the cranes can be automated. But sometimes they're driven manually.

So it's a bit like an arcade. We have a joystick and a grabber. It's like the Teddy picker, basically.

And you get mattresses in there. You can get--

oh, you get all sorts of things. You can get--

even engine blocks, car parts, turn up in there. And then there's also always video cassette tape, stuck to the crane.

OK, so that's a good question. Before we get to making the electricity, or generating electricity, all this rubbish, how do you know--

an engine block. Can you burn an engine block?

But here's examples of silly things that are in there. So have you got to sift through it somehow?

MARK SHATWELL: No. So I talked before a little bit about a gate fee. So the lowest gate fee is for waste that is presorted. So you can have things that are called MRF, Material Recycling Centers.

And there, they can sort the waste, take out any recyclables, shred the waste, and then you get the lowest gate fee for that because they've been pretreated.

So that's where they're picking the bits of metal out, and the good bits that can be recycled. And then you end up with just the rubbish at the end?

Yeah. And then sometimes, they'll even shred that waste so it's of a certain particle size.

QUENTIN: Grading?

Yeah.

Is shredding it better for burning it?

It's better for burning it, yes. But again, going back to the business case, what you want as an EfW, is the highest possible gate fee. And you actually want the lowest calorific value of the waste, so the lowest energy in the waste because you're charging people per ton and so--

I almost want to draw a firing diagram with my hands--

but you need so much thermal input--

If you're listening, there is quite a lot of gesticulating happening. And it is really value add. [LAUGHS]

So to generate a certain amount of steam, so you will control the plant through a steam flow, you need a certain thermal input. But the lower the energy value of the waste, the more you have to burn to get that same thermal input, and the more money you generate.

So I know an operator of an EfW plant, we get people ringing you up, going, I've got some really high-energy waste, here. Will you pay me more for it? And well, no, actually, I'll pay you less for it because I can't put as much through my plant. So there's a lot of the opposite as the way you would think in energy.

That's nuts. All right, let's come back to the--

what do we call it? The big hole.

MARK SHATWELL: The tipping hole--

MARK SHATWELL: --or the bunker.

So let's talk about what's the tipping hole. This waste, we talked about it for a second just before we came on. The bottom bit of the waste, you have to write off. Don't you?

So yeah, so generally, the tipping hole, you'll have a certain distance below the tipping hole that you can tip into.

And this is the two, football-pitcher-sized--

Yeah.

--area, just to get everyone on the same--

right, OK.

Yeah, and sometimes the tipping hole is elevated. So sometimes the vehicles go up a ramp. And that's to give you more storage because as I say, you tip into the bunker, and the deeper your bunker, the less often you have to trench, you have to use a crane to create that space, and the less far you have to dig into the ground, which is all cost.

Again, someone said, as a rule of thumb, it costs 10 times as much to go down as it does to go up. So it's expensive to dig.

Are these open, by the way? Or have they got a ceiling that--

No, they've got a ceiling because you don't want on rainwater coming in. So they're all--

and you want to keep the smell in, as well.

[LAUGHTER]

So they're all internal.

Do you get those pegs? Do they give people a nose pegs when you go? Do you get--

MARK SHATWELL: So generally, they smell a lot less than you think. In fact, I was talking to your colleague before. He'd been to EnviRecover. And he was impressed by how little it's smelled.

And the reason is that obviously, when you burn stuff, you need to take air in.

And so the primary air extraction is taken from the bunker hall. So there's a negative pressure in the bunker hole, which means the air flows into the bunker hole, rather than out.

And takes a lot of stinkiness into the combustion bit--

MARK SHATWELL: Yes.

--and then--

oh.

MARK SHATWELL: Exactly.

Brilliant.

So the only time they really start to smell is when they're off. And then, there are--

actually now, for single-stream plants, the EA insists that you have carbon filtration. So the--

What's the EA, sorry?

MARK SHATWELL: The Environment Agency.

QUENTIN: Yeah.

So carbon filtration is where, when the plant isn't sucking air in, you have a separate fan that sucks air through a carbon filter to take the smell out, and then ejects it at the top. So they're generally not as smelly. But if you're in the bunker hole when it's off, they can be smelly. I've seen people put earplugs up their nose instead, to--

I can imagine, yeah.

I'd be running around, looking for those. So we going to to stop talking about rubbish in a second. But that big--

so you said it could be 20 meters or so high, that you tip the back of a lorry into. And it all gets compacted down at the bottom, doesn't it?

MARK SHATWELL: Yeah.

And that stuff, can you still burn that? Or is that just a residue?

So you'll have a certain height that the crane can't quite reach, maybe half a meter. And then yes, that's almost there for--

That's no-man's land?

Yeah.

OK, all right.

And then you get the waste. You grab it, like--

I can imagine going to the seaside and using one of these grabbers. And you grab it, and you lift it up, and you drop it into the next stage, don't you? What happens then?

So then there's a hopper, so a sloped area like a--

QUENTIN: Like a funnel.

Like a funnel, yeah. And then it goes into a waste chute. And then from the chute, it goes onto the grate. And then to use another arcade analogy, the grate is like the coin--

what do they call it?

The penny machines.

Yeah, so again, I'm gesticulating, not great for the podcast. But you've got--

it's called a reciprocating grate. So you have these steps, that are moving--

Also like--

I don't know if it's still on now. ITV did a show that competed with Pointless, which was--

I don't know if you saw it. I'm a big Pointless fan, so it an annoyed me--

and a big BBC fan. And it's like a load and count--

so basically, that penny machine, but--

MARK SHATWELL: Penny falls or something--

Yeah, something like--

yeah, it's like one of those. And then there's a quiz. Anyway, I digress. So you've got the grate.

And what's the grate do? Is it shaking or is it--

So it's moving in and out. It's a reciprocating grate. So if you like, alternate steps of moving in and out. And there's a--

it's called the ram feeder, at the beginning. So there's a ram that literally pushes waste from the chute, onto the grate.

And what happens is--

so there's called the drying phase, the ignition phase, combustion, and then burn out. So as the waste comes on, it's getting heated up. And you can see this. There's usually cameras on the grate, or this window that you can look in, at the end.

Whoa, whoa, just one second. So this grate--

we're burning on the grate like a barbecue?

MARK SHATWELL: Yeah.

QUENTIN: OK.

Yeah.

QUENTIN: OK, so we're barbecuing this rubbish on the grate. The grate's moving. And there's cameras. This all sounds very exciting.

But then what happens?

So yes, it comes on, dries out, ignites. So there's a big flame. And then that produces a lot of hot gas, flue gas, that we said before.

QUENTIN: Exhaust.

Yeah. And then that's the furnace. And then you have water walls of the furnace, often refractory or in-canal clad, so that's proven.

Water wall? Whoa, water wall.

MARK SHATWELL: Water wall. So you have water walls in every sort of boiler, in a coal boiler. So what it means is, the walls of the boiler have pipes in, that has water in. So the water is boiling, starting to boil in these walls, to generate steam.

OK. Oh, so we haven't actually generated any electricity yet. We've just had a bit--

we've just burned a load of rubbish?

MARK SHATWELL: Yeah.

OK, cool.

Yeah, you burn the rubbish. And then, I suppose if we follow the flue-gas path first, so as it goes up the furnace, you have the--

so you have primary air. So that's the air coming in through the grate, through the bottom of the grate--

Bottom of the barbecue.

Yeah, bottom of the barbecue. So when you barbecue, if you--

you know, you open those holes in the bottom, that's your primary air, essentially. And then you have secondary air, which comes higher in the furnace.

And what you're trying to also do--

we'll go into NOx So one of the things you generate, that you don't really want, as a pollutant is NOx, so oxides of nitrogen. And to avoid NOx--

This is the same stuff that diesel cars produce and--

MARK SHATWELL: Yeah, yeah. And all combustion--

QUENTIN: Nasty stuff.

So what you do, to reduce thermal NOx, is you want to avoid stoichiometric conditions.

QUENTIN: Oh, my.

MARK SHATWELL: So stoichiometric conditions, if you look at your chemical formula, it's the exact amount of air you need to provide the oxygen for the reaction.

And when you have stoichiometric, you have the highest temperatures and you produce the most NOx. So there's nitrogen in the air. And at high temperatures, it forms with oxygen to form NOx.

QUENTIN: To turn into the nasty stuff, yeah.

MARK SHATWELL: Yeah, so you avoid that by first burning rich, which means there's not enough air. And then you burn lean, so you have an excess of air. So the secondary air provides an excess of air, creates the mixing, and ensures you have complete combustion.

OK, so you're aiming to completely burn this rubbish, but in a couple of different ways, to minimize the amount of nitrous-oxide stuff that comes out.

MARK SHATWELL: Yeah.

And then you measure, in the burnt--

so then you get ash coming off the end of the grate, which drops into basically, a water pit, so it quenches the ash. And then that's pushed out by a ram, onto a conveyor, which goes to an ash-storage area. And that's you're bottom ash.

And they also measure the bottom ash for the total organic carbon, which has to be below a certain amount. And that guarantees that you've burnt it out properly.

Total organic carbon, OK.

MARK SHATWELL: Yeah, yeah so that you've got burn out, so there's no--

essentially, there's no nasties left in it. All that's there is inert. And then with an energy-from-waste plant, so--

You still haven't actually made any electricity yet?

MARK SHATWELL: No. But actually, the electricity is the easy bit, in a way. The interesting bit is the burning.

So the other thing you have to be wary of, when burning waste, is dioxins, dioxins, PCBs, and furan. So have you heard of those?

No, they don't sound very nice though.

MARK SHATWELL: No. So--

I wouldn't invite them to my party.

So in the 1970s, we used to incinerate waste. And there was incidence of increased rates of cancer and birth abnormalities around people that lived near incinerators.

QUENTIN: Right. Serious stuff.

Yeah, and that's because some dioxins can be carcinogenic. And so when the UK started building, and the whole of Europe started building EfWs again, there was a thing called the Waste Incineration Directive, that's now part of the Industrial Emissions Directive. And that said that you had to make sure that the flue-gas temperature was above 850 degrees for more than 2 seconds, as the flue gas goes through the path.

So the exhaust gas is going up the chimney. They've got to be above 850 degrees to meet this big regulation? It was trying to stop people getting ill--

MARK SHATWELL: So not going up the chimney, but in the furnace.

OK, in the furnace.

Yeah. And what that does is, that breaks down the dioxins, PCBs, and furans into smaller chain molecules that aren't as harmful. So your first furnace pass is empty. You usually have one, two, maybe three empty passes because you don't want to take too much heat out, because you need to be above this 850 for more than 2 seconds.

And then the other thing that happens in the furnace--

sorry--

as we're going through it spatially, is you're also spraying ammonia or urea into the furnace--

Bloody hell. This is complicated, isn't it? I thought you just burn this stuff. You put out some electricity, and bobs your uncle.

You really have to treat--

MARK SHATWELL: Yeah, because you've got to--

--you have to treat the gases.

Yeah, because this is the thing that sometimes, opposition groups against the EfW are comparing it to the '70s, when there were genuine health concerns. There was no abatement. All they did was take out the dust. But now we have to make sure--

So they were just letting the exhaust fumes just go up into the chimneys, right?

MARK SHATWELL: Yeah. And so now, we have to make sure that what comes out of the chimneys is not harmful. And there's a--

I don't know if it's true. But there's an argument in some inner city areas, what comes out of the chimney is cleaner than what went in in the first place because you've treated--

there might have been NOx that went in, that you've treated in the plant.

If that is true, can someone--

if you're listening, can someone can someone tell us whether that's true or not? Even if it's true or not true, it's still fascinating. So ammonia, right?

Yeah, ammonia. So you douse the ammonia, which reacts with the NOx. So any NOx that you did produce--

obviously, you're trying to produce as little as possible, and you did--

reacts with the NOx to make it not harmful.

This all sounds very expensive. All of this treat--

I guess because your input fuel is so disgusting. no wonder--

and you have to burn it on a grate, like a barbecue--

no wonder you have to do loads of stuff to it afterwards, to stop it being really bad.

MARK SHATWELL: Well, there's more to come.

Oh, there's more?

MARK SHATWELL: There's more to come here.

So after you've doused the ammonia, you've gone through your 850, you then have the super heater. So you've raised steam in the water walls. Then the super heaters steam to the temperature you want for the turbine.

You go through that section. You go through the economizer. So the economizer is what warms the water before it boils. And then you get to the flue-gas treatment plant.

So--

yes. It's the it's the exhaust gases that are heating the boiler, which makes the steam, which generates electricity, right?

MARK SHATWELL: Yeah.

It's not--

just to be clear here because this is a common misconception--

so it's the exhaust gases that are doing the work here, rather than, I don't know, the fire?

Yeah, yeah. But obviously, the fire produces the hot, exhaust gases. But yes, so as it goes through, the exhaust gases are getting cooler and cooler, and giving up their energy, their heat, to the water, which raises the steam, which eventually makes the electricity.

QUENTIN: OK.

But as the flue gases come out the end of the boiler, they're typically 150, 140 degrees C.

And--

well actually, they might be a bit higher. But we cool them so they're around that 140 range. And that's the optimal range that they--

we then douse lime.

So we had talked about before, with flue-gas desulfurization, we douse lime here. And that reacts with any acid gases, so your sulfur dioxide mainly. And then you also have hydrogen fluoride and hydrogen chloride. And that's what would produce acid rain.

So we douse the lime that reacts with them. And then they go through to a bag filter. So a bag filter, think of it as socks. hanging down.

Like a Henry Hoover?

Yeah, like a Henry Hoover, I guess. Yeah, but there's lots--

these are long socks, hanging down. And they have this metal cage inside, which stops them collapsing on themselves. And then the flue gas goes through. So you've got an induced-draft fans, that are pulling a negative pressure, that pulls the flue gas through these socks.

And then the dust and the reacted lime sits on the outside of these, and falls down.

And the other thing that we douse here is activated carbon. And so we douse that. So those dioxins that we got rid of by having them at above 850, as the temperature cools, they can actually re-form at 250 degrees C.

So we doused carbon. And then any dioxins that do re-form are absorbed onto the carbon, which gets taken out of the bag filter, and then mixed into this flue-gas treatment residue.

So we've got all these stages of cleaning the exhaust gas. This is a very--

there's a lot of things to build, to maintain--

to invest in, to build, to maintain, a very complicated process. How close to the end are we?

Of the process?

QUENTIN: Of the flue gas?

Yeah, that's basically it. So you come out the back filter, you go to the ID fan, Induced Draft fan, and then it goes up the stack.

Then it goes up the chimney, which we call stacks.

MARK SHATWELL: Yeah, it's called a stack. And then obviously, the steam you've produced, which tends to be around 420 degrees C, goes to the steam turbine.

Now we're on to the electricity bit. Right.

MARK SHATWELL: Yeah, yeah.

So it's a steam turbine. And this is just a normal steam turbine.

Standard steam turbine. Yeah. So obviously, you've got high pressure and high temperature expanded through the steam turbine makes it spin, turns the generator, produces electricity. Then we condense the steam, usually in an air-cooled condenser.

Cool, cool.

But one of the reasons why--

I said EfW, it tends to be 25% to 30% efficiency. It was a lot lower than a coal plant.

But it's the same cycle, really. It's the Rankine cycle. It's the steam cycle.

Well, the reason that it's a lot lower efficiency, one, you've got higher parasitic load. You've got all these other processes--

I was going to ask you about that. You're generating this electricity. But even running this plant must consume a ton of electricity.

Yeah, so these huge cranes that you're moving about, you're blowing this lime in. You're conveyoring ash. So your parasitic load is 10% to 12%.

But then the main reason that your power output is less is because we can't reach as high temperatures as you can in a coal plant because the flue gases are full of nasty stuff. They're full of chlorine.

Chlorine loves to corrode the tubes. And the higher the temperature of the tubes, the faster the corrosion happens.

So there's a balance between getting more electricity out from higher temperature, but not eating through your tube super fast.

So that's the main reason. We're restricted to around 420 degrees C. And when you're restricted on temperature, you're also restricted on pressure.

So if I've got this right, they're--

in simple terms, because I'm a simple guy--

because the input fuel is so, I want to say unpredictable, but you guys probably know exactly what's going to be in there because people are very--

they're pretty--

No, it is unpredictable. You don't know what it's going to be.

QUENTIN: It's dirty. And you don't know what's in there. And you can't really check.

You don't know--

you've got everything from crisp packets to mattresses. There's all sorts.

And so this wide range of input fuels and horrible nasties in it means you have to spend a lot of time and effort cleaning up that gas, which has an impact. It has an impact on cost, has an impact on efficiency, has an impact throughout the whole thing.

And that means that when you go back to basics, the way these plants make money is by burning waste, not necessarily by making electricity. Is that a fair--

Yeah, that's true. And it's certainly historically been true. I think now, obviously, with electricity prices increasing, there's more and more effort into getting as much electricity out of them as you can. But their primary purpose is still to get rid of the waste.

And I get--

this is a big societal problem that we need to come to terms with, which is, if we're going to produce so much waste, if the bin men don't come one fortnight in a month, people are up in arms. I pay my--

it it's like, all we care about--

we pay our council bill, and it's like, as long as the bin men come, I'm happy.

So we need to, as a society, to figure out what on Earth are we going to do because we can't keep on putting it into the ground.

And so this is our next-best solution. And also, it generates some electricity. But it's costly, right? There's a cost to it.

MARK SHATWELL: Yeah.

How much do these plants cost?

200 to--

it depends on the size, obviously. But for a 200,000 ton a year plant, maybe 250 million.

250 million for 200,000 ton a year. So that's a fifth of the size of the Runcorn one.

MARK SHATWELL: Yeah.

And that will generate what?

20 megawatts.

20 megawatts, so 250 million quid CapEx on a plant that makes 20 megawatts, which is why we need to stop thinking about them as energy plants, right, they're waste plants with a bit of energy on top.

Yeah.

And then the complexity, the design and maintenance and operational complexity of these plants, is just out of this world. For a mechanical engineer like you, you must love it.

Yeah, yeah. They're interesting.

Yeah.

And so is there anything else about energy from waste that we haven't covered before--

I want to give you a chance. We've gone well over time, you see. I'll give you a chance on the last couple of questions that we've started asking. But is there anything else on EfW that we haven't covered, that you think is interesting?

So I guess--

like where is EfW going in the future, perhaps, because the--

Oh, you just ask the questions. That's a way better question.

[LAUGHTER]

So you have the--

Do a one-man podcast. It would be--

honestly, it would be better.

So you have the waste hierarchy, right, which is reduce, so that's less disposable plastics, reuse, so that's your cup--

you cup back to cost or whatever, recycle, and then recover, and then disposal. So EfWs are right at the end of that chain. So we want to reduce the amount of waste we produce. It is better to reuse, recycle.

But there's always going to be some waste left. And interestingly, one of the things we also get challenged on is carbon. So energy from waste, you you're taking plastics.

So typically, in waste, 50% of the fuel's biogenic, so organically derived. But then the other 50%--

As in the stuff that we can stick into our compost heaps anyway?

You can't necessarily extract it.

So it's 50% biogenic, roughly. So it used to be higher. But then we started recycling more paper. So paper's of biogenic, originally. So then it went down.

And then it could go either way in the future. We might produce less plastics. Then the organics could go up. But then we should also--

some councils, you just took your food in with your black bin. So it all goes to EfW. Some have--

Oh, really?

MARK SHATWELL: Yeah. Some have separate food collections, and it goes to AD. That's a whole other podcast you could do on anaerobic digestion.

--anaerobic digestion.

Yeah, so who knows. But we think it's probably going to stay around 50/50. And then there is an argument to say, well, with the plastics, actually, you'll be better to landfill now because when you burn it in an EfW, you're releasing the CO2 into the atmosphere, whereas if you landfill it, you're essentially sequestering that carbon. But then there's two--

That was a lovely word, sequestering.

MARK SHATWELL: Sequestering, yeah.

That's the first time on the podcast.

MARK SHATWELL: Oh really?

We're going to start using that word.

MARK SHATWELL: So when they talk about--

What does it mean, saving it for a future--

MARK SHATWELL: Well, locking it away, essentially, so it's not released into the atmosphere. When we talk about CCS, it's Carbon Capture and Storage. But the S can also stand for "sequester," so where you put it under the ground.

QUENTIN: OK.

So you could--

there's an argument to say, well, we should landfill the plastics. Then it's locked away.

And that might actually be a strong argument if it was only plastics. The thing with landfill is that a lot of--

if it's not just plastics, and stuff breaks down, then you tend to, in absence of oxygen, produce methane--

that's what anaerobic digestion is.

Methane has 25 times more global-warming potential than CO2. And we try and capture that in landfill gas, burn it in gas engines. But you don't know what you're not capturing. And you only need to capture--

you only need to release 1 ton of methane for, obviously, 25 tons of CO2, to have a worse effect.

So there's that argument against landfill. And the other one is, well, you're not doing anything with that plastic. You took it out of the ground. You put all that effort to make plastic. And then you're just putting it back. By burning it, we're generating some electricity. And that electricity is potentially, at the moment, offsetting base-load gas.

So we have to do all these carbon calculations as part of the justification because this is, again--

MARK SHATWELL: --it's planning. Yeah, so at the moment, it is better. It is better than landfilling, but not hugely. And if we stop burning gas as base load, then you could argue that you would be better off not burning in an EfW.

And so that's then where carbon capture comes in. So the--

Let's go there. Sod it. Forget how much time we've got. We'll go over. So carbon capture and storage, can you do that? Can you put the Hoover on the exhaust of the energy-from-waste plant, and suck the carbon out, and store it? Can you do that?

Yes, you can. Yeah. And at Fichtner--

so there's the BEIS have launched the Carbon Capture Cluster Sequencing program. We're on track one at the minute. And there are four EfWs in that track one. And we're supporting them with their prefeed studies.

So that's looking at--

well, basically designing the carbon-capture plant, sizing it, costing it, doing the layouts. And so you count--

again, that's probably another podcast on its own. But essentially, you use amine to suck out the CO2. And then you heat up the amine to release the CO2. And then you take the CO2 to store it.

And then there are two clusters at the minute that BEIS are supporting. There's the HyNet cluster, which is in the Northwest. And--

When you say a cluster, these are places, right? These are areas of the country, in the UK, which BEIS, the Department for--

[STAMMERS]

Business Energy and Industrial Strategy, right?

MARK SHATWELL: Yeah.

They are now supporting these two areas to do special things in?

So what they're basically saying is, it costs quite a bit of money to put in a CO2 pipeline, to run it out into the North Sea. And there needs to be a depleted gas field that you can put it in. So they've identified these two. There is a--

HyNet and East Coast--

where they will support the infrastructure that then, industries that capture their carbon can then put into this pipeline.

Put into the ground, but in the caverns or whatever that we got methane out from in the first place?

MARK SHATWELL: Exactly, yes. And so yeah, HyNet is one of those. And we're supporting the Protos EfW to look at capturing their carbon, to put into the ground. And then what that--

As long as you don't capture it, and then have to put it on trucks, and then move it there, because if that's what's--

I don't know whether that is in the plan. I don't know anything about this project. But I'm really struggling with the amount of projects out there that are--

I've got--

for the transportation thing isn't solved.

Yeah, well, if you're not near a cluster that's your only option, really. And everybody wants to decarbonize. So yeah, projects are looking at putting in trucks. But it's the ones that are in a cluster that it makes the most sense for.

So that's Runcorn as well, that we talked about at the beginning. That's right in the HyNet cluster.

But then if you capture the carbon, because I said it's 50% biogenic content, then you start to be carbon negative. So yes, it would be a big additional CapEx to install CCS. It would also take a lot of heat. So it would reduce your power output.

But you would then start to create carbon credits. And so that's potentially another revenue stream, although there's lots of things in the mix as to whether it's going to make you money or cost you money.

Wow, there's another podcast, there. Let's do that one day.

All right, two important questions to come. So one, this is your chance. What do you want to plug? What are you working on, or what is Fichtner doing, that everyone should know about? This is your chance.

MARK SHATWELL: OK.

And then the second question is a bit harder. Let's do the first one first. What are you working on?

OK, so I covered it a bit in my career trajectory. But what I wanted to get across is, yes, Fichtner has been the leading consultancy in energy from waste for a long time. But we're doing we're doing everything with energy. And I, personally, am working on a big, three-gigawatt hydrogen project at the minute.

We look at energy storage. We do do batteries. We're doing hydro. And we've created a model that we call the Energy Transition Business Case Models--

catchy title. But what that helps to do is, it uses our expertise that we've built up from working on all these different projects, to compare the different technologies, in terms of a levelized cost.

And we use Monte Carlo simulation to take the range. So all the different inputs have a range. And then we model them to come up with what we think is the most likely levelized cost.

And so what I would say is, if you're looking to develop a project, we can help to tell you what you should build, how much it might cost, whether you'll make money from it, what could go wrong, and ultimately, will it work. And so that's what, I'd say, yeah, I'd like to push that model.

OK, cool, Mark. So we'll put, in the show notes, a link to Fichtner. And you can get in touch with Mark for him to do that. And then lastly, probably the most tricky question, which is, what's your contrarian view? What do you believe, about the energy transition or what we're working on, that perhaps not a lot of other people believe?

So I guess as we've talked about energy from waste, I wanted to link it to that. So in that energy-transition business-case model, we've compared levelized cost of generation. And the lowest cost of generation is actually energy from waste because it is.

The lowest cost of generation is energy from waste?

MARK SHATWELL: Yeah, lower than offshore wind, lower than onshore wind because it goes it gets that revenue from the gate fee. And that's what underpins it. So actually, the electricity--

The lowest--

oh, so the lowest cost in pounds or dollars?

MARK SHATWELL: Yeah.

Yes.

MARK SHATWELL: Yeah, of generating electricity, is energy from waste.

And that's a levelized cost. That includes building the site, running it, and decommissioning it afterwards. Is that right?

MARK SHATWELL: Yes.

I'm not sure about the decommissioning, probably. They're definitely building it, yeah, and operating it. So as we've said, there are high operational costs. There are high CapEx costs, pounds per megawatt, for energy from waste. But because there is that gate-fee revenue, because you get paid for your fuel, which is totally unique for energy from waste, that gives you a low levelized cost of electricity.

I guess in order to--

but the thing is--

just thinking it through, right--

you'd have to burn a lot of rubbish to get that. So say peak load in the UK is 45 gigawatts, something like that. It might even be creeping up now. I don't know.

How much energy from waste is out there in electrical gigawatt terms?

So there's 1 and 1/2 gigawatts of EfW--

1 and 1/2--

--roughly produces 3% of the generation in 2021. And that's probably--

the 3%, you'd probably think that's higher compared to the 1 and 1/2, if you look how much wind capacity. But the load factor on an EfW is way higher than a wind because they base load. So that's why it's 3%, which is more than hydro. Solar is about 4%.

So--

Do you guys have to buy carbon? Do you have to buy carbon--

MARK SHATWELL: At the minute--

--the same way that a gas power station has got to buy carbon as an input cost?

So at the minute, they're exempt.

QUENTIN: They're exempt?

Yeah. But from 2028--

so there's a consultation out there from BEIS. And they're looking to bring them into the ETS from about 2028. And that's what's really going to drive carbon capture.

I was going to say, yeah, that'll drive carbon capture. Also, I assume that number's not in the levelized cost from that because--

Well, yeah--

no, it is. So we've run different scenarios. We've run historic prices, current electricity price, and we've run a net-zero scenario. And--

Fascinating stuff.

And then the other--

the only final thing I wanted to add is heat as well. So I've heard you talk about heat pumps. And I think heat pumps are a really good--

Ooh, I love heat pumps.

MARK SHATWELL: --good solution. So we said coefficient of performance about 4 or something for a heat pump?

Yep, 1 in 4 out. I still don't understand the maths behind that. But 1 in 4 out. What more do you want?

MARK SHATWELL: Well, if you go to use CHP, not just from energy waste, but using the energy from waste, then your z factor, which is the same, 1 kilowatt of electricity for 1 kilowatt of heat out, you're looking at--

you can get to double figures.

So your 4 becomes measly. You can go 7, maybe even 10--

Whoa.

--because you're using the latent heat. So what you when you take steam out, even if you take it at a higher pressure, you're condensing it. You're recovering that latent heat, which otherwise goes to the atmosphere. So your z factor can be massive.

So this is why--

again, you've talked about Scandinavia a lot. So yes, they use heat pumps. But in the cities, they use district heating. And we're really poor are using it in the UK.

Sheffield and Nottingham, I think, are the only cities that have any district heating because it's really hard.

You're totally right. So you've done your homework.

Big Scandinavian phile, a Scandiphile, if that's even a word. Love heat pumps. We have to do some research into CHPs and z factors though because if you can beat 1 in 4 out, we can talk about it.

MARK SHATWELL: You can, but it's a lot harder.

QUENTIN: And you can burn stuff, I guess. But with a heat pump, you still have to burn stuff, just somewhere else, unless you're fully--

anyway, we're going down a rabbit hole again.

Look, Mark, I want to say a massive thank you for coming on. This conversation was fascinating. And for everybody listening, do please hit the good stuff, Like, Subscribe, and all the buttons, which mean that we get kudos so our numbers go up. It really does mean the world to us. Thank you very much for coming on, Mark. And see you again soon.

Cheers. Thank you.

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