Heat Pumps: Neil Lawson of Geoenergy Discusses Heat Pumps

So this is one of the biggest things that's being missed, is that if you were to ground couple your cooling and store that energy in the ground, you can halve the carbon of cooling where they store the waste heat from refrigeration in the summer and use it to heat in the winter.

Hello and welcome to Rethink What Matters, the podcast dedicated to aligning the economy with the ecology and everyone for improved business performance, stronger families, and a greener, cooler planet. And today I'm going to be talking with Neil Lawson of lowcarbonfarming.co.uk, and we're going to be talking about something every one of us should be using, and that's heat pumps.

So yeah, great to be speaking with you about heat pumps because, you know, they're some kind of miracle device, aren't they? It generates something like 400% efficiency. So definitely interested to learn more about that. And I went to lowcarbonfarming.co.uk, your website, and it says here the way we produce food needs to become more sustainable. And less damaging. With this in mind, the Low Carbon Farming team set out to improve greenhouse heating systems to meet this challenge, and in doing so created a world first.

Well, a little bit of background about that story. It all comes from walking down the river behind me one day and noticing some ducks enjoying a swim on an area that was slightly steaming. Which got my interests going. So I followed the little stream that they were on, which was a little tributary into the Thames, followed it up to its source, and it arrived at the Oxford Sewage Treatment Works. So I literally knocked on the door, asked what it was about, learnt a bit more, or was invited in officially to learn a bit more about their process. And a quick fag packet calculation while I was there there was around enough heat to heat 15,000 homes just being discharged into the river. So this was a plentiful source of heat that every city would have through its water recycling centers. So you basically take all the raw sewage and rainwater, goes into a sewage treatment works, and it comes out as clean water which is discharged into the river. That clean water has a heat value. Anywhere between 9 and 25 degrees centigrade depending on the time of year. That's a very abundant source of energy for a water source heat pump. So we took that idea, looked for something which was a large demand, and that was seen as greenhouses. Building them local to cities would be good for food miles or transport miles rather than we currently ship things in from Morocco and southern Spain. The idea went from there. The world-first aspect of it was taking waste heat from clean water discharge into a river and using that in a heat pump. When I do a show or a panel discussion, one of my favorite questions is, "Hands up, who's got a heat pump?" 2 or 3 people put their hand up. I enjoy pointing out that everyone has a heat pump. It's the fridge in the kitchen. That is fundamentally a heat pump.

And I think if you put your hand behind your fridge, it's pretty warm back there. Are there other areas, other areas of industry?

Every city has a housing need, it has a schooling need, it has a heat need. So anywhere you require heat, it's applicable.

So this sounds too good to be true in a way. All this heat is, you know, out there that's going to waste and we can turn it into usable heat. What are the challenges in doing this then?

It's actually recognizing the opportunities. A heat pump, in the heat pump cycle, the refrigerant boils at -20. So, anything that's warmer than -20 is a useful heat to us. The warmer, the better. The joy of the sewage treatment works was it was between 9 and 25 degrees Celsius, so you get very efficient heat pumps. But we just need to look around us. Power stations got huge cooling towers. Which are pumping out steam, although thermal power stations are less and less these days. Data centers are being built everywhere. They have to cool their processes inside, so they do that by rejecting heat.

You mentioned -20. Anything over -20? It's pretty much everywhere, isn't it?

It is. Hence heat pumps work in sort of Scandinavia where the temperatures are very cold, even on air source heat pumps. Heat pump. The heat pump cycle is a quirk of physics. We harvest low-grade heat by boiling refrigerant, turning it from a gas to a liquid, and then compressing that— sorry, turning it from a liquid to a gas, and then compressing that gas again back into a liquid. And the byproduct of that compression cycle is heat, which is what we harvest to do space heating or hot water heating.

I need to just have a look. I try and think about that a little bit more. I know you can't get— it's not possible to get more out than you put in, no matter how clever the technology. What's actually happening here?

Well, if we talk about the efficiency and we hear words of 400% or 500%, but actually that efficiency is the ability of the heat pump to turn 1 kilowatt of electricity, which is used by the compressor, which is compressing maybe 3 kilowatts of low-grade heat, which have been harvested from the surroundings. Outside around us, whether it be water or air or a waste heat from somewhere else. So it's 1 kilowatt of electricity plus 3 kilowatts of low-grade heat, which is free, and that generates 4 kilowatts of useful heat. So that's where the 400% efficiency comes from.

But if you've got something that's at -10, what can that become?

The efficiency of a heat pump is its ability to take the low-grade temperature and to turn it into a high-grade temperature. So if, for example, you have air at -10, which we do in winter, to produce 50°C into your radiators, the heat pump or the compressor is having to lift it from -10 to +50. So it's a 60-degree lift. Those efficiencies will be closer to 200%. Hence, the warmer our waste heat, the more efficient the system.

Are there other examples you could give us of where heat pumps have been, you know, used to great effect?

Yes, so we are used to heat pumps for cooling. Perversely, every office or building has a gas boiler for heating and a heat pump for doing cooling. But that same heat pump could do both heating and cooling. So they're seasonal.

Right.

So we just have to challenge the status quo or the norm of the building services engineers who are very used to specifying gas boilers and heat pumps to make them think about air source which can do both or even ground source. The challenge with air source is we are venting our waste energy into the atmosphere, into the air and waving goodbye to it. If we were to employ ground source, we are capturing that waste heat and we're storing it in the ground for the opposing season. So if we use our heat pump in summer to cool down our building, we put the waste heat into the ground, it's then there and available for winter when we want it for heating. So this is one of the biggest things that's being missed is people talk about the decarbonization of heat because we're used to fossil fuels. But if you were to ground couple your cooling and store that energy in the ground, you can halve the carbon of cooling. Or the cost of cooling, which is something that's been done successfully in supermarkets such as Sainsbury's. They installed around 30 of their supermarkets with ground source heat pumps where they store the waste heat from refrigeration in the summer and use it to heat in the winter. Their biggest benefit or cost benefit was the fact that they halved their cooling costs.

Presumably it's quite an expensive exercise though, quite capital intensive. Maybe less easy for private residences, you know, people at home to implement?

Well, if we talk about the challenge and the capital expenditure, we're talking about a ground source heat pump or a water source heat pump, and your energy is very local. It could be under the house, it could be under the building, it could be in the river next door. What it needs is investment from someone like government to start communal collectors getting together where we can share heating and cooling. So, we talk about district heat schemes.

Right.

We currently have a, well, a third-generation district heat scheme is the burning of fossil fuels to generate heat. A fourth generation is a mixture of fossil fuels and low carbon. So, a mix of a heat pump and a gas boiler. A fifth generation is an ambient heat network or a condenser loop. So, this is a pipe full of water effectively. That could be anywhere, it could be around 10, 20 degrees centigrade and it's sufficient for people who need heat to absorb heat from it and those who need cooling to reject heat into it. So this is where you start to join the various users together and suddenly your efficiencies, if 1 kilowatt of electricity into a compressor can generate 4 kilowatts of heat, at the same time it generates 3 kilowatts of cooling. So suddenly you've got an efficiency of 700%.

Right, okay. So what's the— what are the problems in take-up here then? Is it just that alternatives, although less efficient, are just cheaper?

Gas is cheap. We've had it since England converted from town's gas to North Sea gas from the '70s onwards. So we're talking about a whole new technology. So that investment that went into the gas main and gas infrastructure now needs to be put into a communal collector or fifth-generation heat network, then suddenly a heat pump as a box will come down in price as volume goes up. And if we can get it to the point where we just connect to the pipes in the road like a gas boiler, suddenly it's like for like. But that asset in the ground has a 60-plus year lifespan. Yes, so we talk about heat and people think of hot water or 65°C and that's what we have to store. But if we are to store a load-grade heat at maybe 20°C, that actually takes the pressure off the grid because in winter when you need your heating most, your base temperature of 20°C is a lot warmer than your air source heat pump is trying to harvest from something like -8°C. And thermal mass should be at a building level. So a building is built of bricks and mortar and has a thermal mass to it.

Okay.

So you all don't need to come home and turn your heating on at 6 o'clock and hit that big peak. It's now all about matching supply and demand, removing those peaks and reducing our generation costs.

I was speaking with the university earlier today. And yeah, so they're looking at smart heating and distributed heating and looking at heat pumps too. And they mentioned aqua heat pumps, you know, using the water in the ground as opposed to the ground. Is that a third type of heat pump or is that just ground source by another—

No, we would call that a water source. So if you take London, for example, it's built on a huge chalk aquifer. So if you drill down 65 meters in central London or so, you get into a big lake. And actually that water level is rising and starting to threaten the underground. So there have been a lot of studies on dewatering the underground. And there's, as an example, there is passive cooling of Green Park tube station, which are wells drilled near the tube station extracting water from the aquifer, going through heat exchangers to cool the tube. And then discharging back into the aquifer again. There's about 1.8 megawatts worth of waste heat there that could be used by an adjoining building.

If we're just thinking about a company that's maybe a data centre then, what could they look for to see if heat pumps could work for them?

So data centre probably already has a heat pump, but they call it a chiller. So it's currently doing their chilling, it's venting all the energy into the atmospheric air. But the people who design and build data centers are very precious about a tried and tested system. They're very reluctant to try something new. So here we need to challenge that.

Mission critical, I should imagine. Yeah, you don't want those computers to cook. Yeah.

Exactly.

Maybe a different example then.

There was an article in the Telegraph a few days ago about due to the sudden heatwave, they're having to fire up some coal-fired power stations to produce enough electricity to provide people with cooling as the air conditioning systems come on. So, going back to the example of—

That's mad, isn't it?

That's crazy. It is mad. If you had stored your waste coolth from winter in the ground, you could now be using it passively. Passively means you're not running a compressor, you're just running a circulation pump and bringing up water in the ground that's, say, 5 or 6 degrees centigrade, and that's more than capable of cooling a building, whether it be a domestic property or a commercial building. So, in the UK, there's an aspiration to have 600,000 heat pumps installed a year by 2028. Our biggest challenge today for domestic heating is the spark gap. So, the cost of electricity is more than 4 times the cost of gas. Therefore, your heat pump has to be more than 400% efficient. The cheapest type of heat pump is an air source, and a lot of funded systems going in are air source heat pumps. They use the Boiler Upgrade Scheme, which is a £5,000 grant, but it's going to cost them more to heat their homes. If they get an efficiency of 250%, it's going to cost them a third more to heat their homes. When utility bills have gone through the roof, very few people can afford that extra currently.

And what about on the maintenance side of things? Is it more— is it quite costly to maintain?

There are very few moving parts. If you look at an air source heat pump, you have a compressor and you have a fan. Yeah. And an expansion valve. In a ground source heat pump, you'll have compressor and a circulation pump on the ground side. So very few moving parts, right? So the longevity of a ground source heat pump is potentially 25 years. Of an air source heat pump, anywhere between 10 and 15. That depends on its location. Is it near the seaside? Is the salt corroding the fins? Are there leaves on trees around? That sort of thing.

Right, okay. So, um, it sounds like then that it's, uh, you know, from a maintenance perspective, not overly complicated or difficult to take care of. Everything's not buried in the ground somewhere and you've got to dig it up, you know, every 10 years or whatever. So it's accessible?

Yes, very, very accessible. In fact, one of the— yeah, one of the things about, uh ground source heat pumps. It's very much a hidden and discreet technology. So it is buried in the ground, but you're just pumping a fluid around the ground.

Okay.

Okay.

But the domestic market, you mentioned there are some targets there, but they're not going to be able to— I mean, people don't have the money to buy them in and implement them at the moment. So yeah. So there's definitely some work to be done, isn't there, to get people to actually start taking up heat pumps domestically?

Yeah, if we look at somewhere like Jersey, their energy tariffs are, they have a heat pump tariff, which is 12 pence per kilowatt hour for electricity. Their gas is 18 pence per kilowatt hour. So if you look at the efficiencies, if it's a 4 to 1, it's going to cost them 3 pence per pence per kilowatt hour for their useful heat from their heat pump. And if it's 18 pence for gas and it's 90% efficient, it's going to be about 20 pence per kilowatt hour for useful heat from their gas boiler. So suddenly you can get a payback in your heat pump.

Right. Just explain the spark gap again, please.

So we look at the cost of electricity.

It's the difference between the gas and the electricity price, I think you said.

Yeah, exactly that. So currently gas is— sorry, electricity is more than 4 times more expensive than gas. But perversely, our electricity price is driven by the price of gas because we're very reliant in our currently in our centralized grid on using gas peaking plant to make up the difference. And we also have the green levies. The green levies were put onto the electricity price. Whereas now they should be put onto gas to decarbonize.

Yeah. So, I mean, so we've really talked a lot about how to implement and how they work and how applicable they are. But we're really being driven here by the environmental side of things. Because, you know, environmentally, they're much better, aren't they? They, you know, they're not producing lots of CO2. CO2 and nitrogen. So what's the environmental footprint like for heat pumps?

At point of use for a heat pump, there are no emissions. You can have them in a house, there's no CO2, there's no carbon dioxide, there's no NOx, as you say. There is an argument that we're reliant, we're quite reliant on gas and potentially coal at the moment. So there's a very good app called Grid Carbon, which you can log into and you can see what the grid carbon content or the carbon content of the grid is at an instantaneous moment in time. If you go back to the first months of COVID there were satellites in space that could monitor CO2 and greenhouse gases and the cities were just clearing.

Right.

That's a lack of use predominantly from cars and vehicles, but gas boilers are the same.

They do produce And heat pumps are, you know, are a big part of low-carbon farming because they're so efficient, because they're taking heat which already exists, using that to heat the greenhouses. If I've understood this correctly, there are no carbon, there are no toxins coming out of it, no climate warming gases, CO2 and the rest of it. So are heat pumps and low-carbon farming, these two are made for each each other, are they?

They are, especially in this country. A lot of our tomatoes, peppers, and cucumbers are imported from Spain and Morocco and Portugal. And actually, by importing from there, we're exporting drought. We have a huge rainfall in this country. In our two greenhouses, all the rain we capture off the roof, we store in reservoirs, and we use to water the plants. So we're not importing any water. There is actually a need for CO2 to feed the plants for the photosynthesis cycle. And we do that by using CHP gas engines, but we pump all the CO2 from the exhaust into the greenhouses to feed the plants. We mustn't forget that heat pumps also run on electricity.

Yeah, I know. I mean, I think we have to— there have to be two separate conversations, I think. I think we have to separate the efficiency of taking the energy and converting it into whatever we want versus the sourcing of the energy. So, you know, if you plug one of these heat pumps into a wind turbine or a solar panel, you know, then we've got what we want then, I think, haven't we? We've got something which is completely clean.

Exactly that. I mean, the village where I am here, we developed and built the largest hydro on the Thames in our little village, which we then crowdfunded out of the local area. So we got 440 kilowatts of hydro in the river, which runs pretty much all the time. So we could heat and cool and generate electricity for our village out of the river with absolute zero carbon. That's one of the best examples of potentially utopia.

That's fantastic. Yeah, well, that's it. I mean, that's actually, you know, we need to start using this utopia word a little bit more often. You know, because we need to be heading towards a good vision here. How many people or houses is that looking after?

We're not, sadly we're not doing it because the electricity goes into the grid and gets lost. But on paper, there's no reason why we couldn't. So we've got 1,000 people, 500 houses. Actually, the Stanford-on-Thames or the mill used to be the paper press for Oxford University. So it was a mill. Generating its power from the river.

There must be quite a lot of loss though in putting that energy into the grid. It's got to travel down the wires and then get sent off into various different locations. So I should imagine quite a bit of it gets lost in the process of distribution, transmission.

I think it gets used locally. The biggest loss is actually we sell the electricity for 5.5 pence per kilowatt hour and I have to buy it 400 meters away for 34 pence per kilowatt hour. So I think I suffer the biggest loss, which goes to the big sites. Yes, okay.

Yeah, well, you know, we want to get this message out there, you know. So you could do a lot more if you got more, you know, yourself, you know, and you and your business could do a lot more if you got more of that money. And which countries are we, you know, looking to for inspiration here? Are we leading the world with this? I think you mentioned Germany. Scandinavia? Who's ahead of the curve here with either heat pumps or low-carbon farming?

So if you look at heat pumps, definitely Scandinavia. Their heating oil prices were petrol pump prices. So they've been incentivized since the '50s to make their homes efficient. Not only thermally efficient, but also the use of heat pumps and electricity. So a lot of the challenges that we think are stumbling blocks they've overcome. And we need to be looking to them and taking note of what they do. So we talk about the grid can't support all of these heat pumps. Every house in Sweden has a 16-amp 3-phase supply, which is about twice the size of what we have here. But on their heat pump, they have a monitor. So if the cooker's on and the freezer's on and the washing machine's on, then the heat pump holds off for all of 5, 10 minutes. You're not going to see the house go cold in that time. That just stops you drawing or removing the peak. So these are the sort of— this is what a smart meter should be for. Sadly, we have installed a whole network of dumb meters.

Okay. But that's been corrected, I think, isn't it? Because you hear a lot about smart meters today.

Smart meters are good for the utilities to remotely read your bill. They haven't taken them any further. I remember Tomorrow's World program, if you remember that, back in the '70s.

Of course.

Yeah, they had a program where you could have an intelligent meter that could turn your fridge on and off, turn your freezer on and off, your washing machine and things like that, and control what's going on with your grid. Sadly, that never happened.

So from your perspective then, Neil, in your customers and your clients and your clients that you'd like to have. Are there smaller budgets that you work with or domestic? Just give us a bit of a feel of who your typical clients are and who you'd like to work with after this.

Currently we don't have a typical client. We work from domestic all the way up to commercial. Currently there's a lot of investment in the public sector decarbonisation scheme. We're involved with that. We work as assessors for Salex, so we review the bids. We also do feasibility studies for clients, and we'll do detailed design for contractors. One of the gaps I identified in the market was there are a lot of people out there who can weld pipe, fit pipe, drill holes, and things like that. But what was really missing is the in-depth knowledge of applying a heat pump. So we have a design team of engineers who are probably the most experienced in terms of years within the country and have a huge— not only do we design, but we have experience of installation, commissioning, operating, running, and servicing heat pumps. So happy to talk to anyone who is considering their energy, has heating loads and cooling loads, and is serious about doing something, not just offsetting, buying a bit of forestry in the Amazon.

Yeah, I know this whole offsetting thing is— yeah, we've got to try and not offset, basically, or offset as little as possible, haven't we? Brilliant. All right, I really appreciate your time, Neil, on this podcast. It's been really insightful. We've learned a lot. If somebody wants to get a hold of you, what's the best way for people to get a hold of you? Where should they go? Should they go to lowcarbonfarming.co.uk?

Or geoenergydesign or geoenergy.co.uk.

Once again, thanks very much, Neil.

No problem. Thank you for giving me the opportunity.