Heat pumps are highly efficient heating and cooling systems that extract heat from the air, ground, or water sources and transfer it indoors or outdoors as needed. They offer significant energy savings, lower utility bills, and reduce greenhouse gas emissions.
So this is one of the biggest things that's being missed is, if you were to ground couple your cooling and store the energy in the ground, you can halve the carbon of cooling where they store the waste heat 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 climate.
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 they’re some kind of a miracle device, aren't they? It generates something like four hundred percent 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 is a little tributary into the Thames, followed it up to its source, and it arrived at the Oxford sewage treatment works. So 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 five packet calculation when I was there, there was around enough heat to heat fifteen thousand homes just being discharged into the river.
So this was a a plentiful source of heat that every city would have through its water recycling centres. You basically take all the raw sewage and rain water 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. So it's anywhere between nine and twenty five degrees centigrade depending on the time of year. That's a very abundant source of energy for a water source heat pump. So 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 and 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 favourite questions is, “Hands up who's got a heat pump.” Two or three people put their hand up and I enjoy pointing out that everyone has a heat pump. It's the fridge in the kitchen. That is fundamental heat pump.
But 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, has a schooling need, has a heat need.
Right. So anywhere you require heat, it's applicable. So this sounds too good to be true in a way. All this heat, this you know, out there that's going to waste and we can turn it into usable heat. What are the challenges in doing this thing?
It's actually recognising the opportunities, a heat pump in the heat pump cycle, the refrigerant boils at minus twenty. Anything that's warmer than minus twenty is a useful heat to us the warmer the better. The joy of the sewage treatment works was it was between nine and twenty five degrees C, so you get very efficient heat pumps, but we just need to look around this. Power stations got huge cooling towers which are pumping out steam although thermal power stations are less and less these days. Data centres are being built everywhere they have to cool their processes inside. So they do that by rejecting heat.
You mentioned minus twenty. Anything over minus twenty? It's pretty much everywhere, isn't it?
It is. Hence, heat pumps work in Scandinavia where their temperatures are very cold even on their source 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. So 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 heat or hot water heating.
I need to just try and think about that a little bit more. I know you can't -- it's just not possible to get some more out than what 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 four hundred percent or five hundred percent, but actually that efficiency is the ability of the heat pump to turn one kilowatt of electricity which is used by the compressor which is compressing maybe three kilowatts of low grade heat which have been harvested from the surroundings outside around us, whether we water or air or a waste heat from somewhere else. So it's one kilowatt of electricity plus three kilowatts of low grade heat which is free and that generates four kilowatts of useful heat. So that's where the four hundred percent efficiency comes from.
But if you've got something that say minus ten, what can that become?
With the efficiency of a heat pump is its ability to take the low grade temperature and turn it into a high grade temperature. So if for example you have air at minus ten, which we do in winter, to produce fifty degrees centigrade into your radiators, the heat pump or the compressor is having to lift it from minus ten to plus fifty. So it's a sixty degree lift and those efficiencies will be closer to two hundred percent 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 used to great effect?
Yeah. 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. So we just have to challenge the status quo or the norm of building services engineers who are very used 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're 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 (that) people talk about the decarbonisation of heat because we're used to fossil fuels. But if you were to ground couple your cooling and store the 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 thirty 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. And their biggest benefit or cost benefit was the fact that they halved their cooling costs.
Presumably it's quite an expensive exercise. They're 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 low. 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. We currently have 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 the heat pump and a gas boiler. A fifth generation is an ambient heat network or a condensed solute. So this is this is a pipe full of water effectively that could be anywhere, it could be around ten, twenty degrees centigrade and it's sufficient for people who need heat to absorb heat from it. 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 one kilowatt of electricity into a compressor can generate four kilowatts of heat. At the same time it generates three kilowatts of cooling. So suddenly you've got an efficiency of seven hundred percent.
So what are the problems in take up here then? Is it just the alternatives are less efficient or just cheap?
Gas is cheap. We've had it since England converted from town's gas to North Sea gas from the seventies onwards. So we're talking about a whole new technology. 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 heat pumps in 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 flight. But that asset in the ground has a sixty plus year lifespan.
Yes. So we talk about heat and people think of hot water or sixty five degree centigrade, that's what we have to store. But if we're to store a load grade heat, maybe twenty degrees, that actually takes the pressure off the grid because in winter when you need your heating most, your base temperature of twenty degrees is a lot warmer than your air source heat pump is trying to harvest from something like minus eight and thermal mass should be in a building level. So a building is built of bricks and mortar and has a thermal vest to it. So you all don't need to come home and turn your heating on at six 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 they're looking at smart heating and distributed heating and looking at heat pumps, too. And they mentioned aqua heat pumps and 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 sixty five metres 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, go through heat exchanges to cool the tube and then discharging back into the aquifer again. There's about one point eight megawatts worth of waste heat there that could be used by an adjoining building.
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 and it's venting all the energy into the atmospheric air, but the people who design and build data centres are very precious about a tried and tested system. They're very reluctant to try something new. So here we need to challenge now.
Mission critical question. You don't want those computers to cook. Maybe a different example then.
There was an article on the Telegraph a few days ago about due to the sudden heat wave they're having to fire up some coal fired power stations to produce enough electricity to provide people with Tulum as the air conditioning systems come on.
Right. 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 coof 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 out water in the ground that's say five or six degree centigrade. And that's more than capable of cooling a building whether it be a domestic property or a commercial building.
Right. Okay. So a hot country is making good use of this then.
So take a hot country, Dubai or something like that, desert, very hot. All of their cooling is done through cooling towers. Where they're effectively evaporating water or try to discharge their heat into the atmosphere.
If they were to put pipes into the sea and take seawater at a deeper level, they could bring the cost and therefore the carbon and the energy required and they're cooling way down.
And so this is quite a relatively new technology. Is it being developed at a great rate? Is there a lot of investment going into him heat pumps and improving the technology?
So in the UK there's an aspiration to have six hundred thousand heat pumps installed a year by 2028. But there is no -- apart from that policy and that headline, there's no drive behind it. Our biggest challenge today for domestic heating is the spark gap.
So the cost of electricity is more than four times the cost of gas. Therefore your heat pump has to be more than four hundred percent efficient. The cheapest type of heat pump is an air source and a lot of funded systems going in our air source heat pumps. They use the boiler upgrade scheme which is a five thousand pound grant, but it’s going to cost them more to heat their homes if they get an efficiency of two hundred fifty percent. It's going to cost them a third more to heat their homes. When utility bills have gone through the roof, very few people could afford that extra current.
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, and an expansion valve. In the ground source heat pump, you'll have compressor and a circulation pump on the ground side. So very few moving parts. So the longevity of a ground source heat pump is potentially twenty five years, an air source heat pump anywhere between ten and fifteen. That depends on its location. Is it near the seaside? It's the salt corroding the fins, are there leaves or trees around that sort of thing?
So it sounds like that it’s, from a maintenance perspective, not overly complicated or difficult to take care of it. Everything is buried in the ground somewhere and you've got to dig it up, you know, every ten years or whatever. So it's accessible.
Yes. Very, very accessible. In fact, one of the things about ground source heat pumps is very much a hit in the discrete technology. So it is buried in the ground because it's probably a fluid around the ground.
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, you know, and implement them at the moment. 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 someone like Jersey, their energy tariffs are -- they have a heat pump tariff which is twelve pence per kilo hour for electric see. Their gas is eighteen pence per kilowatt hour. So if you look at the efficiencies, if it's a four to one, it’s going to cost them three pence per kilowatt hour for their useful heat from their heat pump. And if it's eighteen pence for gas and it's ninety percent efficient. It's going to be about twenty pence per kilowatt hour or useful heat from their gas boiler. So suddenly you can get a payback in your heat pump. It's massively cheaper to run.
Right. Just explain the spark gap again, please.
So we look at the cost --
That's the difference between gas, and the electricity price, I think you said.
Yeah. Exactly that. So currently, gas is-- sorry, electricity is more than four times more expensive than gas. And perversely, our electricity price.
And why is it called spark gap?
I don't know. It's just a terminology that's been adopted. Probably it's the spark that was –
Let me talk of the stalker and gas music burners.
But perversely, our electricity price is driven by the price of gas because we're very reliant in our currently centralised grid while 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 decarbonise.
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 on there. They they're not producing lots of CO2 and nitrogen. So what's the environmental footprint like?
Our point of view is 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.
Yeah. Exactly. So we need to, I think, pay more attention from environmental standpoint.
If you go back to the first months of COVID, there were satellites in space that could monitor CO2 or greenhouse gases and the cities which is clearing. That's a lack of use predominantly from cars and vehicles, but gas boilers are the same. They do produce CO2.
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 green houses, if I've understood this correctly. They're not-- there are no carbon, there are no toxins coming out of it, no climate warming gases, CO2 and the and the rest of it. So our heat pumps and low carbon farming. These two are made for 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 grouts. A 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 (has) 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. You know? 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. The village where I am here, we developed and built the largest hydro on the Thames in our little village which we then crowd funded out to the local area. So we got four hundred forty 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 absolutely zero carbon. That's one of the best examples, potentially, utopia.
Brilliant. That's fantastic. Yeah. Well, that's it. 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 yet 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, with thousand people five hundred houses. Actually the Sandford-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 to got to travel down the wires and then get sent off into various different locations. So I should imagine quite a bit if 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 five and a half pence per kilowatt hour and I have to buy it four hundred metres away for thirty-four pence per kilowatt hour. So I think I suffer the biggest loss which goes to the big six.
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, and you and your business could do a lot more if you got more of that money.
And which countries are we looking to for inspiration here? Are we leading the world with this? I think you mentioned Germany. Or Scandinavia? Or who's ahead of the curve here with heat pumps or low carbon farming?
So if we look at heat pumps, definitely Scandinavia. Their heating oil prices were at petricom prices. So they've been incentivised since the fifties to make their homes efficient. Not only thermally efficient but also in the use of heat pumps 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 sixteen and three 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 is on and the freezer is on and the washing machine's on and the heat pump holds off for all of five, ten minutes, you're not going to see the house go cold in that time. It just stops you drawing all the way in the peak. These are the sort of-- this is what a smart metre should have been for. Sadly we have installed a whole network of dumb metres.
Okay. But that's being corrected, I think, isn't it? Because you hear a lot about smart metres today?
Smart metres are good for the utilities to remotely read your bill, but they haven't taken them any further. I remember tomorrow's world diagram, if you remember that, back in the seventies.
Yep. They had a programme where you could have an intelligent metre 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, it never happened.
So from your perspective then, Neil, in your customers and your clients and, you know, the clients that you'd like to have. Are there smaller budgets that you work with or, you know, domestic? Just give us a bit of a feel your typical clients are in.
So, currently, we don't. Currently, we don't have a typical client. We work from domestic all the way up to commercial. We currently, there's a lot of investment in the public sector decarbonisation scheme. We're involved with that. We work as assessors for Salix, 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 seven engineers who were 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 by a little bit of forestry in the Amazon.
Yeah. I know this whole offsetting thing is yeah. I got to try and not offset, basically. Well, offset as little as possible, haven't we?
Brilliant. Alright. I really appreciate your time, Neil on this podcast. It's been really insightful. We've learnt 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 get which? Should they go to lowcarbonfarming.co.uk?
Or geoenergy design or geoenergy.co.uk
Once again. Thanks very much, Neil.
No problem. Thank you for giving me the opportunity.