Webinar on Climate Change Adaptation: Low-Carbon Heat Sources

Speakers: Caroline Cattini, David Drewe, Matt

Caroline: Thank you, Matt. Thanks and hello everyone. Welcome to our webinar today which is the second in our series called “Climate Change Adaptation” and today we’re going to be looking at low-carbon heating sources. So, just to introduce myself, as I said, I’m Caroline Cattini. I’m the Team Leader and Principle Engineer for the Building Services team at Historic England. In my role, I advise on installing building services in historic buildings and looking at existing historic systems as well and maybe how we can reuse those and retain them and I’ve also been responsible for writing the guidance on renewables and some of the building services guidance as well. David, would you like to say something about yourself too?

David: Yes, OK. Thanks Caroline. Just quickly, so Caroline and myself are both part of the Engineering and Emergency Planning team within technical conservation. I have been with Historic England and its predecessors, English Heritage, for my sins, for over 20 years and while my background is in building services, I now also get involved with some environmental issues as well as fire safety and emergency planning, although my day job overall is the management and as the head of the team.

Caroline: That’s great. Thank you David. So, before we make a proper start, I’d just like to let you know a little bit about the Technical Conservation Team. We are group of technical specialists, including conservators, scientists and engineers and we undertake research, provide advice and guidance on technical conservation issues and the first link that Matt is posting in the chatroom for you takes you to the main Technical Advice pages on our website and there you can find all about technical advice and that type of information.

All our research reports and PDF guidance documents are free to download from our website, and the second link that Matt will post takes you to the catalogue shown on the right of our slide where they are all listed in there. Also I thought you might like to know that we’re introducing a technical conservation newsletter which is planned for the last Tuesday of each month and this will let you know about new technical conservation guidance and publications or any forthcoming technical conservation training events. Now, if you’d like to add your name to the mailing list and you haven’t already signed up at a previous webinar, if you just click “Yes” and we’ll send you the next edition of the newsletter.

Now, just to be clear, this is just for technical conservation guidance and events. You’re not going to get all the other Historic England publications or training. Oh, that’s great. That’s good. People are signing up there. And don’t worry, if you’ve already been to a webinar and you’ve signed up, we’re not going to send you several of the same email. You will just get the one email, just to clear that up. So, that’s good. I think quite of lot of people voted. OK. That’s great.

Also, I just wanted to introduce here is that we’ve got some specific webpages dedicated to building services. Now, we’re updating these on a fairly regular basis and we’ve just added some new pages last week through internal and external lighting and some of you might have joined our webinar last week on external lighting so you might already know about those but there’s a bit more information up there now and there’s a link there to get to those pages.

And we’ve also got some pages which are applicable for today’s webinar on low and zero-carbon technologies, so such things as heat pumps and solar PV and these are quite new so we’re going to start to populate more information and case studies on these. And this is our first… As I said this is our second webinar in the “Climate Change Adaptation” series and in the next couple of months we’re going to be looking at low-carbon heat sources and in the next year we’re going to be looking at heating and we’re going to introduce a bit more information on that as well.

David: Yes. Thanks Caroline. I think before we talk too much about this today, we’ll just clarify how we view and what we mean by low and zero-carbon technologies. So these are technologies where the power to heat or cool or generate a process are from either some more sustainable [INAUDIBLE] which have low amounts of carbon dioxide emissions than that, say, that’s emitted from some conventional fossil fuels such as coal-fired power stations. So, the way to look at it… So things like solar power, which would be wind and your solar rays, hydro generation would be considered as zero-carbon and whilst things such as ground-source or air-source or water-source heat pumps that still require electricity to drive the equipment to produce the heating or cooling, those are what we would refer to as low-carbon because they still do need some kind of carbon fuel at the moment to make them operate.

Caroline: Yeah. That’s a good point, David. And why do we need to start looking at these sources that are low or zero-carbon?

David: Well, the main reason is -for those of us who are really interested in this- in 2019, the UK government or parliament passed some legislation requiring that the UK reduce its net emissions of greenhouse gases. So, we’re going to ask a little question here I think.

So, Question 1 is: Do you know or can our audience give us an idea of when they think the UK is meant to be reaching its net-zero emissions by? And we’re going to put [INAUDIBLE] can tick the box, we’ll let you know how we’re doing there.

[They discuss sound quality issues for the presentation]

Matt: OK, let’s reveal the results. There you go. So, 50% are saying 2050. Are they right, David?

David: Yeah, that is the correct answer. Yes, that is the correct answer. Yeah, so the answer is that we’re meant to reduce our coal emissions by 2050 but the thing to mention on that though is that this is all based around the carbon or the greenhouse gas levels that we had in 1990, so it’s not going back as far as we can say. I mean, a lot of this is down to the fact that there’s been lots of work done on greenhouse gas emissions and the International Panel on Climate Change 2018 report highlighted, for example, that the built environment needed to reduce emissions to limit global warming to the 1 ½ degrees which we often talk about. However, that was all based around that unfortunately between 2010 and 2018, even though we were aware at those times of greenhouse gas problems, internationally the direct emissions from our buildings actually went up and got worse, it grew. Caroline?

Caroline: Yeah. In the UK since the Climate Change Act in 2008 –this is just for the UK, not internationally- we have actually seen a decrease overall in our greenhouse gas emissions but these emission reductions have mainly been from changes in the mix of fuels that we use now for electricity generation.

So, if we look at these, we can see that in recent years –so if we look at the left-hand side- we’ve got from using coal for electricity generation to natural gas and you can see from that graph that from 2014 those dramatically dropped. So, if you look at this, in 2019 coal made up about 2.1% of fuel use for electricity generation as back in 1990 when, as David said, we took our baseline, we used 65% of coal, so there’s been a huge reduction in coal use for electricity generation. And at the same time, if we now look at the chart on the right-hand side, you can see that there’s been a growth in the use of renewable energy sources for generating electricity. So on and offshore wind, solar power, bioenergy and hydro have been used and these sources don’t have carbon dioxide emissions.

So, if we just look from last week, this is quite a nice little place –I’ve just put the web address in there- that you can actually go and look and you can see currently what that electricity generation mix is for the UK. And you can see there that renewables last week accounted for about nearly 50%, so about 47% of our generation now. And we need to start to reduce our emissions, as David mentioned earlier, and to limit climate change and the effects of which we are starting to experience.

David: Yep. As we know, we do. We have a problem. If you look at this slide, this is a slide that gives you some plots of temperature from the south of London. And as you can see, in both the winter and the summertime, temperatures have increased over the years, and so we expect this to continue into the future. The thing is it’s not just the temperature that’s changing. If we look at this slide, this gives us an indication that we’re getting periods of heavy rain or large amounts of rain that precede -or not- periods when we get much less rainfall. So, again, our weather patterns are changing, so that’s looking at the maximum rainfall in any one day. Also, if we start to look at the annual rainfall, you can also again see from this chart that again, we’ve had last year a very wet year which was actually after a period of quite low rainfall compared to what we’d had in the past. So, weather patterns are definitely becoming more erratic and I think we’ve all experienced in the last few months some strange weather just in the UK recently.

So, we’re now going to have another little question. This is getting back to the subject that we’re looking at today. And so, Question 2 is for those of you who feel brave. What do you think this is? So if you had to consider for heating and hot water, you know, for the energy that we use in our buildings for heating and hot water, what do you think it accounts for? How much of it do you think accounts for it?

Matt: So, David, that is part of the overall energy use of the house, so including appliances, lighting and all the rest of it?

David: That’s right. That would be keeping yourself nice and warm. Yeah, so this is heating and hot water. So this is to keep yourself warm, wash ourselves down to washing up, all of that sort of stuff. So, it’s the heating and hot water consumption. Right, so has everybody done that? That looks like they’ve done.

Matt: OK. Let’s reveal the results. There you go. Woah. 63% say 70%, David. Are they right?

David: OK. Well actually, not really. That’s OK. No, actually… As you said, let’s just go on to the next slide. Yep. So, heating and hot water for our buildings actually make up about 40% of the energy we use in our buildings and actually overall they contribute about 20% of greenhouse gas emissions in the UK, well in the UK they do anyway. So actually it’s interesting that people thought that possibly it was a bit higher than that but anyway, that’s roughly what it is. It does obviously vary slightly but that’s the figure.

So, if we then look at the methods that we use to actually generate this heating or this hot water, this is just a breakdown of how it comes across in different set-ups.

So, this is looking at residential and commercial public space. So, what you can see here is that the predominant use of energy is in our homes and it’s the residential space heating which I suppose is perhaps not surprising to most of us.

And then followed on by that with the hot water that we generate for keeping ourselves clean and washing is the second, but interestingly that seems to be matched very closely, if you think about it, to the commercial space heating. You know, it’s surprising possibly when you think of the number of buildings that are outside domestic that our hot water use at home is also similar to the amount of space heating consumption in commercial space.

I think one thing to note in this slide as well is to look at the small amount that might be allocated to space cooling, so rather than heating. You know, it’s only shown as 3%, which again, probably you might thing, “Well that’s probably fine in the UK”, but of course one of the things we need to remember is that, as we’ve already said, as our winters get warmer and our summers also get much warmer, we might find that there is a shift between obviously keeping our buildings warm in the water to trying to provide some means of artificial or mechanical cooling in the summer. So, we just need to be careful that we don’t just shift the energy demand and therefore the CO2 emissions from one source to another.

Matt: Well, indeed. Air conditioning units account for a huge level of energy consumption in the hotter countries.

David: Yep.

Matt: There’s one quick question I’d like you to address at this juncture otherwise we’ll have to kind of refer back. When we looked at the… When you were talking about 40% of energy consumption was due to hot water and heating, Jane asks: “What’s the other 60% made up of? And does the 40% include industrial or commercial buildings?”

Caroline: Yeah, it wasn’t just for domestic buildings that question. It was actually industrial and commercial, so Jane was quite right there. But the 60% is also, if you think, our electricity use as well, so it’s all energy. So you’ve got the power in the building, as David said, the appliances and everything else, so that’s the remaining 60%.

Matt: Brilliant. Thank you.

David: OK then. Right. So, if we now look at our next one. So, we’ve had a look at that and now this is to try and give us sort of an idea of, you know… We’ve looked at the energy and the energy that we’re using, but now this is looking at where do we actually get the energy from in the first place so, you know it is… And this gives us, again, an indication of how we actually supply the energy to the buildings. So, if you look at this slide, nearly 50% of residential buildings, it’s gas, and as you can see on here, this 19% is non-residential and as you can see, if you look around the pie chart you can see how this breaks down. So, it’s an interesting mix there. Obviously there is a massive demand really on our utility services for the gas supply. We’ve obviously… Not as much in that respect from the electricity supply. But as we saw earlier in one of the earlier slides, with the electricity network being decarbonised –or that’s how we refer to it- by now not using coal and switching to using other sources of energy and renewables particularly, you might think, well the obvious answer is let’s just get rid of gas completely. Let’s just get convert all of our buildings, you know, decarbonise the grid or the electricity supply and just literally heat all of our buildings or the core of buildings using electricity.

Caroline: Yes, it’s a good point David, and let’s just explore that with these next two slides. This is a graph from a briefing note by the UK Energy Research Centre and the briefing note was to set out the challenges for decarbonisation of the heat from our buildings and look at our local gas demand versus the electricity supply that is available to answer that sort of question: “Can we just all swap over to electricity?”. So, if we look at this graph, we can see between the sort of middle part, between June, July and August, the gas demand could actually be met by the electricity supply. But as we move towards the autumn and then the winter when temperatures drop and there is more of demand for heat, we can see that there around about 214 gigawatts peak demand for gas, however the embedded electricity supply that is available at that point is only 50 gigawatts. So you’ve got that 214 gigawatt peak in the winter but only a 50 gigawatt capacity in your electricity supply. So really, in this report, in this briefing note, it really highlights a critical challenge, that at certain times of the year, there is currently not the capacity in the electricity system if everyone just simply shifted from the gas network to the electricity network to heat their homes and places of work.

So, if we just look at this. This is another graph from that same briefing note by the UK Energy Research Centre and this is zooming in into a week in that winter period which we saw in the previous graph and the peak times of the gas demand. And we can see, probably not surprisingly, it’s like 5am to 8am, so when people are getting up and when people are going to work and again, that evening period of 5pm to sort of around 8pm and that’s where those peak gas demands occur. Now, the key thing with looking at this graph is that we can see within the gas system there’s a lot of flexibility, unlike in the electricity system. So, you can see on those blue lines, on a medium week it can be down, let’s say, 100 gigawatts and then on a maximum week we can up at that 214 gigawatts. And this is due in fact that the gas network, unlike the electricity network, they can change the pressures in the gas network so they can store more energy to meet the network demands. So what we’re seeing here, as you can see on the red one, in the electricity system it doesn’t have that same comparable, intrinsic equivalent, so it doesn’t have that storage capability. So, to answer David’s question, no, we can’t at the moment just switch all over from our gas network to our electricity network.

David: OK. So, what does this mean for heritage buildings? So, I suppose what we need to think about is what do we mean by “heritage buildings” rather than “listed buildings”? So, as it says here, in England, 21% of domestic and 32% of non-domestic buildings were constructed prior to 1919 and so if we then want to add on the buildings that have been constructed after 1919 you can get…there’s even more buildings that perhaps we need to be considering.

Some recent work done by Historic England where we did some modelling shows that of 74% of the pre-1919 building stock, they’ve estimated about 15 million tonnes of operational carbon emitted annually could be reduced to almost zero by 2050 from building fabric and airtightness improvements and also it says here, “and move away from fossil fuel-based heating”. And just a point on that, we’re talking about the operational carbon here. Some of you may have heard some discussions about embodied carbon but this is just the carbon that’s produced to run and maintain the buildings and keep them nice and warm and toasty.

Caroline: So, thinking about the slide looking at capacity in our electricity system and what David’s just said, there are some great challenges ahead to move our heat load to zero-carbon. Now, a lot of you probably realise, we don’t currently have a heat strategy from government but back in July this year, at a BEIS Committee hearing, the secretary of state, Alok Sharma, confirmed the UK government will be publishing a heat strategy along with the Energy White Paper and the Building Strategy which will come out with the Autumn Statement. However, I did hear recently also this could be delayed because of COVID maybe to sort of mid-2021. But being as we don’t have that heat strategy from government at the moment to answer the big question of what we do, it might be useful just to look at the report from the London Committee on Climate Change and what they said might be the next steps for heat policy in the UK. Really, if we just sort of ignore the new build for the purposes of today’s webinar and just start at the top there.

David: Yes. So, looking at that Caroline, so are we saying here that the second group of buildings, the existing buildings off the gas grid as it’s shown there, so they’re the ones that they’re going to have to all be somehow heated in the future or get their energy from things like heat pumps and other forms of energy. Is that what we’re looking at?

Caroline: Yeah, that’s right. So, to move away from oil and LPG, it’s those heat pumps and sort of biomass to get those off of there. And yeah, then we look down to the existing buildings on the gas grid and like when David brought that slide up, we can see there’s so many dependant on the gas grid.

There’s a combination there. You’ve got the orange part which makes perfect sense; it’s making those energy efficiency improvements so to reduce that heating load first of all before you actually try and look at anything else. And then we’ve got the yellow box, so, you know, switching over to low-carbon heat networks and what are these? They’re like sort of community heat networks and that could be biomass, biogas, things called ambient networks where you’re using rejected heat, maybe from air-conditioning systems, but also heat pumps as well, so you’ve got that combination, buildings that can then connect onto those heat networks. And then we go down into the big area, the big white box with the red line around it which is that low-carbon solution needed for on-grid properties which can’t connect onto heat networks.

So this is that area there, that massive lot of buildings that currently connect onto the gas network. So, what could that look like? Type of things that are happening are hydrogen is being looked at as an option and in recent years, so in the last couple of years, the Health and Safety Executive approved what’s called the “HyDeploy” and this is a project trialling up to 20% hydrogen blends that can be mixed with our gas network. So, most of our existing gas boilers that are in our properties, they can cope with that 20% hydrogen blend without actually having to change the boiler.

Some of the pipework will need to be changed, but that’s one of things that’s been approved. We’ve also got the first demonstration of the H2 fuelled central and domestic boilers which we saw earlier this year when we went to a show in town and they had those on display, so those are in production.

We’ve also got the Leeds City H2 21 project and this shows what might be possible to repurpose the gas distribution network for hydrogen and there’s actually quite a lot of research projects underway for this, largely funded by government bodies and the gas distribution companies. And this isn’t just a UK thing, in other countries they’re actually doing this, places like Australia where they’re using solar to actually power the hydrogen there. So there are a lot of these projects. Hydrogen seems to be quite a big thing. So currently the national position hopefully will be more clearer when the heat strategy is issued and this could be this autumn but I think now what might be useful is to look at a couple of projects, what we’re doing at Historic England, what we’re working on and where we’ve got to those. So, I think David you’re going mention the first one.

David: Yeah. The first one we’re going to look at is Shrewsbury, just to show the audience that we’re actually starting to consider this ourselves and obviously we’re thinking it would be quite a good idea if we can trial a few jobs out of our own to see how things might work out. So, the first project I was going to run through briefly is the project of the Shrewsbury Flaxmill Maltings.

Just a bit of background on this one, we, as in Historic England, we took on the Flaxmill restoration project back in March 2014. For those of you that are interested, the Flaxmill was the first iron-framed building in the world and along with the Main Mill there are a number of other buildings on the site including –that you can’t quite see there- the Apprentice House, the Dyehouse, the Cross Mill and the flax warehouse stables, the maltings’ kiln and they were all at one time on our Heritage at Risk Register. In this first stage, the Office and Stables were converted by the Friends of the Flaxmill Maltings into a small, interactive visitor centre and education facility which is the small building that you can see I would say at bottom of the photograph to the left, the bottom left.

So, we’re now into what we call stage two which is the main project which is restoring the Grade I listed Main Mill and the Grade II listed kiln building. On the photograph that’s the large, white-covered roof structure that you can see there and the adjacent building to that.

So, as part of the work, we wanted to look at low-carbon ways of heating a building, rather than just sort of going down the usual options of looking at natural gas. So with our consultants we undertook an option appraisal, preliminarily looking at the options of biomass heating, ground-source heat pumps or air-source heat pumps.

The option appraisal were there not only to inform us of the right services solution but with each of the solutions what impact on the heritage would be. Air-source heat pumps were ruled out on the grounds they were presenting significant challenges regarding the sighting of the external heat rejection plant as well as the poor efficiencies in low-ambient air conditions which obviously you would experience in this country. Biomass was also ruled out preliminarily as a potential plant location and the requirements for flue heights as they still obviously would need some kind of chimney and also they would contribute to airborne pollution so we discounted that. So we then looked at in more detail at ground-source heat pumps to see what we could do.

Right. So, a ground-source heat pump is the system that extracts energy stored in the ground or in water if it’s submerged by buried pipework. You circulate a cold fluid through the ground, this absorbs the low-grade heat from the ground and then a heat pump uses basically a refrigeration cycle to elevate the temperature and transfer heat into the building’s heating hot water system. However, when considering things such as ground-source heat pumps, you also need to make sure that… and consider heat losses. You may have to if you were for example… particularly if you were adding it to an existing system, is changes to the radiator sizes because often these systems may not be able to provide the water temperatures that you might need to. You’ve obviously got to look at the thermology of the ground itself. I mean, just because you stick some pipes into the ground, you may not necessarily get the heat out of the ground that you want. You do need places for plant rooms in the same way as you would normally. There is also the air required for boreholes. There’s access for drilling equipment to the site. There’s also the costs and at the moment there’s a renewable heat initiative which will continue to be paid for installations completed and commissioned before March 2021. After that, that’s going to cease so you may want to review that as well as one of those considerations.

So, going forward, we’ve gone with an option of a ground-source heat pump to produce low-temperature hot water but we’re having to do this in combination with gas boilers as well. I think it would have been great if we could have actually been able to provide all of heating just using ground-source heat pumps but when you look into this sort of thing, the problems we had there, there was a lack of external space to enable us to get boreholes that we wanted. The additional capital cost over and above to get us up to the 100% was obviously much higher. And again, because we looked at this at a slightly later stage in the project, to produce just a low-grade heat source for the radiator systems we would have needed to resize all of the radiators and have perhaps larger sized radiators than people may normally think you would have in a building of this type.

But we have managed to get some in. We’ve managed to get sixteen boreholes [INAUDIBLE] on the route of the canal. The canal route is…On the plan on the left it’s the sort of green area which is showing sort of running from the sort of bottom of the page sort of north, up and across. You can see it’s a slightly green line there. That was a route of an old canal that ran through Shrewsbury a number of years ago, so obviously long been since disused and it’s been filled in. So a lot of that is disturbed ground. So that’s the route that we’re following for getting the boreholes in for the… And of course that helps us because particularly when you’re dealing with heritage buildings, you need to consider any disturbance to the ground. You may have archaeological issues to consider as well, so that was one reason we went that way.

So we reckon that the installation will probably provide us around a third of the peak heating demand for the building with the gas boilers providing us a top-up. So this ground-source heat pump is going to give us about 100 kilowatts of our heating demand and we hope that it will operate near its peak output for the majority of the heating season and therefore obviously support the majority and most of the baseload of the building. The gas boilers will then only be utilised as and when required. So I think Caroline’s now going to take us through another job.

Caroline: Yep. Thanks David. So, this is our Swindon office, some of you might be familiar with it. It’s called the Engine House. It was refurbished back in 1992/93 –something like that- and that’s when much of the building services installation dates back to including the central heating plant which we can see those fabulous yellow boilers in the centre there and the distribution pipework and the heat emitters that we’ve got in the office as well. And by now the central heating boilers are way beyond their serviceable life. We’re getting failures from them. They also need what’s called a dry site clean so, you know, we really do need to replace them. And we didn’t just want to do the easy option, just replacing like-for-like, we thought this is an opportunity for us to look at some low-carbon heating options.

But before we actually even considered all of that, one of the things that we knew is that we weren’t entirely sure what our heat load was in the building so we wanted to accurately calculate our heat losses so we could then –whatever we choose- we can size the plant and equipment quite accurately so it’s not oversized or undersized. It’s not really any good, I mean, at the moment there’s a sort of 600 kilowatt boiler capacity, we can’t just say we assume that’s correct because we don’t know when the original installation was done if anyone undertook any heat loss calculations. So when we do these we really do need to have a good look at the building construction –and that’s the entire building construction- so we can determine accurate U-values and so they can be calculated. It was also important to have the elevations, so internal and external plans and sections and ceiling heights. It’s not really any good with some buildings where you’ve got quite ceiling heights just to use a metre squared, you really do want to look at the volume when you’re looking at those.

So, what we did with our consultants is rather than just doing the usual steady state ones where you sort of use an excel spreadsheet or just rules of thumb, we chose to use dynamic thermal modelling. And this is really good because what it does is instead of just be limited by simple assumptions and quite simplified calculations for internal and external parameters, it allows you with full dynamic thermal simulations to model a whole year using site-specific weather data for an unbroken period of time. And we were also able to model individually each room and input what equipment was in that room, how many people use it, the hours of use. I mean, our facilities team pretty much knew hourly, all the different spaces in Swindon, how they were used, so we were actually able to input that all into the model as well. So, you actually come out with a far more accurate heat load and this is just a screenshot of the 3D model of the building and some of the –on the right-hand side- some of the U-value information we were putting in for the make-up of our walls which we had good information from our conservation teams what that was for each of the elevations.

So, we came down to using heat pumps similar to Shrewsbury. And the areas we chose for the scheme would be our carpark. We’ve got quite a large carpark at Swindon. It was quite easy because we knew this ground had been disturbed before so there wasn’t an issue with archaeology to be concerned about. What we also wanted to do is we wanted to retain our radiators and it’s not because they were historically significant in any way, but there’s actually nothing wrong with them.

The system has been very well looked after and they’ve still got plenty of life in them and it would be a waste of the embodied energy and money just to rip those out. So, if we could retain the radiators without having to upgrade them that would be really good.

So where we’ve come to with this is we’re actually looking at high temperature heat pumps. So unlike the Shrewsbury project where you get a low-grade heat, so you’re getting like 50/60 degrees, we’re looking at high temperature heat pumps so we can try and retain our radiators and pipework. However, like with everything, these are more expensive and they do require a bit more maintenance so… And then we come to the point of what we would actually need to run the whole of the building, so looking at 100% of our heating load it would require 100 to 120 boreholes at 150 metres deep.

So, when we look at that, our carpark doesn’t have room to do that because you also need to space them apart as well. And there’s also the cost which could be problematic because we wouldn’t be able to get the RHI either because that finishes in March next year. So it may be that we will still -a bit like Shrewsbury- need to supplement our heating system with some fossil fuel heating so like with gas heating as well, but we’re still looking at this to see whether or not we can use it in maybe other areas to do 100% of the heat load from there. And a way in which we might be able to do this is a bit like when I was talking about the community low-carbon heat schemes –they’re on a much larger scale- but these ambient loops.

So what ambient loops are, is it’s not just using ground-source or air-source, you’re also looking at other places which may be rejecting heating. So, if you just look at the photo, if you look at the north of that photo, there’s a building there just below the Engine House and that’s our archive building and our archive building has cooling in there and the cooling system from there, as part of that process, it rejects heat.

So what we can do is use that rejected heat from the cooling system to actually put that into an ambient loop and mix with the low-grade heat from the ground-source heat pumps and we can use that to heat our building. So this might be a way in which we could achieve 100% heating from our site without needing 100 to 120 boreholes. But we’re still in the process of doing the calculations for this because it’s quite tricky and also weighing up the cost because no RHI to go with that.

So, we have some way to go with this project but it’s looking promising that we will be able to do some of our heating with ground-source and possibly with the rejected heat from our archive. What we’re doing is next year we’re going to run some more of these webinars on heating, specifically on heating and hopefully by then we’ll be able to update you on the progress not just of this Swindon project but also on the Shrewsbury project as well. And we might also have the heat strategy from government so we could give an update on that also.

I think we’re coming sort of to the end. We’re sort of 45 minutes in now, so it would be nice to leave some time for questions.

David: Yeah. Just on that Caroline, you’re right. I mean, the additional webinar is later next year or whenever we get around to doing it on heating. It would also mean that we can start to look at the application of this type of technology and how the actual more interesting stuff of which bits do you replace inside a building which is probably the thing that people are more interested in, you know, what can the low-carbon technology do and how does it actually look in reality in a building when it’s in use. So I think that’s something that we need to make sure we pick up on.

So, yeah. Anyway, so as Caroline said, we’re getting close to the end of the hour slot anyway. So again, just a quick reminder… the advice documents that are available to download and for you to refer to and freely available from the website. I suppose it’s for Caroline and myself to say thanks and we hope you found some of what we said today of interest and that gives you bit of a background to the reasoning behind why this type of technology is now being considered or at least being developed in support of our emissions targets and how we’ve all got to think of different ways of approaching this subject of heating our buildings.

Matt: David and Caroline, thank you so much. Absolutely fascinating presentation and I’ve got loads of questions but I think we’ll save those for another time. But what I’m going to do is we’re going to put this little window up here, so if anyone has any questions for Caroline or David, please feel free to type those in. You’ll notice a little textbox. I’ll point to it actually- Oh, no, it’s gone! I didn’t want to do that, did I? So let’s make that reappear. There we go. So let’s just bring that in there. So please feel free to type in at the bottom of that little box there any questions you have. You won’t see the questions coming up on the box but we will, so please feel free to type any questions you’ve got in there. We also have a few questions coming in in the chatroom as well which is great. So, yes, the slides are being shared. I will provide you with a link to the slides in a moment.

So Peter asks: “What are your thoughts on infrared? Is infrared a possibility?”

Caroline: That’s for the output from the heat. So infrared is electrical powered, isn’t it? Sorry David, you were going…

David: No, I was going to say and that’s partly what we were saying is that so far really what this little webinar has been about it’s about trying to look at where the energy comes from, you know, it’s the source of the energy such as the heat pump can provide you hot water. As I’ve said, we haven’t touched on the other elements, you know. I mean, Caroline said earlier we’re now generating much more of our electrical energy using wind and… So that would generate electrical power, yeah, which obviously would then feed into a zero-carbon grid and then that could obviously be then used to provide heating of all sorts of types. If the hydrogen gas system works -and that’s obviously still in development- there’s nothing to say that the method of heating… you could have gas-fired radiant heating just as you have now, which could easily I see, be supplied and fed from a hydrogen gas type heating system. So, the point there is, as I’ve said, we’ve looked at where the energy is coming from. The seminars or the webinars that we’re going to be doing later will then look at how you take that energy and how you then turn it into the effective way of heating the space inside the building.

Matt: See, I… Not being an expert in such things, I hadn’t really been aware of the hydrogen topic actually. Is hydrogen really coming to the fore as a potential energy source now? I noticed someone commented in the chatroom that Bosch have actually developed a hydrogen-ready boiler.

Caroline: I know. I saw it at the beginning of the year. Yeah. It is. A lot of the manufacturers have boilers and Worcester Bosch were at a show at the beginning of the year and they had a working model of that which is available. Some other countries like Australia, they’ve got massive city schemes that are already done and are already running, so you’ve got big schemes there. They power… Because the other issues is you have the hydrogen but you need electricity to drive that but they’re doing theirs with solar power so it’s just… But as the electricity grid becomes decarbonised -the power from that- so it will end up zero-carbon but yeah, hydrogen will figure as a big part in our network. I mean, they’re even changing parts of our gas pipework to be able to take hydrogen so yeah…

Matt: Someone’s just said hydrogen is already being used to power [INAUDIBLE] in Germany. I see a future populated with wind turbines and photovoltaics so I think that’s the way it’s going to go. Now, we’ve got a lot of questions coming into the Q&A session here so let’s see if we can rattle through these as quickly as we can.

But there was one that I really would like to bring up first, just for a personal reason too. It says: “Thanks for this great presentation” – and it was a great presentation, guys – “You talked about public buildings but what about individual domestic buildings especially in urban historic areas” I suppose that says, sorry, I can’t see the whole thing. The point being, if you’re heating the Engine House in Swindon, you have the wherewithal to spend squillions on boreholes and all the rest of it. As an individual or a family living in a small, old building such as myself, the only resource I have to draw upon is the RHI and the new Green Deal. I personally was looking at an air-source heat pump. The actual cost is prohibitive to an individual. So you’re talking £20,000-£25,000 to install an air-source heat pump and all the relevant piping and so forth, and the RHI and the Green Deal was only really going to come up with less than half that cost. So for individuals living in older buildings, it’s a prohibitive investment that they will probably not see a return on unless you move into a new build which will have it all factored in automatically. I wondered what your thoughts on that would be.

Caroline: So, I should have actually said that the RHI for commercial buildings stops in March 2021 as the domestic will go through till March 2022, so the government have extended that. I am hoping, as part of the heat strategy, there’s some other schemes because you’re quite right Matt, it is very expensive. I’ve looked at it myself and you just think “Wow, that’s a lot of money” and the original Green Deal offered a loan that you’d pay back for it. But yeah, it is, it’s very difficult and particularly those off-grid because if you think on-grid, potentially there’s hydrogen, that’s going to be dealt with, you just carry on and you don’t really need to do anything apart from when your gas boiler comes to the end of its life, you can change it over to a hydrogen one. But for those off-grid, so if you’re on oil or LPG, you’re looking at air-source or ground-source heat pumps or maybe biomass and that’s a huge investment. It’s a huge amount of money. So yeah, I agree with you and I don’t know the answer because the RHI, which doesn’t pay the installation cost, it just gives you a return on how much you’re generating, finishes in March 2022 I think it is.

Matt: Indeed. And it’s a bit of a deal-breaker for individual families I think.
OK, let’s rattle through some of these other questions. “Do you ever foresee a time when reducing our carbon output will overrule historical significance?”

Caroline: Good question. That’s a good question. Yeah. So it’s where we sort of say that we make improvements to buildings and say the historical significance is less important.

David: Well it hasn’t. I mean…Well so far, I mean, although we think this a relatively new subject… Some of us do. Her maybe. I mean, I’ve said –get the violin now- I’ve been here 20 years and I’ve probably started to look at this within five years of joining Historic England or English Heritage as it was then, you know, this whole issue about…We’ve had loads of different schemes.

We had the 40% house back about 10 years ago. There’s always been things coming through where we’ve looked to improve and make our buildings more energy efficient and I think in all of those times –so far anyway- there’s always been a recognition…You know, I think that… You know, we don’t just want to all live in boxes that all look identical and that’s part and parcel of what we like so much about the building of our [INAUDIBLE]. And so really I suppose a lot of this is for us to look for solutions.

I mean, there was also some discussions about, you know, when you talk about we need as a country to reduce our emissions, it doesn’t necessarily mean that it has to be equally shared across the whole of the built environment. It could be that there are some areas of the built environment that could actually contribute more than, say, their 50% to allow other parts of it to not have to do as much.

So it’s about trying to do the best you can and make improvements because I think, going back to the point that was made earlier about the cost of things like off-grid and you’ve got to use heat pumps, I mean, one of the things we should be obviously aware of is we do need to make the building as thermally efficient as we possibly can to start with. There’s no point putting expensive heating boilers, even the stuff we’ve got now, if actually you’re letting the heat escape out the windows and stuff like that. But we have to be mindful that we’ve got to do that, taking account of the nature of the historic buildings and how they perform which is different to modern construction. So, at the moment… I mean, who knows? I mean, in 20 years’ time who knows who knows what government regulations might say but there doesn’t seem to be any direct signs of that at this precise moment in time.

Matt: OK. Let’s move on. Val has asked: “How does this system affect the fabric of a listed building?”. Val, I’d like to know which system you were actually asking about.
Another question: “Is electricity storage technology developing sufficiently for solar space heating for it to become a possibility?”. Yes, that’s a good question. Storing electricity which makes electricity a more viable option.

Caroline: Battery technology is increasing.

David: It’s developing isn’t it?

Caroline: Oh yeah, yeah. With the… Who’s the company? Elon Musk… Not that I’m promoting those ones anyway.

David: Tesla man.

Caroline: Tesla. That’s it. Thank you David. I mean, their battery storage for their PV systems are so much better than they used to be. So, yeah. Large-scale electricity storage from renewables is growing.

Matt: It’s interesting. That feeds into a point that obviously the government currently is putting the onus on the individual owner to find these alternative low-carbon energy sources but we are, I suppose if you like, pray to the vagaries of the market at that point. But actually, if the onus was put on the government to actually create a low-energy source –obviously electricity- but make it low-carbon and low cost, then we could all tap into it.

Caroline: Correct. This is when these low-carbon community schemes are a good idea.

Matt: Yeah. Just flip the coin.

David: [INAUDIBLE] You might remember that was always the aim of nuclear power. When it was first put out there, it was going to be this low-carbon emission, clean fuelled… It was going to power the country.

Matt: “Clean” in inverted commas.

David: But it was, I mean, that’s what they were talking about, you know, “energy of the future”. But obviously things have changed a lot from that. But I think, as Caroline mentioned earlier, I mean, to just overnight effectively try to switch all of the heating demand for our buildings onto the grid system, onto the electricity power system, would be really difficult and the infrastructure probably couldn’t cope with it, well it wouldn’t cope with it.

Matt: OK. Sorry… “In the example projects you spoke about, how did you approach topping up the hot water to reach 60 degrees?”

Caroline: So, for Swindon… I mean, Shrewsbury’s not got any services in there, but for Swindon we have electric point-of-use for the hot water, so it’s not from our central boilers. Because it’s an office building and it’s only for washing hands in the kitchens and bathrooms, we use electric point-of-source there so it’s not… And you’re quite right for, obviously, legionella you need to get that hot water up to a certain temperature. So that’s how we do it in Swindon.

Matt: OK. Val says she’s heard that hydrogen is very expensive.

Caroline: Yeah.

David: At the moment it would be, yeah.

Caroline: The actual… The price they were saying for the domestic hydrogen boilers was slightly… or similar to a normal domestic gas boiler, maybe slightly a bit more, but actually doing the massive hydrogen schemes which would be needed to supply the gas, yeah, it would be.

Matt: There’s another boiler made by –I hope they still make it- made by Worcester Bosch. I’m sure others are available and it’s got a Stirling engine bolted on to the back of it. Have you heard about these Stirling engine boilers?

Caroline: It sounds amazing.

Matt: OK. So basically the Stirling engine was created back in the Victorian times by a Scottish vicar apparently. Maybe he even lived in Stirling. And basically the idea is that it’s a turbine that’s run off the waste heat from the boiler and then the turbine is then used to generate more electricity that’s fed back into your system.

Caroline: So it’s like a combined heating source, combined heating power type of system.

David: There’s been lots of ideas about doing small-scale hybrid-type systems to try and make as best use of every available watt of energy that comes out of the systems. I mean that’s where condensing bodies have come from. Really it was the same idea, you know, they’re trying to squeeze as much out of everything they possibly can.

Matt: YouTube has got some great videos on Stirling engines, people making them out of Coke cans and running them off cups of tea to power a light bulb. It’s great. Let’s move on. We’re bang on two o’clock but we will actually keep answering these questions because it’s going to be on the recording and then people can refer back to the recording if they so wish to do so.

Caroline: Matt, can I just make a quick comment because there’s been a few in the chat that people are saying that we need to be more realistic about our comfort and sort of [INAUDIBLE] and I’ve just noticed there’s a chain of this conversation. Absolutely right. I don’t know if any of you logged into our… I think it was the second or it might have been the first one we did on building services about comfort and being realistic about what comfort is and what affects our comfort, but you’re quite right, it’s people not expecting to sit at home with shorts and a t-shirt on or in their office and just whacking the heating up. So there were just a few comments on that and I think you’re absolutely right, but if you wanted to look, we did a bit more on comfort and the effects of comfort that might be interesting.

Matt: Absolutely.

OK, so: “Why is the carbon used in production of low or zero-carbon systems not part of the calculations as to whether a system is low or zero-carbon?”

Caroline: It is.

David: It should be.

Caroline: You’ll find that a lot of the manufacturers, well most of them that I’ve have looked at, or if you ask them, it might not be necessary straightaway. You can see it on their websites, but they will actually tell you what that embodied energy is in there and how long it takes. It’s… Particularly for PV that question used to come up an awful lot: How much electricity will I need to generate from these to actually pay back for the energy in making the PV? And most manufacturers will be able to tell you that.

Matt: Ruth goes on to say: “Solar panels are particularly polluting, both to produce and to deal with at the end of life”. So, that’s an interesting point, isn’t it?

David: There’s a whole subject around energy efficiency, not just heat [INAUDIBLE] or heat pumps or solar panels but everything you know, the materials that we use to insulate buildings, you know, replacing windows. There’s been lots of discussions about how you should really account for the true carbon and this whole idea of a lifecycle of a building which is a subject for another 10 webinars I should think.

Matt: OK. I’ll schedule them in!

“Where is hydrogen sourced from? Is it easily accessible without using carbon fuels for processing it? Is it green?”

Caroline: The process is essentially from water, isn’t it? But as far as… So that was the point I was making is there’s… If you google “hydrogen Australia” there’s a massive scheme there and the electricity for there is coming from solar PV because they have the sunshine, they have… you know, it’s easier to power it from there. In this country it would come from our electricity network and the hope is that by then we’ll have a lot more wind and solar power so that part of it would be green, that would be zero-carbon. But essentially, the processes, the by-product you get from it is water isn’t it.

Matt: Indeed. OK. I have a specific question on the Swindon case study: “How much time did you need to collect all the relevant data to inform your thermal modelling. How challenging was this process?”

Caroline: I’m laughing because I really underestimated…It’s a really good question and it’s something… We’re updating our heating or we’re trying to put some heating webpages of just that initial information you need. And it was just to input the data into the model from plans and we had to go and measure up because obviously we didn’t have any… all sections for our buildings as well. What we’ve actually started to use now is something called Matterport scanning, so instead of actually going and measuring everything with a laser measure, we’re using… it’s basically laser scanning. So, we’re doing a study on overheating and this would have been so much easier if we’d done it at the time but we didn’t then but we’re doing this now is you can just laser scan and from that model you get… And you know, you can do a day, it would have been the whole of our Swindon office we could have done just in one day. And from that you get a 3D model and that can just be inputted straight into the thermal model. So it would have been so much quicker than going around measuring all the different detailing in the building, particularly the upper floors as well. So yes, it took a lot of time. It took a lot of time.

Fortunately, the thing that didn’t take a lot of time which I thought would was the occupancy data. Our facilities team in Swindon, when I said to them, “Do you know every hour what areas are occupied in the building?”, they were like, “Actually, yeah, we do, we have really good occupancy data”. So they were great in that respect but the data for the building took quite a long while to input but it wouldn’t do if we did a laser scan and the cost of laser scanning compared to going to measure, it would have been basically the same. So, yeah. Good question on that one. Don’t underestimate the time you need for doing all that work. I did.

Matt: OK. I can see people are needing to leave. We will continue answering the questions but before you all do run off you’ll see that little window I’ve just put in the top there. There’s a few links for you, webinars. If you click on the actual title, “Webinars”, “Advice and Guidance” and so forth you’ll see the URL appear at the bottom of that window. So, “Webinars” will take you to our Historic England webinar page where you can register for future webinars and view recordings of old webinars. “Advice and Guidance” is the pages on the Historic England website for all our advice and guidance documents and for a copy of today’s slides, click on the word “Slides” and again you’ll see the URL appear at the bottom of that window.
OK. Really good question here: “Currently considering new heating for a Grade I uninsulated historic church. Building very large, only used once in two weeks, no gas in the village. Would love to include ground-source heat pumps but the graveyard prevents that”. Oh, could you imagine? “Looking at photovoltaics, but what other options might be considered for a cash-strapped congregation. We are finding it a big problem to move away from oil”. Yeah, ground-source heat pump wouldn’t be your best option in a graveyard would it?

Caroline: Also I think… I mean, we have done them along pathways… It’s the drilling equipment, to get the drilling equipment in. But probably the cost of it and the amount you’re going to use, it’s probably prohibitive isn’t it? Air-source? If you can locate the…

David: It’s the equipment location again isn’t it? Yeah.

Matt: Or as someone says, biomass.

David: Yeah. Biofuels was considered at one time, but again excess could be a problem obviously. As you recall, we did some work on this before and sometimes you’ve got to make sure you’ve got a readily available source for the fuel because sometimes, you know, you might be transporting fuel hundreds of miles to get it to you, so you’ve still got the same issues about fuel storage. Sorry Caroline…

Caroline: No, sorry, I was just going to say, and also if it’s only at least once in every two weeks and you’ve got the biomass just going, switching it off and on…

David: Yeah, exactly. Yes. I think going back on what Caroline showed us on the slides, I mean, you know, as she was saying, a big chunk of the building stock, it’s still a bit of a difficulty but it’s going to be as difficult to those buildings that are definitely off-grid or don’t have main supplies of gas or that type of access which are going to be the more difficult buildings in the next 10 years for us to deal with because they’re not going to fit with a majority of the investment or the work is going to go I think. That’s my view I think.

Caroline: And with that one as well is when you think about when you’re going to want the heating which is in the winter -so I know the person mentioned PV- is that, you know, it’s the time when you don’t have the most amount of sunlight and anyway, you probably wouldn’t get all the heating from a PV ray anyway, so it’s probably not the best option for that either. It’s difficult. This one’s difficult.

Matt: I like the idea of heated pew cushions that someone mentioned.

Caroline: Yes. We’ve done that.

David: We’ve done that. There have been studies done on how you can heat people locally in a church including, perhaps not cushions, but heated seats, heated panels on the seats.

Caroline: So you’re heating the people rather the space.

David: There’s been work done on that. So if they look online they’ll probably find some guidance on that.

Matt: It goes back to the other comments in the chatroom about people wearing more jumpers which might actually support the sheep farmers in the woollen industry a little bit more.

“What do you think of Bio LPG for small-scale, off-grid buildings?”

Caroline: Yeah, I mean that’s one of the alternatives to oil or LPG. You’ve got the Bio LPG which is obviously low in greenhouse gas and emissions so yeah, again, another solution.

Matt: Is that something readily on the market at the moment? Or is that still in development?

Caroline: There are biofuels coming onto the market.

David: Bio LPG. It’ll be supply and demand again like all these things Matt. It’s like all these things, you know. There’s people are doing this sort of stuff but you know, it depends on how big a market they’re going to get I would imagine.

Matt: Indeed.
So, OK. Long question for you now: “New green deal contractors locally are pushing air-source heat pumps for domestic. Is that a value-for-money option? A major bungalow refurbishment very close went for a ground-source heat pump with approximately 18 metre boreholes in the front garden. Is that likely to long-term be a more efficient domestic solution compared to air-source? What about solar heat collection panels and inverse refrigeration heat recovery rather than PV installation on the roof?

Caroline: So, it might be worth breaking the question up a bit. I’m not sure what you mean by “new green deal contractors” because there isn’t a green deal but “are pushing air-source heat”, air-source heat pumps are used a lot for domestic. I mean, obviously you’re using it a lot more unlike our person that put the question about only being there every two weeks to use heating which it probably wouldn’t be value for money. So in domestic, you do see it particularly in new build domestic, air-source heat pumps are used a lot.

David: I was going to say on that one, the other thing is that with the air-source heat pump, let’s be quite frank, it’s an easier installation. It’s much easier to turn up and stick an air-source heat pump condenser unit in the back garden than it is to start… As you said, you know, you’ve got to space out the heating coils, you’ve got to dig the ground, you’ve got to do all that reinstatement work. So, from an installation point of view as well, I would have thought that’s a relatively simpler solution if that’s the right word for it than perhaps the ground-source. What do you think?

Caroline: Yeah, I mean, the ground-source, it’s having the land as well so…

David: Yeah, exactly. Yeah.

Caroline: You know, if you’ve got lots of land you could do… Instead of doing the boreholes you do your slinky pipe if you’ve got that much land to do it because it’s cheaper than having to do boreholes down. It depends on the land. I mean, they’re saying for this major bungalow refurbishment that it was boreholes so they actually went down which is more expensive but…

David: You probably get more heat from them I would guess.

Caroline: You do. You do. And you need more land if you’ve got the slinky tubes obviously.

Matt: The land is always the problem with that one, isn’t it? Certainly for privately-owned buildings.

“The RIBA… “The Royal Institute for… sorry.

Caroline: British Architects.

Matt: That’s the one.

“…have figures on relationships between carbon cost of building a new building against the overall carbon cost. They are now advocating to architects that demolition of older buildings should be avoided in favour of rehabilitation”. That’s very good to hear.

Caroline: Yeah. I read this the other week. Very good.

Matt: Excellent. OK, last question: “Is there some demand i.e. more likely on a domestic scale for hydro generation? There are many LB by water courses”. Sorry, I don’t know what LB stands for but…

David: Listed buildings.

Matt: Oh, I beg your pardon. Yes, of course. Sorry. I’ve got to keep up with these acronyms haven’t I? There are many listed buildings by water courses. Indeed, there are many listed buildings, as someone mentioned in the chatroom, in flood areas as well so…

David: That’s right.

Matt: Hydro, yes, well obviously if you go to Scotland and places like that, that’s a significant investment, isn’t it?

David: We have seen projects with people making use of… you know, if they’ve got an available water source to generate a hydro-system, my thoughts on that would be… yeah. I mean we know that rivers are there and they can produce, I mean, it might be a bit of work. It’s not as simple as just sticking a turbine in the stream out the back of garden and generating some energy I’d imagine but I can’t see why you couldn’t do it. Although, again, same as a lot of those types of resources, is it always going to be there? I mean, we talked earlier in our presentation, I showed you the slides with the unpredictable rainfall patterns we’re now getting in this country so as long as you could work out what you think your minimum flow of water is likely to be, then you would have… But yeah, obviously you’d have to work out what the flowrate is of the river and obviously if the river runs low it might obviously then affect what you can get out of it. There’s been examples of old mill buildings particularly being converted back to making use of hydro as an energy source.

Caroline: We do have some… We do have a guidance on hydro and it’s… Quite right, someone’s just put in, and of course you need permission from the Environment Agency.
David: Yes, certainly. That’s what I’m telling you. It’s not as straightforward and just sticking a turbine in the back garden in a river.

Matt: Could you just leave the bath tap running?

David: Could do. Might cost you a lot though wouldn’t it? It would probably cost you more in water then it would in energy.

Matt: Only if you’re on a water meter.

David: Yeah, well that’s not going to take long is it?

Matt: OK. Caroline and David, thank you so much for today’s presentation. Absolutely fascinating and I know this conversation could run and run all afternoon I’m quite sure. At this point we will mute our microphones, but to all our attendees, thank you so much for taking the time to join us this afternoon. I hope you found Caroline and David’s webinar as interesting and informative as I have. So it is just for me to say thank you very much for your time today and we wish you all a very good afternoon. Thank you very much and all the best. Take care.