Hydroelectric Power in Historic Landscapes

2023.11.21 – Hydroelectric power in historic landscapes

00:00:00:08 - 00:00:29:11

Speaker 1

That's great. Thank you. And good afternoon, everyone. My name is Caroline Cattini-Dow and I am Historic England's building services engineering team leader and the principal engineer in the technical conservation team. And I'd like to welcome you to this Technical Tuesday webinar, which will present the findings from the Building Services Engineering Team's latest study, which was undertaken for us by consultants Ove Arup and partners titled Hydroelectric Power in Historic Landscapes.

00:00:29:19 - 00:00:56:16

Speaker 1

Now, some of you may be aware we do have some material on our website about the use of hydroelectricity in the form of our publication Micro Hydro Electric Power and the Historic Environment. This was published about ten years ago, back in July 2014, and the purpose of publication was to provide an overview of how micro hydro schemes work and advice on what you would need to consider if you were looking to implement a scheme at a historic site.

00:00:57:07 - 00:01:15:03

Speaker 1

Now, as I said, the publication is ten years old and it still has some really useful material and hopefully this will work if I share the link in the. Yes, it does. Excellent. So I just put the link in the in the chat. So if you do want to look at that. So as I said, it's got some really good information but is ten years out of date.

00:01:15:03 - 00:01:41:10

Speaker 1

So we really wanted to update the publication and include some real case studies as well. So we considered we commissioned consultants over to undertake the study looking at a number of existing installations across the country so we could better understand the technical and environmental barriers to the adoption of micro hydroelectricity. And the study also includes a whole life carbon assessment of a refurbished and a new build scheme.

00:01:42:08 - 00:02:02:00

Speaker 1

Now we have only just completed this study, so over time you'll find that we have a publication to share and we'll also update the content on the web, web pages as well. So just bear with us on that because we have, Ove Arup have only just finished the study and I'm really pleased to welcome the three presenters today from Ove Arup.

00:02:02:00 - 00:02:12:24

Speaker 1

Our presenters, we've got Tara, William and George Vergoulas. And I'm now going to let them introduce themselves. So, Tara, if you'd like to go first.

00:02:12:24 - 00:02:22:08

Speaker 2

Thank you, Carolyn. Yes, absolutely. Hello, everyone. My name’s Tara Murphy and I’m a heritage consultant at Ove Arup and I’ll hand over to William

00:02:22:16 - 00:02:23:07

Speaker 1

Thanks Tara. William Please.

00:02:23:13 - 00:02:31:18

Speaker 3

Thank you Tara. Yeah, thank you. Yeah, I'm William Holloway. I'm a senior engineer here at Arup. That’s great.

00:02:31:19 - 00:02:33:00

Speaker 1

Thank you. William and George.

00:02:34:09 - 00:02:41:19

Speaker 4

Hello. Nice to meet you, everyone. I'm George Vergoulas, associate director here at Arup with a background in carbon footprinting and sustainability.

00:02:42:17 - 00:03:06:19

Speaker 1

That's great. Thank you. So, I’ll just give a on that basis just an overview of the issues that we're going to, the topics we're going to cover today that Tara, William and George will be covering. So first of all, Tara is going to kick us off with an introduction to the project and what the main objectives were. And then we're going to go on to look at the case studies, and then William will go on to explain how hydropower works and what we mean by micro hydro as well.

00:03:07:07 - 00:03:25:24

Speaker 1

And then we will be looking at some of the key findings from the project. And then George will go on to explain about the whole life carbon assessment that was undertaken as well. At the end we're going to have time for your questions. So while the three speakers are presenting, if you want to put your questions in the chat, that would be great.

00:03:26:05 - 00:03:43:03

Speaker 1

And also, if you have a specific question for one of the presenters, if you just had their name as well, I can make sure I ask that person the question. So without further ado, Tara, if I could hand over to you.

00:03:43:03 - 00:04:14:22

Speaker 2

Brilliant. Thank you, Matt and Caroline. So I'll be taking you through the introductory slides to give you a background on our general methodology. So this is an overview of the project. So the report, as you know, was commissioned by Historic England and a range of Arup specialists who worked on this report ranging from water, energy, carbon and heritage. And we come from various different offices across the UK, for example: London, Leeds, Cardiff and Bristol.

00:04:16:17 - 00:04:49:17

Speaker 2

So why was this project undertaken? So the research aligns with Historic England's climate change and sustainability objectives. We hope the research will contribute to updated guidance and it aims to identify best practices by identifying successes and challenges facing hydroelectricity schemes in historic landscapes. And we certainly hope that it will help to inform future work and strategy relating to hydroelectricity generation plant installations in historic buildings as well as historic environments.

00:04:49:17 - 00:05:17:22

Speaker 2

So in terms of how we went about this, we looked at nine microhydro schemes across the country and the site visits for our case studies were carried out between March and September of this year. The site visits included visual inspections, quantitative measurements and interviews with operators. And it's important to note that we were very much there in an observational capacity and no actual testing was done. At each of the site visits

00:05:17:22 - 00:05:51:24

Speaker 2

there were two of us present; always an engineer and a heritage specialist. And we think this worked really well because we were able to have a well-rounded interaction with the owners and operators. Considering our questions from both standpoints were quite varied. The focus really was on drawing conclusions to highlight the issues faced by the owners and operators simply in construction, and also hearing from them on what they felt were best practice solutions.

00:05:51:24 - 00:06:25:20

Speaker 2

So now as we think about what objectives. Our primary objectives really were to evaluate the technical performance of these micro hydro sites, to record key operational metrics, to identify how environmental impacts have been mitigated, and highlight areas of concern for ongoing considerations. And if we just elaborate on those two final points there, and I certainly found it very interesting from heritage point of view to learn more about some of the impacts on wildlife, which are naturally very key concern in these cases.

00:06:26:07 - 00:06:54:19

Speaker 2

And in terms of ongoing considerations, this might be something like being worried about whether the people with the right knowledge base will be available to take over these sites in the future. So our secondary objectives are a bit more general. So identifying common themes across the different site visits and again identifying potential barriers to entry for new micro hydro sites based on the feedback that we got.

00:06:55:14 - 00:07:30:01

Speaker 2

Yes, the key question really here is trying to establish based on that feedback quite like, you know, what might be off putting or what the potential roadblocks for attempting similar things in the future might be in terms of how difficult consenting processes might have been or indeed physical challenges in terms of construction. So this slide here gives you an overview of the geographic spread of our case studies, and we were very pleased to be able to have quite a lot of case studies that cover quite a lot of area from the northeast to the south west which was great.

00:07:31:13 - 00:07:53:18

Speaker 2

And then this site, which is very heavy on the text apologies, gives you an overview of the type of questions that we were asking. And it's important to note we did this in two ways. We provided all sites with a questionnaire, and also we were obviously able to enrich them with onsite questions during our site visits, which is fantastic.

00:07:54:02 - 00:08:23:24

Speaker 2

So these questions really did range from giving a general overview of the hydrology, how the installation went, construction went, and what's the turbine performance and the outputs, how they formed, the stakeholder engagements, the consenting processes, and what the repair and maintenance regimes might be. And then finally for me, just the limitations. So I think it's very important to be aware of your limitations. So our site

00:08:23:24 - 00:08:59:03

Speaker 2

visits were limited to six locations and we were able to visit just once for all of the sites. It was not always possible to inspect parts of the property that were inaccessible at the time of visits. But thankfully this wasn't the case in all the sites. The questionnaire responses really did varying levels of thoroughness. And this is because the availability of the relevant people to interact with and respond to the questionnaire varies, which is entirely natural, normal, and in some cases information was received verbally on sites where it mightn't have been covered in the written responses.

00:08:59:10 - 00:09:29:07

Speaker 2

So we did certainly find this, you know, sometimes the questionnaire responses might have been a bit sparsely populated, that we were able to get a bit of extra information from attending site visits and having these conversations with the owners and operators in person, which was brilliant. And then in several instances, information on schemes has been lost over time, and this is very much to do with the fact this in some cases the current owner and operators might not be the people who actually started this process.

00:09:30:03 - 00:09:50:22

Speaker 2

So a lot of information can go missing unless records were kept and passed on effectively. And then the last limitation we have here is just as all site studied were low head high flow turbines, all similar in that sense. And I will just hand over to William now, which take you through the hydrology and engineering side of things.

00:09:51:06 - 00:09:53:04

Speaker 2

Thank you so much.

00:09:53:04 - 00:10:28:08

Speaker 3

Brilliant. thank you very much, Tara. Hopefully you can hear me. So, yeah, I'm going to run through some of the technical assessments that we undertook and what we learned. But starting at the high level, what is hydropower? Well, hydropower aims to utilize the potential energy in a flow of water and hydroelectricity is more specifically generating electricity from this. The amount of energy available is directly related to both the flow of water and the height difference between the inlet and the outlet of the plant.

00:10:29:04 - 00:10:53:07

Speaker 3

Since the flow rate is generally given the aspect which is often artificially increased is the height. This is achieved by obstructing, abstracting water from a watercourse and running it at a shallow gradient whilst the river falls away at a greater rate. As can be seen in this diagram. This flow then passes through the turbine, turning the potential energy ultimately into electricity, and then the flows returned to the river.

00:10:54:15 - 00:11:35:11

Speaker 3

And hydropower has been used within the UK for hundreds of years powering water mills and other industry and the UK are actually pioneers of hydroelectricity, with the first production of hydroelectricity being at Cragside in Northumberland in almost 150 years ago. All installations that we looked at during this study have been run of river type. This means that there is no significant storage associated with the schemes in the form of reservoirs and this is typical with these types of schemes since reservoirs come with a lot of inspection requirements and additional infrastructure. All of the schemes studied were fall and the kind of micro hydro bracket which is termed as less than 100 kilowatts.

00:11:36:06 - 00:12:09:15

Speaker 3

And this word micro would lead you to believe that they are very small, but actually 100 kilowatts, if running continuously, would be able to power about 300 homes. So they're not necessarily that small. Looking at the ecological impacts by altering the natural flow and patterns of the river, there is inevitable ecological impacts. The ecological impacts of hydropower schemes are better understood than ever before, and there's a wealth of information available from the Environment Agency on the types of impacts that a scheme can have and how this can be mitigated.

00:12:10:05 - 00:12:32:15

Speaker 3

For example, when a fish passage is deemed by the EA to be made worse by a scheme, if a fish pass will be required to mitigate that. But this cannot see caused issues with existing sites in historic landscapes due to conflicts with planning and will come on to that. This slide gives you an overview of the schemes that we visited and also had questionnaire responses from.

00:12:34:01 - 00:13:01:21

Speaker 3

There was a spread of installations from refurbishments to new turbines and completely new civil infrastructure. They were all installed between 2007 and 2017, for reasons which I'll come on to in a bit. And we had a good range of schemes in terms of heritage status from being in conservation areas to being in grade one listed parks, buildings and gardens.

00:13:01:21 - 00:13:44:02

Speaker 3

Overall, there were four distinct types of turbines which are installed, and these typically cover all of the turbine types which would be expected in schemes of this size and are typical full of low head sites. There was a good range of installed capacity from six kilowatts up to 63 kilowatts. Similarly to the installation date, we didn't actively go and search for schemes of any particular size, but schemes of this type in historic environment will generally fall into this micro hydro bracket and also showing a capacity factor on there, which is a measure you could also term as utilization, which just shows what factor of energy which is produced over a year is compared to

00:13:44:02 - 00:14:09:02

Speaker 3

if that unit had been running at full capacity for 100% of the time. And this is just some of the information that we collated from all the really helpful owners and operators which informed the findings of this study. So moving on to some of the observations around the requirements of installing plants in historic environments, some of the key design requirements.

00:14:09:02 - 00:15:10:12

Speaker 3

So the historic setting in which the various micro hydro sites are situated had several impacts on the installations. The choice of turbine was in some cases impacted by the setting, for example, in sited historic mills. In this case, the turbine would need to be a suitable size to fit comfortably within the building and required minimal alterations. The original space where turbines were installed outdoors, there were naturally less constraints spatially, but the potential impact on the landscape of registered parks and gardens and conservation areas were key considerations, especially in terms. [[Lost sound]]

00:15:10:12 - 00:15:14:22

Speaker 3

Hello everybody. I can see that unfortunately.

00:15:15:09 - 00:15:15:24

Speaker 4

Sound.

00:15:15:24 - 00:15:18:18

Speaker 3

Has gone.

00:15:18:18 - 00:15:20:07

Speaker 4

If you will.

00:15:20:17 - 00:15:50:15

Speaker 3

Can you hear me? Can. Yes, but your back. Thank you. Yeah, I got kicked out. I think I should be back now. Hopefully, I'm not quite sure where I dropped out there. I think so. I'll just jump onto the common types and themes. So typically hydroelectric plants are installed with the primary objectives of generating electricity to offset consumption or feed into the grid.

00:15:52:02 - 00:16:25:11

Speaker 3

In many of the case studies, the installation was actually motivated by a desire to restore an original function, which was in keeping with the historic context and often for additional social benefit as well, such as tourism and education. Though this didn't mean that the scheme didn't also generate income. In terms of turbine selection from the case studies, it's clear that the historic environment context is one of the driving constraints on the types of turbine selected, and this was due to a desire primarily to match an existing or previous installation.

00:16:25:11 - 00:16:52:12

Speaker 3

For example, in Mills side, which had previously housed an internal turbine, a Kaplan or cross flow type turbine will generally be required as the flow to these turbines is within a pipe. In instances where buildings cannot be modified or a turbine has previously been installed externally, such as a waterwheel, an Archimedes screw type turbine will typically be installed, and often the turbine selection was maybe not the optimal for the site.

00:16:52:12 - 00:17:38:01

Speaker 3

Hydrological conditions as in terms of ultimate energy generation, which is what we found. But actually the loss of a few percent of energy generation over a year was worthwhile when considering the civil infrastructure modifications could be reduced, or if the alternative turbine better fits this context and reduces issues with planning and consents and the vibration of certain turbines is also considered in these historic settings to avoid structural damage to the buildings in terms of permitting the general feedback from the owners and operating, sorry, from the owners and operators was that there wasn't a cohesive understanding from the bodies about the historical context and the requirements associated with this

00:17:38:01 - 00:18:10:17

Speaker 3

for hydroelectric generation. This led to conflicts between the by the environmental and planning permissions, which in turn created confusion as to which took precedence and how to resolve the conflict, for example, where a fish pass was required on one site, but that would impact upon the historic setting and was contentious in planning. These kind of potential conflicts increase the risks of a project and the design costs, whilst the may ultimately be a solution which is preferable to both agencies. In terms of financial viability.

00:18:10:23 - 00:18:44:18

Speaker 3

As I mentioned in the overview section, all of the schemes that we studied were commissioned between 2007 and 2017. When we identified the schemes to study, there wasn't we didn't put any restrictions on this so is this coincidental? Well, not really. It's what's clear is that the government feed into our schemes which were available at the time, really drove an industry in its infancy and help towards the increasing decarbonization agenda when those feed in tariff schemes were abruptly stopped

00:18:44:18 - 00:19:14:17

Speaker 3

this really stifled the development of new schemes since the payback periods were no longer viable, particularly with additional costs related to installing them in historic landscapes. However, this study from Historic England is very timely. With the recent rise in energy prices and increasing decarbonization agendas and concerns around energy resilience, many people are again looking at schemes such as this as they want them becoming viable.

00:19:14:17 - 00:19:43:15

Speaker 3

Looking at more of the key findings. As I said before, we had capacity factors for the sites. The capacity factors are tipped for hydro, for small hydroelectric schemes typically vary between 0.2 and 0.95, which is a very large range. And this is typically due to the hydrology of the site. But of the sites studied they were generally towards the lower end of or below this range.

00:19:44:11 - 00:20:11:16

Speaker 3

This indicates that the installations have restricting factors on their generation or that the ultimate energy generation may not have been the key driver for the scheme. Of all the case studies, four were completed on time, another average 32% overrun. This is not thought to be abnormal when compared to schemes which aren't in a historic environment. Generally, all of the schemes were very well understood and planned for from the outset.

00:20:12:20 - 00:20:42:10

Speaker 3

The looking at the retrofit challenges. So all of the schemes seem to be well planned and designed. So challenges are often known about. Liaising with the multiple parties involved, such as the Environment Agency Planning and UNESCO's and other required and others required research by the designers and diligent correspondence and collaboration throughout the project. Also, a lot of the challenges faced were self-imposed, with owners and designing designers wanting a scheme which added to the site

00:20:42:10 - 00:21:12:23

Speaker 3

and was fitting for the environment. Some sites are challenges with grid connections not being suitable, so energy has to be used on site or curtailed, and challenges were often noted around access to sites. Actually, two of the different schemes even considered helicopters to get their turbines in. But access issues are not unusual with hydroelectric schemes in general due to their inevitable locations next to watercourses.

00:21:12:23 - 00:21:42:00

Speaker 3

Climate change. This is affect the hydrology in all rivers and ultimately impacts of flow patterns which have been seen at the sites with longer dry periods during the summer and larger peak flows in the winter. With often limited flexibility in these sites, on the civil infrastructure due to planning constraints, softer measures such as natural flood management in the upstream catchment are likely to be required.

00:21:42:00 - 00:22:08:13

Speaker 3

Looking at the costs, the typical cost of installed small hydropower plants is between 1000 and £6,500 per kilowatt. The mean of the schemes in this case study was £18,000 per kilowatt, which is three times the top of that usual range. And of the case, studies all cost more than the initial estimate and they were on average 34% above the initial estimate.

00:22:09:14 - 00:22:41:05

Speaker 3

So installing hydropower plants within a historical context is expensive, but it has often come with the benefits outside that of just energy generation. And I will pass on to George to talk through the carbon assessment. George, we don't seem to have your audio.

00:22:42:23 - 00:22:50:16

Speaker 4

Hello? I think you will. Yes. Taking a little while to connect the microphone. Hopefully everyone can hear me clearly.

00:22:51:04 - 00:22:52:05

Speaker 3

Yes. Thank you, George.

00:22:52:17 - 00:23:26:22

Speaker 4

No problem. Thank you, Will. So great to see everyone online today. Before I jump into presenting findings of the Whole Life Carbon Assessment, have a couple of slides I want to go through, basically to introduce the concept of whole life carbon footprints and the basics, how it works, the kind of data we need, and so forth. So whole life carbon assessment is essentially the measure of amount of carbon released into the atmosphere, which can contribute to climate change.

00:23:26:22 - 00:23:58:03

Speaker 4

Usually whole life carbon assessments are are undertaken to establish a baseline, but more importantly to to inform decision making. And it's particularly common with infrastructure projects, renewable energy technologies like hydropower, which you know, are regarded as as low or zero carbon when compared to the generation of grid electricity. So in this instance, we carried out a high level whole life carbon assessment for our schemes.

00:23:59:12 - 00:24:27:07

Speaker 4

Just look at the comparison between them and what are the savings that we can achieve with regards to grid electricity and also where the hotspots are. The little image I have at the bottom of of of the slide just kind of spells out the steps, the very basic steps of carrying out a carbon assessment. On the left hand side, you have an activity. Activity

00:24:27:07 - 00:24:53:10

Speaker 4

could be anything. It could be the use of fuel, it could be embodied material. But usually we're looking at yes, material, tonnages of materials used or fuel used, which is then combined with the carbon factor, which I'll talk out a little bit more about later. You combine the two to essentially estimate carbon emissions. Now, I wanted to just quickly touch on terminology.

00:24:53:10 - 00:25:33:16

Speaker 4

The term carbon, carbon dioxide, greenhouse gas emissions, are often used interchangeably. However, they're technically different. Carbon is a chemical elements which is present in many gases. So when carbon combines with oxygen, it produces carbon dioxide, which is the most common greenhouse gas contributing to greenhouse gases. Carbon dioxide sometimes is confused with greenhouse gases, the difference being that greenhouse gases or the greenhouse gas term is used to describe and report a combination of different gases.

00:25:33:16 - 00:26:05:07

Speaker 4

So it's not just carbon dioxide that contributes to climate change, but other common gases such as such as nitrous oxide or methane, also contribute to greenhouse gases. So to save our to save some time and simplicity, we combine them all together and report them as greenhouse gas emissions or CO2 equivalents. So for simplicity over here, I use the term carbon, but what I actually mean is we've reported and looked at greenhouse gas emissions in totality.

00:26:05:16 - 00:26:49:13

Speaker 4

So that gives us a little bit of a background as to what we're looking at. This slide is trying to illustrate the scope of our carbon assessment. There's a lot to digest in here and don't worry, I will quickly explain how it goes from left to right. What was included in the whole life carbon assessment. This image is essentially taken from a very common British standard on looking at carbon emissions for buildings and infrastructure. Essentially, in the carbon world, we try and break out the carbon footprint in terms of embodied, material use and energy use and end of life.

00:26:49:21 - 00:27:19:07

Speaker 4

So what you can see on the left hand side that's highlighted with the the red boundary is the product stage. And what that basically means is the whole life carbon study that we looked at, we considered the embodied carbon of the material used in our scheme. So for example, the concrete and steel, the manufacturing impact of extracting raw material and processing the transportation and manufacturing of those materials were included in our assessment.

00:27:19:07 - 00:27:53:11

Speaker 4

So that's what that red circle on the left hand side is illustrating. We also looked at construction processes, so transport to our specific sites of the materials, and we also looked at construction installation processes. So any diggers, generators and so forth. The fuel associated with the construction process was also included. In the middle we have the B stage and there it’s the operational energy use I'll touch on a little bit later on.

00:27:53:12 - 00:28:13:20

Speaker 4

That was not very significant at all. There was only one site that needed a little bit of energy to get it started, but that was captured as well. As you can see, there's a whole bunch of other phases or steps that were not included, and I'll discuss a little bit more about that later on. It's basically to do with data availability, but we're not able to look at maintenance, repair and replacement impacts.

00:28:15:01 - 00:28:44:00

Speaker 4

End of life was looked at. What are the impacts if we're going to deconstruct, remove those at the end of their life? And we also had a quick look at the indirect impacts where we compared the carbon impact of generating energy with power with regard to in comparison to electricity, essentially. So that covers the scope of the assessment.

00:28:44:00 - 00:29:10:22

Speaker 4

Now like most like all carbon footprints or whole life carbon assessments, data collection is the most important, is the most important elements. The quality of the data will essentially determine the quality of your whole life carbon assessment. So I'm trying to illustrate over here is I mentioned earlier that we wanted to look at activity and we gathered data.

00:29:10:22 - 00:29:45:17

Speaker 4

And what we mean by data is we try to gather information in various forms. Data came in the forms of drawings and site layout. In some instances, instances we had bills of quantities which are frankly the best type of data where we get from primary sources, information such as the volume of materials actually used on site. Of course, we had descriptive information and energy generation information, kilowatt hours generated on an annual basis.

00:29:45:21 - 00:30:13:00

Speaker 4

So we gathered that data through the use of our questionnaire. The data was patchy, but there were a couple of sites that actually had very good data which we focused our assessment on. Now, once we gathered that data, we then had to convert that information in into carbon and to convert input data or information we got into carbon, we usually need to convert it into a volume cubic meters or a tonnage of material.

00:30:13:14 - 00:30:42:24

Speaker 4

And we have and we then combine that with carbon factors and carbon factors can be sourced from multiple, multiple areas. Some databases such as the ICE database is publicly available. The government also has carbon factors available for free on their website, but we also combined it with more, let's say, specialized whole life carbon modelling software such as OneClick which we have the like are we have a license for it.

00:30:43:05 - 00:31:09:18

Speaker 4

So we use multiple or sources to to estimate carbon emissions. And ultimately we reported whole life carbon emissions in total. But like most of our whole life, carbon assessments, we also want to report emissions in terms of a functional unit that makes sense and can be benchmarked and compared. So we also worked out what is the carbon emissions per kilowatt hour generated for for each site.

00:31:10:07 - 00:31:31:12

Speaker 4

Now, as I think mentioned, it's important to note the data gathering was a little bit patchy, but two sites provided the best quality data to be used. One was a new micro hydro scheme, which was able to provide general arrangements and drawings information, but they also were able to provide the actual weight of the turbine, which is really useful.

00:31:31:23 - 00:31:56:03

Speaker 4

And on this particular new micro hydro site, we use those drawings and combined those with the software known as Blue Beam, where essentially it's possible to put in the dimension, for example, of the turbine house height, width, length, and it actually works out volumes of materials and concrete for you. So that was very good for that new micro hydro site.

00:31:56:16 - 00:32:18:22

Speaker 4

The second site was a refurbished site which also provided very good data there. We actually had bills of quantities, so volumes of concrete and steel was used again. We also had the weight of the hydro turbine that was used there, which was very useful. Now, it was interesting. I believe Tara kind of touched on it a little bit earlier on in the presentation.

00:32:19:05 - 00:32:46:07

Speaker 4

In this instance, the quality of the data for this refurbished site was was very good due to several factors. One was that the ownership had remained the same since the time of the installation and and the owner actually kept very good records of all the information. And hence participation in the survey was very easy in that instance, we were able to convert that information into a carbon assessment.

00:32:46:22 - 00:33:12:20

Speaker 4

So that covers a little bit kind of the methodology and the data element of the assessment onto the results. So there's a couple of there's a lot on this on this graph. I'll go again through it from left to right. On the left, we've got the table. There are no surprises over here. As you can see, we have our new build micro hydro scheme and our refurbished next to each other.

00:33:13:20 - 00:33:44:13

Speaker 4

They both have the same embodied carbon emissions. It's not a very large difference. 67 tonnes versus 69 tonnes between the two. And again, no surprises. This is very common with many infrastructure and building projects where most of the impact the hotspot is essentially in the construction materials. So in the embodied carbon of the concrete and steel and the actual hydropower unit transport emissions and construction emissions are again relatively minor.

00:33:45:06 - 00:34:12:20

Speaker 4

And it's interesting to note on the right hand side of the table, the refurbished micro and micro scheme in this instance did need a little bit of energy just to kick start the turbine, from what I understand. So hence why there's a little bit of of a footprint, a very tiny one, in terms of energy consumption. And at the bottom, we can see the functional unit that I mentioned, what is the carbon impact per kilowatt hour generated?

00:34:13:01 - 00:34:44:03

Speaker 4

It's all there and they're both very low for the new build. It's eight and the refurbished. It's two grams per kilowatt hour. Um, we tried to present the same information, but maybe in some in a different format. Let's say that others might make more sense of it. On the right hand side of the slide, I've, I've compared the two carbon footprints, but rather by whole life carbon, let's say, processes of construction and transport.

00:34:44:10 - 00:35:10:04

Speaker 4

I'm looking at specific assets that we can make sense of. And you can see both both sites were there where the the biggest footprint is. Of course, the turbine, the wing walls are quite common and they're a different elements that one can make sense of, including the turbine. Now, these were the two preferred sites. The other sites had very patchy data.

00:35:10:04 - 00:35:46:06

Speaker 4

So we used the functional units at the bottom of the table on the left hand side to scale up an estimate and estimate what the emissions would look like based on the energy yield of the other sites. So as you can see on this graph, for the remaining five sites that we had a little bit of data, we grossed up an estimated emissions based on the energy yield and the numbers range from, from 5 to 69, which is a little bit of which is linear.

00:35:46:14 - 00:36:12:17

Speaker 4

However, to make sure that we were in the right range, we compared our results with a published paper of 11 micro hydro schemes that was carried out in Wales in 2019, and those results were more or less in the same range as well of between 3 to 15 grams, which gave us a little bit of confidence that we were not too far off, barring one or two that were a little bit high.

00:36:13:00 - 00:36:58:00

Speaker 4

So the results were encouraging. However, I would use these with caution as it is a quite small sample size that we were working with. And in terms of some conclusions and, and recommendations, um, this slide is, is illustrating kind of low carbon design principles that are applied across the construction sector and all it's trying to illustrate, particularly the image at the bottom is that at the decision making where you're deciding what you want to install is where the biggest savings can be achieved so you can actually avoid unnecessary emissions.

00:36:58:06 - 00:37:22:05

Speaker 4

At the concept of a project, once you make a decision, then you can start progressing towards selecting particular materials, looking at low carbon, recycled concrete and steel, which is what the switch element is looking at. And then we're looking at tweaks towards the end up in terms of improving what can you do to reduce emissions during construction? Is there connection to the grid?

00:37:22:20 - 00:38:02:21

Speaker 4

Can you not use any diesel generators on site if possible? So those principles are still valid and are and are generic that can be applied in this instance. However, we looked at the payback period of the micro hydro schemes and they all came back as less than three years. So carbon payback period is a is an estimation of how long it would take a renewable energy project, in this case, a micro hydro scheme to offset the greenhouse gas emissions, emissions of the construction process, essentially based on the difference with traditional grid electricity.

00:38:02:21 - 00:38:24:06

Speaker 4

So there's a very quick it looks like there's a very quick payback period in the schemes that we've looked at. So whether it's it's a refurbished or a new construction scheme, it does look from a carbon perspective that of course it's a worthwhile investment. And finally, one of the recommendations would be to revisit the sites for a more robust carbon assessment, if possible.

00:38:24:06 - 00:39:00:00

Speaker 4

Now that we know what good data looks like. So in summary, to close this off. The key to a successful consenting process and therefore successful scheme, according to most case studies, was early and open and open communication with the relevant, relevant authorities. Additional factors in play and historic landscapes meant that the installations were more expensive than comparable examples elsewhere.

00:39:00:09 - 00:39:25:17

Speaker 4

However, reuse of elements were possible, were beneficial. And of course there's a clear carbon benefit with micro hydro schemes both refurbished and new built when compared to grid electricity. Albeit being cautious with the with with the sample size that we're looking at over here and with that, I think I'm going to hand back to Caroline for the Q&A.

00:39:26:23 - 00:39:28:06

Speaker 1

That's great. Thank you, George.