It’s Friday 16th June, I’m Anthony Day, it’s the Sustainable Futures Report and we’re talking about Sustainable Energy. Find the podcast on iTunes, Stitcher or via susbiz.biz.
Not a word about the election. I’m sure you’ve heard far too much from multiple sources already. Oh, all right - just one word. This government. It’s not sustainable you know. And that Michael Gove for Environment Minister? A former Education Secretary who is reputed to have attempted to exclude climate change from the geography syllabus? I’m sure we’ll be talking about it at length in the future.
But now, Sustainable Energy. I recently had the pleasure of hearing Professor Andy Heyes speak about sustainable energy. I contacted him afterwards and he agreed to share his thoughts with listeners to the Sustainable Futures Report. If you’ve been to the patreon site at patreon.com/sfr you’ll know that I’ve set a number of targets. The first was to get all interviews transcribed for the blog. I haven’t reached that target yet but I thought that this interview was too important to miss, so there is a transcript here.
Professor Andrew Heyes is Head of the Department of Mechanical & Aerospace Engineering at the University of Strathclyde. He’s also visiting professor at University College London. We met in the first week of May, and here’s what we talked about.
SFR: Sustainable energy. Why do we need it?
HEYES: We need it because just about everything, every aspect of modern life requires us to consume energy; transport, heating our homes, lighting our homes, entertainment, so just about every aspect of modern life requires energy but the sources that we currently use to get energy are finite and we are consuming them at a rate which is not sustainable. Take fossil fuels as an example; took nature hundreds of millions of years to accumulate the fossil fuels that are existing in the earth's crust but we will consume or we could consume if we don't change our current trajectory, we could consume all of that in the space of a few hundred years. So that's clearly not sustainable; so were we to carry on and not find alternative sources of energy our current sources would run out so we need to find energy that we can consume at a rate where, that we can continue to consume for the foreseeable future, in other words it's sustainable. So a typical example would be solar energy. It is often said that there's enough solar energy falling on the surface of the earth to provide all of our needs many times over, as long as we can figure out a way of getting access to it.
SFR: Yes a lot of people seeing solar and wind as the main sources of renewable energy but they say “Ah but the wind doesn't always blow and the sun doesn't always shine and they're all very expensive to put in so are why we wasting our time with it?”
HEYES: We're not wasting our time with it, ultimately the sun is arguably the only long term source of energy that we’ve got, even the wind is arguably just another manifestation of solar energy, it's a function of the sun's heating of the atmosphere of the planet.
HEYES: So, and that will be available for thousands, millions of years to come, coal, oil, gas, uranium will not. They are all finite resources and can be consumed to exhaustion. Renewable energy is expensive? Well arguably, no it is not. The cost of solar energy has come down dramatically, the learning in wind energy technology is reducing the cost there as well to the point where if you had a greenfield site and asked yourself I want to build a power station what kind of power station should I build? Then from that starting point wind is very close to being the cheapest option in terms of the cost of each unit of electricity that you would generate.
SFR: But can we build enough of these wind turbines to meet demand because there are a number of constraints. Surely there's the constraint in terms of the amount of land area that it would use, there's also surely a constraint in terms of rare earth metals which you need to put into the actual mechanics of the generator? Is that being thought through, can we actually work with that limitation?
HEYES: The honest truth is I don't have the facts and figures on whether or not we can continue to make enough magnets and whether the rare earth is the constraining factor. I suspect, I suspect it isn’t, because it is true that you would really struggle to run your entire energy system based on wind for the very simple reason that as we know there are times when it's not available, so there's, there are rules of thumb that dictate how much energy or electricity you could sensibly get from wind and it's to do with the capacity credit calculation that you do. If you have an electricity system based one hundred percent on coal for example and you install a wind farm and the wind farm has the same capacity as say a coal fired power station and the very first wind farm that you install if it has the same capacity as the power station then you can probably close down the power station. So you get a full capacity credit for the wind but of course you then introduce some uncertainty into your system, but that's okay because the system already had some uncertainty in it, it already had the capacity to react to a trip of a power station for example. So that's okay, you can you could live with the extra risk that the wind provides but then if you put in another wind farm equivalent to another coal fired power station, can you do it again, can you close another one? And the answer of course is no, the more wind you install, the less conventional it can displace because you do need that sort of backup in the system and it is difficult, it's not a precise calculation, there are rules of thumb that imply that you can reliably get about twenty percent of your electricity and that's probably a conservative estimate. So you shouldn't try to get more than that from wind without I suppose having some new technologies which are not already on the system that help you manage the uncertainty. In other words if we left the system exactly as it is and just started closing down coal or gas and replacing it with wind, you probably shouldn't go past twenty percent and if you want to go past twenty percent you're going to need something else to manage the uncertainty in wind.
SFR: Right, something else.
HEYES: Storage would be one option and using energy demand management is another option.
SFR: Demand management.
SFR: Smart meters and things like that.
HEYES: Smart meters would be part of the equation I guess but what you really need is the capacity for consumers of electricity to stop consuming periodically to help you manage the system because if a large consumer ceasing to consume is rather the same as a large power station starting to generate. It has the same net effect and there are clever ways of managing end use energy demand and that does include storage for example.
SFR: Some of the end use energy management is with major industrial uses, where they have interruptible tariffs but we don't have an awful lot more heavy industry these days, so and you can't just turn off London Underground nor can you stop the trains on the East Coast Main Line. So, are we not having to move towards the domestic consumer?
HEYES: Possibly yes and you know there are some clever technologies that have been suggested for allowing even domestic consumers to take part in end use energy demand management and the smart refrigerator is the, is a nice example that was, made an appearance in the press a few years ago.
SFR: But is that available and that will need some sort of super smart meter to actually work, won't it?
HEYES: Not necessarily. The technology required to allow your fridge to take part in end use energy demand is actually relatively simple. The fridge needs to receive a signal that says there is stress on the system and it would be good if you could stop consuming electricity and it needs to make a decision about well “Is it safe for me to do that?” Given that, you know, what is the temperature of the contents of the refrigerator and if it is safe to do that, to switch off. Well that sounds very complicated but in fact when there is stress on the system the frequency drops ever so slightly, so what you really need to do detect the frequency of the AC.
SFR: As easy at that, so you don't need special smart meters and interfaces, it's just a frequency detector.
HEYES: You could do it on that basis I mean of course you'd have to be certain that the frequency was reliably indicating stress on the system but that is basically what happens, when a system is under a great deal of load. The generators turn a little bit more slowly because of the load and the frequency will start to drop and that's quite a detectable phenomenon.
SFR: That is really interesting but presumably you could also send signals through the grid because I sent my computer signals at home, my network through power line adaptors, so you can actually send signals.
HEYES: You could, so I mean the frequency is perhaps a crude and overly simplistic way of detecting stress on the system but you're absolutely right, you can send signals down power lines as well.
SFR: Okay, so demand management, yes, I do feel that the emphasis that we have particularly in this country is on supply management and constantly increasing supply to meet increasing demand but maybe that's a function of the fact we have a privatised industry and it's not in the interests of energy suppliers to sell less energy.
HEYES: I think there is a great deal of truth in that, yes it is difficult to, say if you sell less then you arguably make less profit unless you've got some other way of monetising the service that you're offering. So, yes it's very difficult to see how to create the motivation for supplies of electricity and energy to encourage you to use less.
SFR: Talking about sources of energy, you mentioned in passing nuclear, but in discussions we've had you also mentioned these small modular reactors, a neighbourhood nuclear power station. Now that sounds interesting, sounds possibly scary. How feasible is it? Where would get this from?
HEYES: So small modular reactor is, the modular implies that it can be assembled offsite and delivered as a package, palletised perhaps, arguably a bit bigger than that and the technology to do that, there are various technologies, they are basically the same basic physics that are in large scale power stations but they can be assembled in a factory and delivered to site. So, it's simpler than the extreme cost and large timescales that are inevitably involved these days with building grids, conventional large grid scaled power stations. So, the advantage would be they could be rolled out more quickly, of course they're smaller in capacity, so hundreds of Megawatts at the most rather than the gigawatts scale you would have at a power station and yes indeed if you were going to try and meet your demand with these kind of devices there would have to be a larger number of small units. But, you know, again, given the extreme complexity of large scale power stations and the difficult and the challenges that we're going through for example to get the Hinkley Point power station built, perhaps there’s an argument for this kind of technology.
SFR: Yes, yes, so these units are presumably similar in size to what you might find in a nuclear submarine.
HEYES: Yes, not wildly different and you know arguably that's a technology that could be adapted to provide a modular reactor design and good news there of course is that the UK has manufacturers that work in this area so it's perhaps an industry that we might have more ownership of our own and indeed, were it to be successful, perhaps a potential export market, export technology for us.
SFR: So, we still have expertise in that particular field.
HEYES: We do have some expertise, yes, in the power plant for ships and the like.
SFR: Yes, okay. On one hand people might say I don't want a nuclear power station at the bottom of my road but on the other hand a nuclear submarine has a nuclear reactor and some of the missions go on for months, if not as much as a year, and there are people living in this structure very, very close to a nuclear reactor, apparently in perfect safety, so...
HEYES: Indeed, that's absolutely right, I think when the US Navy for example transitioned from diesel-powered ships to nuclear-powered ships, aircraft carriers in particular, that transitioned from refuelling about once a fortnight to refuelling once every decade or so, so you know almost a sealed unit, consumes, needs very little fuel, it’s fuelled when it's installed and can operate for a very long time, almost, hesitate to say without any maintenance at all, you would want to make, you'd want to do some maintenance make sure everything is safe, but managing reactors on that scale is something that we have experience of.
SFR: And there are no emissions.
HEYES: There no emissions of carbon, that's right.
SFR: It is interesting that we've got quite a lot of nuclear reactors in the defence fleet but it doesn't appear to have gone into the merchant fleet and the merchant fleet is notoriously dirty in terms of the fuel that it burns, so maybe it's because that is still cheaper than putting a nuclear reactor into your container ship.
HEYES: Yeah, and I think also, I think there is no doubt that operating a reactor in a ship does require a degree of expertise and that maybe the merchant fleet is cost sensitive to the point where you don't want, you don't necessarily want highly trained nuclear physicists on every single one of your cargo ships.
SFR: Yeah, yes, yes. Just go back to energy storage, well there's a project which is the Swansea Bay Tidal Lagoon which is partly storage and partly a source of energy because the tides fill it up and the tides empty it as well. That is a project which has been on the go or at least has been, the design has been around for several years, it looks as though the government's decision is going to be deferred till after the election, what do you think that should do, do you think that should say, it should go ahead, it's going to cost a lot less than the Hinkley C nuclear power station across the bay, although of course it will a lot smaller but it'll be a lot cleaner.
HEYES: It's interesting isn't it, I mean the other hydroelectric scheme that's been on the books for a very very long time is the Severn Estuary so there's another arguably similar technology and a natural lagoon that is filled by the tide and which can be managed to provide storage and power generation. And we obviously dither on these things, there's obviously energy there, there is obviously a storage capacity there, there are obviously some advantages but it's clearly not a very, it's not cheap and there are clearly some issues with the Severn Estuary. There are some issues with regard to the damage to the environment. It’s hard to know what really stalls the decision because again one can go back to the 1970s and find reports about the potential of using the Severn Estuary as a storage. Difficult, it is a hard one to answer and part of the reason it is hard to answer is that the cost of alternative renewable technologies is changing so rapidly that even something which looks cost effective and sensible today might, you know the economics might look very different even in two or three years time. What we've experienced in the last five years or so is a dramatic change in the cost of for example solar power, so you know it is a difficult decision to commit to some very large high cost infrastructure project like that and it's therefore not really surprising I think that politicians dither a little bit. I think as an engineer, if you want me to nail my colours to the mast as an engineer, I'd say let's do it.
SFR: Yeah, yeah, okay, let's look at biofuels. The U.K.'s biggest power station Drax, near Selby in North Yorkshire is big and it is one of the biggest polluters in the country and they have converted half of their turbines and boilers to biomass. They burn wood pellets and the theory is of course if you burn wood, yes, it will emit carbon dioxide but the carbon dioxide is absorbed by new growth of trees. And that sounds as though it is a really good idea but then we find that Drax is actually importing its wood chips from American forests that it’s had to invest energy and carbon in building pelleting plants, in upgrading the harbour where the ships go from, I don't know if it had to buy any new ships but it certainly had to buy new trains to bring the stuff from the U.K. ports to the power station and it's had to build massive great storage because you have to have specialised storage for wood chip. So is bio fuel the future or is it a big con?
HEYES: I wouldn't say it's a big con, I think as you rightly said it, a cursory examination of burning wood to generate electricity implies that it is potentially carbon neutral because carbon is extracted from the atmosphere in the process of trees growing and then released again as you combust the wood to generate electricity. But of course it's not entirely carbon neutral for exactly the reasons that you mentioned. Without having to give precise figures, I'm fairly sure that it emits less carbon than burning coal does and it's closer to sustainable.. well yeah and of course that will require a detailed calculation of how much carbon you're emitting by getting it from the place where it is, where it is actually growing to the place where you consume it and in the right form to be consumed. And you know that calculation needs to be done and if it is not actually reducing CO2 emissions then that seems to be a rather wasted effort but that doesn't, so co-firing wood in power stations as a replacement for coal may give you some advantages in terms of CO2 emissions, it does not feel to me like the long term solution.
SFR: That's one sort of biofuel of course, that is biomass but we can make a diesel substitute or even possibly a petrol substitute or in fact we can make gas from organic materials. Is there more of a future there?
HEYES: I think so, yeah, but you know and there are new technologies coming along, biomass developed from Algae as a third generation biofuel is one example of a technology that probably isn't at commercial scales yet but it looks as though it holds a lot of promise, but you're right we can make transport fuels from biomass and that feels like it like a sensible way to go and you mentioned diesel and petrol but you didn't mention kerosene and I would that aviation is potentially a good use of bio based liquid fuels, because in you know if you have a car, arguably you can use a battery and an electric motor but you can't do that in aircraft because of the energy density that you need. The aircraft is very weight sensitive, you can't easily put batteries on aircraft and liquid fuels have got an enormous amount of energy per unit mass so very difficult to replace liquid fuels in aviation but if we could move to bio based aviation fuel, that might be at least part of the solution for decarbonising the aviation industry and that's important because aviation is growing and growing rapidly.
SFR: So, bio kerosene would have a similar sort of energy density to traditional kerosene.
HEYES: It's chemically identical to it and it has been burnt in you know in aircraft engines already. Bio based kerosene is chemically perfect, it's been constructed in a chemical plant and whereas natural kerosene has a variety of different components in it and actually you have to manage that process, some of the some of those additional components are necessary for the reliable operation of the engine, so actually making chemically perfect aviation fuel is not necessarily quite what you want but you want you want that blend of fractions, a blend of components that works effectively in aircraft engines but that's not an insurmountable challenge.
SFR: Right, so from a sustainable energy point of view, we've got quite a wide range of options.
SFR: The question I think is whether the politicians who control all this are aware of it and are actually working on the right track to keep the lights on. Do you think we're going to keep the lights on in the U.K. in the next few years?
SFR: Is that because it's getting warmer and having milder winters?
HEYES: No, it's because I think National Grid do a good job of managing the system, been doing so for a very long time.
SFR: I think they deserve immense respect because it is a very, very complex task.
HEYES: It absolutely is and it is getting more and more complex as time goes by as different renewables come out on to the scene and the capacity margin gets really, really small and a little bit scary in the winters but again that is very carefully managed in a very, and it's understood and yes arguably the risk goes up when you, as more renewable come on the system but I think the risk is well managed. And we spoke earlier about industry that is prepared to disconnect from the system, so there are backups in place, so before the lights went out in your home, various industry consumers would already have switched off, so there are a number of ways, number of tools in the toolbox for managing the electricity system and I think, I'd like to think, I think, I do think we can rely on the National Grid to do that.
SFR: Andy that's been a very fascinating review of energy issues. I think we could go on for hours but thank you very much for your time and maybe in a year or two we'll come back and we'll see how things have moved on.
HEYES: Indeed, my pleasure, thanks very much.
SFR: Thank you.
Lots to think about, especially when technology is constantly changing the rules.
Lots to think about in the wider sustainability context. I’m already looking into the Great Barrier Reef, combustible ice and automated ships. That’s all for next time. Who knows what else will have happened by then?
Have a great week and don't forget if you need a conference chair, a host for your awards night or a keynote speaker for your event I still have a few dates free in the diary. Get in touch.
I’m Anthony Day. Until next time.
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