Low C energy transition: electrochemical technology | Energy and Environment Webinar Series

hello everyone and welcome to our third um webinar series we have today the pleasure of having professional professor nigel brandon from imperial college london who will be talking about the role of electrochemical technology in the low energy transition uh just to tell you a bit about professor nigel er brandon and his research is focused on electrochemical devices for low carbon and energy applications with a particular focus on fuel cells electrolyzers and batteries he is the directors of uk hydrogen and fuel cells supergen hub and the chair of imperial sustainable gas institute and he's the founder also of a few spin-offs amongst them the serious power and also the rfc power and so with no more delay i'm i'm sure that everyone will be looking forward to hear and his talk so whenever you are ready nigel the floor is yeah thanks for the kind introduction let me just go through the customary slide sharing exercise you can see the slides okay great okay well look thanks for the kind introduction and it's a pleasure to be here it's it's a pity we have to as we were just saying off-camera it was a pity we have to still do this remotely given how close we are between imperial college and university college london but anyway it's a still a pleasure to be here um yeah i'm going to give a relatively high level uh presentation today about the role of electrochemical technology in uh the transition to a low-carbon future um i'll touch at the start about why why do we need electrochemical technologies or where might they be used in a fairly general way i'm going to focus on three of the uh quite numerous electrochemical technologies uh that's fuel cells electrolyzers and flow batteries i'm not talking about lithium-ion batteries or a family of technologies around that in terms of my presentation i'm focusing on the three kind of topic areas where i mainly work but obviously happy to take any questions on that as best i can um and then and then think about some of the application areas really so green hydrogen from electrolysis hydrogen fuel cells for transport applications fuel cell combined heat and power energy storage for system balancing and the role of hydrogen in green hydrogen in industrial decarbonization so something of a move through the different areas and then happy of course to take questions at the end of the presentation um i i use this slide a lot and i'm very grateful to grant wilson at the university of birmingham and his colleagues and his team who provide it and it's i think it's a useful slide to start a talk about energy in general and this is a flow of energy through the uk energy system um in gigawatt hours per day on the vertical axis against time and it shows the the the to some extent the scale of the challenge the red line at the bottom is the flow of energy is electricity and actually it's by far and away the smallest size of energy flow through the system it's also the area where we've made the greatest progress in decarbonisation and of course going forward the thinking is how can we make how can we use electricity more decarbonized electricity more to decarbonize other parts of the economy than than we than we currently use it for so a case in point would be this uh horizontal line here which is the supply of uh liquid fuels essentially gasoline and diesel for transport applications you can see effectively flat except for the recent interesting fall in demand associated with the covid lockdown um but otherwise essentially flat and of course there's interest in taking electrons generated renewably and using those directly in a battery electric car or as we'll talk about today perhaps making green hydrogen and using that in a fuel cell electric car but again just to give a sense of the scale of the challenge this is about 1600 gigawatt hours at least pre-covered we'll see where it recovers to in the fullness of time um and a fuel cell or battery electric car is going to be sometimes somewhere between two and four times more efficient than that so you'll need somewhere between another 800 or 400 gigawatt hours of generation so somewhere between 50 and a hundred percent of the current capacity if we then look at the blue line and this is the flow of natural gas through the energy system um not significantly impacted by covid actually if you look at the peaks here because we we use a lot of natural gas for heating uh so in the winter season with probably more of us resident at home perhaps we've used slightly more rather than slightly less contrast to the liquid fuels and this seasonality between the summer low demand and the winter peak demand is a big challenge for how we try and decarbonize this natural gas supply it's certainly the case that we can't continue to use unabated natural gas in a zero or very low carbon energy system and so there's a real challenge about what we do about that for heat applications for example obviously gas is also used as a power generator and a feedstock for certain chemical processes but if we talk about heat for a moment and we think well how do we replace natural gas if we wanted to entirely replace natural gas use with electric heat pumps for example and let's say our electric heat pump has a coefficient of performance of four which is quite generous in a uk context um nonetheless this kind of four thousand gigawatt hours peak here would become a thousand gigawatt hours and again it would it would double the size of the peaks of this electricity flow up to here so we'd get very big seasonal variations in our electricity demand and that gets quite tricky to build and quite tricky to manage and rather expensive so the question is across all of this landscape where do electrochemical technologies play a role and i think what i'm going to hopefully show you is that they have the potential to play a role in all aspects of our decarbonisation journey of course it's not only about carbon it's also about other emissions and um these are the nox emissions it's a little bit old now but it also talks it shows you the nox emissions in london where the dark the bright reds are higher levels of nox emissions and you can see that they're associated with the main arterial roads so mainly associated with with fossil based road internal combustion engine road transport and this is heathrow out here back in the day when people used to fly on airplanes so hydrogen is is a carrier that's um i'm going to talk about quite a bit uh it's it's a carrier that can work alongside low carbon electricity um and indeed we can think about how we make hydrogen from low carbon electricity by electrolysis and i shall talk a bit about that we can also make low lower carbon hydrogen from fossil reserves or indeed biomass based reserves through steam methane reforming provided recapture the co2 and take that out of the system um through carbon capture and storage or some similar process this produces what's referred to as blue hydrogen so not zero carbon but low carbon hydrogen and we produce green hydrogen so called by renewable electrons through an electrolyzer uh once we've made that hydrogen then that hydrogen could be used to replace natural gas for example so it's a decarbonized molecule that could go in for heat or it could it could go into certain types of transport applications as a transport fuel or it could go into various industrial processes again to replace natural gas or to replace coke in steel making for example so by by making hydrogen in a low-carbon way of which electrochemistry plays in a potentially very important role we can think about this utilization in a variety of applications where again electrochemistry has the potential to play an important role so having given that kind of introductory comment let's talk about um some of the specific where where the field is today uh for those that are perhaps less familiar with with it and there is the old adage if you work in fuel cells and indeed hydrogen fuel cells are almost 40 years away and always will be well that's changed and um industry ships something like one and a half gigawatts of fuel cells last year um actually all the sales so there is a change in uh in pace here um i want to talk about some green hydrogen to start with though and talk about electrolysis and this is a subject of increasing interest to policy makers they've really latched on to the opportunities around green hydrogen and there are different flavors and types of electrolyzers alkaline electrolyzes being the most commercially mature uh and widely available at 100 megawatt sized unit about 65 percent efficient um quite big large footprint pieces of equipment and not very good at load following but a very good base load generator and a very mature technology that we've had for over 100 years perm electrolyzes a new technology uh relatively speaking now coming through increasingly through commercialization and available at the kind of megawatts ish level again about 65 or so percent efficient today uses quite a lot of precious metals and so there is an open question a little bit around the supply of platinum and iridium and also titanium um for this type of technology but um produces hydrogen flexibly under pressure which is useful for things like vehicle refueling in particular and then a technology i'm particularly interested in which is solid oxide electrolysis this electrolyzes steam and to hydrogen and because of its high temperature of operation gives you an electrical efficiency that's much higher than the low temperature process it's about 90 percent efficient um uh and again and the efficiency can be higher than that if you have low if you have waste heat available to heat to meet the heat of vaporization of water and raise steam and this this paper here which i've taken this graph from is a useful summary for anyone that's interested in the field and paints a picture of current density which is effectively the rate at which you produce hydrogen from a reactor so the higher the current density the higher the power output and so the at least in principle the lower the capital cost and efficiency up here we see the picture for alkaline pem and solid oxide painting a landscape across the uh across the picture here and there's been some useful work uh to look at the cost implications of of green hydrogen and i think one of the things that we should be very clear about at the start is that green hydrogen hydrogen by electrolysis from renewables is currently by far and away the most expensive way to make hydrogen it's more expensive than blue hydrogen from carbon capture and storage and fossil and that in turn is more expensive than unabated hydrogen so hydrogen made by steam reforming natural gas which is how we make hydrogen technologically today in fact 96 you know much of the world's hydrogen is made so 96 of the world's hydrogen today is made from fossil fuels and is made for the chemical sector in particular in petrochems but this irena report paints i think a good picture of the potential for cost down of green hydrogen and the critical factor here is the cost of the electricity that's going into the electrolyzer 60 to 80 percent of the cost of green hydrogen is the cost of the electricity and if we start to consider green hydrogen electrolysis taking place in countries with low cost renewals that makes a huge difference to the cost of that green hydrogen it's one of the reasons why the world's largest green hydrogen project today is in saudi arabia taking low-cost solar and wind into green hydrogen and then in turn actually into green ammonia for export to europe but as well as the cost of the electricity there is also room for improvement in the actual electrolyzer and so the electrolyzer efficiency does play an important role also because it defines how much of that expensive electricity you need to use but there are trajectories now for getting green hydrogen costs down to around a dollar per kilogram and at that point you're competing directly with fossil based hydrogen i'm not really talking about my research today i'm happy to take questions on it but just to pay for those who are interested in the more uh sort of underpinning aspects my group spends a lot of time thinking about the materials for these sorts of devices and how you engineer cells and stacks utilizing them and this is an example of one of my recent phd uh students and now in the postdoc with us mong zhang yueng who did some work on electro spun the application of electric spinning to make some interesting fiber-based materials and some fiber structures which we think give us some performance advantages in high temperature electrolysis and electron fuel cells and much as i know there's huge amounts of work at ucl also in these sorts of areas um particularly in in the groups of poor shearing and danbred in in chemical engineering and we touch base with them regularly so we're very interested in these types of materials innovations and its relevance to this field so moving then on to um from electrolysis to make hydrogen and what can you do with the hydrogen and particularly now looking at transport applications and the application of hydrogen in fuel cells and and whilst fuel cells can run on fuels that are not hydrogen they work very well on hydrogen and so there's been a strong coupling for many years between the generation of hydrogen and its conversion back into electricity in a fuel cell um you know the fuel cell 101 slide says that there are broadly speaking and today really mainly two types of fuel cells there are actually a range of other types but these are the two main types of commercial uh interest today um the pop the proton exchange or polymer electrolyte membrane fuel cell the pen this is the type of fuel cell that we will find in the majority of our fuel cell cars trucks and buses that i'm going to show you pictures of in a fuel cell we put fuel on one side shown here as hydrogen we put our oxidant on the other side normally air and we have a membrane separating the two with two electrodes that are catalytic for the electrochemical reactions that need to take place in a low temperature fuel cell this uses platinum group metal catalysts which are needed to be stable in the chemical environment and sufficiently active to drive the reactions at the right rate um we oxidize our our hydrogen forming protons those protons pass across the membrane that's selective to proton transport where they combine with oxygen and the electrons pass around an external circuit when the device is connected across a load generating current and a voltage is generated based on the thermodynamic driving force for the reaction and typically an open circuit where no currents being drawn that's about one volt but it falls down to perhaps 0.7 or 0.65 volts as we as we draw current and that and that gives us power and that's the we directly generate dc power but we do so very efficiently and so it's the most efficient way of turning a chemical fuel into power that we can consider and typically even at a kilowatt or so in size these devices are 60 to 65 percent efficient there are another type of fuel cell i will also mention that that's the type on the left here this is the solid oxide fuel cell same principles but now our ionic conductor is a ceramic which conducts oxide ions and at when it's at elevated temperature somewhere between 500 and 900 c depending on the material so now we form our reaction product which is water on the fuel side but overall reaction chemistry and principles remain the same but this is a high temperature device and is much more able to operate from a wider range of fuels the low temperature type requires high purity hydrogen because otherwise the platinum metal catalysts get poisoned the high temperature variant does not and indeed can use carbon monoxide for example as a feedstock as well as hydrogen okay so let's look at where things are technologically this is the hydrogen fuel cell mirai that we have at imperial i think you have hydrogen fuel cell mariah ucl as well um courtesy of toyota uh and and that's a really good example of the type of hydrogen fuel cell car that's uh available uh that toyota bringing out the latest mirai this year which has which is still relatively expensive at about 50 000 pounds and goes further at 400 miles but it's you know it's an impressive piece of technology uh hyundai's fuel cell nexo is also very well regarded as an example in the field and these cars are nice to drive i have had the pleasure of driving them of course the challenge is where can you refuel them and even in london where we have almost the highest concentration of hydrogen refueling stations in the uk um then we still don't have that many um so there is a sort of circularity as always between the refueling infrastructure and the vehicle infrastructure and then that still remains it's fair to say a kind of working progress i think if we move right away from light duty vehicles where i think it's a it's a tougher cell actually against battery electric but we move into larger vehicles like buses it's much clearer i think in my mind that hydrogen fuel cell electric solutions are going to win um the top picture here shows a uk uh initiative this is uh a uk built hydrogen fuel cell double decker bus built by opt and arcola energy arcola are a london-based uh fuel cell uh company that um work with both imperial and ucl um a really interesting little company doing some great work um and when we come up to buses with the high end higher energy requirements the fact that they can be refueled at a single place they don't need a widespread hydrogen infrastructure they meet a public good a societal benefit in terms of low low better air quality um i think the economics and the motivations here are are easier than for consumer vehicles alone and indeed there are ambitious fuels hydrogen fuel cell electric bus programs around the world particularly in asia and the us i think the other really interesting opportunities on on trucks um battery electric trucks uh once you come to long distance vehicles or very heavy duty vehicles with high energy requirements delivering that entirely with batteries starts to get quite difficult this is the hyundai hydrogen fuel cell truck this is the jcb hydrogen powered excavator again really interesting opportunity areas to consider hydrogen linked with a fuel cell as the prime mover for those vehicles and it's interesting to see moves by companies like bosch into um hydrogen fuel cell power trains with the focus on this application area another area that i've been working in this area a long time but you know we hadn't i certainly hadn't seen coming perhaps you know a number of years ago is hydrogen fuel cell electric trains um so this the interest here is to replace diesel uh and to replace it with hydrogen on train lines that are not don't warrant full electrification because of the capital cost um germany and austria have led the way here with with um alstom's hydrogen fuel cell trains now taking fair paying passengers for several years and clocking up many thousands of kilometers in service um the breeze here has just come over to the uk this is a variant effectively of this um alstom technology but customized for the uk market we need to my understanding at least is that we now need to put the hydrogen storage under the under the train rather than top of it because our bridges are not as high um so it's an adaptation of this technology to to meet the uk market and this is hydroflex this is testing uh collaboration with university birmingham testing in the uk at the moment oops yeah okay so so the landscape on on transport is interesting i haven't spoken about air i haven't spoken about shipping but all of those are relevant and happy to take questions on it i want to move on to kind of stationary heating power now and the role of fuel cells in that um fed on hydrogen or indeed fed on other fuels um the introduction mentioned our sustainable gas institute at imperial college and if anyone's interested in this space you're very welcome to go and look at the white papers we've produced and this is uh one from a few years ago now looking at the options for decarbonizing the gas grid essentially with biogas or hydrogen and this whilst it may be tricky to read i don't know this slide on the left highlights the scale of the challenge for the uk so this is different countries here and the the axis along the top is the percentage of households connected to the natural gas network and you can see that the uk's uh the second highest number of our buildings are connected to the natural gas network for heat particularly heat but also in cases some cases for cooking uh at 85 percent the next higher the higher the only higher one is the netherlands just the other side of the uh of the uh north sea there with a 95 and not surprisingly these are all countries that have optimized for the availability of north sea gas and and built in infrastructure around that but we've made it clear already we can't continue to do that we have to decarbonize that that energy supply either by replacing it with decarbonized electricity all by decarbonizing the gas and that's one of the opportunities of interest around hydrogen asia i think has been focusing on some of these challenges for a long time this is a program in japan the so-called japanese any farm program in which 300 000 customers probably more than that now have purchased a fuel cell micro combined heat and power units so a micro combined heat and power unit is a unit that generates power within the home and captures heat locally and uses that heat within the home and japanese homes use a lot of heat so they have a very high heat power ratio in this particular vision here is there's a fuel cell in fact they show here operating on natural gas and that's true it will work very well and natural gas or lpg and in the future of course could work on hydrogen perfectly well and and that's coupled then with renewable generation to top up the electrical demand so that's a kind of japanese vision of the technology space um and if you'll bear with me we we set a company up um a long time ago now in 2000 to try and innovate in this space it was called series power it was mentioned in the introduction um and we filed a patent based at the time of um some an epsrc project and this was the epsrc project that we had um back in the days before full economic costs and 260 000 pounds went a long way um but uh it funded a postdoc for three years uh doctor in the aikido issue did a fantastic job for us and um this uh uh allowed we'd filed a patent and we were like we the grant gave us the opportunity to develop that further and um indeed 20 odd years later that's what's happened and many people at the company have taken put in many hours of effort to advance the technology forward this is public information uh from uh sarah's publications looking at what materials they use and in this case you can see the technology relies on the porous steel support coated with a particular anode composition and then an electrolyte which is the oxygen ion selective material and then a cathode material that is not disclosed and in fact for those who are interested in the details of these things the electrolyte itself actually contains an electron blocking layer uh because otherwise you get too much short circuiting current through the mix otherwise mix conducting electrolyte um but the use of the the the steel support is really important it gives significant durability it allows you for example to have simple uh joining with gaskets and simple joining with welding this is a picture of the cell without the cathode layer on top of it and it gives you a very robust technology and this is a sort of kilowatt stack built out of series cells and this is the pilot uh fabrication line at the company's facilities in horsham to the south of london and if anyone's interested they did feature in a robert lewellen fully charged video available on the internet with the manufacturing line being shown so this is a technology this is a solid oxide fuel cell technology the company are looking at trying to also develop a solid oxide electrolyzer variant but in solid oxide fuel cell mode um bosch are taking that invested in the business and helping develop develop the manufacturing which of course is really important in all of these areas how do you get a volume manufacturer which i are a big a very large company in china and are working with series to put this technology in as a range extender into electric buses in china doosan of course a very well known uh south korean industrial conglomerate working with them on shipping applications and miura they are actually selling a product in japan you can buy a 4.2 kilowatt fuel cell chp unit in japan uh for sorry a fuel cell generator unit in japan with the series uh stack inside it so very interesting to see these products starting to get over the line 20 years after the research grant that started it all off um so i want to move away from fuel cells now and talk a little bit about energy storage and the role of electrochemical technologies in energy storage i'm not going to talk about battery electric vehicles unless you've got questions for it because i think there's a lot of work already in that space i'm really going to talk about grid energy balancing rather than batteries for electric vehicles um and the first slide really picks up some of the challenges that we that was highlighted in that opening slide i gave about energy flows through the uk energy system as we put if we if we want to use decarbonized electricity to decarbonize other parts of the sector we need to put in a lot more capacity and it needs to primarily be renewable capacity um and this is some work really led by my colleague laurence trebek imperial college and it's published in this paper that we we we put out in progress in energy recently on the value of flexibility and what it says is if we put in more and more wind capacity into the uk if we don't manage that system differently we need to have increasing amounts of curtailment of that wind as we install more wind so it becomes increasingly expensive as we put more wind on the system and then don't use it for more of the time unless we try and think about how we do things differently and that's what this slide is really about it's basically saying if we continue to input more and more electrical renewable generation in to meet the growing requirement for that power to decarbonize other parts of the economy but we don't think about using it differently the asset utilization will go down and down and down so we're going to spend a lot of money on building kit when we're going to use it less of the time and that is you know is an expensive way of addressing the situation the question is what can you do with flexibility to time shift effectively or even spatially shift the demand and production side of um of our power system and what value does that give and in others what are the value of technologies that deliver flexibility to the system now energy storage is one such technology um it's not the only option uh greater interconnection to other parts of europe uh is an option and looking at demand side uh regulation is another option but here we're talking about the use of energy storage and its potential and there are some interesting parallel studies to take into account um in elsewhere in the world and this particular piece of work comes from california um california will have very high is going to it has an amp has a target to be a zero carbon electricity system by 2045 it will pro it will do that with extensive use of solar photovoltaics and this is a piece of analysis that's available you can look up the report which makes the prediction that the biggest demand for energy storage in california will be diurnal energy storage so that's balancing the supply of energy at night from the supply of energy harvested in the day and that requires energy storage technologies of about they give you about 10 hours of energy storage and that's worth the worth remembering because most of the energy storage technologies for grid storage that we're developing today our lithium-ion based solutions building off the back of the great work that's taking place on lithium-ion batteries for electric vehicles and for one or two hours of storage that technology works very well it's not so clear it's the right answer for 10 hours of storage because you need to 10 times more batteries than you need for one hour and therefore you need 10 times the cost so the question is are the technologies that offer that are scaling differently and the answer is yes they're called flow batteries and um and and other technologies like compressed air energy storage or liquid air energy storage also decouple as we describe it power and energy and this is the theme of our uh also work we've been doing for some years now this is also been spun out into a company the company is called rfc power whereas serious power is a well-established business now with a market cap of about two billion pounds at the moment uh rfc power is a much more nascent company with six employees based at imperial college's innovation campus in um in white city in west london the idea of a flow battery be this technology or any other flow battery approach is that we have a power unit in the center um which when we want to charge our battery works like an electrolyzer we put electricity in and we produce an oxidized and reduced form of a redox couple and then we store those oxidized and reduced forms of the redox couple in tanks and if we want more energy we simply have a bigger tank and this means that the power is defined by the stack in the middle and the energy by the size of the tank and if we want to go for example for 10 times the energy storage relatively speaking that is a much smaller increase in cost than just having 10 times as many batteries and so this type of technology tends to win out economically as the energy duration starts to go up now in in rfc's powers case we've taken an approach to the chemistry which is very different conventionally most flow batteries use a vanadium redux couple so they have a liquid redux coupled in one tank and a liquid redux couple in the other tank vanadium can sit in four oxidation states so you can have vanadium two three on one side and vanadium four five on the other to give you the different redox couples in the case of rfc power we've developed a solution which uses manganese in the one redox couple and hydrogen in a closed loop in the other redox couple why have we done this well manganese is a much much lower cost material than vanadium vanadium is actually rather expensive and very volatile its price tends to be spin pinned to the price of steel where it's used in steel making and most of the wealth supply is controlled by china and russia manganese is the fourth most used metal after iron copper and aluminium and is much more abundant and available from a wider range of geographies shall we say um hydrogen in closed loop gives us high power density because it's a fast reaction so the combination here can give it replaces the much slower vanadium equivalent reaction of the vanadium 2 3 which is quite a slow reaction so we end up with a faster reaction kinetics on the hydrogen side and a much lower cost electrolyte on the manganese side so combined we believe this gives us a number of significant benefits over current approaches um i have to stress this is a collaboration with my colleague professor anthony kusunak in the chemistry department uh and anthony of course is well known to colleagues at ucl as well because they have a strong collaboration um with the team here at in the electrochemical innovation lab on fuel cells but anthony and i along with two postdocs develop this javier rubio garcia and vladimir yufit sort of patented this technology and they're taking and he's now being taken forward by rfc power um and the chemistry is is here it shows the manganese couple on the cathode side and a hydrogen couple on the anode side so in charge mode we produce hydrogen like an electrolyzer and we um on the one electrode on the other electrode we oxidize manganese two to manganese three and then when we want to discharge it we flow those back into the stack and the magnesium three goes to manganese two and the hydrogen acts in the fuel cell mode now as the reductant um that all looks jolly good and it is um but it's only possible because of some nice work in the department of chemistry by anthony's group finding a way of stabilizing this manganese couple because otherwise it disproportionates and forms manganese dioxide and so the innovation here is not only the concept and all we've patented all different liquid gas configurations here but also the the means by which we stabilize this solution and this is somewhat we published on this in the open literature showing that we can get very high power densities in a laboratory environment using this couple so this is the vision for the company uh the lowest cost form of long-duration energy storage um for uh typically you know more than four hours eight ten twelve hours of energy storage using this hydrogen manganese approach which gives us good round trip efficiency over eighty percent uh can discharge down to a hundred percent from the hundred percent state of charge to naught state of charge and therefore a low level is cost of storage and it's also a technology that segues nicely into the hydrogen economy because you could link the hydrogen side into a hydrogen system and provide a round trip efficiency of 80 for energy storage where a electrolyzer fuel cell combination would never be more than 60 and i'm grateful to rfc providing them some data this is some data from some of the test cells work that's going on at the moment and i don't know if you can read it but this shows you over 700 full charge discharge cycles without any drop in efficiency a little bit of capacity drop after 720 cycles because of an instrument issue but that we have a patented electrolyte regeneration process that recovered that back to full capacity and these are rfc powers i own cost projections um and the blue line here shows how the flow the cost of this system in terms of dollars per kilowatt hour installed falls as the storage duration goes up and this reflects this balance between tank size and stack cost um in contrast your lithium ion cost or indeed the cost of any conventional secondary battery uh is flat as the storage duration goes up because you simply need more of them um the line you draw here depends on your vision for future lithium-ion battery costs this is shown at 150 dollars a kilowatt hour on this particular graph but you can pick your line depending where you think the future is um certainly at the moment we get below a hundred dollars a kilowatt hour ten hours of storage with the flow battery technology and down to below 50 sorry down below fifty dollars a kilowatt hour for us over 24 hours of storage which is very cost competitive okay i want to move a little bit away from the few hours of storage to the few weeks of storage um and i think if we start to think about um the uk system so for solar it's more about diurnal storage but for wind which of course will be an important renewable source in the uk it's more about those periods in the winter when the wind does not blow and we may have multiple weeks with low wind generation and how will we going to address that as a system level um again in this paper on the value of flexibility we touch on this and this is a calculation from my again my colleague goran strabak's team looking at the level of hydrogen reserve you'd need to deal with a low wind period so if you're saying well we're going to have a strategic gas reserve to deal with a period of low wind and we're going to have it as hydrogen how many what how much hydrogen does that mean and indeed if it's not hydrogen in general how many how many terawatt hours do we need to store and as a function of the number of weeks with low wind you can see say for two weeks of low wind we need approaching 20 terawatt hours of storage for one week about 10. what does that look like well this is a photograph of the de norweg pumped hydro station in wales in snowdonia national park if anyone's had the chance to visit it's well worth a visit and not open at the moment of course um and this uh is a pumped hydra facility in which a very large amount about a million cubic meters of rock were excavated from this mountain because it's in a national park and a pumped hydro facility built this gives you 9.1 gigawatt hours of

storage 9.1 gigahertz okay so if we need uh if we go back to this slide here and we need 10 terawatt hours we need a thousand of these uh if we need 20 terahertz we need 2 000 of these so it gets very hard to envisage a system in which we deliver that level of strategic reserve without storing our energy and chemical molecules like hydrogen um does that sound far-fetched well no because we already store natural gas in salt in caverns under the ground and typically in solution-lined caverns and salt reserves and indeed we store hydrogen that way in places where we want to provide a strategic reserve of hydrogen for the for the local petrochemical industry so it can certainly be done of course we don't normally do it for this reason um but it's certainly technologically uh capable um and this i think is a very useful report it came out from um in the international journal of hydrogen energy and it's actually a german-led assessment of the technical potential for salt cavern storage for hydrogen in europe and the different lines here obviously for different countries show the amount of cabinet storage capacity in terawatt hours uh either near shore onshore or near shore in in the uh sorry uh onshore in the um uh like line here or on nearshore in the hash line here bearing in mind we need what was it about um 10 uh uh sorry yes let's just remind myself here my own self yeah about about 10 terawatt hours in the uk um you can see the uk is where are we here but here we are so we've got then and this is a hundred terawatt house so we've got loads of capacity and so have most other countries in europe if that's what we chose to do and my final slide is because i'm about right on time my final slide is about industrial decarbonization and the role of hydrogen in that and again it has to be stressed here that this has to be either green hydrogen or blue hydrogen it has to be low carbon hydrogen um and there are two big opportunities in particular i think that we can think about one is about ammonia synthesis ammonia production accounts for just about 1.4 percent of global co2 emissions of which the biggest contributor to that is hydrogen production from fossil fuels coal or natural gas and so that is uh a big factor about six percent of the world's natural gas is used to make hydrogen today for for ammonia synthesis and other petrochemical uh processes so we could replace that with uh with green hydrogen directly and and mitigate that level of global emissions um there are also other thoughts and other more novel concepts around the system configuration which would also give other advantages this is the large project i've mentioned in saudi arabia already i think the other big opportunities around steel making steel produces about just under three gigatons of co2 per year and if it's not changed alone will use 50 of the world's carbon budget by 2050 and this is clearly not a viable outcome of course most steel is made in a blast furnace using coking coal coking coke as the source of heat and the reducing agent um steel is made from direct uh iron reduction in some parts of the world using natural gas but again a fossil based approach um the opportunity here is really to replace that natural gas-based direct iron reduction process with hydrogen as the direct eye reduction process a little cartoon of the flow sheets that's shown here but let's not underestimate the scale of the challenge here that would make all blast furnaces obsolete all require carbon capture and storage to be put on the back end of blast furnaces for steel making but it's clearly a gives a sense of the scale of the decarbonization challenge so my concluding slides i given a bit of a whistle stop tour but i hope i've shown you is that electrochemical technologies offer high efficient and flexible means to segue and convert between electrons and molecules and as we move to our future low carbon system that ability to flexibly move between electrons and molecules is likely to be increasingly important all electrochemical technologies are underpinned by materials science and engineering and for those of us interested in high temperature devices the mechanical engineering of those is extremely important as well the thermal management and we have to be able to make things a volume that's important too i've focused on electrolysis i've talked about fuel cells for transport and heat and power and the use of hydrogen for system balancing and decarbonization these are all important topics and at the forefront of policymakers minds at the moment the uk does have a great science base in this field including really excellent work at ucl we like to think we contributed imperial as well but we've got a great base in the uk and some great companies as well so we're well placed to take it forward i'll close with leaving some links on the page here to the electrochemical science and engineering work at imperial if you're interested in the research the hydrogen and fuel cell supergen hub which is the national program for hydrogen and fuel cell academic research professor paul dodson ucl is the lead on energy systems for example within that hub like the sustainable gas institute imperial and our broader energy program so i'll leave it there thank you very much thank you very much and nigel it has been an extremely informative and presentation touching from different aspects and we have a few questions from our audience and so the first one is from helen chersky she was mentioning that she's interested in the slide about your research and that mentions a nickel as an important component and saying that there are already big discussions about how to source um metals for batteries in an identified world and shortages of nickel are forecasted and yeah i don't need it is there any fault um to avoid the metals that are likely to be needed for that yeah i mean it's a very good point and and nickel nickel is used because it's electrochemically active sufficiently electrochemically active adequately low cost and um uh and and and adequately electronically conducting so those those are the characteristics and it's active for steam reforming uh which for this type of solid oxide approach um if you're not putting in hydrogen you're putting in a say methane you can actually drive that methane reaction to acetate to syn gas using the nickel because nickel catalysts are used to drive that steam reforming reaction um it would be nice to replace nickel for several reasons one it's not without its problems it's when you're processing nickel powder it's a carcinogen so there's a ha there's a health hazard you have to pay attention to on the manufacturing process um it isn't the cheapest material either right so obviously there is a cost benefit in replacing it with something lower cost it's not impervious to damage so if there are sulfur in the fuel which the can be with some bio gases for example um then it can be poisoned by that sulfur species you have to take care to remove it also some it has a propensity to trigger carbon formation so some carbonaceous fuels um can result in carbon formation so it's not without its problems there are interests in replacing it with some oxide type materials like titanates and um they'll have some advantages in terms of their oxidation resistance their failure modes they're not as conducting but um you know nonetheless they're looking attractive it's people have tried to replace it with copper but copper's not really very electrochemically active so it's uh it's it still remains the industry standard at the moment um there's been quite a lot of work because of its because it's not a perfect material there has been quite a lot of work to think about replacing it but as yet none of the sof none of the solid oxide development companies have found a replacement they're happy to live with so they still work in progress there and she had also a follow-up question is how do you see the law following performance of the state-of-the-art vm efficiencies when the loads are highly dynamic in transportation applications yeah so the the most commonly used technology fuel cell technology in transport is is this is the pen right so this this runs at about 80 to 100 degrees c ish so it's relatively low temperature it's extremely fast responding so i i can give my answer in two ways one is all electrochemical technologies have very fast electrical response so they will electrochemically respond very quickly the high temperature technologies then also have a thermal response which is a slower response so you have a very fast electrochemical response so the instantaneous voltage change for example will be very quick the thermal transient on a high temperature fuel cell will take you minutes but you it's much less of a concern the thermal transient on the pem is much less of an issue so you get very fast load following on a pen and no problem no problem at all for example meeting the uh the duty cycle for a transport application also to be clear in in a transport application it's really a polymer fuel cell battery hybrid they all have batteries in there as well and that makes sense because you you can't capture regen braking in a fuel cell you need a battery to capture regen braking and the battery can also help you with really fast transients you know if you really wanted to give a as much as it does is in an ice battery hybrid so you can get a battery fuel cell boost if you want to go for maximum power output for example so it's it's it's very similar to an ic battery hybrid in that respect except that it's a pen an electrochemical engine rather than an internal combustion engine okay thank you for that and for we have also another question er pengu would you like to to ask the question sure can hear me yep yes we can hear you thank you very much for the very informative talk professor brendan so i have two questions the first question is about the uh the uh the imperial toyota car cars cars powertrain do you have any uh battery or supercapacitor in the system for the load leveling or transit i mean so so yeah obviously it's toyota's car right so it's a toyota toyota technology not um so just to be clear it's a toyota mirai it's made by toyota um it's it's it's it's the same powertrain as a prius but with the internal combustion engine replaced with the fuel cell so it has a nickel metal it has this it has the same nickel metal hydride battery in it in this particular version has the old old old tile nickel metal hydride battery you find in the original prius so so toyota have deliberately gone with a relatively low technology risk approach which makes a lot of sense they've tried to just leave the technology risk around the fuel cell and the hydrogen storage system and use a well tried and tested nickel metal hydride battery so it's it's got the same battery configuration as a prius okay thank you very much if i may i have another question the second question would be about the salt oxide fuel cells as i can see the energy power density for the salt oxide fuel cells is is much lower compared to the panfield cells actually the power density is quite important for transportation applications because we have very limited space and weight margins for the system so the question is for the for the solid oxide fuel cell in terms of the power density uh how much potential you can see for the improvements for solid exercise yeah i mean you're absolutely right i mean pems are up to about five or six kilowatts a liter now which is you know getting to be quite power dense solid oxide fuel cells are not they're perhaps around a kilowatt per liter um i think you'll never get the same power density of a pem as you can as with the solid oxide the power the current densities will be lower uh and you know you will never reach pen levels if that's what matters if that's the critical aspect so i think for um small vehicles yeah they will remain powered i say small light duty you know cars vans things like that certainly motorbikes and bicycles um for larger vehicles i think it's a more open question you can see that which i are putting solid oxide fuel cells on buses however it's not the engine it's an auxiliary power unit on the bus as part of a hybrid system of course solid oxide fuel cells gives you heat as well which can be quite useful uh in cold climates to warm the passengers as well as for other applications once you come into even larger vehicles like trains and ships i think it's it's a much more open question about what the right technology is um because you've got different weight and volume requirements uh so i think for the very largest vehicles it's it's a more it remains an open question but as we go to smaller vehicles i think it's hard to beat a pen thank you very much for for answering the question yeah so in marine applications what i can see is salt oxide fuel cell is mainly used for auxiliary power units just as you mentioned that's right yeah that's right today let's see where things go yeah um i i think there are more opportunities and and let's also be clear there is an opportunity here to have more than one type of fuel cell in a large system right if it's a multi-megawatt configuration it may well be that you will have a difference between a kind of base loaded high temperature device and a more flexible low temperature device and that may that may make a lot of sense and i'm sure of course submit some energy storage integrated in there as well so there are going to be opportunities for hybridization of these electrochemical power sources in the same way that we see in hybridization with um heat engines thank you very much thank you we have another follow-up question from helen and she's asking us these components the electrolyzers and the fuel cells and become more intricate and do they become harder to recycle or is is it straightforward to design them to be easily recycled yeah it's it's a very good question around recycling um so the answer depends a little bit where you sit so so uh platinum group metals are extensively recycled already so pem fuel cells have platinum group metals in them and so do uh pem electrolyzers and there's an extensive um you know the value chain is such that you want to recycle platinum group metals because they're expensive so that that in terms of that metal recovery that's in train um the the other the main components of a pem in terms of mass are going to be the interconnect plates which are metal so obviously you can recuperate those the membrane itself contains fluorine and that's a bit of a nuisance because that produces uh you know you have to be careful if you go to burning for example as part of the process because it's it's a it's a it's a polymer so you know how are you going to extract the carbon and the electrodes are carbon platinum group metals and and this perfluorinated sulfonic acid membrane so you've got to find a way of managing that without worrying too much about the fluorine the high temperature devices are less valuable intrinsically because they've got less valuable materials in them nickel has been mentioned already and there is nickel in there and it would be good to recuperate that um but there are other rare earths on the cathode side that i haven't really spoken about they can contain cobalt which i know you know is a concern you know we're big concern about cobalt in battery materials we should have a concern about cobalt in fuel cells um lanthanum strontium um and and other things like that so they're effectively an oxide ceramic so probably a pyrometrological process but i think it's fair to say that there isn't uh a big focus on recycling the high temperature there isn't an obvious focus on the recycling of the high temperature devices at the moment the majority of the mass again a lot of the mouse is metal and you can recover that and there's well-known processes for that um but it's it's uh it's an absolutely valid and fair question it will be the next step right after well i think you you would quite rightly argue that it ought to be concurrent so there has been some work done on it and there are some processes um but i think not as much as the focus on batteries for example but that that's partly because batteries are putting to are being put into use much more quickly than fuel cells at the moment but as the interest rises and particularly in electrolyzes where the interest is extremely high an entirely valid question le pem electrolyzes contain titanium as well so you'd want to recover these metals they have lots of iridium and platinum and you clearly want to recover that economically let alone uh from a circular economy perspective i have a question myself it's not about recycling but about retrofitting how we see do you think that it would be to retrofit the current gas network to be using the carbonized gas as it would be the hydrogen yes it's a really interesting and important question um uh so we currently uh in uk have been re-like so several answers several types of answer to it firstly can you put hydrogen safely down gas pipelines the answer is you can't you can't just take an existing victorian uh built gas distribution system and put hydrogen in it yeah it's leaky it's very leaky as it's leaky for methane it's really leaky for hydrogen um but we have fortunately been addressing this because it's leaky for methane and we've been realigning that that gas network with polyethylene piping for some years now and polyethylene is it's a plastic piping that goes inside the old victorian um distribution system and that is impervious to hydrogen so that's safe to use with hydrogen there are trials going on to absolutely verify uh things like joint integrity and so on to make certain that uh you know that it's not only safe in the bulk but also the interfaces in the joints i think that's probably an entirely doable situation so i think we can put hydrogen quite safely down the low pressure distribution system that's the pressure lines that go to your house for example um there is a question that when the hydrogen goes into your home if that's what you're using for your heating or then you also need to make certain that your gas fitter is hydrogen trained so there is a there is a qualification piece around all of the gas engineers okay if we then start to look up to the higher pressure distribution system uh it's certainly not my area of expertise but but i do hear some people say they think it'll be fine and other people raise a concern so i think it's a valid question around the ability of the high pressure gas transmission system which runs down the spine of the uk um and how hydrogen able that is and there are people working on that at the moment looking at it far more expertise than i um there are also trials going on from the national from the health and safety lab are involved and others looking at the safety aspect of using hydrogen in homes and in buildings to make certain that their codes and standards are in place the training's in place um there's another asset which isn't uh aspect which is not a safety aspect but that the hydrogen can pick up contamination as it's going down these pipes so whilst it may start off as high purity hydrogen it may not end up as high purity hydrogen and if we're going to put that into a polymer fuel cell then we will be concerned about its impact so there is also work going on thinking about how do we put in uh end of pipe treat you know clean cleaning facilities so if you're going to put hydrogen down a pipe that you've got natural gas down you're likely to pick up all sorts of impurities off the surface that'll desorb off the surface into the hydrogen so there's work going on on that so the safety which is being addressed and um as well as as well as these other concerns but there's a lot of work going on to be able to be comf

2022-09-04 11:02

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