 Guillermo Salatier, Director of International Services at HSI, and I am your host today for Perspectives on Energy. And welcome. Today, we'll be talking about, basically, power systems for the rest of us. It is a second in the series of an intro on power systems and fundamentals, right? And welcome to the show. And I know we had the part one a couple of weeks ago, this would be a part two. So thank you once again. Thank you for joining us. And we'll jump right in. So hopefully this, the whole purpose of these series of this one and then last part one really is to get personnel or viewers that are not in the actual energy industry or in the electric utility industry, more familiar with how these systems operate, specifically to get them a better, a better grasp on how this all works, and to give them an understanding of how the language of vernacular the fundamentals in a power system or the grid or how the electric utility work, how systems work so they can get, be better prepared to whether they're engaging in conversations, dialogue, even policymaking or legislation. So hopefully this is helpful on that. There's again, this is just a very small slice of all the content and knowledge areas. But hopefully this gets people in the right direction and it gives them an idea of how these systems work. And let's go ahead and go to the next slide. So I believe I may have had this earlier on in the previous week, but this is an example of how a system generally works, right? You have a generation station over there on the left in black that had then you have a step of transformer. You have in blue is your transmission system, which is the lines that everybody complains about all the high voltage power lines, typical NIMBY problems that we encounter, not in my backyard. And those are things that are very large, unsightly, they take up a lot of space and a lot of real estate. But you need them. They're a vital part of the grid. You need those to be able to move power from a lot, not just one, but several power plants, interconnect the power plants over to where the load is at. And the load is usually everything on the right, all those different customers, whether they're the residential customers, industrial, commercial, and things along the way. Now, mind you, everything in blue is usually stepped up to high voltage. So in black, we start with the generators and they usually start at a lower voltage because of the five of the ways designed. It's easier to design these systems such that they generate power at a low voltage and they step it up. And then the reason I step it up is because easier to transport power across some vast distances. And you also don't need to build infrastructure so thick. In other words, you're moving a lot of electrons without the need to make the conductor so thick. So it's economies of scale and also makes it a lot more economic. Also the fact that it's easier to manage high voltages than it is to manage high current. Remember current, the equation power is equal to voltage times current. So higher the voltage, the lower the current gets to be, and you get the same amount of power. In a nutshell, I mean, AC circuits have a little bit of differences too compared to DC circuits, but that's basically inheriting the basic concept. There's different levels, 138 kilovolts, 1,000 volts, 130,000 volts, all the way up to 765,000 volts. I very have voltage transmission lines that of course just move across vast distances. And then at some point, when you get to the green portion, you get to stations where they step it down. And the reason they step that voltage down is so they can move that into the different areas more like your neighborhood, right? All the power lines you find that are not that tall, they're sitting either in your backyard and in your streets. And before they go on the ground to feed your residential customers, which is your house, your apartment buildings, your commercial places, your malls, airports, whatever it is, eventually everybody serves from a distribution circuit. And that's why it's written, it's painted in green in this diagram. Now mind you, this is one, this is a single two-dimensional cross-section of the grid. In reality, this is many dimensions deep, right? Because it is a grid and there's many power plants attached to many different layers of that blue stuff, right? Of that blue transmission grid. Now at many different points from that blue transmission grid, you have many points where you have those substations that don't transformers, where you're stepping down from transmission voltage down to distribution voltage. And that's usually anywhere you have the load center, right? And that's why that works. So with that in mind, let's make sure we understand, right, that this is a very vast, big system and it's all interconnected, right? Now in places like Hawaii, right, you're going to have islands, literal islands, but then you also have a lot of electrical islands where each island by itself is its own system with its own little, it's also the generators, it's also the load, and they're not interconnected, you know, like they are, for example, in the mainland where a power station in Florida is electrically connected all the way to through the grid to a power station all the way in like Maine or New York. And all that offers support. Whereas in a smaller island like in Hawaii, any one of the different islands, they're more subject and vulnerable to disturbances. And which is when we'll show that in the next few slides coming up. Next slide, please. So talk about that a little bit. Now we have, of course, the operations. We also have a regulatory environment and we just touched on that briefly the last time, but really it's part of not into generation, transmission and distribution. And in between those, you have transformers where they either step the voltage up and they step it down. And that is in a nutshell how the power grid is basically segmented or divided. Now on the distribution side, you're going to be seeing more and more of the distributed energy resources, which is solar and batteries and everything happening behind the meter for a lot of the customers, right? Residential, commercial, industrial. And that will be a new age in our industry. But it's still developing and I'm curious to see what will happen. Next slide, please. And that's illustrated here, right? We're seeing different inverters you see in green in the slide. So everything with that circle on the left, for example, those are all power plants and it depicts a present configuration. You're going to see more and more of these inverter-based resources popping up everywhere, some large, some small, but a lot of them are contributing to the grid. As you see more of those, you're going to see an interesting change in the behavior of the grid as you have disturbances and then some reliability, which is why you have new standards on these inverter-based resources. But I think ultimately you're going to see some of those as well on the residential side where customers behind the meters will be producing power and sending power back to the grid through the distribution site into the transmission system. So it'll be a real different change whereas power is going to flow back the other way in a way that it never has before. So it'll be a really interesting challenge and it's exciting and we'll see what the future holds here. Next slide, please, number five. Right, so generator, right? So as you can see, most generators are connected at this here. We're only showing two of them across one bus, but in reality there's like hundreds and thousands of generators across the entire system. Most of them have the same angle, same frequency, and their balance. Problem is that when you have a generator that's unbalanced or several generators unbalanced, the primary symptom of that sort of imbalance that usually manifests in the fact that the angles are changing between one and the next. They could be either operating at slightly different frequency or they are worse oscillating back and forth for the angle changes. And what you see here basically is that you notice at the rotor angle between one and the other slightly different, well that changes the way they produce power. And if these angles begin to oscillate back and forth, usually on a weird undamped oscillation, you could pretty much work your way into a blackout if that isn't arrested. And there isn't some place to be able to control that, whether they're automatically regulators or more importantly the power system stabilizers. But an unbalanced system usually can be brought about by a simple disturbance. Now the more generators you have in the system, spinning around the same speed and the same frequency, same angle, the more stable you are. As you begin to remove some of those and replace them with like invertebrate resources, this unbalanced situation tends to happen a little bit more often. So I'm going to keep in mind. Next slide please. So here on assistant demand and generator loading, it's basically what we're looking at as far as a typical day in this case from like midnight all the way out to like minutes and midnight and two hour increments. And what it is looking at, for example, your load curve in blue, your X, your generation capacity in green and how the different horizontal bars, units one, two, three, and four, five, six, seven, they are basically units that are run at different times depending on what you need. So when you see unit one, for example, that thing runs pretty much all the time. So those unit two until midnight. And in midnight, that unit kind of basically either backs down or shuts off. Units three and four, they will either back up and shut down. And then units five, six, and seven, those are run as needed. So what's happening now, as you can imagine, units one and two are pretty much inexpensive to run once you're running, but they're very expensive to shut down and start up again. So at the further up you go and units three, four, five, and six, the more expensive they are to run, but they're quicker to start, quicker to shut off. But the problem is, remember, it's everything has a startup on a shutdown cost. Mind you, one and two have a very expensive startup and shutdown cost, but their cost of running is really, really inexpensive. Relatives with the other units, this is why they kept running all the time. These are known as base load units. So if you are now forced to shut these down, that's maybe twice a day or something, or back them down because you have a lot of exercise generation renewables, then you are then incurring a cost, which is rather significant, and measured in a number of ways, whether it's maintenance, fuel, emissions, and a bunch of different problems. Also remember, as you're shutting these off, you're losing a lot of system inertia, and that's just cycling them off and on. And on top of that, some of these units have a limit to the number of times they can start up and shut down in one day. So one thing to remember, these units are usually running at excess capacity. It's anything that's above that green line that's curving, and then that is your load curve for the day, meaning behaviors, as we, for example, as a society, as an economy, as an infrastructure, we wake up, usually four o'clock, or somebody were getting up, so it's like everybody gets up for six to ten, everybody's either driving or work. Then at ten, I guess that's when all the renewable resources come in, sunlight, wind backs down, and then later on five, all that disappears, and then everybody goes home, turns on their, they call it the cooking peak. A little bit later, you have the lighting peak, which is the sun sets, when you have all the lights turning on, and then everybody kind of stays up for like eight or nine, and then at nine p.m., everybody just goes to bed, and that's where the load begins to drop off again, and then it repeats again the next day. And that's your typical load curve for the day, and it shows how your generators are staggered, depending on what's needed for that time. Next slide, please. Okay, so here we have an example of what a coal-fired power plant looks like, and I know it's become the big villain in the, in the climate change initiatives, and usually those are the ones they want to shut down. You've got to remember, right, the reason they burn the coal is just really it's actually generate heat to heat up that boiler, where you have water going through some pipes, and those boiler tubes they call them, and then eventually that water heats up, becomes superheated steam, goes through the steam lines, spins a turbine off to the right, and that turbine is mechanically connected to the generator, as that turbine spins at a certain specific speed, that generator produces electricity, and then the electricity goes off to the step of transformer, and you have power. This is one example, not every, most of the power plants are the same from the boiler off to the right, they usually have some kind of heat source that's heating water, with the steam, to spin a steam turbine, it spins a generator, and that's how your water is produced, so the less of that heat source that varies, that can be nuclear, that can be gas, that can be some other different kind of thing, but this is your typical boiler fired steam turbine generator, and power plant in this case is coal fired, but usually these boilers pretty much you need a heat source to heat up that water to create steam. All right, let's go to the next slide, and as a close up some more, more simplified, this is of course a combustion turbine, and here what they've done is that they basically replaced all that steam, and what they do instead is actually treat this like a jet engine, so they're putting fuel into these turbines, and then they're compressing the air, igniting it, and then now it's spinning like a jet engine, again this is still connected to a generator to produce electricity, but the spinning of the turbine here is done with actual combustion, and combustion turbine, and it operates like a jet engine basically, so it takes in air, it's compressed, it's mixed in with fuel, it's ignited, spins this turbine along the shaft, and as it spins then they have exhaust coming out the other end which is hot, keep that in mind, this is wasted heat for now, we'll recover that in a different type of process, but this is a very simple cycle they call it, and there's a combustion turbine, and these are really really quick, they start them immediately whenever they need them, they're expensive in some cases right, but then what they do is they run them as needed, they shut them off when they don't need them anymore, and they're pretty handy to have around, and these will run anywhere between 30 or the way to like 200, 260 megawatts about right depending what they need, usually those are GE7FAs, I think they just make a lot of them in different sizes, but they're pretty much the same, and they dominate the industry quite a bit, most of these are gas fired, natural gas, and they're easily built, easily deployed, easily run, they do require maintenance quite a bit, you know with these turbine blades, but that's your combustion turbine power plant, otherwise known as a simple cycle, what are the next sites please, so now we go from simple cycle to combined cycle, and here we have like a very, the first stage is the same as your simple cycle combustion turbine, except you know here you are capturing that heat, right, so this first stage is connected to a generator and it's running, but then the exhaust gases are captured, and remember the whole boiler thing that I showed you earlier was the same thing, that those exhaust gases are heating up all this like water and tubes in this boiler, those boiler pipes it would create are capturing steam, the steam turns to turns that the steam turbine, and that steam turbine then spins the generator to produce electricity from this heat that otherwise would have been wasted and bent into the atmosphere, so this is called a combined cycle power plant, and that whole second stage where you have that boiler is called the heresy, it's a heat recovery steam generator, so this is a very efficient system, great to have, and there are a lot of them in the grid out in the U.S. in the world, take a little bit longer to build, but they're highly efficient, the problem with them is that cycling them off and on is a little bit more involved, and it incurs quite a bit of a cost, and then they do cycle them off often, but not as often as the simple cycle CTs, right, and certainly not like these, but they will cycle these before they cycle a base load unit, okay, next slide please, okay, now here we go with the nuclear power plant, an example here basically is you're using a nuclear reaction to basically heat up water, and you're heating up water to the point that you create steam, that steam goes to the steam, the steam is an steam generator, spins the steam turbine, steam turbine then spins the generator and you get power, same thing as before with the whole boiler system, right, but you're heating up water to spend the steam turbine, so again what you've changed here is the heat source once again, right, let's go to the next slide, okay, so there's different types, there's a pressurized water reactor and this is pretty much most of the western world has this so much safer system, not your Chernobyl's, and in this case you have a containment building, right, which pretty much prevents a meltdown, contains a steam blast, whatever that is, and you have, for example, you're reacting with the control rods, that's where you have the nuclear material and then there you have a lot of heat generated and water is running through there, you see the pump down there, you have a water line and that water runs in and out of that steam, out of that the, that reactor, and the steam generator is basically what that is, the heat exchange, where you have a lot of these pipes are wound together but the water is never coming in contact, the two different water circuits are not coming in contact, they exchange heat but they don't come in contact, so the steam line that goes outside that containment building is not radioactive, and which is important to keep in mind, now mind you, there are some losses here, considerable losses, it is not as efficient as the next system I will demonstrate, but in this case it's then from this point on, the turbine onwards is the same as the other boiler system, where you're just basically heating up steam to spend a turbine that in turn spends a generator that by any produces power, so this is a pressurized water reactor and so keep that in mind, it has a pressurized steam generator and that has a heat exchanger to heat up the steam or the steam line on the outside, next slide please, here we have a boiling water reactor and this is somewhat like Chernobyl's, a lot more efficient, but the problem is that you are now getting radioactive water coming out to the steam turbine and back into the containment area in the reactor core, so the issue here is that now the actual steam turbine is hot, hot meaning is radioactive, so again there's no losses as much as the pressurized water reactor, but this boiling water reactor is a lot more efficient but you also run the risk of having more exposure of those like radioisotopes and particles and radiation outside of the system, so again this is closer to the Chernobyl design and you don't see too many that use any more, but these two are the large-scale nuclear reactors or nuclear power plant in the US, the pressure of water reactors is designed that pretty much is dominated for decades and it's safer and that's what we see the most, okay next slide please, hydroelectric here, there's no heat going on, all you're using is the pressure of the water flowing from the reservoir out to those like those water turbines called the wicked gates and that turbine spins the generator and I can show you that in the next slide and the example here is you see the reservoir on the right with the dam remind you of that pressure down there's way higher than it is the surface so that pressure pretty much in there goes through these control flows the wicked gates and that spins that captain turbine that captain turbine has a shaft that is connected to a generator and that generator pretty much spins creates electricity and then that's stepped up with that voltage with that in voltage with that transformer and it goes off to the grid to fit pretty much everything else, mind you this is a very clean efficient and has zero emissions and it's renewable, but building one of these is a really huge undertaking as a capital project and it has a huge environmental impact when you dam up a river you pretty much float a whole valley and create a giant lake or reservoir but again this is a very very clean water source and reliable next slide please related to that you have a pump storage plant and it is it is the same design it has a reservoir it has an area to keep water but then you also have a in most cases you have this is like an open circuit type of a pump storage plant but the nice ones have like for example two different reservoirs one on the high level and one on the low level the way this works basically is that it moves water back and forth right so when you have the reservoir and the intake up there after the upper right hand corner that's like a regular hydroelectric dam you open the gates water flows out you generate power and then the discharge is all collected in this lower reservoir when you have excess power in the system then this generator becomes a pump it's reversible and then this pump begins to like pull water out of that lower reservoir and it pumps water up to the to the high reservoir and then you basically recharge your system right this is basically one of the oldest energy storage devices out there and a lot of them are making a comeback I know in places like West Virginia and some of the carolinas some of the areas are on the bluish mountains and in the and then even in some places up in the azores right they're using these systems to basically supplement you know their grid in lieu of buying expensive batteries now interesting thing about the what's about the Blue Ridge and the Appalachian mountain ranges that you used to have a lot of like coal mines there right and a lot of like open open open air pit mines that have giant pits that are not full of water and they're at different levels so these these particular bits of real estate can now be repurposed and leveraged and then converted to these like pump storage plants and there's quite a lot of them so there's a lot of opportunity to be able to deploy the system in places that have otherwise been abandoned right so there's there's a lot of hope that this could actually have a huge amount of like in the gigawatts of capacity but also be able to actually create a very very workable proven solid energy storage devices that are reliable and that can be used you know day in and day out pretty hopeful on that okay next slide please geothermal and we do have one in Hawaii and what that is really is that it's using it's using heat geothermal heat to to either heat of water or use some of the heat itself and the steam that's coming out to spin for example those steam turbines now these applications generally have also a lot of other district heating systems that they that that they're applied for the heat for example different homes in an area but then again these geothermal plants are also a useful resource to generate electricity and I know of a few that are in the Hawaii islands quite a lot of them as well in Iceland and Greenland and all parts of northern Europe but this is a very efficient system it's just susceptible to a lot of you know geological problems right whether you have a seismic issue or something like that but other than that it's definitely a very very efficient and clean renewable resource and the last slide when turbines uh these were somehow things have slowed down a little bit but I'm seeing a lot of offshore wind being installed which is probably the most efficient way to actually deploy these these resources but as you can see here there's quite a lot of mechanisms that are that that are in place in these nacelles right whether it's like you're changing the pitch of the blade you can feather them you can change the angle depending on the wind speed that's happening the wind speed is too high that you tend to just feather them and not and that really uh been as much because you run the risk of damaging the blades or the actual mask or actually falling over destroying it but if you look you know there's quite a bit of systems in there usually it's like a reduction gear or actually it's it's uh it's an it's an increasing gear where the blades put a certain speed but that by gearing makes the generator spin a lot faster and then it produces power but then it is produced back to DC and then at that point from DC it goes back to AC through an inverter it's really interesting how that works but again these things even though they're spinning they do not provide system inertia so always seem to keep always seem to keep in mind and then of course there's anything else these things all have like a limited useful life means about 15 20 years maybe less than that in some cases they need to be like dismantled and usually enough in length but for the most part they're they're pretty popular in the offshore wind usually at sea level all right so I think that is all we have for today hopefully we'll have another installment pretty soon and uh but thank you all for joining us and if you have any questions please feel free to put them in the comments below I'll try and get back to you and answer so thank you again and have a great afternoon we want to announce that think tech hawaii is moving into a new phase and will not be producing regular talk shows after april 30th we will retain our website and youtube channel and will accept new content on an ad hoc basis we are also developing a legacy archive program to provide continuing public access to our content if you can help us cover the costs of the transition and the development of our legacy archive program please make a donation on think tech away.com thanks so much aloha