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Lecture 03 Introduction : Part 3 — Transcript

by IIT Roorkee July 2018 · 5,107 words · 932 segments · language en · Watch on YouTube

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0:00[music]
0:06[music]
0:11[music]
0:22[music]
0:25>> Welcome back all of you.
0:27So, today is the last part of the
0:29introduction.
0:30Earlier we studied some basic
0:32definitions and
0:34the classification of energy sources,
0:36the definition of renewable energy and
0:38the need for renewable energy
0:40followed by
0:42Indian energy scenario and global energy
0:44scenario. Like what is the primary
0:45energy consumption, what is the
0:47electricity consumption.
0:49So, in those
0:50scenarios
0:51you might have seen the diagrams which
0:53we have drawn in some
0:56specific format.
0:57So, those balancing diagrams or the
1:00like pictorial representation of the
1:03flow of any quantity, whether it's mass,
1:05energy, money, it's called a Sankey
1:07diagram. So, in today's lecture we'll
1:09study about
1:11what is Sankey diagram, how to draw it,
1:13and how it can be used in the energy
1:15sector.
1:16Uh followed by two very important
1:18concepts in the power sector. One is
1:21capacity factor and other is the load
1:23factor. Both are associated with the
1:26power plants
1:27which run on different fuels.
1:29And load factor is mainly on the
1:30utilization basis. And what's the
1:32difference and how both of them
1:35help
1:36like either electricity producers or the
1:39consumers
1:40to manage their supply and demand
1:42respectively, that we'll see in this
1:44lecture.
1:46So, Sankey diagram
1:48it is a specific type of flow diagram
1:51and mainly used for visualization of
1:54material, cost
1:56or energy flows
1:58on a system level or regional level.
2:02Okay, we can draw a Sankey diagram
2:04for a small reactor, for a small unit,
2:07or an entire power plant, or we can draw
2:10it for
2:11regions like for a town, city, state, or
2:14a country, or even we can represent the
2:16global energy uh supply and demand using
2:20a Sankey diagram.
2:21It helps to identify the important
2:24contributions to a flow.
2:27Mainly
2:28based on the size of the arrow or the
2:30width of the arrow, it can tell us
2:33which of the flows or whose contribution
2:36is higher and uh whose contribution is
2:38lower. And it shows conserved quantities
2:41within defined system boundaries.
2:43Conserved quantities means
2:45suppose if input energy is, let's say,
2:49100 MJ to a system,
2:51output has to match
2:53100 MJ.
2:55It can include
2:56losses as well as useful part of the
2:58energy, but since
3:00input was total 100,
3:03total output including losses has to
3:04match 100, then only the
3:08Sankey diagram would be balanced and can
3:09be drawn correctly. So, that's the one
3:11basic requirement.
3:13It should It is applicable to the
3:15quantities which can be conserved.
3:18It has directed arrows.
3:20The directions of the arrow
3:23shows the uh supply to demand or like
3:26from where to where
3:28the energy is transferring or mass is
3:30transferred or money is flowing. Okay.
3:33And it has directed arrows between at
3:35least two nodes.
3:37It can have multiple nodes like higher
3:39than two nodes also. Suppose energy is
3:41transferred from A to B.
3:44So, we can represent it by one arrow,
3:46but if energy is transferred from A to
3:48B, C, D, multiple, so we can have
3:51multiple arrows. Okay. So,
3:54it has directed arrows and it should
3:56have at least two nodes and it can have
3:59higher nodes also, which features in
4:00different flows in a process, production
4:02system or a supply chain.
4:04And
4:06the most important thing
4:08after these two points, one is
4:11quantity should be conserved.
4:14Second,
4:15at least two nodes should be there so
4:17that it has directed arrow
4:19to show the direction of the flow.
4:21And third is the width of the arrow
4:24should be proportional to the flow
4:25quantity. For example, if we represent
4:29this width
4:30by the value
4:31say 10 MJ.
4:33So, obviously the 5 MJ should be
4:36something
4:37half of this. Okay. It cannot be like
4:40very small or it cannot be bigger than
4:4310 MJ. So, that proportionality should
4:45be maintained and the width of the arrow
4:48it is proportional to the quantity of
4:50the flow.
4:52And this Sankey diagram, though in the
4:54definition or in the first line I
4:56mentioned it can be used for material,
4:57cost or energy, it can be used for
4:59multiple quantities in wide range of
5:01applications, like energy, material,
5:04supply chain, business, marketing
5:05analysis. It's a widely used tool.
5:08Let's look at some examples so it is
5:10more clear to you. We'll start with some
5:12simplistic examples and then we'll look
5:14at some detailed one. How it can be
5:17helpful to visualize complicated or uh
5:20comprehensive system in a simplistic
5:22manner.
5:23This is a Sankey diagram for a typical
5:25electric hand dryer. So, you know how
5:27electric hand dryer works.
5:29You plug
5:31the socket into the switchboard and
5:33switch on the button.
5:35And uh the electricity the electrical
5:37energy is converted to kinetic energy
5:40because there is a blower a fan which
5:43blows the air hot air.
5:45It makes a lot of sound also, hand
5:47dryers, so sound energy. And then it
5:50provides hot air, so there is a
5:51generation of heat, thermal energy. So
5:53most of this heat is going to thermal
5:56energy, so you can see if this width
6:00is represented by 750,
6:04this is representing 550, it's
6:07proportional, and these two widths are
6:10150 and 125.
6:13Just now, like that based on the
6:15definition what I told, I think this
6:18diagram is giving a wrong representation
6:21because 150 J line cannot be thinner
6:26than 125 J, right? Either this should be
6:31150 and this can be 125 to make it
6:35correct, or else the values should have
6:37been changed or the width of the arrows
6:39should be changed. Okay. So this example
6:43which we have shown, even though
6:45some representation, the conversion and
6:47flow is correct, the Sankey diagram is
6:50wrong. This is a mistake there.
6:52The second example is of energy balance
6:55for a coal power plant.
6:57So you know what happens in coal power
6:59plant, you burn coal and then generate
7:02steam in boiler, which goes and runs
7:04turbines, and then it is connected to
7:06the generator which generates
7:07electricity.
7:09So if you just do a basic simple Sankey
7:12diagram depending on
7:13the coal's potential energy which is
7:16supplied to the power plant. So almost
7:1935 to 40% in the is the efficiency of
7:21power plant. So 35% is converted to
7:24electricity, almost 45% is lost, and 10
7:2810% are lost or either used in power
7:32generation or is lost in generator. So
7:35you can see this Sankey diagram is
7:37much more appropriate and correct. We We
7:40don't know the values, but if we know
7:42the percentage wise, that also that
7:45representation is also
7:47correct. In fact,
7:49more than the values, percentage wise
7:51representation is easy for decision
7:53makers to understand. Because once there
7:55are values, we'll have to do some
7:57addition and subtraction and then
7:58convert it to percentage to find it out.
8:01But, Sankey diagram,
8:03the picture itself gives you the clear
8:06indication like which of the flows are
8:08important, which of the flows are not
8:11important, which of the flows represent
8:12useful energy, which of the flows
8:14represent losses. Just by looking at the
8:16width of the arrow, we can tell that.
8:18This is a Sankey diagram for a solar PV
8:20power plant, a detailed one where all
8:23the
8:23major power plant inputs or components
8:25are concerned.
8:27So, that's the solar energy incidence.
8:29Let's assume that
8:3110,000 MW hour is the energy incident on
8:34that solar PV array field.
8:36>> [snorts]
8:36>> So, out of 10,000 MW hour, almost 20% is
8:40converted to power, that is DC power,
8:43and 80% is lost, either as thermal
8:46losses, 78% and optical losses, like say
8:492%.
8:51Then, this DC power generated, it goes
8:53to the power conversion system
8:55where we convert it to AC. And inverters
8:58usually have high efficiency. So, out of
9:002,000, you can see almost 1,800
9:03is converted to the AC power with
9:0750 and 150 MW hour getting lost, either
9:10as DC losses or as inverter losses.
9:13And then, when it is sent to the
9:15substation or step-up transformer, and
9:18what we can use actually,
9:21it is little less than 1,800, that is
9:231,760,
9:25because
9:26in stepping up or substations, there are
9:29not huge losses. So,
9:31small amount of electricity or energy is
9:33lost in those stages. So, you can see
9:37this is also one way of representing the
9:38Sankey diagram or the energy flows.
9:41Where
9:42in the middle of the arrows, we are
9:44representing a
9:46system. Like what is the stage at which
9:49that transformation is happening. So,
9:51here it's a solar PV array field. There
9:53is an input energy going, output energy
9:56going.
9:56Then we have power conversion system,
9:59where we have input and output. Then we
10:01have substation and transformer, where
10:03again we have input and output. So, this
10:06is This way also we can represent the
10:09flow using a Sankey diagram. And last
10:11one,
10:12or maybe I think couple of them. For
10:15fixed bed downdraft gasifier. So, it's
10:17like for biomass.
10:19If you have a like big gasifier,
10:23you add
10:24biomass
10:26feed into it. And it's a downdraft
10:28gasifier, so the producer gas
10:31will come from the bottom.
10:33And then the ash will be collected at
10:35the bottom only, because there is a grid
10:38above which the feed stocks will rest.
10:40From here you can send air or any
10:42gasification agent.
10:44So,
10:45and typically in downdraft gasifiers,
10:47along with biomass, to prepare the
10:49initial bed, we may use some
10:52coal also. Like one or two kg coal for
10:5540 kg batch reactor. And that way, so
10:58the energy which is going into the
11:00gasifier, it is coming mainly from
11:02biomass and coal. And the energy which
11:05is coming out of the gasifier, it is
11:07coming mainly in the form of producer
11:08gas and the sensible heat of producer
11:10gas.
11:12>> [snorts]
11:12>> So, this is the gasifier,
11:14the batch
11:16downdraft gasifier.
11:17And you can see it's like almost 2 m
11:20tall height for this 40 kg batch.
11:23Pellets are fed into the gasifier, the
11:25biomass pellets and the coal.
11:28So, the energy wise you can see, and
11:30since coal is a very small amount, like
11:32say 2 kg or 1 kg or 3 kg or 2.5 kg, and
11:36pellets would be like 38 kg or 37 kg. Uh
11:39so, based on the calorific value, we
11:40have the energy going in.
11:42And whatever is converted to producer
11:44gas, the cold producer gas, it is around
11:4751%.
11:48And since the gas which is coming out of
11:52the gasifier, it would be very hot. It
11:53will have some sensible heat also. So,
11:55that accounts for almost 17%. So, the
11:58energy efficiency of gasifier If you
12:00talk about thermal energy efficiency, so
12:02it's like 51 plus
12:0417. So, almost 68 69% and if you're
12:08talking about cold gas efficiency, it is
12:1051%. So, Sankey diagram also helps you
12:13to calculate the efficiency of the
12:16process. And then there are some losses
12:18of energy which goes with the residue or
12:21as a heat loss.
12:23This is the last example for supply and
12:25demand of hydrogen globally and the unit
12:28is million metric tons. So, at present
12:32if you take into account the global
12:35hydrogen supply and demand with respect
12:37to 50 million metric ton,
12:39we know that most of the hydrogen is a
12:42gray hydrogen.
12:44Gray hydrogen is the one which is
12:45produced from fossil fuels, mainly by
12:48steam reforming of natural gas and
12:51coal or
12:53naphtha.
12:54Okay. So, you can see the 20 out of 50,
12:57almost 23, 15, and 10. So, very like
13:03almost 45% more than 90% of the hydrogen
13:06is coming from fossil sources.
13:09And very small amount,
13:11like less than 5% or close to 5% is
13:14coming from
13:15electrolysis and renewable grid. Now,
13:19that accounts total for 50 million
13:21metric tons. Where is it being actually
13:24used?
13:25So, most of the hydrogen is used in the
13:28refineries
13:29and in fertilizer sector or
13:31ammonification. Like we convert it into
13:34ammonia, ammonium nitrate.
13:37And in refineries, there are two
13:38processes which consume a lot of
13:40hydrogen. It is hydrocracking and
13:42hydrotreating. So, 17 + 47 again, 45%
13:47is consumed in the
13:49two sectors only. And very small amount
13:51of fractions of hydrogen are used in
13:53fuel cells, metal glass industries, food
13:56beverages, pharmaceuticals, and
13:58plastics. And accordingly, you can see
14:00the width of the arrows in the Sankey
14:02diagram
14:03are changing.
14:05So,
14:06one way
14:07to understand global hydrogen supply and
14:09demand would be going through a lot of
14:11data which is in the form of a table
14:13taken from variety of sources of
14:15literature.
14:16And that way is this Sankey diagram
14:19which is in a very
14:21simplistic way gives us a overall like
14:26overview of entire hydrogen supply and
14:28demand throughout the globe. So, that
14:31way Sankey diagram is very helpful to
14:33make representations
14:36of either energy or the supply and
14:38demand related to energy and energy
14:40quantities.
14:41The next
14:43topic that we are supposed to cover is
14:45capacity factor.
14:47So, it is related to the power plants.
14:50So, as the name indicates,
14:52like every power plant has some
14:54installed capacity. Like let's say we
14:56set up a 1 MW power plant.
14:59If it is a rated capacity,
15:01when we actually use that power plant,
15:04we won't be able to get 1 MW because
15:06there are certain
15:08many reasons
15:09because of which we cannot operate the
15:12plant to its fullest capacity. There
15:14would be certain losses. There maybe
15:16there is sometimes there is shutdown.
15:18Okay? And efficiencies are limited.
15:21So, if the plant is rated at 1 MW
15:24capacity and we are unable to run it at
15:28full of its capacity because of certain
15:30reasons,
15:31so whatever capacity we are running,
15:33that will help us calculate the capacity
15:35factor of that power plant.
15:37So, there are two terminologies
15:39which defines the capacity factor. One
15:41is installed capacity and second is the
15:43actual electricity generation.
15:45So, what is installed capacity?
15:47If you remember the first lecture slide,
15:50in India, how much we have installed
15:52capacity? Almost
15:54524 GW.
15:56That's our installed capacity.
15:59And even if we run it
16:01for say 24 hours a day,
16:04it won't be giving us 524
16:07into 24
16:08because each of the power plants
16:12based on different sources will have
16:13different capacity factors.
16:15So, installed capacity is maximum rated
16:18output of a power plant.
16:20And that maximum output can be produced
16:23under ideal conditions, which hardly
16:25exist. Unit will be in watt, kilowatt,
16:28megawatt, or gigawatt.
16:29And actual electricity generation is
16:32what we are actually getting. Like what
16:34is being produced through that power
16:36plant over a specific period of time.
16:38So, you multiply that
16:40power by time and you get kilowatt hour,
16:42megawatt hour, or gigawatt hour. That's
16:44the actual electricity generated.
16:46Now, capacity factor is the ratio of
16:48actual generation by installed capacity.
16:51Okay? So, it is always going to be less
16:54than one because we cannot generate more
16:57than what it is designed for.
16:59So, ratio of actual output over a period
17:01of time
17:03to its potential output if the plant
17:06operates at full installed capacity
17:08indefinitely or continuously.
17:10So, in the form of formula, you can
17:12write it as megawatt hours of actual
17:14electricity generated upon rated
17:16capacity or sometimes it is also called
17:19as nameplate capacity
17:21and into time.
17:23So, if once we have these three
17:25quantities, we can easily calculate the
17:27capacity factor for any of the power
17:29plants.
17:30So, by different energy sources, these
17:33are some of the numbers in 2024
17:36and you can see nuclear, geothermal, and
17:39gas based and they have much higher
17:41capacity factors than coal, hydro, wind,
17:45and solar and the simple cycle of
17:47natural gas.
17:49So, you can see
17:51the renewables have
17:53lower
17:55capacity
17:57factor.
17:58And why is that?
18:00Because sun, wind,
18:02they are not available all the time.
18:03They are intermittently available and
18:07so power plant won't be able to operate
18:09for 24 hours day and night in all the
18:11seasons.
18:12Whereas,
18:13like the power plants which run on
18:16nuclear, geothermal, or even coal, if we
18:18have sufficient fuel
18:21in our storage,
18:23it can be operated continuously. It is
18:26possible to achieve higher capacity
18:28factor in these power plants. Like
18:30nuclear, very small quantity of fuel is
18:32able to produce lot of power.
18:34And that much is already kept in the
18:37stock, so we don't need to rely on daily
18:39supply. Whereas in coal power plant,
18:42even though it is possible to do like
18:44store, but because of lower energy
18:47density, much lower energy density than
18:50nuclear fuel,
18:51we need
18:53huge amount of coal on a daily basis.
18:55So, storage is not possible for a long
18:58period and that's why
19:00it doesn't go to as high capacity as
19:03nuclear. But in geothermal, again it is
19:05dependent on the earth's interior heat,
19:09which is not affected mainly by the
19:11seasons or day and night. So, it can be
19:14operated continuously. The reasons for
19:17these plants going at lower capacity
19:19other than the source of energy, there
19:21may be some additional reasons related
19:22to maintenance and operations
19:25or reliance on utilities or ancillary
19:28consumption of electricity. So, all
19:30these factors would design would govern
19:32the capacity factors.
19:34The reasons for reduced capacity factor,
19:36some of them are listed here. Plant is
19:39out of service maybe. There may be some
19:41operational and maintenance issues or
19:43labors are on leave or on strike. If
19:46they are absent, then the plant can be
19:48out of service and it will be operating
19:50at reduced capacity factor.
19:52Uh intermittency and unavailability.
19:55For renewable sources, this is a big
19:57problem. It won't be available for all
19:59the time, 24/7.
20:01And for other fossil fuels,
20:04there may be
20:06like less availability or varied
20:07availability. Like biomass, it may not
20:09be available throughout the year in
20:10required quantity. So, that's another
20:12reason.
20:13Grid curtailment.
20:15Sometimes
20:18because of the reduced demand, the grid
20:20may be over supplied and electricity is
20:22not actually needed. So, when that
20:24scenario is clear, the power plants
20:26would prefer to operate at lower
20:28capacity because whatever electricity
20:30they are producing, it may not be
20:31required and grid is already over
20:34supplied. Economic dispatch.
20:37If for certain power plants, the
20:39production cost of electricity is higher
20:42than the market price of electricity.
20:44So, during such time,
20:46they won't prefer to run it and produce
20:48electricity because it's not going to be
20:50profitable. So, that's economic reason.
20:53Then many power plants, they sometimes
20:56go for ramping and starting up times
20:58vary
20:59which changes their efficiency. So,
21:01those are the other reasons. And now
21:04with global warming and climate change
21:05taking the central picture on the globe.
21:08Environmental regulations
21:09also sometimes ministries can instruct
21:12or pollution control boards can instruct
21:14power plants to operate at lower
21:15capacity during certain times of the
21:18year. Because like in North India during
21:21the months of winter
21:23during time of harvesting of rice crop
21:26the pollution increases a lot, air
21:29pollution. So that time the power plants
21:30in the nearby area may be asked to
21:33operate at lower capacity. So that net
21:35emissions
21:36coming from at least power plant are
21:38reduced and the conditions are well
21:40taken care of. So these are different
21:42reasons
21:43for reduced capacity factor.
21:45There may be few more.
21:47Let's take one example on capacity
21:50factor like how do we calculate it and
21:53how it is useful.
21:55So plant A, let's say nuclear plant, has
21:57a rated capacity of 50 MW.
22:00And it produces 40,000 MW hour in 1,000
22:03hours.
22:05Plant B
22:07it's a solar based plant has a rated
22:09capacity of 100 MW and produces 20,000
22:12MW hour
22:13in 1,000 hours.
22:15Which plant has a higher capacity
22:16factor?
22:17If you remember that figure which I
22:19showed like the comparative capacity
22:21factors of different power plants answer
22:24is obvious nuclear is going to have
22:25higher capacity factor. Let's check for
22:28this numerical.
22:29So
22:30what will be the capacity factor for
22:33nuclear power plant?
22:35Actual electricity generated, how much
22:37it is?
22:3940,000.
22:43And
22:44what is the nameplate capacity?
22:47Or rated capacity it's 50 MW
22:49into
22:52operating for 1,000 hours.
22:54So 40 4, it comes out to be around
22:57.8 that is
22:5980%.
23:01So capacity factor is 0.8 for nuclear.
23:04Capacity factor for solar, similarly,
23:08it is producing 20,000 MW
23:11hour.
23:12Rated capacity is
23:15100.
23:16Operates for 1,000 hours.
23:21So, 2 by 10
23:24point
23:26two.
23:27So, obviously, the capacity factor for
23:29nuclear is much higher than
23:31solar. So, nuclear
23:34base plant, that is plant A, has a
23:36higher capacity factor than plant B.
23:40Now, what is the significance of
23:42capacity factor? Like, once
23:44we know what is the capacity factor,
23:48or based on the value of the capacity
23:49factor,
23:51how does it help the different
23:53stakeholders involved in the power
23:55sector?
23:56The first
23:57significance is
23:58it actually help to determine what is
24:01the actual energy generation over time.
24:03If we know the periodic capacity factor
24:05for a power plant, we have some idea
24:07that, okay, in 1 year, this much energy
24:09can be generated.
24:11It drives the cost of electricity.
24:13Because, if capacity factor is higher,
24:16per unit cost would be lower.
24:18Once the plant is installed,
24:20already we have put the capital cost.
24:23For operational cost, it won't vary much
24:26with the changing capacity, except for
24:27the
24:29cost of the fuel, but other costs
24:31may be like constant. So, if we have the
24:34higher capacity factor,
24:35per unit electricity cost is going to be
24:38lower. So, it drives the project
24:41financial viability also. It directly
24:43affects the revenue, internal rate of
24:45return, and payback period for the power
24:47plant operator or owner.
24:49It indicates resource availability and
24:51site quality.
24:52If you have like historic data of
24:54capacity factors or
24:56uh for a
24:57We can like based on the capacity
25:00factor, some indications can be made
25:02based on whether the resource or the
25:03fuel is available. Uh and what is the
25:06quality of the
25:07site to produce power.
25:11It supports grid reliability and
25:12planning, and it prevents overestimation
25:14of installed capacity.
25:16Suppose we have a solar-based power
25:18plant in one part of the world, and we
25:22know its installed capacity and capacity
25:24factor.
25:25So, while planning a similar power plant
25:27in some other part of the world, having
25:30knowledge of the capacity factor of
25:31those power plants will help
25:33overestimation of installed capacity in
25:35other parts of the world. So, that way
25:37it is a
25:38a significant value. So, that was all
25:40about capacity factor.
25:41The last point for today, that is load
25:44factor.
25:46So, just like capacity factor is from
25:48the production side, like the supply
25:50side, the power plant side, load factor
25:52is from the utilization side. It It is
25:54defined as the ratio of average load
25:57over a given period of time
25:59to the maximum demand or the peak load
26:02occurring in that period. So, this load
26:04or demand is from customer side. Okay,
26:07it's from the grid
26:08user side.
26:11In the in terms of definition, it's
26:12average load by peak load. Average load
26:14is total energy generated. Peak load is
26:18the maximum demand
26:20into time.
26:22So, it actually determines how
26:24efficiently we are using the energy
26:25which is produced.
26:27Capacity factor tells us how much of the
26:29energy is actually produced compared to
26:32its rated capacity.
26:33And once that energy is produced, how
26:35efficiently we are able to use it, that
26:38is determined by the load factor.
26:40So, basically,
26:43it's a load factor which can influence
26:45or govern or give some idea to capacity
26:47factor, and not vice versa.
26:49Okay, demand can
26:53like help change or manage the supply.
26:56But supply won't manage the or like
26:59govern the demand.
27:01So demand patterns can determine how
27:03much of the installed capacity is to be
27:05actually utilized. So if the load factor
27:07is high
27:08it will ask or it will
27:11force power plants to operate at higher
27:12capacity factor. But even if power
27:15plants can operate at higher capacity
27:17factor, but if the load factor is low,
27:19it will
27:20give some relaxation to the power plants
27:22and ask them to operate at lower
27:24capacity.
27:25Let's take one
27:27numerical example where we have this
27:29combined concepts of load factor and
27:31capacity factor.
27:33A coal-fired power station, it has rated
27:35capacity 1,000 MW.
27:38It is designed to supply power to a
27:40nearby city whose peak demand in summer
27:43reaches maximum of 800 MW. So we have
27:47peak demand is 800 MW. Rated capacity is
27:521,000.
27:54Annual average power consumption is
27:57600.
27:59The coal plant always generate exactly
28:01what the city demands. Calculate load
28:04factor of city's usage and capacity
28:07factor of the power plant for that year.
28:10So let's calculate load factor first.
28:13It's the
28:14average load by peak load. So average
28:16load is
28:17600 MW for that city.
28:20Peak load is
28:22800 which reaches certain times during
28:24summer mainly.
28:26So 600 by 800 it comes out to be
28:2875%.
28:30So load factor is 75%. It means the
28:32city's demand is almost 75% steady.
28:37And the grid or the utility, they have
28:39to keep some extra equipment ready to
28:42manage that 800 MW peak demand.
28:46Or else most of the year the city needs
28:48only 600
28:50MW.
28:51But even if for 1 day, if it is reaching
28:54800 MW, the
28:57equipment has to be ready. So, utility
29:00has to keep that much extra equipment
29:02ready. So, that's
29:03what governs the load factor. It is
29:06based on the demand of the city and how
29:08they are using the power. Now, what is
29:10the capacity factor?
29:11Actual generation by
29:14the installed capacity. So, installed
29:16capacity is 1,000.
29:18Actual generation
29:20average is
29:21600, but sometimes it needs 800 also.
29:26So,
29:27if you look at actual energy produced
29:30based on the annual average,
29:32annual average is 600 MW.
29:35It's for 1 year. So, 1 year it's 365
29:38days
29:40into 24 hours. It comes out to be 8760
29:43hours. So, if you multiply by that, you
29:46will get five some MW hour.
29:49And the maximum potential energy or the
29:53installed capacity, it's a 1,000 MW.
29:57It is when you multiply it for 1 year,
29:598760, it comes out to be 876 trip four
30:03times zero.
30:05So, capacity factor would be the ratio
30:06of these two, actual energy produced
30:08upon rated capacity into time,
30:12which is around 60%.
30:14So,
30:16capacity factor of the plant is 60%.
30:18Load factor is 75%. What is the
30:22significance of these two values?
30:25See, 75% of load factor means it is a
30:28high value actually. It tells us the
30:30city has a fairly consistent demand for
30:34power throughout the year.
30:36Okay? And capacity factor of 60% tells
30:39us
30:39even though it's slightly lower value
30:41compared to load factor, we say that
30:44plant is oversized.
30:46Because the demand is 600 MW, we have
30:48designed the plant for 1000 MW. Uh but
30:52even though let's forget about the
30:54average demand of 600 MW, even if we
30:56take the highest 1 day or 2 day demand
30:59of 800 MW,
31:01that is the highest need,
31:03our plant is still over designed. So, if
31:06the highest demand is 800 MW, I think
31:10even 810
31:12or 820 MW plant would have solved the
31:16city's situation. So, that way
31:19load factor or capacity factor can help
31:22us guide whether the
31:25supplies proper, whether the demand is
31:27proper, and based on the demand,
31:30how to manage or govern the supply.
31:33Let's look at like comparative
31:35distinguishing or differences between
31:36the two factors
31:38based on different features.
31:40The capacity factor and load factor,
31:42the perspective is capacity factor is
31:44based on the supply side. It measures
31:47utilization and performance of the power
31:48plant, okay, based on its capacity and
31:51based on actual electricity generation.
31:53Load factor, it's on the demand side. It
31:56measures the consistency and efficiency
31:58of consumption or use of energy. Once it
32:01is produced, how efficiently, how
32:03consistently it is being used, that
32:05tells us
32:06that is told by load factor. Primary
32:09variable here in capacity factor is
32:11rated capacity.
32:13It is a fixed quantity. It's a
32:16hardware limit, it's a physical hardware
32:19limit of that power plant. It cannot go
32:20beyond that particular number.
32:23But load factor, it depends on the peak
32:25load or the demand, which is
32:27human-centric. So, it's a variable and
32:29behavioral metric. It's not fixed or
32:31constant.
32:33Capacity factor indicates the
32:34reliability of plant,
32:36the availability of resource, and
32:39operational efficiency of the power
32:40plant.
32:42Whereas load factor, it tells us how
32:44stable the grid is, how efficiently the
32:48electricity infrastructure is being
32:49used. How efficient are the
32:51transmissions and
32:53how efficient are the
32:54usage appliances
32:56which consumes the electricity.
32:59The preferred value for both the factors
33:01is obviously the higher the higher the
33:02value,
33:03better would be the cost. So, if we have
33:06a high capacity factor,
33:07it can help us lower the unit
33:10electricity cost and for quick recovery
33:12of capital cost.
33:13Because whatever is money is being
33:15invested in setting up that
33:17infrastructure, it is a capital cost.
33:19And to be able to recover that capital
33:21cost soon, maximum utilization of that
33:26setup is preferred.
33:28High load factor is also desirable
33:30because it will tell whether the demand
33:33is steady or not. And once it is known
33:37that demand of electricity or any like
33:39power
33:40in a region is consistent and steady,
33:43accordingly the new power plants can be
33:45designed.
33:47Primary stakeholders who would be
33:49interested in capacity factor values
33:51would be the owners of the plants,
33:53operators, and investors who put money
33:54in the power plant, like mainly on the
33:57generation side, supply side.
33:59For load factor, it will be mainly the
34:01utility companies, the grid operators,
34:03and consumers who are
34:07involved in once that electricity is
34:09produced, how to transmit or distribute
34:12it and how to consume or use it.
34:14So,
34:15that this sort of summarizes the
34:17difference between these two factors.
34:19One is capacity factor, other is load
34:22factor. So, I think that was all for
34:24today's lecture. Just to summarize,
34:28we started with Sankey diagram, which is
34:30used to represent or the visualization
34:33of different quantities. It can be mass,
34:36energy, cost.
34:38You can represent all the values which
34:40can be easily conserved.
34:42It should have direction between at
34:45least two nodes or multiple nodes and
34:48the width of the arrow should be
34:50proportional to the
34:52numerical value or the magnitude.
34:54Capacity factor,
34:56it tells us actual electricity generated
34:59by installed capacity and it's governed
35:02by the supply side. Load factor, it's
35:05the average load by peak load and it is
35:08governed by the demand side. And then we
35:10saw couple of numericals related to
35:12capacity factor and load factor to help
35:15you understand these concepts.
35:16So with that, we'll stop here. Thank
35:18you.
35:30>> [music]
35:40[music]

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