YT YouTube2Text

YouTube2Text → Transcripts → Lecture 01 Introduction : Part 1

Lecture 01 Introduction : Part 1 — Transcript

by IIT Roorkee July 2018 · 5,416 words · 832 segments · language en · Watch on YouTube

Open in transcriber Summarize with AI Download SRT/VTT

Full transcript

0:00[music]
0:06[music]
0:11[music]
0:22[music]
0:25Welcome all of you to the course on
0:28renewable energy sources. Fundamentals
0:30and technologies.
0:32Since it's the first lecture, let me
0:34introduce myself. My name is professor
0:36sonal kit hanging. I'm associate
0:39professor in the department of hydro and
0:41renewable energy IIT Ruri. I joined here
0:43in 2020 and since then I have been
0:46teaching this course on renewable energy
0:48sources in my department.
0:51>> [snorts]
0:51>> So considering it as a first lecture I
0:54think let's first go through the
0:56syllabus and then the content for the
0:59today's lecture. So this course syllabus
1:02as the name indicates renewable energy
1:05sources fundamentals and technologies.
1:08So there are different types of
1:09renewable energy sources like solar,
1:11wind, biomass, hydro, geothermal.
1:15So we'll be studying about the
1:16fundamentals about all these
1:18technologies first and then see what are
1:21the advancements so far as technologies
1:24are concerned in these renewable
1:26sources. Uh [snorts] so we'll start with
1:28the introduction uh where we'll look at
1:32the global energy scenario, the Indian
1:34energy scenario, some basic definitions
1:36related to energy, work, power or
1:39electricity [snorts] and what is the
1:41need for renewable energy and what's the
1:47driving force behind like as we see like
1:50the entire world is moving towards
1:52renewable energy to address the issues
1:54of climate change and global warming. So
1:57we'll see like what are the other
1:58factors which uh pushes the world or the
2:02global energy transition towards
2:04renewable energy and since directly or
2:07indirectly all the energies come from
2:09sun. The first and the technology that
2:11we'll be talking about is solar energy.
2:15This unit will cover some basics about
2:18solar geometry. the different types of
2:20radiations from solar energy,
2:23[snorts] solar PV technologies and solar
2:25thermal technologies because these are
2:27the two major roots by which we can
2:29utilize solar energy. The second would
2:32be biomass. So there are different
2:34sources of biomass coming from plants,
2:36animals, municipal sources, industrial
2:40sources, forestry, agriculture. Okay. So
2:43we'll look at those sources some
2:44properties characterization
2:47[snorts] and in conversion we will look
2:48at primarily thermmochemical conversion
2:51processes of biomass followed by
2:53biochemical conversion processes for
2:55biomass.
2:57Uh next in line would be hydro power and
3:00wind power. I am showing them together
3:03because some of the aspects related to
3:06like types of turbines and plant
3:08components would be quite similar in
3:10both the technologies but is we will be
3:12studying them separately with respect to
3:14their plant components turbines
3:16efficiency and in wind power we'll look
3:20at the derivation for power equation
3:22beds limit and again the different types
3:24of windmills or turbines along with
3:27generators that are used in the wind
3:29power plant. Last we'll also look at
3:32some brief overview and technologies
3:35related to geothermal ocean and hydrogen
3:38because hydrogen is also considered as a
3:41like energy carrier and can be a game
3:43changer
3:44so far as energy storage is concerned
3:47[snorts] uh and transportation sector is
3:49concerned. So we'll we'll have like
3:51maybe couple of lectures on hydrogen
3:53also. Towards the end we will discuss
3:56India's renewable energy road map on the
4:00basis of its policies market and
4:02challenges. And when I say case studies
4:05it is actually connected to each of
4:08these renewable sources. So whenever we
4:12study about solar or biomass we'll be
4:15going through some real world case
4:16studies particularly in India focusing
4:18on those technologies. So [snorts] that
4:21sort of covers the entire syllabus for
4:24this 20 hours or like say 8 weeks of
4:28course on renewable energy sources
4:30fundamentals and technologies. [snorts]
4:32Coming to the lecture content today. So
4:35today we'll start with some basic
4:37definitions
4:38and then move towards energy sources and
4:41classification of those energy sources.
4:44Uh finally ending with the need or the
4:47importance of renewable energy. So the
4:49first concept energy. What is energy? We
4:54all have studied in the school books
4:56that it's a capacity or ability to do
4:58work. Yeah, it's the same definition.
5:02Capacity or ability to do work or cause
5:05a change in matter. [snorts] And this
5:08energy has different units depending on
5:10which sector we are using the term
5:13energy. Like if it is related to heat,
5:16we would be using the unit of jewel. If
5:17it is related to electricity, we'll be
5:20using kilowatt hour. And if it is energy
5:23related to say food, we talk in terms of
5:27calorie where 1 calorie is 4.184 joule.
5:30And since energy is property which
5:32depends only on the magnitude and not on
5:34the direction it is a scalar quantity.
5:37[snorts] There are two major forms of
5:40energies
5:41depending on whether the body is in like
5:45having a stored energy or whether it's
5:47in motion. So first one is potential
5:50energy which we define as mg where m is
5:53the mass, g is the acceleration due to
5:55gravity whose value is around
5:589.8 m/s squared because we are talking
6:01with reference to earth and h is the
6:03height of the object from the surface of
6:05the earth. And second is kindinetic
6:06energy which depends on the mass and
6:09velocity of the body. So there are
6:12different types of potential energy and
6:14different types of kinetic energy as you
6:16can see in this picture. Uh most common
6:19type of potential energy is chemical
6:21energy which we obtain from like maybe
6:24fossil fuels like coal, oil, gas, they
6:26all have a lot of chemical energy stored
6:28in their hydrocarbon bonds, right? And
6:31when we combust them or burn them, the
6:34energy is released as exothermic
6:35reaction. Then [snorts] we have
6:37mechanical stored energy. Something like
6:40pulling a trigger or pulling the bow
6:43arrow and holding that. So that's a
6:45stored mechanical energy. And the moment
6:47we leave that arrow, it converts to
6:50kinetic energy. Then gravitational
6:52potential energy and nuclear energy. In
6:56kinetic energy, it's about the energy
6:59which is in motion. So it's mainly
7:01electrical energy where the energy is
7:03carried by the flow of electrons, ions
7:07or [snorts] holes if it's a
7:08semiconductor. Then radiant energy it's
7:11carried by light. Thermal energy carried
7:14by heat. Then motion energy and sound
7:17energy. Sound of energy is also like
7:19because of vibrations and there are
7:21crest and truffs because of the movement
7:24of the particles in the medium and sound
7:26waves travel through them. So that was
7:28all about energy. The second is work.
7:32[snorts] So work is it is related to
7:35energy because it happens only when
7:37there is a transfer of energy. So when a
7:39object is displaced by an external force
7:43in the direction of that particular
7:45force then we call that there has been a
7:48energy transfer that has occurred which
7:49is actually called as defined as work.
7:52For example, here you can see the person
7:53pulling a box with the force F and this
7:58box is getting displaced
8:00by distance D
8:03and since force and displacement both
8:07are like say vector quantities. So work
8:10is actually defined as the dotproduct of
8:13two
8:15vectors F and F dot D and dot product of
8:18two vectors is a scalar. So that's why
8:21work is also a scalar quantity which
8:23won't depend on the direction but only
8:26on the magnitude of the quantity and the
8:29unit of work is similar to energy it is
8:32jewel and it can be also related in the
8:35form of newton meter or kg m/s square
8:39meter because the force has a unit
8:42newton [snorts]
8:43so that's the work for which we need
8:45energy and the third concept which talks
8:48about the rate of energy transfer or the
8:50rate of work done is called as [snorts]
8:53power. So power is nothing but rate of
8:55energy transfer or the rate at which
8:58work is done. So we have work divide by
9:02time that gives you power and work uh we
9:06have seen like force into displacement
9:09and time is there distance by time is
9:12nothing but velocity. If you know
9:15remember the unit of velocity it's
9:18displacement by time or distance upon
9:20time. So these are different formulas
9:22that can be used for calculating power.
9:25It is also a scalar quantity because
9:27since work is a scalar quantity
9:31time is scalar. It doesn't depend on
9:33direction. It depends only on magnitude.
9:35So the division of these two quantities
9:37it's going to be a scalar. And the units
9:39of power is going to be joule per second
9:42which is also called as watt or
9:44sometimes in commercial world we use the
9:47units of horsepower. And there are two
9:50types of horsepower. Basically it
9:52depends on the connection between the
9:57power employed by a horse or a pony. And
10:00in different parts of the world we use
10:02different there are two major
10:04definitions of horsepower. One is
10:06imperial and one is metric. So as you
10:09can see in this picture the imperial
10:10horsepower it is based on 550 pounds of
10:14mass lifted by 1 ft in 1 second which
10:17comes out to be 746 W. And in metric
10:21horsepower which is most commonly used
10:24in Europe and Asia uh unlike the
10:27imperial horsepower which is used in US
10:29and UK the distance is measured in
10:32metrics like 75 kg lifted by 1 m in 1
10:35second gives you 736 watt. So there's a
10:38difference of only 10 watt in both the
10:40definitions but it depends on like in
10:42India like if you go through uh
10:44different machineries mainly the pumps
10:46or the cars or the motors depending on
10:49where they are imported from whether if
10:50they are imported from US and UK they
10:53will have the units in terms of imperial
10:55horsepower but if they are made in
10:57Europe and Asia they will have the units
11:00of metric horsepower but [snorts] the
11:03way it is calculated by multiplying mass
11:07by like delta h and divide by t. One
11:11simple like I can do for metric. So it
11:15is like 75
11:17uh this is the mass and the weight or
11:21the work done for lifting this mass
11:23would be 75 into 9.8 which is
11:27acceleration due to gravity divide by 1.
11:30So this comes out to be 736 watt
11:34approximately. That's why metric
11:36horsepower unit is 736 watt. So now with
11:40those basic definitions of energy, work
11:44and power, let's move towards
11:48the type of energy and power which we
11:50are more interested in this course which
11:51is electrical energy and electrical
11:54power. Their definition is also going to
11:56be similar based on energy and power but
11:58with respect to the electrons or the
12:01electricity. So electrical energy is the
12:03total work done by electric charge
12:06moving through a potential difference or
12:08voltage V representing the capacity to
12:11do work. So if we have like say uh the
12:14equipment has power p rating and it is
12:17used for time t the energy transferred
12:20or the work done would be power into
12:22time and power is voltage into current
12:25that is bit and by ohms law if you
12:28remember voltage is directly
12:30proportional to the resist uh to the
12:32current and [snorts] the constant of
12:34proportionality is called the
12:37resistance. So v equal to I or if you
12:38substitute that we can get energy in
12:40terms of I² RT where unit is jewel or
12:43kilowatt hour. The electricity bills
12:46that we get in our houses if you uh go
12:50through it you will see this number
12:52written there units at some uh states
12:56there will be like free 100 units and
12:58then after that you may get charged. So
13:00that unit one unit is nothing but 1
13:03kilowatt hour. It represents the
13:06electrical energy in the unit of
13:08kilowatt hour. It means the 1 kilowatt
13:11power rating
13:13equipment is used for 1 hour. That's the
13:16equivalent 1 kilowatt hour. So
13:18electrical power it is again the rate of
13:21work done the rate of electrical work
13:23done the rate at which work basically
13:25the movement of charges is done in an
13:28electrical circuit or the rate of
13:30consumption of electrical energy by a
13:32device that is called as electrical
13:34power it's defined as potential
13:36difference or voltage into current and
13:38unit will be joule per second or watt or
13:42kilowatt it can go all the way to
13:44megawatt or gawatt those are just the
13:46higher
13:47multiples of the basic unit which is
13:49watt. So now we have seen the definition
13:52on the difference between electrical
13:54energy and electrical power.
13:56Now if I ask you a question like what do
13:58you mean by electricity? Because in real
14:01world we keep on using this term
14:04interchangeably.
14:06If there is a power cut or electricity
14:09cut sometimes we say power has gone.
14:11Sometimes we say energy has gone
14:13sometimes we say there is no
14:14electricity. Okay. So because of the
14:17common interchangeable use of these
14:19terms in daily life, it becomes
14:21confusing sometimes like which term is
14:23actually correct. So let's look at what
14:26exactly is electricity. Electricity is
14:28not a measurement. It's not a property.
14:30It is the physical phenomena itself.
14:34If you have to define it, you can define
14:36it as the presence and flow of electric
14:39charge. Okay, it's a flow presence and
14:42flow of electric charge or it can be
14:45called as a medium through which
14:47electrical energy can be transferred.
14:50[snorts] So that's the definition or the
14:52difference between electricity,
14:55electrical energy and electrical power.
14:57Let me try to explain it with the
14:58example of this water host system also.
15:01Before that electricity it can be of two
15:04types. You see the static electricity if
15:07you rub a balloon or if you rub a pen
15:09through here and try to lift up the
15:11pieces of paper which we used to play a
15:14lot in our school days. So that
15:17electricity which is because of the
15:19friction and charge it's called static
15:21electricity
15:22and current electricity is what we get
15:25flowing through our electrical lines and
15:27cables to electric devices. It will be
15:30mainly through the flow of electrons or
15:31electrons and holes. [snorts] In some
15:34cases it can be through the flow of ions
15:36also. So if you have a hose like a if
15:41you have a tap the hose there is a water
15:43flow and then we use the water. So this
15:46entire system can be called as
15:49electricity. It's not a quantity. Okay.
15:51It's just a general physical phenomena
15:54which has the concept of water flow and
15:56the pressure that can be called as
15:58electricity. Now if you look at the
16:00total volume or the total work done or
16:03the energy stored as water in the form
16:06of in this bucket or how much water is
16:09actually used that total volume is
16:11nothing but electrical energy. So it is
16:14a measurable quantity and electrical
16:17power is the rate at which this water is
16:20being filled or water is being used. Uh
16:23so if we have high power it means large
16:25flow rate. If if we have small flow rate
16:27if we have low power so that power is
16:29voltage into current that shows you the
16:32flow rate. So the system is electricity
16:34the total volume of that system is
16:36electrical energy and the flow rate of
16:39that volume can be called as electrical
16:41power. So hope that distinguishes the
16:44three concepts of electrical power,
16:46electrical energy and electricity for
16:48you. Let's do one simple numerical to
16:52see like what's the energy and like
16:56what's the difference in energy and
16:58power or [snorts] how we can calculate
17:02the same number in different units. So
17:04if you have a 220 volt 1 ampere electric
17:07lamp to provide light for 30 minutes.
17:10Can you find energy in kilogjles and
17:12kilowatt hour and assuming that if we
17:15use it for 1 month that is the month of
17:18June which has like say
17:2130 days non-stop. So it means 30 days
17:23into 24 hours it is used non-stop. How
17:27much will it add to the electricity
17:28bill? Uh you can assume 6 rupees per
17:31unit. So what we what do we need to find
17:35energy? Okay. So what is electrical
17:38energy? It's power into time. Power is
17:41voltage into current into time. Voltage
17:44is given to you 220.
17:49Current is given 1 aere and time is also
17:53given that is 30 minutes. If I convert
17:56it into seconds you can multiply it by
17:5960. So 220 into 180 0 it will come out
18:03to be 3960 0 something. So that's W per
18:06second. If I convert it to kilojoule we
18:09can just divide it by,000
18:12we get kilo. What second is joule? So
18:16kilowatt second is kilojoule. So that's
18:18the first part of the answer. We got
18:20electrical energy in kilojoule. Now if
18:23you want to convert it into kilowatt
18:25hour there are direct correlations uh
18:29like
18:30one one kil 3600
18:35joule
18:39but if you don't know those correlations
18:41we can still follow the same approach
18:43and try to find electric energy is22
18:47kilowatt because it's like 220 what 220
18:51into
18:54So it's in watt. So if I convert it to
18:56kilowatt, it's 222. 30 minutes. If I
18:58convert it into hour, how much will it
19:00be? 5 hours. So.5 into22, it's1
19:04kilowatt hour. If you multiply this
19:06number by 360, you will get this number
19:10396. So that's [snorts] why we
19:12calculated electric energy in both
19:14kilogjle and kilowatt hour. Now the
19:16second part of the question is if we use
19:19it for 1 month non-stop.
19:22So units consumed for month of June
19:24would be 30 into 24 hours into the
19:29rating that is 222 kilowatt. So it comes
19:32out to be 158. Now this is the total
19:35number of units
19:37per unit price is 6 rupees. So how what
19:42will be the additional cost to the
19:43electricity bill? it will be 6 into 158
19:46it comes out to be 950 rupees.
19:47[clears throat]
19:48So this is a simple numerical to help
19:50you understand how how we can use the
19:53power and energy interchangeably and and
19:56calculate energy in different units uh
19:58and how it is affecting the monthly bill
20:01also if we know the electricity tariff
20:04that is the price per unit. This slide
20:06shows the common appliances that we use
20:07in our houses. And you can see the
20:10rating or the electric energy consumed
20:13in each of those equipment. It goes on
20:16increasing as we move from lights and
20:18TVs and CFL fan or refrigerator to all
20:22the way to gazers, air conditioner,
20:24gizer and washing machines. So what can
20:28you see here like when there is just
20:31direct conversion of electricity and
20:33usage of electricity in the form of like
20:35light or small motors the consumption is
20:39less but [snorts] when we try to use
20:40electricity for large power requirement
20:43like for for say heating it will have
20:46the highest energy demand for motors it
20:48will have like medium energy demand and
20:50for electronics and lighting it is low.
20:53[snorts]
20:53Washing machines and dryers they have
20:55the combination of both the heating
20:58demand as well as the motor requirement
21:00and those motor spinning with all those
21:02clothes and water inside the uh washer
21:06it needs it consumes lot of power. Uh
21:09similarly in gizer like we heat water at
21:12a very fast rate so lot of work has to
21:15be done in a short time. So there the
21:17power requirement is very high. So
21:19that's why you can see the varying power
21:21requirements in different types of
21:22equipment that are being used at home.
21:25So the idea behind showing this was like
21:28everyone knows what are the appliances
21:30at their homes and if these are the
21:33approximate ratings and if you know the
21:36monthly consumption or the monthly usage
21:39of these products you can just do some
21:40simple numerical calculation and
21:42calculate the number of units
21:45consumed and cross check with your
21:47electricity bill whether it's coming
21:50plus - 10 20% what the bill says or not.
21:54The main source of energy
21:57obviously it's the sun because directly
22:00or indirectly all the energy in this
22:02world is coming from sun. There are few
22:04exceptions like which physicists also
22:07called as stellar sources which can be
22:09for nuclear and some aspects of
22:11geothermal. But majorly whatever energy
22:14we see here around us comes from sun and
22:17the source
22:19of energy for sun is the process or the
22:23reaction called as nuclear fusion. What
22:25happens in this reaction? Because of
22:28very high temperatures and pressures
22:29inside the sun's core which is in like
22:31say millions and billion so million°C or
22:34billion bar such high pressure and
22:36temperature the hydrogen atoms which are
22:38there inside the sun they fall apart and
22:42their nuclei they fuse together. So like
22:45four
22:48nuclei of
22:51hydrogen atoms they fuse together to
22:54form one helium atom. But what happens
22:57during this reaction? The mass of that
22:59one helium atom
23:02is not equal to the mass of these four
23:04hydrogen nuclei. It is always less than
23:07the mass of that hydrogen
23:11nuclei. So that difference in mass is
23:14emitted in the form of energy or heat
23:16and light which we get from sun and that
23:18process is called as nuclear fusion. So
23:21since high pressure and hot temperature
23:23they cause hydrogen atoms to come apart
23:26and their nuclei to fuse to form a
23:29helium atom and the mass of that helium
23:31atom is always less than the mass of the
23:34four nuclei that were combined or fused
23:36to form them and that difference in mass
23:38is released as energy which is called as
23:40nuclear fusion. So this energy when it
23:42reaches the surface of earth it goes to
23:44the plants it goes to it can be obtained
23:46in the form of fossil fuels. million
23:48years later it can be responsible for
23:51renewables like solar, wind, hydro and
23:54all these energies then ultimately is
23:56used by human beings or animals or
24:00biodiversity for different purposes. Can
24:03be for electricity, can be for
24:04transportation, can be for consumption
24:07but all these energies as you can see in
24:09the form of light or heat it comes
24:13directly from the sun. So once that main
24:17source of energy is sun, we'll study
24:19about it in more detail when we talk
24:21about solar energy. But now since all
24:24the energy sources come directly from
24:25the directly or indirectly from the sun,
24:27let's see how we can classify them. So
24:30the basic way to classify energy sources
24:33whether it's renewable, non-renewable
24:35doesn't matter. We can call it as
24:37primary and secondary
24:40depending on the one which are either
24:42found or stored in nature. It can be
24:44directly some of them can be directly
24:46used. So those are the primary energy
24:48sources. For example, fossil fuels,
24:50coal, oil, gas, even biomass, hydro and
24:53nuclear they are found in nature and
24:55they can be directly used or they can be
24:58processed and later used again. So those
25:00are the primary sources. Secondary these
25:04are mostly the industrial utilities and
25:07energy sources which are produced from
25:09the primary sources like steam,
25:12electricity, heat and chemicals and then
25:14we use these secondary sources for
25:17satisfying our requirement. So that's
25:19the difference between primary and
25:20secondary. The second way we can
25:22classify the energy sources is renewable
25:25and non-renewable.
25:27Renewable as the name suggests they keep
25:29on getting renewed in nature. They are
25:31not exhaustable continuously produced in
25:33nature like solar, biomass, geo, wind,
25:36tidal, hydro all these things.
25:38Non-renewable they are accumulated in
25:40nature for a long time and cannot be
25:43replaced timely if exhausted because it
25:47took millions of years to form this
25:49coal, oil and gas.
25:52And if we consume the coal today the
25:54same amount of coal it will take much
25:57long time to get it formed. So the
26:01timely replacement
26:03if we take a reference of human one
26:06human life generation like say 100 years
26:08or 200 years it cannot be replaced and
26:10that's why those are called
26:11non-renewable energy sources. So these
26:14were the classification that on two
26:15basis primary secondary renewable
26:18non-renewable. Next,
26:21now since we have seen different
26:22sources, ultimately the sun is the
26:24source. We have seen different types of
26:26energy. The question is, is the world
26:29running out of energy?
26:32No, the world is definitely not running
26:34out of energy. As long as sun is there,
26:36energy is going to be there. So, what
26:39are we running out of? Can the world run
26:41out of fossil fuels? Yeah, that's a
26:43possibility. That's a possibility. And
26:46that's why there is a need to find
26:49alternatives to fossil fuels like
26:51renewables. So coming to the last point
26:53of the today's lecture why renewable
26:55energy. The one thing is obviously if
26:58there if the day comes when we run out
27:00of fossil fuel we need to have
27:01renewables. [snorts] But there are other
27:04reasons also. It's a solution to issues
27:06of climate change, emissions and energy
27:08security. it. They are clean and
27:10eco-friendly with long-term certainty
27:12because sun, wind, hydro, they are going
27:15to be there. Oceans, water, they are
27:17going to be there. So we if we develop
27:19technologies that can generate energy
27:22from these renewable sources, they have
27:24a long-term certainty definitely than
27:27the fossil fuels. Other reason why it is
27:30important the investment in this sector
27:33uh whether it's R&D or the
27:35implementation the commercial pilots or
27:37commercial plants that has been
27:39increasing steadily I think from 2016 it
27:43has increased exponentially
27:45and this has led to like the investment
27:49in R&D as well as this renewed interest
27:52led to the declining of the cost of
27:54renewable technologies as well as the
27:56rise in the efficiency of these
27:59technologies like the solar PV this
28:02example started from like say less than
28:055% efficiency and today we have crossed
28:0820%. At large scale some of the solar
28:12cells have reported even 48%
28:14efficiencies and so with soon I think a
28:17day will come when we would achieve such
28:20kind of efficiencies even in the
28:21commercial scale also but that has been
28:25possible because of the increasing
28:27investment in this sector for R&D and
28:29implementation.
28:31The last point which pushes the world to
28:34go for renewable energy or supports
28:36because the re technologies are heavily
28:39encouraged by policy measures, banks and
28:41environmental legislations
28:44nationally as well as globally. So at
28:48present like when the world is concerned
28:51about the 2° C like limit of climate
28:54change crossing it and we talk about
28:57sustainable development. The shift to
28:59renewables in this era of energy
29:02transition is no longer a choice. It's a
29:05force or mechanical necessity for global
29:08climate stability and industrial
29:10resilience. [snorts] This doesn't mean
29:12that we don't have challenges in the
29:14renewable sector. We do have a lot of
29:15challenges which need to be addressed
29:17and we'll be talking about them when we
29:21discuss about road map to renewable
29:23energy scenarios.
29:25So
29:27if you look at the history of energy
29:29transition you can see like the shift
29:31has how there has been a shift towards
29:34renewable energy. So [snorts] all the
29:36economic and technological advantages or
29:39the advances over the last two centuries
29:43they have transformed how we produce and
29:46consume energy. [snorts] If you look at
29:48this graph simply in 1800 or before 1800
29:52before the industrial revolution started
29:54almost entire human race heavily relied
29:58on biomass to for their supply of heat
30:01as well as food energy and they would
30:04rely on human muscles or animals for
30:07kinetic energy for taking things here
30:10and there for transportation. Okay.
30:12After 1850 when the first commercial oil
30:16well was drilled the usage of fossil
30:20fuel mainly coal started increasing. If
30:24you look at from 1850 to 1950,
30:28okay, before 1900 it was mainly coal and
30:32later towards 1950 the shift towards oil
30:36started with some emphasis being given
30:40towards gaseous fuel.
30:42>> [snorts]
30:42>> But what we see in terms of renewables
30:45which came after like say 1960s or 1970s
30:49that segment has been increasing
30:53considerably. And this [snorts] is the
30:55data for I think 2020 where you can see
30:58the share of renewables and nuclear has
31:01increased enormously compared to like
31:04say few decades or one century before.
31:08But the at the same time since the world
31:11population has increased exponentially
31:14uh we are like 8 plus billion right now
31:17the total amount of energy consumption
31:19or the demand has increased drastically.
31:21So this global primary energy
31:23consumption has almost touched 180
31:26terowatt hours where the major share
31:29even today comes from coal oil and gas.
31:32This traditional biomass is still there
31:35but these are not accounted in the
31:37renewables. The share of biouels coming
31:39in the renewables is different from this
31:41traditional biomass which has been used
31:44for other purposes than electricity. So
31:47with that history of energy transition
31:50we can see the shift towards renewables
31:54is increasing but still we are heavily
31:57dependent on fossil fuels to satisfy our
32:01primary energy requirement. So if you
32:04look at the global investment which I
32:06was talking previously why it is
32:08important to study or know about
32:10renewable energy because investment has
32:12increased in this sector a lot. So
32:15obviously the future of energy is clean
32:17and electric and almost $2.2 2 trillion
32:22has been invested in clean energy in
32:242025 alone where China has been the
32:28leading investor and still with this
32:31investment this much investment the
32:33world's energy transition is much much
32:36far from being complete okay if you look
32:39at the scenario like it shows the blue
32:42colors shows the fossil fuel so this
32:45graph the first bar shows the investment
32:47in fossil fuels and second bar shows the
32:50investment in clean energy energy which
32:51includes renewables, nuclear as well as
32:54low emission fuel and energy efficiency
32:56in grids and storage part. So right from
32:592015 to 2025,
33:02this is the estimated figure for 2025.
33:05But if you look at 2024 also the
33:08investment in renewable power has been
33:11increasing steadily along with the
33:14investment in the other clean energy
33:16sources or the other initiatives aimed
33:19at providing clean and efficient energy.
33:22[snorts] Uh at the same time the
33:25increment in the fossil fuel based
33:28investment is negligible. it it has
33:31either dropped or it has either stayed
33:34constant. So it's not like new
33:37investments are not coming in the fossil
33:38fuel sector but percentage wise or the
33:40growth wise the investment are more in
33:43the renewable sector and as you know in
33:462016 Paris agreement was signed and it
33:49was that year where for the first time
33:51the annual renewable energy investment
33:54in the world surpassed or overcome the
33:57fossil energy investment. So uh that
34:02agreement the Paris agreement which
34:05included like all the member nations of
34:08the world and all the major countries
34:11giving their nationally determined
34:13contributions NDCs towards climate net
34:16zero where India has given the net zero
34:18target of 2017. It confirms that the
34:22world's energy transition is ongoing
34:24with lot of investment being made in the
34:27renewable sector and renewable energy is
34:29going to play a key role in this energy
34:31transition. So with that I think we are
34:35coming towards the end of today's
34:37lecture. So to summarize we started with
34:40the basic definitions of
34:44energy,
34:46power,
34:48work. Then the type of like electrical
34:51energy, electrical power and
34:54electricity. Okay. After those basic
34:56definitions, we saw how all the energy
34:59is coming from sun directly or
35:02indirectly and the source of that energy
35:04being nuclear fusion. Then the energy
35:07sources and their classification primary
35:11and secondary. The other classification
35:13was renewable and
35:17non-renewable. And then we looked at the
35:21need for renewable energy or the
35:23importance of renewable energy in
35:25present world like it provides solutions
35:28to climate change. There has been a lot
35:30of investment and on the basis of energy
35:33transitions history we see that the
35:36interest in renewable energy is growing.
35:37The shift is a forced shift as well as
35:42no longer a choice now because the
35:45fossil fuels can go down any time and
35:48now with recent news of like US Israel
35:52Iran war you can see the impact on
35:54fossil fuels it has. So there is no
35:57stability in the fossil fuel sector. So
36:00if all the countries which have ample
36:03renewable energy resources, if they
36:05become self-sufficient and develop
36:06infrastructure based on renewable energy
36:09in addition to having good storage
36:11capabilities, it can prepare the world
36:14better for any such unexpected conflict
36:17also. So with that, let's stop here and
36:20thank you so much.
36:26>> [music]
36:35>> Heat. Heat.
36:42[music]

About this transcript

This page contains the full transcript of Lecture 01 Introduction : Part 1 by IIT Roorkee July 2018, generated from the public captions YouTube serves with the video. The transcript has 5,416 words across 832 segments, with the original timestamps preserved so you can click any line to jump to that moment in the embedded player.

What you can do with it

Use the transcript to take notes, quote the speaker, build a study guide, generate a summary with ChatGPT or Claude via the YouTube Summary tool, or export it as a timed subtitle file with YouTube to SRT. You can also re-open it in the transcriber to translate the transcript into 100+ languages.

Free YouTube transcript tool

YouTube2Text is a free YouTube transcript generator — no signup, no daily limit. Paste any YouTube link and get the full transcript instantly, with timestamps, click-to-jump, translation to 100+ languages, AI prompts for ChatGPT, Claude, and Gemini, and exports to TXT, SRT, VTT, or Markdown.