Renewable Sources of Energy Continued

so let us continue our renewable sources of energy session here so the next kind of energy we have here is fuel cell so what is a fuel cell what is a fuel cell fuel cell is a electrochemical device so what does it do what does a fuel cell do so it consume energy this is electrochemically wise that is fuel cell consumes not energy consumes a fuel and convert this fuel into electricity so this is very much similar to a battery so if we compare fuel cell and a battery the working is very much similar but the major difference is that in which in this fuel cell we have continuous supply of fuel and in battery you have discontinuous supply that is it has chemical stored inside so battery has hm stored chemicals stored chemicals which react and produce electricity so for the stationary fuel cell power systems which are valid for commercial power generation the major fuel that is used here is hydrogen so this hydrogen fuels are hydrogen ah fuel would say is input is input to produce electricity so electrification different tools may take place in the form of different chemical process is electricity generation so a typical fuel cell that is hydrogen fuel cell can be seen here so we have hydrogen that is going in here and electrons hydrogen is here we have it is bitted into ions ionization happens here and electrons are going through we have oxygen a going in here water and air is going in here and un used gases gases go out so this flow of electrons here generates electricity so we have a node cathode and this electrolyte here in this case this continuous supply is here this is whats these the major property of fuel cell continuous supply the phenomenon is very much similar to battery but this is a continuous supply so the kind of reaction that is happening here is in at anode side the reaction is this hydrogen is being split into hydrogen ions h plus electrons this is two into two i would balance this direction four ah then four electrons then we have cathode so at cathode what is happening this oxygen is reacting with our hydrogen ions that is

this thing plus electrons to produce water which is this water is made to go out here so in this case also we have four and four so net reaction becomes the hydrogen plus oxygen is producing water this is combining these two reactions so this is how electrons are being produced here and electricity is generated so another source in place of hydrogen may be natural gas so in current stage of fuel cell application there is a limitation of hydrogen production now hydrogen production has limitations hydrogen production is an issue so this is ah is limited as well as cost is high in this case so stationary fuel cell power systems are available in the market which are primarily built for natural gas fuel so natural gas is mainly composed of methane which is the major component in natural gas so in this case the power system leads to generation of carbon dioxide the reaction becomes c h four methane plus water generates carbon dioxide plus h two so this is directly i am putting the net reaction here so we can see that we have carbon dioxide as an output here so a tradeoff has to be made that we are using a kind of renewable energy or may kind of fuel cell which is a renewable energy but this resources these resources are being used used here and carbon dioxide which is a green house gas let say green house gases is produced so if natural gas based fuel cell power system is to be used for energy supply for a manufacturing system or for a big and concerned a quantitative tradeoff analysis must be conductive ah i would better here write quantitative quantitative trade off analysis that is the impact on both the sides that is a use of impact use of a natural resource then emissions of carbon dioxide that is carbon foot print these must be evaluated guest the energy efficiency that is the energy output only so net environmental vision savings of using the fuel cell power system over local grid electricity that is the local grid electricity might be ah thermal power plant thermal if hydro power plant is there then it is good so it has to be compared with this one so in such case the life cycle emissions of the fuel cell power system must be considered in this trade of analysis so this must be considered to access the affect of environmental mission mitigations so next kind of energy

i have is geo thermal energy so what is geo thermal energy how do we utilize this one are the question what is and how so geo thermal energy is the heat from the earth ah geo thermal energy is the heat from the earth so it is also a clean and sustainable kind of energy that is sources of geo thermal energy ranges from ah the shallow ground hot water then may be hot rock if it is found at some distance beneath the earth if it is found at some distance and this distance is beneath the ground surface or i would write earth surface so these can be the sources of geo thermal energy here so this difference in temperature is utilized to generate electricity so even down deeper to stimuli high temperatures of molten rock for example i would even write ah molten rocks or magma these can also be utilized so almost everywhere the shallow ground or the upper three meters of earth surface three meters is about ten feets maintains a nearly a constant temperature for example if i say this is my earth surface and this is three meters height then this temperature here is about ten to ten degree to sixteen degree centigrades which is equivalent to fifty to sixty degree fahrenheits so this temperature is always there so most power plants needs steam to generate electricity the stream rotates sector wind that activates a generator which produce electricity many power plant still use partial fuels to boil water for stream so geo thermal power plants what they do they use steam produced from reservoirs of hot water ah that do there found couples of miles and more below the earth surface so when we go below the temperature is higher at certain places so this difference this hot water found at a few kilometer below the earth surface is used to produce steam so there are three kinds of power plant ah where that use geo thermal energy so this a kind of power plant the cold water is pumped down and steam and hot water is coming up so this difference is used to generate electricity here electricity even transported to the grid so the transportation is happening here so this is being the cycle is being running so this cycle is running continuously here so the main issue here is building this set up to take our connection to the this much depth so this is i say if it is may be five kilometers so there are three kinds of geo thermal power plants number one dry steam geo thermal power plant number two flash steam

geo thermal power plant number three is binary cycle now dry steam power plants draw from the underground resources of steam the steam is piped directly from underground wells to the power plant so where it is directed into a turbine and generator unit so this dry flash and binary cycle geo thermal plants have ah different kind of mechanisms of use number one dry geo thermal plant so the dry steam of geo thermal plants draw steam from the underground resources stream from underground resources the steam is actually directly made to pass through the pipes for underground wells so we have underground wells here so these are well this is ground surface here we steam is made to pass through pipes under where we have pipes going through here and steam is made to pass through here so this steam is made to pass through these underground wells to the power plant where it is directed to turbine so we have the power plant here and the generator or turbine is here with its spins and this steam is made to fall to this turbine and this one turbine is rotating this shaft and we have generated electricity so ah as this steam flows upward the pressure decreases and some of the hot water boils into steam the steam is then separated from the water and used to power the turbine generator now left over water here condensed now next i have here is my flash steam power plants these are similar phenomenon but it used because see the name here is flash so it uses steam that is ah there in water so they use geo thermal reservoirs of water with temperatures may be ah of the order of two hundred degree centigrades so this hot water flows upward ah under its own pressure and when its flows upward the pressure decreases some of this water boils into steam so this water we have water here the water reservoirs at some places we have high temperatures here so this high temperature made the water to flow up in form of steam so this steam is captured here we have steam here this steam is captured here and it is made to flow to our power plant so ah this is again we have the similar kind of arrangement here turbine is being run by this steam and steam is electricity is generated so ah anyway water or condensed steam here are injected back into the reservoir here so anyway water is injected back so another is third one binary cycle now these a pattern water at low temperatures so they have the temperature these less that is of the other temperature was this was of the of the order of the two hundred degree centigrade if it is specifically in us they say it one hundred eighty two centigrades so in this case temperature is less than one hundred and eighty two degrees

so these plants use the heat from hot water to boil a working fluid ah and which usually an organic compound with low boiling point so this working fluid that is an organic compound is then vaporized in a heat exchanger to turn a turbine so the water is an injected back to the ground that is reheated so this cycles is made to run again and again so there are no air emissions or very little air emissions in this case so this is similar to this process flash but the difference is that in place of ah taking this steam directly to the reservoir this steam is used this steam is used to heat a fluid here used to heat a fluid here this fluid is this is an organic compound generally now this fluid is heated and is then made to to the turbine to generate an electricity for generating electricity so this is only difference from the flash steam process so next i have is bio mass energy so what is biomass bio mass is an organic material bio mass is an organic material that comes from plants and animals plants and from animals so you might have heard of the term photosynthesis what is photosynthesis plants absorb the energy of sun and this process is called photosynthesis this energy of sun is again then turned into the bio mass which is used as then renewable source of energy here this bio mass so ah ah when bio mass is burned this chemical energy energy in bio mass is released as heat so this photo synthesis actually this is sun that stores energy in plants so when this is burned chemical energy is released is released as heat which can be used so this is used to generate electricity so this bio mass can be either burned directly but this creates smoke or it can be converted into bio fuels if you could recall we had an energy ladder in which we had the bio mass here and here we had the advanced fuels that is petroleum etcetera so this was actually if we burn this directly if here this was the condition if burnt directly so some examples of bio mass

and their uses of energy are wood and wood processing waste i can even write it here wood and wood processing waste than these are burned to heat buildings to process process heat in industry and to generate electricity then we have agricultural crops and waste materials then these are burned as fueled or they are converted to liquid bio fuels they are converted to bio fuels then along with this we have food or wood waste in garbage also we have animal manure so this animal manure are may be human sewage so these are also converted into bio gas these are converted into bio gas which can be burned as a fuel so in this case food wood waste garbage these are also burned to generate electricity in power plants or they are also converted in to bio mass bio gas here so i have a kind of electricity generation plant in which we have this bio mass materials as input so in this case this electricity is produced and being supplied to the grids here the bio mass here is the pulp paper plywood cotton anything can be used and from animal sides also we have ah animal residues say dung etc so here also we have process residuals so this fiber can be ah used to make materials then consumers used at then food products also the consumers could used here and when the consumer use the waste is produced waste that is bio you can be uses as bio mass the solid waste the municipal corporation can segregate the waste into the categories the waste that can be used as bio mass that is from construction demolition wood yard trimmings non recyclable organic compounds here they can be used so this decomposition and combustion can be ah done to have electricity which can be again used by the consumers here this is a kind of a bio mass cycle here ah bio mass can be used in this way so next as i have discussed certain kinds of renewable sources of energy it is cost benefit analysis so to conduct the cost benefit analysis various models are available ah to know the pollution reduction to have the tradeoff between the cost and benefit and to ah have the relation between the various efficiency levels and for all kinds of energy here so one of the model here is developed by yaum in two thousand thirteen which can be applied to all kinds of clean energy in this model we have ri this model takes into consideration the emission factor this is actually vr we have emission factor that is of pollutant from local grid power supply another factor it takes into a count is the life cycle emission

life cycle emission of what of the pollutant if i say one pollutant pollutant i this pollutant i may be carbon dioxide this may be ah the some other air emissions so if i say pollutant i here this may be carbon dioxide sulphur phosphorus or other pollutant emissions so in certain cases if i say life cycle emission of pollutant this same i from ah ah the clean energy right so ah in this case ah for example in certain clean energy cases this pollutant might even be zero so ah here we have the difference of these two factors if i say this factor is e for i pollutant emission for i pollutant from local grid and this is emission of i pollutant from my clean energy here j is my clean energy so this is kilograms of carbon dioxide that is produced per kilowatt hour if i say carbon dioxide is the pollutant that is chosen here or this is again kilogram of the pollutant per kilowatt hour these are the units here so this difference ei local minus ei of my clean technology is a factor here so this factor also involves total installed capacity of clean energy now this total installed capacity is again multiplied here i will put it a j installed capacity aj clean energy system here the system j now i have tj here as well tj here is operational lifetime of clean power system here the operational lifetime ah i can put some unit may be in hours in minutes whatever like so this is also a multiplicative factor here so this ri is proportional to that is what is ri that is also needed to define here ri is the emission reduction of pollutant that may be this pollutant i which the units may be hm kilograms per rupees one lakh may be these are the units and also this emission reduction factor is inversely proportional to our cost so here i have the cost over i would say overnight cost of clean power system so this cost is rupees per kilowatt this is overnight cost of my clean power system j is my clean power system and plus i have variable cost variable cost of operation and maintenance

of my clean power system this is clean power system j this is clean power system this is also the time is for my clean power system j j this cost is rs per kilo watt hour so this is variable cost of my clean power system j so this variable cost of my clean power system j also comes here so because this is variable cost this highest dependent on time so the time for which my equipment is operating also comes into play here so i also have the fixed cost of operation and maintenance of my system j so this c fixed cost of my this is fixed cost of operation and maintenance of this clean power system j this is again rupees per kilo watt hour so this cost also needs to have this factor aj so this is my emission reduction of the pollutant this j j can be my solar wind geo thermal fuel cell biomass any kind of clean energy may be chosen and how is this related to my local grid this is explained or this is considered here in the present model so this cost benefit analysis can be applied on any emission reduction from the grid electricity conversion manufacturing using clean energy supplies so this quantitative result ri is the amount of emission reduction per unit scale of economic unit input or investment so we can we can see economic input or investment is on the denominator side so per unit economic input or the investment is also there fixed cost is also there so it must be noted here that the results are the site dependent on the geographical locations due to difference of emission factors of local grid power supply and the actual powers output of the clean systems so it is dependent on site here so in this section the application of clean energy supply for conventional manufacturing systems are demonstrated the reductions are taken into account and we have discussed various kinds of clean energy resources and how do we even evaluate their efficiency so i would like to have a break here and in the session that would be a continuation of this session only will discuss the ah renewable renewable energy status in india also we will discuss the concept of industrial symbiosis so let us meet in the next lecture thank you