BIO-105 Lecture 9 – Energy Part 3

Just another WordPress site

BIO-105 Lecture 9 – Energy Part 3

energy sources come in renewable and nonrenewable types we’ve already covered the non renewable energy sources there would be nuclear power and the fossil fuels coal gas and oil and now we’re going to move on and do the renewable energy sources we’re not going to cover every single my new type of renewable energy source that’s out there we’re going to hit just a select few one thing we can see on this slide is the price of generating electricity now one of the things that is true is these prices change constantly as innovation and research takes place the prices are fluctuating all the time if you watch the price of gasoline you’ll see how the price of gasoline fluctuates all the time and that’s a energy source that we know how to make we know how to produce and really not a lot has changed and yet we still see wild fluctuations in price so for example at the moment our slide here is saying that solar full solar photovoltaics are producing electricity about 30 cents a kilowatt hour and the price of that has actually dropped a little bit since the slide was made it sits in the mid 20 cents range nuclear power we can see there it’s 10 to 21 cents notice the bars colored in a little bit different there so nuclear power is actually selling electricity around about 3 or 4 cents but this 10 to 21 cents would be if we actually will include in the price of containing the nuclear waste so that’s more of a realistic cost than the actual cost of new to nuclear electricity and we’ll go through the other solar systems but on the whole you can get average for solar is about 20 cents a kilowatt hour so wind power wind power has actually gone down at the moment when power is roundabout in that four to seven cents a kilowatt zone so where do we need to have it to be competitive in the marketplace and actually make a profit well electricity sells for about eight cents a kilowatt hour so if you were to look at your bill you’ll see that you’ll being charged about eight cents for every kilowatt that you’re using in your home now to make money the electrical generating company needs to be able to make its electricity for about four cents a kilowatt hour so coal power is making electricity at the moment for about four cents natural gas it’s slightly cheaper than that it’s making it at about three to four cents hydroelectric about four cents wind power is in at four to five cents so it’s a little bit more expensive than it should be solar power is really making it in that six seven eight to twenty cents so that’s more expensive than it needs to be nuclear power if you include getting rid of the waste is way more expensive than it needs to be so obviously some of our fuel sources are economical to use and some of them are not economical to use so what we need to do is go through our renewables see which ones are economic to do now and which ones may become economic in the future if we do enough research and development and get our technology better one thing that’s definitely true is that the cost of generating electricity using renewable resources has dropped dramatically over the last twenty thirty years the price of making electricity using solar power has dropped dramatically since about 1988 and now it’s getting close to a point where with a few more tweaks you could actually do it sustainably and still make a profit wind power has dropped dramatically and with new technologies you can now build wind that will make it at about four or five cents a kilowatt making it close to what coal and oil actually make electricity for the price of coal is only set to go up because it’s a non-renewable resource and as we start to run out the price will increase price of nuclear power is definitely going to go up if we include trying to get rid of the waste so we knew Abell energy prices are dropping as research and development continues the price per kilowatt goes down non-renewable prices keep rising the price of having a clean up coal when we include cleaning up air pollution the

price of having to seal away the waste when we talk about nuclear power keeps adding to those costs as well as the fact that the fuel sources themselves are non-renewable and therefore becoming depleted they become rarer and because of supply and demand that cost goes up so if we’re going to get sustainable society we have to look towards renewable energy sources and those renewable energy sources need to be produced at energy at about 4 cents a kilowatt around the world renewable energy sources provide almost 13% of the energy that we use now you don’t remember that most of this is going to be in less developed nations and they’re primarily using biomass as their energy source now biomass may not be able to provide enough energy to run a modern economy like that of the US so we need to look through the different types of renewable energy sources to see which can actually support an industrial nation the first thing to understand is that no single energy source will support an industrial nation if it’s completely renewable you have to diversify if you’re going to use renewable energy sources solar power will not work in every area of the country when power does not work consistently all the time in every place you have to find have a diversified energy structure and the plan is not to get rid of non-renewals altogether we can use non-renewable resources as long as we use them at a slow rate so that we don’t run out in a very short term so what we should be using is some natural gas natural gas is available in large amounts provides extremely high quality energy source and is very low pollutant biomass which we can produce and is totally renewable and can also be converted into natural gas so we get a large amount of biomass obviously you can’t cut down trees and use their wood to feed the industries of the United States but you can convert biomass into gas that’s usable or in electricity the primary renewable energy source would be solar radiation virtually all of the other energy sources we’re going to look at already have looked at I just packaged solar radiation so why not jump to the front of the queue and just use the solar energy directly don’t convert it into evaporated water and then rain and then use that energy don’t package it into plants and then convert those plants into oil and use that for energy just utilize the solar energy as it comes onto the planet the Sun produces way more energy than the nations of the world need every day so if we can find a way to harness it it’s an extremely efficient and long-lasting source of energy if you look at the map you can see that not every state in the United States can use solar energy all of the year some parts of the United States just do not lend themselves to be in good solar energy producers what we need is areas with large amounts of sunlight during summer and winter where that sunlight is gonna happen every day it’s not going to be cloudy for weeks on end so that we can collect our solar energy efficiently and produce stable energy production so when you plot that on a map of the United States and Canada this is what we see obviously Alaska would not be a place where you’d want to try and run your economy on solar energy but down towards the southwest and southeast there is solar energy available most days out of the year a rate of delivery suitable for producing electricity so as we’re saying before one of the things you cannot do if you move to a renewable energy system is say it’s a one-size-fits-all energy producer Malt ng in michigan from solar radiation will not be continuous enough for of high enough quality to be able to put solar thermal power plants that expect them to work whereas if you work in about New Mexico then for most of the

time there is harness of all solar energy there that can be used to make electricity and therefore some states are going to have to be exporters of electricity made from solar energy and some states would have to be importers of electricity from solar energy electricity is not the only way to use solar energy though so low energy connection we produced three basic ways the first one is just passive solar heating and I’m sure with all parked our car in the summer gone to college or gone shopping and then come back open the door and jumped in the car and it’s just a furnace particularly if you’ve got vinyl seats now if you’ve ever had known somebody with the car with vinyl seats and you jump on the seat and your skin just Sears to those seats you know exactly what I’m talking about well that’s an example of passive solar heated you didn’t do anything to make the car warm you just parked it in the Sun and because of the physical nature of the materials the cars made from the inside warms up it gets harder and harder at the inside of the car becomes much hotter than the air around the car the way that works is that the solar energy passes through the gap of the glass of the car through the windshield through the back screen through the windows and when it passes into the car it changes its not now just light but with it interferes with the other materials in the car actually becomes infrared it becomes heat and that heat can’t pass back out through the glass therefore is trapped inside the car so passive solar heating just needs an area of collection which is normally going to be glass and an area of absorption the place where the heat will be collected there’s no pumps there’s no special way to make this happen all you have to do is just do a design where you have an area that lets the light end and an area to collect the heat so the heat collection could be a concrete or stone floor area oh it could be a fluid area for actually warming up a fluid this is an example from a house in Atlanta this house belongs to the South Face organization and they’re an organization designed to helping people build renewable and high-efficiency housing so the windows let in sunlight and our floor is a thermal tile and a very high thermal density concrete so what happens is sunlight comes in heats up the floor and then throughout the rest of the day that floor radiates back that heat now in Georgia it’s not heat that we really need as I sit here doing this it’s 101 outside so you can see that the room looks dark that’s because there are shades sticking out over the windows so that in the summer the heat does not make it onto the onto the floor and during the winter this room is provided in large amounts of heat for the house my parents still live in England and they have a system that’s very like this they have on the right-hand side of the diagram here a conservatory a glass walled room sunlight comes into that room and makes it hot and this thermal floor and at the base of of the room there that film of flooring absorbs the heat and passes it in to the rest of the house so at my parents house the conservatory will absorb heat heat up the floor and then pass that heat into the dining room adjacent to it so the walk the the warmth will pass through the floor and the floor will be warm to touch that floor then radiates the heat into the rest of the house so in the wintertime heat is collected outside the house in the conservatory in the glass filled area and passed into the rest of the house in the summertime you have to put shades up and you have to insulate the floor to stop heat being passed into the room now of course that’s not a problem because we’re in England so summer’s only three weeks long a very different problem than we find here in Georgia we’re cool in the homes is the most important thing so that was a passive solar system the heating just happens and the heat is then passed to other areas of the rooms with active systems you have to actively move the heat from one place to another you’re actively collecting it at a series of collectors and then depositing

the heat elsewhere so an active system always is going to have a pump somewhere and that pump will be pumping a fluid of blowing hot air through the system so you deliberately move in the solar energy collect in it moving it to where you’re going to use it now a classic example of this is in a building in Sacramento that I visited recently Sacramento the capital of California where they have some college buildings that have active solar heaters on their roof now when you go to college students always you know need to go to the restroom and after we own a restroom they should wash their hands so all colleges have water heaters that are heat in the water so people can wash their hands and those water heaters are either electric or gas they use large amounts of energy but studies show that very few students ever actually benefit from it a large number never bother to wash their hands after using the restroom and the rest of them turned the tap on washed their hands turn the tap off before the hot water has ever even made it to the sink so this building in Sacramento they designed it so they could put water pipes over the roof so embedded into the flat roof of this building right underneath the black tar sealant or a series of water pipes and all day long the Sun beats down on the roof now if you’ve ever left a garden hose out in the middle of summer and if a garden hose is just sat there filled with water with a Sun beating on it all day and then you turn the water on the first water that comes out the hose is extremely hot well that’s the idea here waters sitting in pipes up on the roof the heat from the Sun warms that water up and then the pump pumps that water down and that water is what people are using to wash their hands so during the summer months they’re using very little electricity or gas to heat the water up to a comfortable hand-washing temperature during the winter they just turn off the section on the roof there and it just goes back to an average normal water heater type system so this is what our system in California would look like with the solar collector absorbing energy up on the roof of the building and the water then being fed down towards where people are using it and it doesn’t have to be on the roof of the building also in Sacramento there’s a building where the parking lot is the solar collector the water pipes run underneath the parking lot every day in summer the parking lot absorbs large amount of heat heating up the water for use in the building now this is an active system because of the pump the fluid is being moved through the solar collector it’s been pumped and collected energy in one area and then the energy is delivered to somewhere else so in an active system there must be a pump so passive systems no pump it’s just fed through just through the natural flow on the movement of the heat just normal natural movement from an area of high concentration to an area of low concentration along its concentration gradient active systems that must be a pump we’ve got to physically be pumping a collecting fluid to a solar collector and then bringing it back into the area where it’s going to be used both passive and active systems though are only useful in heating areas if you live in Georgia and you do that during the winter months but for most of the year we’re more interested in cooling areas and if you want to run your computer or you want your lights and your honor on your TV active and passive solar systems won’t do that so a more interesting way is to turn solar energy into electricity how can we harness that solar power and use it to make electricity and there are two different ways of doing that the first is called a solar thermal power plant so solar thermal so sun’s heat now remember this is a power plant and in most power plants what we’re trying to do is boil water so in a solar thermal plant we’re going to collect sun’s energy and use that energy to boil water in most plants that involves a Heelys that field Heelys Nats are focusing moveable mirrors they have to move because they have to track the Sun as the Sun moves over the sky Joe in a day there focusable because they’re going to focus that solar energy if you’ve seen a Toy Story the boy grabs woody and he uses

his magnifying lens to focus the Sun and burn Woody’s head so that’s what we’re trying to do here we’re trying to collect large amounts of sunlight and focus that energy so we can collect it and use it to boil water so we can run a turbine driver generator and make electricity now obviously this is going to use large amounts of space solar thermal power plants use a lot of land because you’ve got to have a lot of area for those numerous here’s one example of a solar thermal power plant the Gila snap field that’s using up all that land is focusing its sunlight onto these bounce down lures now again the bounce down mirror is focusable it can change its focus to get the maximum concentration of the sun light so the the mirrors are bouncing the sunlight back onto these focusable mirrors here this bounces it down to this collector this is the outside view at the same time you can see that there’s mirrors in here that also focuses in the light they’re moving the light down making it more and more concentrated this is the top looking down that collector so the solar collector is focusing the light all the way down to the bottom where there’s a plate of maybe 3/4 inch steel and that’s where all that sunlight is being focused now that sunlight is extremely concentrated at that this time so to stop the metal plate from melting from burnin it has a coolant flush by it and that cool it’s just water so this continuous water flowing behind the metal plate at the bottom of this count that water absorbs all the heat flashes to steam drives the turbine spins the generator and that makes our electricity this is a different type of solar thermal power plant this one doesn’t have a bounce down mirror now you can see the he Lestat field and the Gila snap field is focusing all the sunlight into the black cylinder and the black cylinder is therefore boiling the water and then the steam comes down into the cream square bowl then on the right hand side there and that’s where the generator is so solar thermal energy is collecting sunlight and using it to produce steam so we can make electricity it does have the downside that it takes large amounts of land it does have the downside but not every state can use this only certain states because you need to have sunny weather you’re gonna have so many weather for most of the time be no good if you live somewhere where it’s snowed and all the mirrors covered with two foot of snow it’s got to be in a sunny place New Mexico is our example but even with those downsides there’s another downside that happens all the time and that is night at night there is no Sun at night is when everybody comes home and turns on their lights and turns on the TV and wants to cook dinner and we get a big spike of electricity use right when the Sun Goes Down right when our power plants would no longer be generating the electricity so to the left of the center there is a big silver building looks a bit like a battery and that is a natural gas container so during the day this power plant runs on solar energy and each night it runs on natural gas so it’s got a natural gas backup now downside right there it means that this power plant is more expensive to build you’ve got to build a gas plant and a solar thermal plant at the same time it’s going to be more expensive upside the natural gas lasts you twice as long because it’s only being used at night during the day it’s using solar energy and the other upsides Coster off national security the USA has its own sunlight we don’t have to import it from any one Sun lights right here within our borders nobody can stop the Sun coming out so it is very good for national security economic security it’s our own sunlight we’re the ones producing it so it does have benefits in terms of natural security pollution during electricity production solar thermal power plants are producing no pollution whatsoever they do decrease the work force solar thermal plants need very few workers most of it’s controlled by computers so compared to coal where we have all of the coal miners all of the railway engineers all over the railway builders to deliver coal to our power plants nobody has to work to

deliver sunlight so the number of jobs in the industry is significantly less and at a time when our economy is struggling when we have a high unemployment rate and getting rid of jobs can have some very negative impacts so this is a slightly different solar thermal power plant this is a non-central Clacton type so rather than all the heel stats collecting the solar energy and focusing it into one central point this is more diffuse power plant each individual Heelys that focuses the light onto the black bar running down the center there and boils the water inside that black bar it saves the need for having to align all of the mirrors and so this this makes it just a little bit cheaper it’s not quite as efficient but it makes it a little bit cheaper without having to align all of the noise with that central collection area so solar thermal plants aren’t working at night but they are generating electricity close to the amount that we need to generate close to that for five cents a kilowatt hour this next one is solar panels and the correct term for solar panels is photovoltaics now photovoltaics have been around for a long time I’m sure you’ve got a calculator that runs on a solar cell I’m sure that you’ve seen watches that went on out and you can buy battery charges that a fault of Voltaire so for producing small amounts of electricity photovoltaics X the Space Station the International Space Station has tons of solar panels and produces large amounts of electricity for itself using photovoltaics but the space station has got a big advantage over the rest of us number one it’s out in space so there’s no clouds to cover up over the photovoltaics there’s no rain or snow landing on it and the energy from the Sun is much higher out there and also you can position it so it can stay within the sunlight much more often than your house can you can’t position your house to make sure the Sun is always going to strike it so photovoltaics have a lot of the same downsides as normal solar power they also are slightly more expensive to produce so photovoltaics do not produce energy in that four percent so four cents per kilowatt hour slot that were looking at they are more expensive than that really pushing up into 10 to 20 cents per kilowatt don’t think that the solar photovoltaics have to look like a big nasty solar panel like you see out on Space Station this section of roof is actually shingled with photovoltaic shingles now the photovoltaic shingles here are deliberately a black color so you can see which ones are the fault fault acts which one’s the normal shingles they won’t have to be that color they could just be an all more blended color so that you wouldn’t tell but the fault of our techs just come as a sheet looks just like shingles from normal and what you do is you wire them together as the roof is put together and as they kept together they generate electricity for the house every time the Sun shines the cost of those fault of our tech shingles really makes them out of the reach of most people often so if we’re trying to provide realistic energy sources photovoltaics at the moment just did not provide cheap enough electricity to supplement what we’re doing with natural gas so when we’re looking at solar power solar thermal power stations supplemented with natural gas seem to be at the moment the most economic renewable source after solar power now going to move on to wind power and we wind power and all we do is we miss out a step we’re no longer going to boil water to generate steam have the steams turn a turbine and that turbine spin the generator the turbine becomes the wind mill so the turbine is spun by the wind so there’s no boiling water here this is a new system so we’re just going to take a windmill let the wind blow the wind more and that is the turbine that turbine will spin the generator the generator will make the electricity a wind turbine generating area is often called a wind farm so here’s a wind farm found in Scotland you’ve got to find in

a windy area you need to put up your windmills and then those turbines have to generate the electricity now that means you can only put them in places with large amounts of harness of all wind george w bush’s administration did a survey to see if there was enough harness ville wind energy in the United States to actually make an impact on our energy supplies and their study suggested that just the Dakotas alone had enough harness able wind energy to supply the electrical the electrical needs of the entire United States so harness for wind energy is out there now of course there are some problems one problem is the places that have lots and lots of harness of a wind energy tend not to be the places where all the industry and homes are so they tend to be in more wilderness areas so we have the problem of should we be destroying wilderness areas to build wind farms and then we also have the problem of well how do you deliver all of the energy that’s produced there to our large industrial areas so if you’re going to use wind power you have to have a very robust national grid system the series of powerlines that spread throughout the nation to deliver power where it’s needed the problem of using up wild lands for our wind farms can also be overcome it’s one of the main benefits of wind power is that you can still utilize the land for other resources and if you have a nuclear power plant or a coal plant that land is not being used for anything else it is a coal plant it is a nuclear plant but if you have a wind farm you can still continue normal farming and right underneath it you can grow your corn you can grow your cows you can grow your sheep you can continue to utilize that land for any other purpose that you need you can have an apple orchard right underneath it and you don’t even have to have it on the land and there are a number of wind farms that are offshore and this is an offshore wind farm and what I want to do is switch to the next slide just so you can get an idea of just how large these wind turbines are now surprisingly the number one most often quoted reason for not putting up wind farms would be aesthetics that is people saying that they’re ugly and there’s one of the weird things that I would guarantee that a coal plant is always ugly a nuclear plant is always ugly and given the choice of a coal plant a nuclear plant or a wind farm wind farms would definitely be the least ugly of the three I’m not saying they’re not ugly but given the choice of having to produce electricity or not making electricity of the types of power plant that you could use wind farms are probably the least ugly they do have some real problems though the book probably talks about them killing birds and the amount of birds kills has dropped dramatically because the modern wind turbines spin much slower their main problem is the wind the wind does not blow consistently at the same speed it comes in two fits and spurts and therefore the electricity that’s produced is not consistent in its amount so unlike your car battery that always provides 12 volts unlike the electricity that’s coming to your house that’s always a hundred and ten volts the wind turbines spin faster and then slower and faster and then slower so they tend to peak and then drop off peak and then drop off so you don’t get a nice constant steady supply of electricity that is incredibly difficult to deal with you cannot allow these spikes in the electricity system imagine what spikes of our crew City do to your computer when it gets one of those little things it just turns off so you have to be able to even out the flow of electricity and on an on windy day that means you have to supply extra electricity from another source so again we’re back into you can’t just use wind power on its own on a non windy day you got to get your electricity from somewhere else so that’s pushing the price up because you can’t just have a wind farm you’ve

got to have a natural gas plant that can produce electricity when you need it to so there’s two areas there that we definitely have to overcome number one we’ve got to even out the amount of electricity that comes from the wind farms it doesn’t matter whether the wind is blowing at 10 miles an hour 50 miles an hour it doesn’t matter whether it’s smooth wind or really gusty wind where it’s blowing hard one minute blowing softly the next the power plant has to produce a nice steady even amount of electricity and if we can do that then we’ve just got to overcome the problem of even when days when it’s not windy where do we get our electricity from on windy days it’s easy you get it from the wind but on non windy days where do you get that electricity from so if we can fix both of those then wind energy becomes viable because there’s plenty of wind around the United States it would be good for national security and as long as we’re building the wind farms here it would be good for the economy the last renewable energy source were going to do is biomass now biomass is BioLife mass stuff is stuff produced from living things so biomass as we’ve already said is the number one fuel for people in less developed countries but how can we more developed countries use biomass as an energy source there are four main sources of biomass energy fuel wood municipal industrial wastes agricultural crop wastes and energy plantations few weren’t as the name suggests is cutting down trees and utilizing the wood for energy right burning wood produces large amounts of air pollution if you’ve ever sat next to a campfire and had the smoke blow in your eyes when you’re trying to actually cook your hot dog or cook you your s’mores you know about the pollution that’s in that smoke gets in your eyes you can’t see feels like you can’t breathe and wood itself is fairly slow growing so there’s no way we could use fuel word to support a industrial society it doesn’t grow fast enough it’s too pollutant crop residues and animal wastes I would different idea this is now not growing trees and using those for energy this is utilizing scrap trash waste now if you think about corn when we grow corn we grow a field of corn what we take away from that corn is the actual corn kernels and what we’re left with is the cob and all the shuckin’s and all of the leaves and all of the stems that’s our crop residue that’s what’s left when we go wheat will take away the seeds and we’re left with everything else if we have a pig farm we want to eat the meat from the pig but during its life that Pig produces large amounts of dung and that dung is our biomass residue now because this is a leftover this is now not being produced deliberately as an energy source it’s just leftover materials it does have large amounts of usable energy we haven’t used any energy to produce this we were growing these crops farming these animals anyway this is leftover stuff so how can we get that energy out we collect the energy from those crop residues in exactly the same way as we would collect the energy from an energy plantation the difference being that energy plantations are deliberately glandt grown to generate our biomass now the downside here is that we are growing a crop specifically for energy use and that always has the downside the downside is we produce in a crop using lots and lots of energy input we’re putting into the crop diesel fuel because we’re using a tractor to plow the field diesel fuel because we’re using a contract to plant the field diesel fuel because we’re using combine harvesters to collect the crop we use in oil products because we’re using pesticides and herbicides on that on

that crop we use a natural gas and oil because we generate in fertilizers for that crop so when we look at all the energy that we put into our energy plantation the actual net amount of gain that we get is usually quite small so actually using an energy plantation is not as efficient as using crop residues a classic example right here is corn and the United States we’ve been obsessed with you getting energy from corn using corn to make ethanol the problem being that you have to put large amounts of energy into that corn production before you can actually use it to make any ethanol and normally we’d be eating the corn so as soon as you use corn as an energy source the price of corn to eat goes up so we’re removing a food source to gain an energy source doesn’t seem to make a lot of sense for most environmental scientists so got a bit off track there what we’re supposed to be talking about is so how do we use our crop rennet residues to make energy and there’s a couple of different ways we’ve got direct combustion ethanol production and anaerobic digestion right so notice that it’s now making stuff round about nine eight cents a kilowatt it’s a little bit too expensive to work right now we definitely have to utilize some more research to get this down to the four cents a kilowatt that we need so let’s go through each one and see how they work all right the first one is direct combustion and as the name says it’s directly combusted you just take your cooperated you and you burn it so you could going to up and feed it into a coal-fired power plant as a supplemental food a food fuel item you could feed it into a trash dieter burner an incinerator just as a supplemental fuel for that incinerator not the most efficient way of doing it the only thing you can use of the product of this is electricity that’s what you’re generating and of course with our economy using so much electricity it’s very hard for us to generate enough residue and to support a high energy use economy like that in the United States number two that was ethanol production and the state of Georgia is really pushing ethanol production here in exactly the same way that you would make whiskey you would take a crop you take those seeds you ferment the seeds those fermented seeds then get distilled and in the alcohol the whiskey is produced from that what we would do is we would take this organic material we would ferment the organic material you would make alcohol from it that alcohol is then distilled off and you produce alcohol that can be mixed with gasoline or used instead of gasoline to do that efficiently is extremely difficult there are two basic ways of producing this alcohol the first is to ferment in sugars the second is fermenting the cellulose or lignin now the fermentation of sugar is what we do at the moment because it’s nice and easy at the moment in the US we grow corn we collect the corn syrup the corn sugar and then we digest that corn sugar down with bacteria and it produces alcohol we ferment it and generate the alcohol and that’s no different than making whiskey it’s no different than making wine o different than making beer it’s nice and simple we convert sugar into alcohol the problem is we use in a food product a sugar to generate our alcohol what would be much more beneficial is if we could turn the cellulose the non-food product as cellulose is the leaves and the stems you can’t digest cellulose or the lignin lignin is wood the product that is would if we could digest those down convert those to a sugar use an enzyme that would break those down to make sugars and then those sugars would be converted into alcohol it means we could use waste products so all the people that you throw away could be converted into alcohol all of the grass clippings could be converted into an alcohol or we already talked about the corn stalks and corn shuckin’s and the corn on cobs all that would be converted into alcohol and he leftover pallets and he left over building materials just ground down and could be converted into alcohol any wooden material would be made into alcohol that would be by far the most efficient because then for every crop

you get you get to produce the food crop and everything else is collected could be converted into alcohol the hard step in there is the enzymes needed to digest down that word or that cellulose so that it becomes a sugar that can be used by the digester by the fermenter now a lot more research needs to be gone into that area before we can do this efficiently here in Georgia we recently had two plants built within the last two years just to produce alcohol from wood and one of them lasted less than a year before it went bankrupt the technology is just not quite there yet Georgia wants to go this route because we used large amounts of wood for chicken farms our farms do a type of chicken rearing called deep litter where the chickens live on bed of pine shavings and when they finished their chicken mashed the chicken poop and all the pine shavings are a waste that has to be gotten rid of well that’s a prime foods feed sauce for a digester if you could have a ligase digester get the lignin in there digest it down make the sugar from it it’s a huge source of energy and hopefully Georgia will actually get through that research and be able to make large amounts of energy from that we are not there yet and the last time that would be our anaerobic fermentation instead of breaking it down and turning it into alcohol this time we’d break it down and turn it into natural gas so same types of thing you can collect all of the waste this time it’s not only food type waste and Ana and plant waste it’s now also sewage so any cow sewage any Pig sewage any sewage coming from chicken farms can all be collected together digested down and produce natural gas we actually have this in most sewage treatment plants around the United States will have small versions of this they do it out in Seattle where they produce large amounts of natural gas that are actually used to make electricity so this is being used around the world to actually produce electricity and they take the gas they burn the gas or they take that gas and they put it into a fuel cell and that fuel cell then makes electricity so the last one is actually doable right now so methane digestion is a very efficient way of using leftover agricultural materials as well as sewage to produce energy again the price is not competitive with using natural gas straight out of the ground at the moment we need to get more efficient in our digesting works the enzymes that we use to break down on nutrients so that they become methane it’s very close it’s only sitting about six five six cents a kilowatt-hour but methane digestant is very close to generate in electric electricity at the price that we need to to be efficient and if we’re doing our agricultural wastes then why not do all the rest of our waste one thing that we could do is do a trash to energy system where we have an incinerator and you would burn your normal waste and when we look at trash municipal solid waste we’ll talk more about how to convert trash into electricity and the last idea in this lecture on energy is not a natural energy source it is energy conservation by far the cheapest way to make more energy available is to just be more efficient with the way that we use energy we are extremely inefficient at the moment in the United States and most more developed countries now we said way back at the beginning of the course that the second law of thermodynamics says every time you do energy change useful energy is lost well when we take the internal combustion engine only about one dollar for every ten dollars of gas you put in pushes the car forward the cars that inefficient it’s the same with incandescent lights only of you know about 10% of the electricity that goes into a normal light bulb makes light so we are extremely inefficient at utilizing the

energy that we provide if we can be more efficient you have more efficient engines get more miles per gallon then the gasoline will last as long or oil as a resource will last as longer if we can use less energy and light in our homes like compact fluorescents then there’s more electricity to go around so we have to burn less coal so we need less solar power or wind power to generate the amount of energy we need instead of having engines that’s been more efficient and used for your cells your textbooks got a whole chunk on how fuel cells are much more efficient because they’ve got no moving parts than normal engines and generate high-quality energy very very simply so if we could just become more efficient even though that doesn’t produce more energy for us it means that there’s more energy to go around remember that the population of the planet is increasing so every year there were more people trying to use energy so if we continue as we are today that just increases the rate at which we’re using up on non-renewable sources if we’ve become more efficient then those same non-renewable resources will last for much longer and will supply the needs of many more people so we can switch this is that South Face house again the energy efficiency house and this is not in fact a light this is a solar tube it collects sunlight from the roof and with a series of lenses and mirrors focuses that light and passes it out into a room it looks like there’s a light bulb in there it looks like the light is on to light that room you can see the two lights each side of it that switched off so this is just passing sunlight down into the room so that no energy is actually required to light this room during the day there’s no windows in the room so normally it would have had a light in there and everybody coming in and out would have kept the light on and what we’re doing is we’re lighting it more efficiently we’re just being efficient in our design we’ve got more efficient water heaters actually covering your water heater with water heater blanket and insulating the pipes from the water heater to make it more efficient so that you use less electricity for the same amount of hot water we’ve got an efficient front-loading washing-machine trying to be more efficient with using less water so that we don’t have to heat as much water to do our daily washing we’ve got a high-efficiency dryer drying the clothes using less electricity even better still don’t put them in a dryer use a line outside we’ve got more efficient vehicles this one happens to be a plug-in station for an electric vehicle so that you don’t use any gasoline at all moving around but that would only be good if we were generating the electricity in an efficient way if we were using an inefficient power plant and this really wouldn’t help much but as long as the electricity was actually being produced in an efficient non polluting way this could help and this is probably the number one thing that you can do to help and that is when you buy products actually look at their lifecycle cost you have done a worksheet on lifecycle cost so you should know what that is by now and that worksheet and this slide is really just to remind you when you buy things if you buy the most efficient one that is often over the life of that item the cheapest decision to make and if you buy the things that are the most efficient that tells manufacturers that they need to build more efficient things and therefore we become a more efficient economy