hey everybody it's mr smeeds and welcome to apes video notes for topic 6.7 which is energy from biomass so our objective for today is to be able to describe the environmental effects of using biomass as an energy source and the skill that we'll practice at the end of today's video is describing responses or solutions to an environmental issue so the first thing we'll talk about today is biomass versus biofuels so biomass is just basically any organic matter this could be wood charcoal dried animal waste or just dry you know brush or grass that is going to be burned and it's usually going to be to heat a home or to cook food over so one thing i want to point out here is that this is primarily used in developing nations this is because it's easy to harvest it's also going to be oftentimes free or very inexpensive so it's used as a subsistence food remember that means just getting by essentially just meeting your basic needs so we can see a picture here of someone uh presumably in the developed world or in the developing world gathering what looks like you know some dried palm trees to take home and again probably burn to either heat their home or to cook their meals over it can be used to generate electricity but this is pretty rare there was sort of a biomass push for generating electricity a while back when it was thought to be more environmentally sustainable but it's not used as often as fossil fuels because it's just so much less energy dense and it's kind of you know time intensive to gather all that biomass compared to mining coal or oil so we can see a diagram here of basically this idea that you can just kind of chip up your wood or grind it into small pellets and then feed it into a fire that's going to you know turn water into steam and produce electricity just in the same way as if we burn fossil fuels but it's not really widely used so that's just something to be aware of then we'll talk about now biofuels so biofuels are going to be liquid fuels such as ethanol or biodiesel and these are created primarily from biomass such as corn sugar cane or palm plants and so typically we plant these and then harvest them to convert them again into a liquid fuel this is primarily because we rely so heavily on gasoline as our liquid fuel for transportation and so it's a great either replacement or sort of supplement to liquid fuels like gasoline and next we'll talk about the idea of modern versus fossil carbon so it's important to note that burning biomass does release carbon dioxide but it doesn't increase atmospheric carbon dioxide levels in the same way that burning fossil fuels does so this is because when we burn biomass we're releasing what we refer to as modern carbon what this means is that this is carbon that was recently in the atmosphere in the form of co2 and it was recently taken into a plant via photosynthesis whereas when we burn fossil fuels we are releasing fossil carbon so this is carbon that was basically stored underground and out of circulation for millions of years so we are essentially effectively adding new carbon to the atmosphere that was not previously in circulation so burning biomass is something that we consider carbon neutral and again it's not a perfect wash it's not a perfectly you know carbon neutral activity but overall it's not going to increase atmospheric carbon levels in the same way that burning fossil fuels does another way to think of this is spending a dollar that you just found kind of easy calm easy go it doesn't really change your net worth but if you're starting to pull a lot of money out of your life savings and spending that money you are decreasing your life savings you're decreasing your net worth and so again think of it as spending a long term savings dollar versus a dollar that you just found on the ground if we look at this diagram here we can understand a little bit better how this works so we have the atmosphere carbon dioxide is taken in by a tree then when it's burned it turns that carbon dioxide uh releases it back in the atmosphere and so it's a relatively balanced cycle but when we burn fossil fuels we're burning carbon that had been out of circulation under the ground you know for millions of years and adding essentially what we would consider new carbon back into the atmosphere next we'll talk about some of the environmental and the human health consequences of biomass burning so one thing that we should know is when biomass is burned it releases carbon monoxide nox particulate matter and volatile organic compounds or box these are all respiratory irritants to humans so this is a big cause of respiratory irritation and respiratory disease globally overall about three billion people around the world cook the majority of their meals on open biomass fires and so again when this is done indoors this is going to basically exacerbate or make the problem worse when you're burning a fire indoors for heat or for cooking the pollutants are trapped and they're not allowed to be dispersed as easily and so this is going to worsen asthma worsen bronchitis copd emphysema it's going to irritate the eyes so we can see a picture here of a woman again cooking food here in a relatively closed space and so all of those pollutants that are produced are going to be trapped in that house and they're going to be building up in higher concentrations and they could lead to respiratory problems for both this woman and her small child so when we talk about environmental consequences we should know that biomass burning leads to deforestation and the release of specific air pollutants remember really making an effort here to emphasize air pollutants and not air pollution air pollution is a vague kind of fluffy eco-jargon term air pollutants are specific compounds that are released so one reason that this occurs so much in developing nations is a lack of environmental protection laws or the enforcement of those laws and even more so the lack of these sort of financial resources to be able to afford other fuels besides for subsistence fuels and so both of these things contribute to deforestation for energy use in developing nations it also is going to lead to habitat loss as we are cutting down trees and removing forest ecosystems it's going to lead to soil erosion as there are fewer roots in the ground to stabilize the soil it's going to decrease the ability of forest to take in carbon and sequester it through photosynthesis and then finally we're also going to have the release of specific air pollutants in this case nox or nitrogen oxides vox volatile organic compounds and particulate matter and it's important to know important to point out that from an environmental standpoint these are all contributors to the formation of smog so that can decrease sunlight it can lower the rate of photosynthesis and we'll talk more about smog in depth in unit 7. next we'll take a look at biofuels which again are liquid fuels primarily from corn and in some cases algae so in this uh example here we have corn and sugar cane which will be fermented into ethanol which can then be mixed with gasoline and so the basic process is that corn and sugar cane are harvested they are broken down or ground up uh to break down some of the cellulose and make their sugars more available and then yeast is added to the sugar mixture and that's going to enable the yeast through the process of fermentation to convert that sugar into ethanol and so if we take a look at a diagram here again what we can see is that we have the collection of the corn it's going to be milled or broken down and that's because cellulose is very hard to digest and so if it's broken down mechanically first the yeast are able to access those sugars so the sugars are kind of concentrated and then the yeast are added so there's fermentation and then distillation to distillation to separate out particularly the ethanol which is valuable and that can be transported and mixed with gasoline to basically lower the amount of petroleum we need for transportation and so it's important to point out though that this is typically not used by itself so typically ethanol will be mixed with gasoline in a mixture called e85 or flex fuel so this is about 51 to 83 ethanol with the rest of the mixture being made up by gasoline and it can only be used in flex fuel vehicles that's important to point out it does decrease the oil consumption needed for transportation but since ethanol is less energy dense than petroleum you need more ethanol or more e85 to get the same distance out of your vehicle we should be aware here that while this may seem renewable and it is renewable by a definition by the fact that corn can be replanted and sugarcane can be replanted over and over and over again uh so it is technically renewable but it's only as sustainable as your agriculture to produce that corn and to produce that sugar cane is so if you're degrading your soil through intensive tilling and through fertilizer use it's not going to be sustainable long-term and so just very important that we point that out it is renewable by the textbook definition but it is not necessarily sustainable if your monocropping or your agricultural methods are not sustainable so we should be aware of environmental consequences that come with ethanol production and these are basically all of the consequences from unit 5 where we covered consequences of big agriculture and so these would be things like soil erosion habitat losses would clear land to plant the corn the release of greenhouse gases from the soil and from the machinery used as well as from the fertilizers that are applied to the fields and of course water consumption one thing to point out is that a lot of corn is needed to generate ethanol enough to be used for transportation so that can compete potentially with human or animal consumption of corn so it may impact corn prices in the us that could be an issue now one way that we can produce ethanol a little more sustainably is through algae so algae are actually able to be grown cultivated and then harvested and the algae can be basically dried out and you can do fermentation with algae to produce a bioethanol similar to the way that we do it with corn but it can also have oils that are extracted and those oils can be turned into a biodiesel so it's important that we know that algae is a potentially more sustainable option for producing biofuels or biodiesel and finally we'll wrap up today by looking at biodiesel so this is going to be different than biofuels biodiesels are still liquid fuels but they're produced specifically from plant oils so there's no fermentation there's no ethanol being produced it is the oil from the plant that can be burned as a fuel source and so the most popular form of biodiesel comes from palm plants and so these are typically grown in tropical climates but it's important to point out that some recent studies have concluded that palm bio diesel actually produces 98 percent more so almost double the greenhouse gas emissions compared to equivalent energy production through fossil fuels and this is due primarily to the fact that you have to clear land oftentimes tropical forest for the palm plantations so if we look at this graph here we can see that over time the share of the total contribution to global climate change of palm uh has risen over the years as it's become more popular to basically generate this alternative or seemingly renewable fuel source and so again we should point out it is technically renewable by this idea that we can continually plant palm trees and we can't continually get more and more fossil fuels but it's not necessarily sustainable if the underlying agricultural methods are not sustainable so it can be more sustainable if we're using land that's already been cleared or land that is not productive in a forced ecosystem already or if you reuse plantations over and over and over again then you can bring down the greenhouse gas emissions sort of per unit of energy but again with all biofuels i want to point out that they are only as sustainable as the agricultural methods that underlie them and then if we take a look at this picture here it can just kind of remind us of some of those environmental consequences that can come with producing energy through biodiesel so we have carbon dioxide release as forest is cleared and can no longer sequester carbon in the future and also decay releases some of the carbon stored in those trees we have loss of habitat of course there's going to be soil erosion when you clear land and then finally we lose the ecosystem service provided by those trees which is you know loss of air and water purification so for practice frq 6.7 today our skill is describing a potential response or approach to an environmental problem so the first thing i want you to do is explain why biodiesel fuels have a different effect on atmospheric carbon levels than fossil fuels do and then also to describe two environmental benefits of using algae for biofuel production rather than corn or palm oil or sugar cane