[MUSIC] Hi, welcome to the first class on Energy Accounting. We, in this class, we'll provide the general framework to be used or to organized and understand the quantitative characterization or the qualitative energy in social-ecological systems. And in the first session here, we will look at the possible narratives and labels they are used to do accounting of energy and especially how we can generate coherence quantitative assessment. So energy is semantic concept that is associated with non-equivalent and non-reducible measurable quantities, when using different narratives. So, we have to be very careful when we are start making numbers about energy because the issue is extremely complex. Let's look at a few examples of quantitative energy assessment. We can say the energy of a molecules of oxygen in the air is 0.03 electronvolts. Electronvolt is a unity of energy, extremely, extremely small as in the order of 10-19 joules. And so this is a useful quantitative assessment. These works only on when starting behavioral things very very small and the time of submission that you do are very limited within a specific experimental setting. We could have another type of quantitative assessment. For instance, the ATP, the ATP is a energy rich molecules is the biochemical fuel that the gasoline uses itself we can even measure these, In molecules of ATP be 58 joules per gram of ATP, assuming 3,600 turnovers of 50 grams per capita. Again, we can use this assessment, this is valid only within a specific reference framework. We could have another assessment, the calories of a chicken breast 100 grams, we can use a calorimetric bomb to measure. The equivalent would be 150 kilo calories, very useful assessment for diet. Still, this works in a specific narrative. What if we go in an assessment of the consumption of New York City? At what type of energy force should be considered? And, of course, if we're looking at the solution adopted by the US Department of Energy, they are describing the consumption of New York City by using a set of energy fuel. Petroleum, hydropower, natural gas, nuclear electric power, they have to define first a set of energy forms and then give an assessment on the chosen set. Of course they are not using electronvolts, ATP molecules, chicken breast kilocalories. There are other forms of energy that's probably are important to maintain the metabolism of New York, the gravitational energy. If you don't have gravity, all the skyscrapers in New York will just fly away and we are not considering solar energy. Keeping the atmosphere and the temperature in New York within a range or value that make possible life. But I mean, we don't consider that, so there is always an arbitrality in what we define as the energy consumed by a metabolic system. So we are attempt to include only at energy forms they are directly ride to the function express by the metabolic system. So this is extremely important because then we can not mixed all types of energy forms. For instance, if we are looking at a energy consumed by horses, you have a chain of energy conversion. You have a converter inside the horse, these are the horses, then this is the fuel that is converted by the converter inside. This is the primary energy source, pasture, from which you can get hay. And then, at that point, when you have, a combination of outside view and inside view, and a sect of energy forms there, primary energy sources, carrier, and use, and final users, you can defined energy form that we can measure, 11 megajoules per kilo. But let's imagine that we do the same for a car, then we will have the energy converter is an engine, and that is used to power the car, and the engine is using gasoline as energy input, and the prime energy source is a reserve of oil. Again, we can get into this chain of energy forms, but this chain of energy form is not equivalent to this one. That is, we cannot sum 11 megajoules of hay to 44 megajoules of gasoline. Why is this important? Because the definition of energy is very generic which the ability to induce change in a given state space or the ability to work. But this definition are impredicative in the sense you have to define what is the state space, what can be changed in order to define and measure what has been changed or the same for the work. You have to define what is work and how much work has been done? And moreover at times is not easy to define this biophysical transfer if you are measuring the energy effort of a policeman directing the traffic and of orchestra director. A directing an opera, it will be difficult to find out the qualitative difference in the work done by the two, a person. It is even worse, the problem is that when we talk about energy we're not addressing the time dimension, the power issue. We would see that the power issue is crucial in defining the difference between endosomatic, exosomatic energy. Our society, modern society, has changed compared with the society because we have access to huge amount of power that I mean, the ability of doing things, a lot of work or moving heavy objects in a very short period of time. So energy per se is only one part of the story. So, before getting into a quantitative assessment of energy, we should define first the descriptive domain. So what energy forms are we addressing, so what is the scale of the analysis? That a lexicon, what are the energy forms including in the finite set that we are using, and that a set of a production rules determining the expected relations on all the different energy forms. If this is true then there's a question to be answer, how it is possible if we have all of these different energy forms in the different levels of analysis? That energy statistics are using only just one energy form for their analysis. As a matter of a fact, this is a problem if you are looking the energy going into a society, if we're looking in terms of primary energy sources, so in the interface, outside view, inside view, you can see that we're looking at the amount of primary energy going into electricity. Process heat of fuels, for instance, electricity is 36% of the total. But then, if we are looking at the final use, the pattern of consumption of energy carriers. So we are measuring this time electricity in terms of actual joule of electricity. So what is inside of our grid? We see that comparing the joules of electricity, the joules of heat, the joules of fuel. Electricity is only 18% of the consumption here. What's going here that, of course, the joules of energy carriers are different from the joules of primary energy sources. And this is a sort of confusion, is a situation in which we cannot win because since these fittings are different, you cannot compress one into another with a single protocol. Let's see an interesting twist of this problem that you can get when comparing statistics. The statistical office use two approach to deal with this problem that the primary energy sources. The mix of primary resources is different from the mix of energy carrier. One is called partial substitution method and is used by the Bridge Petroleum of the American Statistics. And another is physical content method is used by Eurostat and the International Energy Agency. So that would give an example, let's imagine that you have the production of electricity, you have 500 joules, 200 joules, 300 joules produced by 3 different way. And we will see now how, so this is assessed by a British by statistics our assessed by yours. So let's imagine if 50% is done by using chemical energy, 20% is done by using nuclear energy and 30% done by hydro. So what the partial substitution method does in this case, is assuming that all the electricity is produced using chemical energy in that sense. The conversion thermal mechanical is came from thermal and chemical is 2.6/1. So this is a qualitative weighting of the importance of the electricity. So whatever, if the electricity is produced actually with chemical and thermal, they are saying 2.6 to 1. If it's produced by hydro, doesn't matter because this will be mechanical energy use to produce mechanical energy because electric energy is a mechanical form of energy. This is the problem. We cannot store it. So the sum here would be 130 joules of chemical energy. These are actual joules. And 520, 780, these are not real joules. They are equivalent joules. That means the joules that will be required to produce this amount of electricity using chemical energy. And this is why this is called tons of oil equivalent. They are not actual tons of oil. This gross energy requirement thermal that will be primary energy in the form of thermal chemical energy will be required to produce this mix of electricity, this amount of electricity with mixed primary resources. Let's see now what happen if we're using the Physical Content Method. Again, we are at the same rate, 50, 20, 30, producing a chemical over in hydro. And what are the conversion factors? And then, what is important to see here, that the aerostat, using a category of accounting that is bizarre, it's called energy commodity. Of course, that doesn't have any bio-physical meaning and then, so the conversion is 2.621. This is how much thermal you use to make one of electricity for nuclear, the conversion is 3 to 1 because it's formation is the nuclear is more heat than in power plant. And the last is the most bizarre solution is that hydro synthesis mechanical energy getting in and mechanical energy getting out. And hydro is cold, is no heat in the power plant, is 1 to 1. So basically, this is the sum, and these are actual quantities of energy, this is why it's a physical content method. So you don't have equivalent, but this may be a problem because as a matter of fact, in this way, you are summing 1 joule of mechanical energy as if it were with the sum of thermal energy, in this sum. This is something that goes against anything known by engineers. I am an engineer, I studied in school because of thermodynamics was exactly established to handle the fact that 1 joule of mechanical energy is different from thermal energy so the thermodynamic cycles were exactly introduced to establish quality conversion factor, we do mechanical thermal energy. In this protocol of statistics, they are just examining one-to-one. What are the consequence of these fact? Because it's not just theoretical problem with thermodynamics. It's that in Sweden, in 2005, hydroelectric produced more electricity than nuclear. But I mean, if you are looking at the statistics, those who are using Partial Substitution Method more or less reflex this difference. Those that are using the Physical Content Method are statistics used by Eurostat in the International Energy Agency will tell you that nuclear is produced three times more than electricity renewables. Again, there is no body full. You cannot win. In this case, you are calculating a quantity of energy do not exist don't some equivalent. In this way, you are under estimating the contribution of alternative energy because they are producing mechanical energy that is under estimated in the account. So what would be important here that, to be clear, one would have to learn what the energy consumed by a society, you are to have two big categories that cannot be mixed. Primary sources, these are important because they are energy. They are outside human control. They must be available. They cannot be produced an energy carriers that are produced and under control and they must be viable at the sense they have to be other probably you have enough labor and power capacity to ample that. The primary energy sources refer to the external view and energy carriers to internal view the inside the societies or outside the society. Then, there is another important difference. The one Given by thermodynamic, there is thermal energy and mechanical energy. By using a full two-by-two matrix, basically we can have, when we are talking about primary energy thermal, we will have a gross energy requirement. This will be the type of thermal that you need to make energy carrier. In the end, you will have the supply of kinetic energy from natural processes, you can use to do, for instance, electricity or whatever else. On this side, you have either chemical energy in fuels, or thermal energy in process heat. And then, in this case, you will have the electricity supply. So this will be, an example here, would be tons of oil equivalent. An example here would be the amount of kinetic energy or mechanical energy given by hydro or weight power. This would be the amount of energy in a kilo of gasoline, and then this will be 1 kWh of electricity. Of course, if we are calculating this in joule, this will be 3.6 MJ of mechanical energy. We could have these calculated as an equivalent, multiply, for instance, by 2.6. But then this would imply, they will no longer belong to this place but will belong to this. When we are multiply a joule of electricity by 2.6, then we are changing the quality of the assessment, is no longer an energy carrier. But it is how much primary energy would be required of thermal to produce that electricity. So we are getting into another category of account. So conclusion, we have to be aware that there is a difference between primary energy sources, coal, crude oil, waterfalls, uranium. These categories of energy cannot be created or produced. First Law of Thermodynamics tells you, we cannot make energy. We must have available energy, so prime energy sources are energy sources that we cannot make. We have to have that. And then it would be nice to keep a physical accounting of that, and not energy accountings of tons of actual oil, no tons of oil equivalent. Tons of coal, kilo of uranium to have, these have gradients that the catabolic part of the society can use to make energy carriers. The energy carriers, electricity, fuels, steam, heat, whatever. These are inputs required by energy converter used by humans to generate useful energy, for example, car, a vacuum cleaner. This is a converter that require a physical input, and these are the energy carriers. This input bring energy to the machine. So energy carriers can be produced, but they need a primary energy source to be exploited. So in order to produce energy carrier, you have to consume energy carrier, and then the energy carrier as a cost of production. The time and energy sources do not add. The logical criteria is that AC must be measured in energy unit. All the energy used may be reduced in joules, but we should be aware that a kilowatt-hour, for instance, a joule of electricity, a joule of fuel, or joule of for heat, you could use kilocalorie or BTU, should not be mixed, because there are different things. You cannot fly an airplane on kilowatt hour for the moment, and we cannot run a mobile phone on a joule of gasoline. So the more we are keeping the different categorical accounting separated, the more effective is our categorization of the metabolic pattern of energy. Finally, we have the last category that is end use. What you do to end use? What you do with the energy carrier? Also, what are the function that be performed by the society? So the logical criteria is that the end use must be useful for the society to reproduce themselves. So the different end use are reflecting the integrated set of function that the society is expressing. And unfortunately, it is very difficult to express, assess, and use in quantitative form outside the context. We could have some, Generic, useful energy, figure is how much you can cool down something, or eat, or lightening a room, or kilogram, kilometer for transportation. But in general, when we are looking at the big picture at the performance of the society, end use our better measure by contextualized what the end use means within the metabolic pattern. That is what we will do in the next session.
