# Presentation: 180490

## EMERGY & ENERGY SYSTEMS

**Session 3 **
**Short Course for ECO Interns, EPA and Partners**

**Notes:**
In the previous session, the concept of energy flow through a system network was reviewed, along with a diagramming language for representing the network.  These diagrams will be used extensively from this point on to illustrate emergy definitions and theory.  As you absorb the material about emergy, pay close attention to each diagram.  Every detail of every diagram has a particular reason – the order of the components, the direction of the pathways, and so on.  The more diagrams you work your way through, moving from left to right and verbally describing what you think is being represented, the easier it will be for you to translate your own system’s concept into an accurate diagram that other emergy researchers can follow and that could be turned into a simulation model later.

## Introduction to Emergy

- Emergy definitions and concepts
- Fundamental emergy budgets and human interfaces

**Notes:**
In this session, we will talk about some basic emergy definitions and concepts (beginning with emergy itself).  We will present an overview of the fundamental earth budgets and the derivations of the emergy values that are used for every evaluation regardless of scale.  We will also talk about the way emergy bridges the interface between  natural resources and socio-economics.
This will be strictly a conceptual discussion, with more details and sample calculations reserved for later sessions.  Remember to refer to Environmental Accounting (Odum 1996) for more examples and in-depth discussion of principles whenever needed.

## Emergy Definitions

- Emergy
- Available energy of one kind previously required directly or indirectly to make a product or service (emjoule)

-  Solar emergy
- All energy beginning with solar inputs to the environment (solar emjoule or sej)

**Notes:**
Emergy is defined as the available energy of one kind previously required directly or indirectly to make a product or service.  Remember the pyramid chart that we turned on its side in the first session and the blue boxes that tracked all the energy lost in each energy or material transformation.  In effect, this is the emergy associated with the end product.  Of course, this simplified approach leaves out energy that comes into the system at various points in the chain that increases the total emergy as you convert energy into the next level.  However, it illustrates the principle of tracking all the energy required to make an entity at any point in the transformation process.  Emergy can be thought of as the energy memory for an end product.
Any kind of energy could theoretically be used to track this process, and at one point emergy was calculated using coal equivalents.  However, this makes it difficult to establish values for materials less concentrated than coal, and because solar energy is for all practical purposes the only input to the otherwise closed earth system, all emergy is now calculated using solar energy equivalents.
Emergy calculates a quantitative measure of any item or service based on its donor value, what is required to provide that service or product.  This removes the fluctuating and sometimes uninformed user defined value.

## Review: Concentration

**Review: Concentration**

**1E10**

**5E5**

**5E5**

**1E6**

**1E6**

**1E6**

**2E6**

**5E5**

**5E5**

**2E6**

**1E6**

**J/t**

**5E4**

**3E4**

**2E4**

**1E4**

**9.99E9**

**9.9E2**

**9E4**

**1E10 sej/t**

**1E10 sej/t**

**1E10 sej/t**

**1E10 sej/t**

**Notes:**
As energy comes into a system, it is used in a process of transformations that continually decrease the total amount of energy available for work at the next step, but that increase the amount of useable energy in relation to the amount coming in.  This can be thought of as increasing quality of energy – the quantity of energy is lower but the ability to do measurable work is higher.  One example is the conversion of vast amounts of sun into a large amount of plants over time converted to lumps of coal which by itself can heat a room, but, when transformed one more time into electricity flowing through a wire, can light up a city.

## Review: Concentration

**Review: Concentration**

**Energy**
**Transfers**

**1E10**

**1E7**

**1E5**

**1E4**

**1E10 sej/t**

**1E10 sej/t**

**1E10 sej/t**

**1E10 sej/t**

**J/t**

**Sun**

**1E10**

**1E7**

**1E5**

**1E4**

**1**

**1E3**

**1E5**

**1E6**

- Energy Transfers
- Joules/time

- Transformity
- Solar emJoules/Joule

**Notes:**
The diagram at the top is an aggregated view of this energy concentration process.  The previous diagram has been simplified by combining all of the photosynthetic units into one, then doing the same for the herbivores and again for the carnivores.   The middle bar graph shows the decreasing levels of energy available at each stage.  The original energy coming into the system from the sun is being tracked or “remembered” all along the chain from left to right, and since no other energy is crossing the boundary at any point, this original value (1E10 Joules for every unit of time) is the “energy memory”, or emergy, for each transformation step.
When the emergy at each step is divided by the energy outflow, a ratio is calculated that is known as the transformity of the item at that point in the hierarchy.  The bottom bar graph illustrates these ratios, and you can see that the ratio increases with progress up the hierarchical chain.
At this point don’t worry about the terms such as “sej” or “transformity” being new.  All of these and more will be defined in a few slides.  What is important to remember is this:
 The energy along any pathway can be quantified 
Energy is lost to the system at every transfer process
The ratio of total energy coming into the system to the energy leaving any component is a useful number known as the unit emergy ratio, either transformity or specific emergy..

## Emergy Definitions:Unit Emergy

- Transformity
- Emergy per unit available energy, solar emjoules per joule (sej/J)
- Specific emergy
- Emergy per unit material, solar emjoules per gram (sej/g)

- Emergy values for specific items

- 100 sej
- 10J

- 100 sej
- 1g

- T = 10 sej/J

- SE = 100 sej/g

**Notes:**
The technical name and definition for these unit emergy ratios differ dependent upon whether the entity is better represented by an energy measure (joules) or a material measure (grams).  If the ratio compares emergy inflow to unit energy outflow, that ratio is called a “transformity”.  If it compares emergy inputs to unit material outflow, the ratio is the “specific emergy”, similar to specific heat associated with the mass of compound or element.

## Emergy Definitions

- Empower
- Emergy flow per unit time
- Solar emjoules per year (sej/yr)

**Notes:**
Just as we defined power in the energy review as energy per unit time, empower is defined as emergy per unit time.  Most regional evaluations are actually evaluations of empower since we collect data defining the annual flows into a system.

## Emergy Concepts

**Emergy Concepts**

- No loss along paths
- Emergy is cumulative
- Maintenance
- Accumulation stops when entity is made
- Different uses for different data
- Input/output vs. internal processes

- Internal

- Input/output

**500 sej**
**50J**

**100 sej**
**50J**

**800 sej**
**20J**

**1420 sej**
**15J**

**120 sej**
**5J**

**300 sej**
**10J**

**500 sej**
**10J**

**20 sej**
**5J**

**620 sej**

**800 sej**

**1420 sej**

**Notes:**
Emergy, although linked to energy, is not a physical entity and has defined properties rather than physical.  For example, while energy is dissipated with every transformation into another form, emergy is not lost along the same pathway.  In addition, once an entity is complete, the energy required to maintain it is not added to the emergy value of the item.  This begins a completely different process and is better evaluated at a larger scale rather than for a single item.
Emergy can be computed along any pathway in a process or system.  How these values are used depends upon the purpose of the evaluation.  If you are trying to determine the value of a region or commodity, the emergy crossing the defined boundary is added together.  However, if you are trying to evaluate the net benefit of a system to different groups or other systems, the values are used to complete more complex equations assigning positive and negative attributes appropriately.

## Emergy Calculations

- Energy versus emergy
- Multiply energy by unit emergy ratios
- Unit emergy ratios used here
- Environmental average: 2.61E4 sej/J
- Purchased average: 5E5 sej/J

**Notes:**
This is a simplified diagram of the inputs to a hectare in tomato production.  A certain amount of energy is derived from the environment and other energy is added from the economic sector in the form of fertilizers, gas to run tractors, money for services and farm labor.  For this illustration, all of these disparate additions have been converted to joules, but grams would work as well. These values are obtained from real systems in operation.
The top diagram presents the raw data for the system and is called an energy diagram.  It is instantly recognizable by the arrow at the bottom indicating that the second law of thermodynamics applies.  In this diagram with the heat sink at the bottom of the boundary, the energy inputs equal the outputs, with the majority of inputs dispersed as respiration or heat.  
The bottom diagram illustrates several emergy principles.  First, emergy is not “lost” in a process, and hence, no heat sink is shown.  Secondly, energy is converted to emergy using unit emergy ratios from previous studies. Third, all the emergy accumulates and passes into the outgoing product. Last, the bottom diagram is called a three-arm diagram, and represents a highly aggregated view of a system from which it is easy to calculate some key emergy ratios.

## Emergy Calculations

- Transformity
- Use known unit emergy ratios for inputs
- Divide total emergy inputs by output energy or mass

**Notes:**
One of these ratios is the transformity.  When yield data for a process is available in energy terms (joules), a transformity can be calculated.

## Main Energy Sources

**Main Energy Sources**

- Solar, deep planet heat, tides

- Geobiosphere

- Air

- Solar
- Insolation

- Deep
- Earth
- Heat

- Ocean

- Crust

- Tide

- 8.06

- 3.93

- 3.84

- Global emergy flow
- 15.83 E24 sej/yr

- E24 solar emjoules/year

**Notes:**
Three main energy forms work together to drive all earth processes.  The source of these energy forms is independent – the sun, deep earth heat and tidal influences, and the total of these flows represents the total emergy flow into the geobiosphere.
Because solar energy is the starting point for all emergy evaluations, by definition the solar transformity is 1, its energy and emergy being equal.  This inflow and defined emergy ratio is the basis for determining the values for the other two primary sources.  This baseline emergy flow may change as time and refinements occur in measuring the actual energy associated with each flow, but because this total global flow is the reference point for all other emergy evaluations, assessments using the same baseline can be compared regardless of changing knowledge.  Evaluations done with earlier reference points can be adjusted using a ratio of these global emergy flows.  Consequently, it is important to be aware of, and to include a statement in your own evaluations about the global flow value used as the baseline.

## Calculating other earth budgets

| Unit Emergy Ratios of Coupled Global Energy Flows |  |  |  |
| --- | --- | --- | --- |
| Item | Solar Emergy
Sej/yr | Energy or Material Flux per year | Unit Emergy Ratio |
| Total global flow | 15.83 |  |  |
| Latent heat |  | 1.26 E24 J | 13 sej/J |
| Wind circulation |  | 6.45 E21 J | 2450 sej/J |
| Precipitation on land |  | 1.09 E20 g | 1.5 E5 sej/J |
| Precipitation on land |  | 5.19 E20 J | 3.1 E4 sej/J |
| Average river flow |  | 3.96 E19 g | 4.0 E5 sej/J |
| Average river geopotential |  | 3.40 E20 J | 4.7 E4 sej/J |
| Average river chemical potential |  | 1.96 E20 J | 8.1 E4 sej/J |
| Average waves at shore |  | 3.10 E20 J | 5.1 E4 sej/J |
| Average ocean current |  | 8.60 E17 J | 1.8 E7 sej/J |

**Notes:**
The three energy sources presented in the last slide work together to create all of the oceanic, atmospheric and land energy flows, each sub-system interacting with the other.  These large “engines” do work at a global scale, losing energy to smaller and smaller sub-systems capable of using this “lost energy” to do work.  In this way, the energy coming in diffusely over the entire globe, but concentrated at the equator, is dispersed over the entire globe, creating warmth, rain, rivers, mountains, valleys and so on.
Once the total flow of emergy is determined for the earth, transformities for these major global disbursements of the incoming energy can be determined.  The energy and material flows have been determined by various experts in their respective fields, and, when divided into the total global emergy flow, provide unit emergy ratios for all of the important environmental services performed on a global scale.
These major global flows are often called renewable flows, because at the time scale we humans operate at, their flows are significant, and the source is relatively infinite.

## Coupled Sources

**Coupled Sources**

- Avoid double counting

**Planet**
**Earth**

**Ocean &**
**Atmosphere**

**Land**
**Area**

- Deep
- Heat

**Tide**

**Local**
**Analysis**

**Sun**

**Sun**

**Wind**

**Wind**

**Sun**

**Rain**

**Rain**

**Earth cycle**

**Earth cycle**

**Notes:**
While the primary energy sources are independent, the work done to disperse this energy comes from the coupling of these forces.  It is difficult to separate out the energy being contributed to these processes by any one of the primary sources.  Consequently, a standard method for avoiding the double counting of energy has been adopted.
As we move to a smaller scale than the entire planet, we evaluate the energy of all environmental renewable services entering the system in question.  We list most of these in every evaluation table.  However, we only use the highest emergy value from the coupled flows mentioned above when we add the total emergy used within a system.  
You will see that the calculations for these flows has been standardized and are presented in the spreadsheet template provided.  However, no choice is made for which renewable to count in the total emergy value.  The sun is rarely ever the renewable chosen; depending upon the geographic location, one of the other renewable energies will almost always be higher.  Even in deserts, the wind is usually higher than the solar emergy value. 

## Environment-Economic Interface

**Environment-Economic Interface**

- Sun,
- Tide,
- Earth
- Heat

- Environment

- Reserves

- Recycle

- Environment

- Economic
- Use

- Main Economy,
- Consumers

- GNP

- Interface

- Global System

**Notes:**
We now need to examine the connection between the environment and human systems.  While natural systems are driven by the three global energy sources, human systems are superficially driven by trade.  However, all economic systems are dependent upon resources for production and use.  Without oil and coal to use as electricity or fuel, large scale production would be impossible.  The current world population growth rate has been made possible by the use of oil in agriculture, in  transport and in inexpensive goods.  The same is true for all economic processes – production of a good or service uses some raw material or energy source that has been extracted from the earth or harnessed from environmental resources.  It is important whenever evaluating an economic sector to include the environmental services upon which that system relies.  This may be the use of raw materials converted to finished product or the use of other energy sources such as river water in production or the use of the atmosphere to dilute emissions. 
Although money is not paid directly to the environment (we don’t use dollar bills as compost), money circulates through the system when it is paid for the services that extract or concentrate environmental resources.  This is shown as the dashed line entering and leaving the interface between a primary resource and its conversion to an economic commodity.

## Important Input Categories

**Important Input Categories**

- Sun
- Wind

- River
- Rain

- Soil

- Goods &
- Services

- Fuel
- Fertilizer

- Coal

**Renewable**

**Non-renewable**

**Purchased**

**Notes:**
We discussed the concept of renewable inputs several slides back, these being environmental inputs available free to the market that are relatively infinite on a human time scale.  Other inputs that cross a system boundary are usually purchased.  Raw materials from inside the system boundary are referred to as non-renewables.  This might include ores and other minerals, but it also refers to renewables whose concentration time is higher than the rate at which it is being used.  For example, coal deposits require milleniums to build to a level that makes it feasible for use as a primary energy source.  Theoretically this is a renewable resource, but because we are extracting and burning it at a rate thousands of times higher than its creation rate, it is considered a non-renewable resource.
Several examples that will be presented later in the course separate inputs into these categories.  This makes it easier to calculate some key ratios and indices that are useful for policy direction, but is not absolutely necessary.

## 3-Arm Diagram

**3-Arm Diagram**

**Renewable +**

**Non-renewable**

**Purchased**

**Yield = Sum of all **

**System**
**Name**

**Variation**

**Renewable**

**Non-renewable**

**Purchased**

**Yield = Sum of all **

**Notes:**
Using these three main categories, a highly aggregated diagram of the inputs to a system can be presented.  The 3-arm diagram at the top provides a clear separation of the inputs free from the local area and those inputs that have been purchased from outside, as well as the overall sum of emergy associated with the system.  As you get used to seeing emergy values for different systems, a simple diagram like this will provide a quick assessment of where the system fits in with others.  It also allows identification of problems in the analysis if the numbers for any category are highly unusual.
The bottom diagram separates the renewable inputs from the non-renewables, but the yield emergy remains the same.  This slightly less aggregated version gives an overview of how much emergy in the system is sustainable (renewable) versus emergy that may or may not be available in the future.

## Services versus Goods

**Services versus Goods**

- Inherent value _in an item_, _*not*_ money paid
- Paying for services to retrieve that item

- Sun
- Wind

- River
- Rain

- Soil

- Forest

- Harvest

- Fuel
- Fertilizer

- Services

- Market

**Notes:**
We will explain this concept in more detail when we review the actual methodology for completing an emergy evaluation, but remember, the price paid for a raw material – a ton of coal for instance – is NOT the value of the coal.  It is the price someone is willing to pay for the labor and machinery required to mine that coal.  When evaluating coal as an input, it is important to evaluate the energy required to MAKE the coal.  It is important to put a value on the services as well, being careful to not include profit if at all possible, just remember that services do not include the real wealth value of the coal.
We often diagram the use of services in this way, illustrating that the level of service available is a force driving the amount of inputs to a system.  Services are the higher level input and enter the top of the interaction symbol, increasing the flow of fuel and fertilizer in this particular diagram.

## Evaluating Materials

**Evaluating Materials**

- Industrial concentration

- Goods

- Furniture

- Sun
- Wind

- River
- Rain

- Soil

- Forest

- Harvest

- Fuel
- Fertilizer

- Services

- Market

- Electricity

**Notes:**
As the amount of finishing done to a raw material increases, so do the inputs, usually purchased from outside the system.  Sometimes it is easy to list every feedstock and commodity that is used in a production process.  Sometimes it is not, or else there are a number of small items that by themselves might get lost in the larger evaluation but added together are too substantial to lose track of.  This input is often aggregated and represented as a “Goods and Services” source.  Usually there is a money path drawn in the diagram, because the local currency in this lumped category is sometimes the only data available.

## Emergy and $$ Value for Nature

**Emergy and $$ Value for Nature**

- Emergy to dollar ratio: emdollars
- National economic productivity tied to total emergy consumption and flow

- Sources

- Environmental
- Production

- Non-
- renewables

- Economic
- Production

- Macroeconomic Overview

- Assets

- Imports

- GNP

- Fuels
- Goods &
- Services

- Exports

- $

- $

**Notes:**
The conversion of flows through the physical world into energy may seem straightforward (or not - maybe not easy, but it is logical!), but converting currency into energy requires something other than the laws of physics and thermodynamics.
We know that economic production is based on the amount of environmental resources available and moving into the economic interface.  We can calculate the total amount of emergy then that is being consumed for any state, nation or other economic region by determining the renewables, non-renewables and purchased imports being used in any given year.
At the same time, economists are determining the total economic activity in the region and using their formulas to derive a gross state or national product.  This is given in terms of currency circulating within the region – dollars for America and its states.
If we divide the total emergy in circulation by the total dollars in circulation for the same year and region, we get an emergy to dollar ratio that defines the amount of real wealth each dollar was able to buy for that year.  This is similar to, but the inverse of, the dollar per an amount of commodity, a ratio we are all familiar with - $/gal for gas for example.
This emergy ratio is presented as sej/$ so that it can be used to convert money flows into emergy flows and is another example of a unit emergy ratio.

## Emdollars

**Emdollars**

- Changes all the time
- Different for every nation

- Sources

- Environmental
- Production

- Non-
- renewables

- Economic
- Production

- Macroeconomic Overview

- Assets

- Imports

- GNP

- Fuels
- Goods &
- Services

- Exports

- $

- $

**Notes:**
Because the Gross National Product (GNP) changes every year, as does the rate of raw material extraction and imports, this emergy to dollar ratio changes every year as well.  It is also very different for other nations, and as you complete regional evaluations you will find that it is very different for smaller states and regions within a nation.
The evaluations that this particular short-course is aimed at presenting – regional evaluations – are the kind of evaluations used to determine the economic interface within the region and to provide this important emergy to money ratio, along with some other important indices.
A rapid update of a good baseline study can be completed by evaluating those items that change the most – all the items in the red boxes.  While it is true that environmental inputs fluctuate from year to year (drought years for example), it is the long term average environmental basis and its reserves that the economy is built on.  Consequently, long term averages, 25 t0 50 years, are used in regional evaluations, and do not need yearly updates unless you are looking for a comparison of specific fluctuations.
In the next session we will be discussing how to find and convert all the data we have been suggesting is important for evaluating the economy of a region.

## Exercise

**Exercise**

**Notes:**
Using all of the studies and folios provided, try to complete this emergy evaluation of a banana crop production process with what you have learned so far.  Use whatever transformities and specific emergy values you can find in past examples or in Folio 4.  Try completing this without looking ahead to the next three slides.

## One way to answer

**Notes:**
If your answers are very different from these, use the notes following the table to see how your data compares to mine.  Mine may not be right either – if you believe that your method is more accurate than mine, let’s talk about it.

## One way to answer

**Notes:**
In setting up this table you may have separated renewables from non-renewables, or you may not have separated into categories at all – either way is fine.  I have included the transformity calculation at the bottom of the table.

## Slide 24