Daniel E. Campbell, PhD.

Systems Ecologist

Institute of Geography, Henan Academy, Zhengzhou, China

July 1, 2010

An Introduction to Energy Systems Theory, Emergy Analysis,

Environmental Accounting, and Ecosystem Modeling

Outline of the Presentation

• I. Introduction • II. Energy Systems Theory

II A. The Energy Systems Language II B. Common Patterns in Nature

• III. Emergy and Transformity• IV. Emergy Analysis• V. Energy Systems Modeling• VI. Environmental Accounting• VII. The Future of Emergy Research

I. The Odum Brothers

H.T. Odum teaching students about forest ecosystems

两 个男人 创 这个 概念

哥哥

弟弟

A Famous Father

• Father, Howard Washington Odum (1884-1954), was a famous sociologist, who thought in terms of systems.

• He realized that a physical basis was needed to understand society and social organization.

• Sons, Eugene P. (1913-2002) and Howard T. (1924-2002) were pointed toward this task for their lifework by their father.

他们 闻名 的 父亲 - Howard Washington Odum - 给了他们 最好 的生 命 帮助 社会 .

The Fathers of Systems Ecology

• In 1953, Eugene wrote the first book on the principles of ecology from a top-down systems perspective in collaboration with H.T.

• H.T. wrote the chapter on energy that was included in that book.

The Brothers Life Work

• H.T. was the younger brother but he was the more original thinker. He has been called the great innovator.

• Eugene was a great synthesizer. He was able to express his brother’s complex ideas and his own in simple terms. He has been called the great communicator.

• They were awarded many prizes and honors together including the Prix de L'Institut de la Vie and the Crafoord Prize.

• I am a student of H.T. Odum and I studied with him for 26 years.

Quote from “Energy Basis for Man and Nature”

• “Everything is based on energy. Energy is the source and control of all things, all value, and all the actions of human beings and nature. This simple truth long known to scientists and engineers, has generally been omitted from most education in this century.”

• H.T. and E.C. Odum (1976)

H.T. and Betty Odum (Alaska 2000)

H.T. Odum’s Unique Insight

• An integrated and comprehensive understanding of all phenomena can be achieved through a systematic consideration of the laws and principles governing the creation and use of available energy, i.e., energy with the capacity to do work.

• From this insight he and his colleagues developed a comprehensive accounting system for man and nature.

II. Energy Systems Theory (EST)

• Perhaps, H.T. Odum’s greatest contribution to science was to bring together a set of unifying concepts within EST to consolidate our understanding of all kinds of systems.

• Knowledge from general systems theory, irreversible thermodynamics and ecology were synthesized to create EST, which was applied to better understand all natural phenomena

What EST Seeks to Accomplish

• Unification of all systems through the expansion of equilibrium thermodynamic principles to include principles that explain nonequilibrium phenomena.

• This is thermodynamics (sensu lato).

Thermodynamic Laws (sensu lato)1st law Energy is neither created or destroyed. Being. What is.

2nd law Available energy is degraded in any real transformation process, increasing entropy.

Becoming. What happens.

3rd law No molecular motion at 0°K. The baseline for order.

4th law Network designs that maximize empower prevail in competition.

Decision criteria. Why something happens.

5th law or

Corollary of 4th law

Energy flows of the universe are organized into energy transformation hierarchies.

Transformity indicates position and action within the hierarchy.

6th law or

Corollary of 4th law

Material cycles are organized hierarchically, because of their necessary coupling with energy.

Specific emergy indicates position and action in the hierarchy.

7th law or

Corollary of 4th law

Money flows are organized hierarchically, because of their coupling as a countercurrent to energy transformation.

Money flow indicates hierarchical position with

$ , $/J, sej/$ , $/sej

The Human Condition

• We are embedded in a universe that is organized in a hierarchical fashion in space and time.

• Being within and a part of this complex network, we see so many details that it is easy to become bewildered.

• In this situation the ability to create models is a necessary survival skill.

Gödels Theorem

• No system can understand itself because more system components are required to analyze and understand than to simply function.

• People create models to understand the structure and function of the complex world in which we are embedded even though we can not perceive this world all at once.

II. A Energy Systems Language (ESL)

• The primary tool that Dr. Odum developed to better represent and understand complex natural phenomena from an energy perspective was the Energy Systems Language.

ESL continued

• Language was developed to combine kinetics, energetics, and economics.

• ESL does mathematics symbolically and at the same time keeps track of the energy laws.

• The ESL diagrams are really a form of mathematics that extend the capacity of the mind to see wholes and parts simultaneously.

• ESL is useful for teaching, research, and comparison of systems languages.

Energy Systems Language Symbols

• The symbols of ESL are used to trace causality and show interrelationships in networks of energy pathways, storages and interactions.

• Each symbol is mathematically defined thus the diagram when drawn specifies a set of simultaneous 1st order differential equations to be solved.

• ESL is a meta-language, therefore all models in other languages can be translated into ESL, since the phenomena that they represent must have an energy basis.

Energy circuit A pathway whose f low is proportional to the storage or source upstream.

Source A forcing function or outside source of energy delivering forces according to a program controlled from outside.

Tank A compartment or state variable within the system storing a quantity as the balance of inflows and outflows.

Heat sink Dispersion of potential energy into heat accompanies all real transformation processes and storages. This energy is no longer usable by the system.

Interaction Interactive intersection of two pathways coupled to produce an outflow in proportion to a function of both; a work gate.

Consumer An autocatalytic unit that transforms energy, stores it and feeds it back to improve inflow.

Producer Unit that collects and transforms low-quality energy under the control of high quality flows.

Box Miscellaneous symbol to use for whatever unit or function is needed.

Switching Action A symbol that indicates one or more switching actions controlled by a logic program.

Primary symbols used in the Energy Systems Language.

Application of the Energy Laws in ESL

• Every energy systems model must have an evaluated 1st law diagram that insures conservation of energy and matter.

• Every ESL model disperses heat from work gates and storages through the heat sink satisfying the 2nd law.

• ESL models are used to look for design principles that follow from the maximum power principle (4th law).

ESL Modeling:Features of an ESL Model

• System boundaries• Outside energy sources or forcing

functions• Internal components or state variables• Outflows across the boundaries, e.g.,

exports, or the heat sink.• Outside sources and inside storages

interact through work gates to generate fluxes of matter and energy within the system.

EnergySource E1

EnergySource E 2

EnergySource E3

Structure Q7

process p11

Structure Q6

Structure Q3

process

p7

Structure Q4

process

p9

Structure Q5

process p6

process p12

process p10

process p8

Structure Q2

process p3

process p4

Structure Q1

process p1

process p2

process

p5

JR

J1

J2

J4

J5

J6

J8 J7

J9

J10

J11

J14J17

J16

J15

J12

J13

J18

J19

J21J20 J23

J22

J25

J24

J27

J28

J29

J30

J31

J32

J33

J26

J34

J35

J36

J37process p13

Figure 7. Campbell, An Energy Systems...

A Generic Energy Systems Model Showing Main Features.

II B. The Unity of All Systems

• Everything is connected within one universal system.

• A window of attention in space and time simplifies this complexity.

• Common patterns are created by the transformation of available energy governed by the 4th law of thermodynamics.

Common Patterns

• Storage of energy and material.

• Energy transformations.

• Feedback reinforcement.

• Circulation of materials.

• Hierarchical organization.

• Self-organization for maximum power.

The Energy Systems Approach

• The existence of common designs and similar patterns is a starting point for modeling using Energy Systems Theory.

• The transformation of energy underlies action and organization at every scale.

• Hierarchical design occurs on all scales.

• It has distinctive properties that help us understand systems.

Environmental Policy Window

Hierarchy of Systems Organization

A Common Design on all Scales

• As potential energy flows from source to sink self-organization for maximum power generates stored potential energy that is more organized than its background.

• This difference constitutes a low entropy source of available energy that can feedback special work.

• Materials cycle between the ordered and disordered parts of the system.

Strong source of potential

energyWorkTrans-formation

Stored Potential Energy

Positive

feedbac

k

Used energy

Heatdispersal

Diffusion

Dispersed energy

Weak sourceof potentialenergy

Autocatalytic designs develop when enough potential energy is available. A positive feedback, PF, from storage to a work gate that further stimulates energy inflow maximizes power in a system.

Weak energy sources degrade without developing

positive feedback loops.

Positive feedback is a widespread design principle in nature.

PF

Nature’s Pulsing Paradigm

• The pulsing paradigm replaces the old concept of growth followed by steady state.

• Systems with coupled pairs of components can oscillate.

• Such pairs are found on all hierarchical levels of organization.

• Pulsing pairs contain one component, the accumulator, that slowly builds up resources and a second component, the frensor, that rapidly consumes the accumulated resources.

EnergyE= 5 X

X

Material, MTM = 200

Resources R = 2

Consumers C =2

k1

0.02

0.01

k3

0.0003

k4

0.2k5

0.005

k2

3E-4

k6

2.5E-5

k7

Design of a Pulsing System

Accumulator

Frenzor

Energy10000ST = 1

10000

1000

10000

100

10010000

10000

10000

Accumulated Resource

Resource Consumption

DispersedMaterial

Energy1000ST =1

1000

100

1000

10

10 1000

1000

1000

Accumulated Resource

ResourceConsumption

DispersedMaterial

Energy100000ST = 1

100000

10000

100000

1000

1000100000

100000

100000

Accumulated Resource

ResourceConsumption

DispersedMaterial

0

4

8

12

16

20

0 400 800 1200 1600 2000 2400 2800 3200

Time

Em

erg

y, s

ej

Accumulated ResourceResouce Consumption

A

B

C D

Level 3

Level 1

Level 2

0

4

8

12

16

20

0 400 800 1200 1600 2000 2400 2800 3200

Time

Em

erg

y, s

ej

Accumulated ResourceResouce Consumption

0

4

8

12

16

20

0 400 800 1200 1600 2000 2400 2800 3200

Tim e

Em

erg

y, s

ej

Accumulated Resource

Resouce Consumption

Pulsing on nested levels of hierarchical organization.

III. Emergy and Transformity

• The concepts of emergy and transformity can be derived by considering the transformations of energy in a hierarchical network.

• The position of an energy storage or flow within the network determines its transformity and the kind of work that it can do when used.

SolarEnergy

106

104 103 102 10

Joules per time

Transformity =106

104= 102

Solar Joules per time

103 104 105

SpatialHierarchy

Hierarchical Design is a corollary of the maximum power principle.

Definition of Emergy• Emergy is all the available energy of

one kind previously used up both directly and indirectly in making a product or service.

• Emergy has units of emjoules to connote energy used in the past.

• A quantity of emergy is always tied to an underlying quantity of available energy flowing through or stored in the system.

Transformity

• Solar Transformity is the solar emergy required to make one joule of available energy of a product or service.

• It increases with each successive transformation in the network.

• Transformity has units of sej/J.• The transformity of a item is its emergy

divided by its available energy. • Emergy(sej) = Available Energy (J) x

Transformity(sej/J)

Maximum Power Design

• System designs that maximize empower prevail in competition.

• Nature’s ubiquitous patterns are the result of such designs.

• Pulsating systems at all scales may be one such design.

IV. Emergy Analysis

• Emergy as a Basis for Systems Analysis Emergy Evaluation is required for both

analysis and synthesis Emergy Analysis, starts with the whole

and examines the functions of the whole and its parts

Emergy Synthesis starts with the parts and integrates them into a functional whole.

Both approaches are methods used in Emergy research.

Emergy Analysis Method

• Construct Model Diagram• Collect Necessary Information• Evaluate Model• Calculation of Indicators• Formation of Indices• Interpretation of results within the

framework of Energy Systems Theory.

Two Major Classes of Emergy Analyses

• Analysis of whole systems like a state, province, nation or region. Also subsystems such as agriculture, urban systems etc. fall in this class.

• Analysis of production processes, like steel making, rice growing, aquaculture, etc.

Additional Emergy Methods• Development of Indices• Comparison of Alternatives, i.e., determine

the affect of incremental or marginal changes on system empower or other output that result from alternative designs or policies.

• Emergy matching in development and production processes

• Evaluate the effects of trade in terms of the emergy exchange

• Evaluate the effects of alternative policies on multiple levels of hierarchical organization.

MY

N01=DB Y

Large EcosystemZ

AnimalResources

YN

Wetland Reserve

MudN02=OM

PeatN1=P

RainTide

Waves Plant ResourcesB

ReserveInfrastructure

DonorsVisitors

MD+MV

YM Market

FC

FEF ¥

Government

MG

ServicesGoods

R

MY

MD+MV

YMD+YMV

Conservation Value, CV = Q+YN =P+B +OM +YN

SSR =(YM+YMD+YMV)/F =(MY+MD+MV)(Em/$)/(FC+FE)

ECR = CV/Fc

EBR =(CV+Y)/FEBE =(CV+YM+YMD+YMV)/(CV+Y)

EISD = EBR×EBE/ELRMY -- the money received for economic services and products; MD -- the money contributed by private donors for conservation;MV -- the entrance fees paid by visitors; YMD -- the emergy purchased with money contributed by private donors;YMV -- the emergy purchased with money from visitors;YMG -- the emergy purchasing power of the money contributed by government to support

the reserve;FC --the emergy purchased to support conservation, which is equal to YMD+YMV +YMG;FE --the emergy purchased to support economic production.

Emergy Analysis: Normalizing the

Phenomenal Universe• Emergy can be used to express all

phenomena on a common basis so that values are directly comparable.

• This is true if (1) the transformation of energy underlies all phenomena and

• (2) if the energy previously used up directly and indirectly to make an item can be accounted for as energy of one kind (e.g., solar emjoules).

Emergy Evaluation of Cobscook Bay Ecosystem

Eastport

4m Tidal Range

Lubec

Pembroke

High VelocityChannels

Cobscook Bay: Overview

• A macrotidal ecosystem that is naturally eutrophic due to new nitrogen supplied from the sea.

• Plant production is stabilized by benthic macrofauna grazing.

• Phytoplankton production is light limited.

• Fuciods, kelp, red algae and benthic diatoms are best adapted to utilize the energy signature of the Bay.

Low Tide

High Tide

Cobscook Bay : Forcing Functions

Fog High Nutrients and Green Algae

Salmon Aquaculture

Freshwater Streams

System Components

Starfish of unusual sizeEagles

Herring Weir 19th century sardine factory

Phytoplankton

P 0.22 gC m-2

MacroalgaeMA1239 gC m-2

EelgrassEG 15.2 gC m-2

BenthicMicroalgae

BM 2.1 gCm-2

SolarRadiation

J m-2 d-1

3.74E4

JI

JR

3.64E3

Nitrogen NR

0.08 gN m-2

m3 m-2 d-1

CobscookWatershed Runoff

gN m-2 d-1Atmosphere

m3 m-2 d-1

TidalExchange

0.052 gN m-3

NTPT

0.03 gC m-3 0.004 gC m-3

ZTSalmon

AquacultureNitrogen

gN m-2 d-1

Nitrogen0.78 gN m-2

NX

JN

0.007

JNA0.01

JW

0.018

JNP0.002

DT

JT

0.067J33 0.021

Bird and FishMigration Program

Fish

ShorebirdsShorebirds

Eagles

Detritus

BacteriaMB

JFI

JFE

0.065

0.061

JBI

JBE

3.47E-6

3.51E-6

Zooplankton

0.006 gC m-2

Z

D

B

E

5.2 gC m-2

BenthicMacrofauna

M

12 gC m-2

FishF

8.3 gC m-2

0.002 gC m-2

SealsS

0.064 gC m-2

6.4E-5 gC m-2

CommercialFishing

X

J2

J1

J3

J4

0.27

4.28

0.35

0.95

J5 J6

J7

J8

0.0450.32

0.013

0.16

J9

0.0012

J10

J11

J12

J13

J14

0.16

0.19

0.35

0.32

0.36

J15

J16

J17

J18J19

J20

J21

J22

J23

0.470.19

0.09

0.350.09

0.33

4E-4

0.17

5E-4

J36

J25

J34 0.067 J35 -7E-4

J240.0035

J38

J37

8.5E-5

0.0068

3.7E-6

6.4E-7

J26

0.017

J27

0.031

J281.1E-4

J29

8E-5

J30

6E-8

J32

7E-5

J310.017

Cobscook Bay Ecosystem

Phytoplankton

Kelp

Fucoids

Green

Red

Eelgrass

BenthicMicroalgae

Sunlight

Zooplankton

Fish

Detritus

Seals

Eagles

Macrofauna

Shorebirds

X

CommercialFishing

Shorebirds

Fish

Other Areas

Cobscook Bay Ecosystem

Bacteria

Waves

2.35E20 sej y-1

River

1.45E20 sej y-1

7.12 374

Tide

3.74E20 sej y-1

Seawater(nitrogen)

7.47E19 sej y-1

Emergy E18 sej y-1Energy E12 J y-1

235

145

7830

2900

0.015

636 369

400 816

18.36.8

46.265.1

26270.7

15.1 32.4

9.913.2

258 150

375

219241 492

5.9

3.4

157 321

6.1 16.6

0.7 1.8

63.6

237

7.1 26

58.6

41.4 6.5 4.6

13.6

29.4

1.5 3.2

11.9

9.1

1.31

332

604

0.95

0.27

4.9

1.4

618 210

0.42

0.22

448 233

8.8

4.6

0.0008

0.006

24.6

3.8

0.6

0.09423

66.1

0.020.006

0.4

0.11

24.6

2.4

0.004

0.028

160 83.1

172

312

15400

67.8 123

X

Salmon culture(nitrogen)

1.38E18 sej y-1

Land Runoff(nitrogen)

9.31E17 sej y-1

Atmosphere(nitrogen)

2.71E17 sej y-1

0.0031.38

0.93 0.002

0.27

0.0006

81.3 148

5.15E17 sej y-1

Emergy Analysis of the Ecosystem Network

• Energy and Emergy Signatures

• The Physical Basis for Biological Productivity.

• Comparison to Other Systems.

Energy Signature for Cobscook Bay

1.00E+10

1.00E+11

1.00E+12

1.00E+13

1.00E+14

1.00E+15

1.00E+16

1.00E+17

1.00E+18

Sunlig

ht

Wind

Rain, ch

emical

Tide

Estuar

y wav

es

Geolog

ic up

lift

Ground

water

, che

m.

River,

chem

ical

River,

orga

nic m

atter

Seawat

er, n

itroge

n

Energy Sources

Ene

rgy

sej y

-1

Emergy Signature for Cobscook Bay

1.00E+16

1.00E+17

1.00E+18

1.00E+19

1.00E+20

1.00E+21

Sunlight

Win

d

Rain, c

hemic

alTid

e

Estuar

y w

aves

Geolog

ic u

plift

Ground

Wat

er, chem

ical

River,

chemic

al

River,

organ

ic m

atter

Seawate

r, ni

troge

n

Salmon, n

itroge

n

River,

nitroge

n

Atmosp

here, n

itrogen

Energy Sources

Em

ergy

sej

y -1

Analysis of Transformities

• The most efficient primary producers have transformities of 105 sej J-1

compared to 104 sej J-1 in other estuaries.

• This difference is carried through into the grazing and detritus food chains,

• But disappears by the time energy transfer reaches the top carnivores.

Transformities of Primary Producers

• Brown algae (fucoids and kelp), red algae, and benthic diatoms are most effectively using the emergy of the Bay’s resources.

• Phytoplankton has a higher than expected transformity and is much less efficient probably because of light limitation.

Comparative Empower Density

Estuary Empower Density Source

sej m-2 X 109

Cobscook Bay, ME 7375 This Study

Newnan's Lake, FL 3488 Brown and Bardi (2001)

Estuary in B.C. 2300 Odum (2000)

York River, VA 1600 Campbell (2000a)

Lake Okeechobee, FL

1114 Brown and Bardi (2001)

Mosquito Lagoon, FL 144 Campbell (2000a)

Prince William Sound, AK

100 Brown et al. (1993)

Empower Density and Human Use

• Empower density in Cobscook Bay is equivalent to that required for intensive Tilapia culture in Mexico.

• It is 3 times the minimum estimate for salmon culture made by Odum (2000).

• Salmon aquaculture may be a good human use of the Bay’s rich emergy signature.

Evidence of Human Impact

• Alteration of water column chemical constituents during dragging.

• Increased suspended sediment during dragging.

• Degradation and enrichment of benthic communities below salmon pens.

• Repeated overfishing of abundant shellfish populations.

• Long term loss of benthic biodiversity (Trott 2004)

Conclusion (Evaluation)

• Cobscook Bay is a macrotidal ecosystem that is naturally eutrophic due to new nitrogen supplied from the sea through tidal exchange.

• Plant production is stabilized by benthic macrofauna grazing.

• Phytoplankton production is light limited.

• Fuciods, kelp, red algae and benthic diatoms are best adapted to utilize the energy signature of the Bay.

Low Tide

High Tide

Conclusions (Emergy Analysis)• Emergy Analysis indicated that

primary producers are unable to use the estuary’s emergy sources as efficiently as in other estuaries.

• The additional emergy goes into creating rare physical, geological, and biological structures.

• Energy transfer indicates that the system appears to be productive and healthy overall.

• But not without local disturbance in space and time.

Reversing Falls

“Old Sow”Fog and hard bottom

Giant fauna

V. Energy Systems Modeling

• First have the system in mind, consider system energetics and kinetics and then write the equations.

• The appropriate mathematics comes out of a gestalt or unified overview of the system and not vice versa.

• All symbols have precise mathematical definitions. Thus each diagram gives a starting point for specifying equations.

WordModels

Mathematics

Equations

Energy Diagram

Model Making

A network diagram representation of a system contains more information than the differential equation representation.

ESL Models and Equations

• Many different system configurations can generate equations with similar behavior.

• Diagramming shows that these different configurations are distinct systems when translated into mathematical form without manipulating terms.

• Traditional use of equations implies free manipulation to get analytic characteristics, therefore, as generally used an equation does not necessarily clearly define a systems characteristics.

• A set of state, loop, or node equations do not uniquely determine an energy systems network, but only an equivalence class of dynamically similar networks.

ScientificIntuition

WordModels

What makes a good ESL modeler?The art of modeling is in observing and interpreting the world.

Force-Flow Filter

Part VI: Environmental Accounting Using Emergy

• Environmental debt.• What is emergy?• Environmental accounting using

emergy.• Emergy Income Statement and

Balance Sheet.• Determining the true solvency of our

enterprises.

Environmental Accounting Using Emergy

• Provides a powerful alternative value system that gives an objective measure of ecological and economic costs and benefits.

• Allows for comprehensive income statements and balance sheets for the ecological, economic and social aspects of human systems.

• By documenting environmental liabilities, it allows us to determine the true solvency of human enterprise.

Sustainability: Going Beyond Indicators

• To illustrate the application of environmental accounting methods to the problem of sustainable development, we will consider the concept of society’s debt to the environment and how it can be measured using emergy methods.

Humans Need

• Both economic prosperity and a healthy environment.

One Life-Support System

• Environment, economy, and society are organized into a single interconnected system.

• Today human activities threaten this system.

EconomyEconomyEnvironmentEnvironment

Economic Growth and Environmental Quality

• The trade-off between economic growth and environmental quality is illustrated by the following Energy Systems diagram and numbered chain of events.

Henan Province

X X XEconomy

Environment

-X X

Groundwater,soil, clean air,timber, etc.

Minerals, etc.

RenewableEnergies

Fossil fuel,Minerals

Markets

Goods &Services

GSP $

(1)

(2)

The Conflict Between Economic Growth and Environmental Quality

(3)

(4)

Nature’s Work

Environmental Debt• Money is paid only to

people for their work.• The environment

contributes work to economic production without payment.

• Anything taken without payment is obtained on credit and becomes a liability on the balance sheet.

Business Analogy

• A business cannot continue for long, if it cannot pay its debts.

• Natural systems cannot continue, if we borrow their assets at a rate greater than they are renewed.

Assets and Liabilities

• Assets: economic resources, cash, land, products

• Liabilities: economic obligations, debts

• Solvency: the capacity to pay our debts (Assets >Liabilities).

• True solvency depends on our ability to pay both monetary and environmental debt.

The Problem

• Economic activities use resources and damage the environment accumulating debt.

• Outstanding debts must be serviced for both economic and environmental systems to be sustainable.

• We don’t have a currency that measures these debts in a fair way.

Two Questions

• At this point, two questions come to mind.

• Should society acknowledge its debts to the environment?

• If we choose to do so, how will environmental debt be measured?

Do We Need to Acknowledge These Debts?

• If ecological systems are carrying debt for economic systems, will economic systems be solvent in the long run?

Ecol

ogic

al

Syst

ems

“Vivantary” Responsibility

• Society recognizes human responsibility for the welfare of economic and social institutions.

• Today recognition of a similar responsibility for the environment is needed.

• Vivantary = Fiduciary

Measuring the Debt

• Environmental debt is mostly external to the market system, thus it is not easily measured by money.

• Value can be measured by what was required to produce an item as well as by what someone is willing to pay for it.

• Environmental work can be measured by the former method.

Available energy is a common denominator

• All action is accompanied by the transformation of available energy or exergy.

• The exergy used in the past to create an item is a measure of what was required to produce it.

• But exergies of different kinds have different ability to do work when used in a network.

EmergyThis pictographic equation illustrates the emergy calculation for a hypothetical production process to make a quantity of bread carried out using only two inputs the Gibbs free energy of the rain and the available energy of the oil used in growing, harvesting, transporting, milling, baking, etc.

= +X X=

Joules Joules

Bread

Joules

Rain OilEmergy of Bread

Solar emjoules

Solaremjoules

Joule of rain

Solaremjoules

Joule of oil

= +X X=

Joules Joules

Bread

Joules

Rain OilEmergy of Bread

Solar emjoules

Solaremjoules

Joule of rain

Solaremjoules

Joule of oil

What is Emergy?• It is the Energy Memory of

everything that has been used to make a product or service.

• It is a scientific expression of the folk idea of energy.

• More energy = a barn instead of a shed and when the barn is built the energy is used up.

Emergy to money ratio

• Monetary and emergy accounts are reconciled on the balance sheet using a combined emergy-money measure,e.g., the emdollar.

• The emdollar value of an item is its emergy divided by the emergy-to-money ratio for an economy in a given year.Emergy to money ratio

Environmental Accounting Tools

• Emergy accounting makes it possible to keep a single set of books for the environment and the economy.

• And to create a balance sheet that includes environmental liabilities from which the true solvency of our economic activities can be determined.

Monetary Ledger

1575015750

2000020000

CreditDebit CreditDebitCreditDebit

Owner’s Equity

Extraction damage (Em$)

Liabilities +

Accounts payable ($),

Extraction damage (Em$)

Assets =

Coal purchased increases assets

Emergy Ledger

1.05E18

1.56E161.56E161.05E18

CreditDebit CreditDebitCreditDebit

Emergy EquityEmergy of Liabilities +

Extraction damage is an environmental liability

Emergy of Assets =

Coal purchased

Coal used

Emergy Balance Sheet

The emergy balance sheet gives direct information on what is sustainable.

Emergy Balance Sheet

46181563410Total Liabilities + Equity

44775546010Total Equity

44695545278VariousVar.Natural Capital7

607321.22E12 (1997)

$6.0E10Paid in Capital6

Public and Private Equity

142617400Avg. 1.0E5J1.25E19Extraction Damage5

Liabilities

46181563410Total Assets

3153837VariousInd.1816000Knowledge of the People

3

4562655664039200J1.42E21Coal2

240293328200J1.04E19Forest biomass1

Assets

Emdollars

X E9 Em$

Emergy

X E20 sej

Emergy/Unit

sej/unit

UnitDataDescriptionNote

What is Sustainable?

• Renewable resource use and degradation can not exceed renewable resource production.

• If use exceeds production a credit is given to the environmental liability account.

• Lost production accumulates as interest on the debt.

• A reasonable payment schedule must be established.

• Repayment debits the liability account.

The Upshot

• To date almost all use and degradation of renewable resources to support economic production has been done using credit.

• This practice has put our future prosperity and our way of life at risk.

The Future

• The environment and people are our most precious resources.

• To preserve the environment and to promote the well being of the people should be our foremost task.

• Environmental accounting using emergy can help ensure the solvency businesses, institutions, and nations.

VII. The Future of Emergy Research

• The development of comprehensive, verifiable environmental accounting and analysis methods using emergy is the best way to guide the development and operation of human systems toward a prosperous and sustainable world.

• Economics alone is not sufficient.• The Chinese people have the historical tradition and mind power

to help us move toward this goal. • Many studies have been done; however, we need more good

quality studies in the future. • World leaders need to find the political will and courage to

consider the consequences of their decisions to the “real wealth” of their people.

• Healthy institutions have emergy balance sheets that account for debts to the environment, and society as well as to the economy and have determined the debt that they can carry and the payments that must be made to service their debt.