industrial ecology favrat december 2006 1 integrated energy systems: a key to sustainability prof...
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1Industrial Ecology Favrat December 2006
Integrated energy systems: a key to sustainability
Prof Daniel Favrat
LENI-ISE-EPFL
Industrial Ecology Favrat December 20062
Energy integration as a key word
• Integration of technologies and/or energy services offers a large potential:– Combined cycle (Brayton-Rankine) or hybrid FC-GT
plants– Integrated solar combined cycle systems (ISCCS)– Hybrid vehicles, – Energy networks with tri-generation…
• Strong need for improved indicators (exergy efficiency)
• Need for better information structuring tools (pinch technology, environomic multi-objective optimisation, improved LCA,…
Industrial Ecology Favrat December 20063
Evolution of Worldwide key parameters
400 800 1200 1600 2000 year0.
10
20
30
ener
gie
[G
tep
]
x
x
x
xx
x
x
yearly primary energy consumption
En
erg
y
0
1000
5000
7000
[Mill
ion
s]population
230
250
270
290
310
330
350
CO
2 [p
pm
]
mean CO2 concentration in atmosphere
Industrial Ecology Favrat December 20064
Energy Trends• Significant projected increase of
energy use (mainly in dev. countries, electricity and transport)
• Part of thermal conversion processes > 90% (>80% of non renewable), and major source of pollutants and inefficiencies
0
2
4
6
8
10
12
14
Developing countries
OECD
Eastern Block
world
1900 1930 1960 1990 2020
Coal0.26
Oil0.32
Gas0.19
Nuclear0.05
Hydro0.06
Non Com.0.1
Renew.0.02
Efficiency Costs
Emissions
Disponibility
Industrial Ecology Favrat December 20065
Society and sustainability• Difficulty to define sustainability and to have a
holistic view– complex systems with many factors but major ones
are:• Environment (local and global)• Resource conservation or even better, closed loop (including
recycling, renewable resources, etc)• Economics (in line with available capital)• Social (the most difficult!! - not dealt with in this talk)
• How to:– match top-down with bottom up frameworks
and have cross-domain coherence– account for the dynamics of technological and
economical evolution
Industrial Ecology Favrat December 20066
Reactions to complexity• Over simplification
• Focalisation on isolated criteria, one at a time
(example: CO2)
– Partial view, potentially negative action (ex: taking
out car catalysts would reduce CO2)
• Environmental policies mainly based on fixing
of regulatory limits without economical benefits
for better technologies or combinations of
technologies
Industrial Ecology Favrat December 20067
Major Methodologies for Design
• Structure independant (pinch technology, etc.)
• Structure based (environomic optimization, etc.):• Starts from a superstructure of all feasible components and heavy use of operations research tools• Easier extension to LCA and other factors (pollution, reliability-availability, time dependant investments, etc.)
Industrial Ecology Favrat December 20068
Energy systems and Environomics
• Background:– Energy systems increasingly consist of integrated
technologies– Technologies are not fixed but, like living bodies,
adapt to their environment (based mainly on economic factors and regulatory issues)
– Assessments should be made in a coherent framework allowing all technologies to freely compete (particularly when a major departure from the present day economic environment is anticipated)
Industrial Ecology Favrat December 20069
Thermoeconomic & environomic
min. Cuseful energy = f(Cfuel + Cinves + Cemissions - Bproducts)
External costs
emissions
Cemissions
min. Cuseful energy = f(Cfuel + Cinvest - Bproducts)
ThermoeconomicDesign
EnvironomicDesign
min. Cénergie. = f(Cfuel + Ccapital)min. Specific pollution
orMulti-objective
Industrial Ecology Favrat December 200610
Pelster (98)
Combined cycle superstructure
Industrial Ecology Favrat December 200611
40
42
44
46
48
50
52
54
56
58
60
basecase
0 1 2 2.5 3 4
CO2 unit costs (cts/kg)
percent
0
50
100
150
200
250
300
350
400
450
500
specific emissions
efficiency CO2 (g/kWh)
NOx (mg/kWh)
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
basecase
0 1 2 2.5 3 4
CO2 unit costs (cts/kg)
(cts/kWh)
CO2
NOx
CO2 sep.,disposal
resourcecosts
capitalcosts
300 MW: Exergetic efficiency, emissions, costs versus CO2 unit cost
Pelster (98)
Industrial Ecology Favrat December 200612
•Collaboration within AGS with MIT and University of Collaboration within AGS with MIT and University of Tokyo Tokyo•Development of QMOO (multiobjectif, multimodal, Development of QMOO (multiobjectif, multimodal, evolutionary optimisation algorithm) evolutionary optimisation algorithm)•« Environomic » optimisation of integrated energy systems« Environomic » optimisation of integrated energy systems
Two objective optimisation of trigeneration in part of a large city
Post Combustion
anode cathodeelectrolyte
reformer
naturalgas
air
Heat Pump
ColdSource
District Heating water
District Cooling water
Compression Chiller
Absorption Chiller
Heat Recovery Device
Gas Turbine
Solid OxideFuel Cell
Boiler
AdditionalFiring
Feasible Domain
Pareto Frontier
Cost
CO2 emissions
Burer M, Favrat D., Tanaka K., Yamada K, Multicriteria optimisation of a district heating cogeneration plant integrating a Solid Oxyde Fuel Cell-Gas Turbine combined cycle, heat pumps and chillers, Energy. The International Journal, 28/6 pp 497 – 518, 2003
Part of Tokyo: Results with different Pareto Curves
[ton
CO
2/ye
ar]
[million US$/year]
50
Annual Cost [m$/year]
CO
2 E
mis
sio
ns
[T
on
s/y
ea
r]
anodecathodeelectrolyte
air -50%
2.2 2.84000
10000
14Industrial Ecology Favrat December 2006
Power generation technology typification
Thesis Li 2006
Industrial Ecology Favrat December 200615
Overall Technology Assessment (China)
1MW
10MW
100MW
1000MW
CO2 Abatement Cost vs CO2 Abatement Percentage
0
50
100
150
200
250
300
350
0 20 40 60 80 100
CO2 Abatement Percentage (%)
CO
Abatement Cost (US$/ton)
Supercritical Coal plant + ESP +FGD
IGCC
PFBC GCC
GCC+CO2
separationIGCC+CO2
separationCHP(GT)Wind Power
PV
SOFC/GT
AZEP
SOFC/GT
Cogeneration
Gas Engine
SOFC
SOFC
Cogeneration
Gas Engine Cogeneration
Possible Baseline Assumption
For Power Generation: The conventional 600MW coal plant is taken as the reference plant.
For Cogeneration:
Heating Gas boiler for heating, power need by pump is imported from the electricity grid
Electricity National average CO2 emission rate from power generation
Industrial Ecology Favrat December 200616
Relative Consumption of technology combinations for heating
1 2 3 4 5 6 7 8 9 10 11
0.0
0.5
1.0
1.5
2.0
2.5
3.0
PAC
Q
PAC
PAC
PAC
PAC
Q
PAC
Q
PAC
Q
Tch=65°C
Tch=35°C0.270.310.38
hydro
PAC= pompe à chaleur
Q = cogénération
pile à combustible
turbine à gaz
Moteur thermique
Electricité nucléaireFlamme (chaudière)
Résistance électrique
Industrial Ecology Favrat December 200617
Two examples for a more rational use of fuel or Nat Gas for heating
Fossil or biofuel resources
Environnement 1.43
Twice as much heat
Electricity0.44
Heat0.46
1.00
Cogeneration with Fuel cells
or engines
Electricity0.57
1.00
Combined cycle power plant
(ou 1.1)
Industrial Ecology Favrat December 200618
Illustration of heating and cogeneration services in the exergy bowl
Source (partielle): Borel L, Favrat D Thermodynamique et énergétique. PPUR 2005
Industrial Ecology Favrat December 200620
Previous solar power plant work at EPFL: thermo-economic optimisation of an ISCCS plant for Tunisia (120 MWe)
KANE M, FAVRAT D ET AL. Thermoeconomic analysis of advanced solar-fossil combined cycle power plants. Int. Journal of Applied Thermodynamics, vol.3, No 4, pp191-198, 2000
Industrial Ecology Favrat December 200623
Better indicators: Exergy
• Introduction of an energy concept including an exergy performance index, in the Law on Energy in Geneva
• Necessary simplifications (engineers and architects, diverse customers, etc.)
• Initial focus on large projects with the following main services:– electricity, heating, air conditioning and
refrigeration
Industrial Ecology Favrat December 200624
From local to global
€
η = η1 η 2 η 3 η 4Example: Combined cycle power plant without cogeneration (1)+District heating heat pump (2) + DH heat exchanger in the building (3) +convector (4)
€
η = ˙ E el,1
−
˙ E y,1+
⎛
⎝ ⎜ ⎜
⎞
⎠ ⎟ ⎟
˙ E y,2−
˙ E el ,2+
⎛
⎝ ⎜
⎞
⎠ ⎟
˙ E y,3−
˙ E y,3+
⎛
⎝ ⎜ ⎜
⎞
⎠ ⎟ ⎟
˙ E q,4−
˙ E y,4+
⎛
⎝ ⎜ ⎜
⎞
⎠ ⎟ ⎟=
˙ E q,4−
˙ E y,1+
Building plant 3
fuel
Room convector or radiator 4
Power plant
1 Cogeneration District unitwith or without heat pump 2
electricity
Industrial Ecology Favrat December 200625
Examples de technologies Power plant
Dist. plant
Building plant Room convector Overall exergy efficiency [%]
Supply/return temperatures 45°/35°
65°/55°
75°/65°
45°/35°
65°/55°
75°/65°
45°/35°
65°/55°
75°/65°
Direct electric heating (nuclear power) 0.32 0.07 0.07 0.07 2.2 2.2 2.2
Direct electric heating (combined cycle cogeneration) 0.55 0.07 0.07 0.07 3.7 3.7 3.7
Direct electric heating (hydro power) 0.88 0.07 0.07 0.07 6.0 6.0 6.0
District boiler 0.2 0.54 0.76 0.86 0.53 0.38 0.33 5.8 5.8 5.8
Building non-condensing boiler 0.11 0.16 0.18 0.53 0.38 0.33 6.1 6.1 6.1
Building condensing boiler 0.12 0.53 6.6
District heat pump (nuclear power) 0.32 0.61 0.54 0.76 0.86 0.53 0.38 0.33 5.6 5.6 5.6
Domestic heat pump (nuclear power) 0.32 0.45 0.45 0.45 0.53 0.38 0.33 7.6 5.4 4.8
Domestic cogeneration engine and heat pump
0.22 0.25 0.26 0.53 0.38 0.33 11.8 9.4 8.7
District heat pump (combined cycle power)
0.54 0.61 0.54 0.76 0.86 0.53 0.38 0.33 9.4 9.4 9.4
Domestic heat pump (combined cycle power)
0.54 0.45 0.45 0.45 0.53 0.38 0.33 12.9 9.2 8.1
Domestic heat pump (cogeneration combined cycle power)
0.55 0.45 0.45 0.45 0.53 0.38 0.33 13.2 9.4 8.3
Cogeneration fuel cell and domestic heat pump
0.25 0.27 0.28 0.53 0.38 0.33 13.4 10.4 9.5
District heat pump (hydropower) 0.88 0.61 0.54 0.76 0.86 0.53 0.38 0.33 15.4 15.4 15.4
Domestic heat pump (hydropower) 0.88 0.45 0.45 0.45 0.53 0.38 0.33 21.2 15.1 13.325
Industrial Ecology Favrat December 200626
Transport and car
One of the largest inefficiency inherited from the 20th century:
• Non recovery of the kinetic and potential energy
• Regulation by throttling of Otto engines
Industrial Ecology Favrat December 200628
Conclusions• Rational Use is an essential strategy• Structuring knowledge is a key word in design
and planning of energy systems• Multi-objective optimisation is a major tool• Better indicators like the exergy efficiency can
help• Systems integrating several technologies
and/or energy services (cogeneration) represent major opportunities
Industrial Ecology Favrat December 200629
Stone age did not end because of lack of stones!
Let’s not wait until the end of oil resources to be more intelligent