valorisation de la géothermie : le rôle clé des...
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Valorisation de la Géothermie : le rôle clé des réseaux de chaleur
25. Fachtagung von GEOTHERMIE.CH
Dr Jérôme Faessler
Energy Systems Group
University of Geneva
1. Oktober 2015
[email protected] (phone +41 22 379 06 48)
www.unige.ch/energie
Key Key Key Key ElementsElementsElementsElements
• Energy Introduction
• Geothermal Energy : multi-resource for multi-uses
• Importance and Role of District Heating and Cooling (DHC)
• Multi-ressource
• Linear Heat Density
• Temperature level
• Funding model (capital cost)
• Conflits or synergies with retrofits buildings
• Conclusions
Energy : two main principlesEnergy : two main principlesEnergy : two main principlesEnergy : two main principles
• First law :
• Conservation of energy
• Energy balance (neutral)
• Second law :
• Entropy
• Energy is irremediably degraded → waste energy
• Efficiency
Carnot’s principleCarnot’s principleCarnot’s principleCarnot’s principle
• Importance of Temperature difference
• Typical efficiency for electricity generation :• Geothermy 10-15%
• Wood 20%
• Nuclear 35%
• Coal 35-45%
• Gas turbine combined cycle 55-60%
• Hydoelectric 100%
Source at high
temperature
Heat
Engine
Low
temperature
Qin, Tin
Qout, Tout
Wout
Tout < Tin
ηc : Carnot’s efficiency
Source http://www.energiestatistik.ch
Observation 1
> 75% fossil fuels
Observation 2
Electricity < 25%Observation 3 : Nuclear ≈ 10%
EnergyEnergyEnergyEnergy StatisticsStatisticsStatisticsStatistics (CH)(CH)(CH)(CH)
Observation 4 : Geothermy ≈ 1.5% (Umweltwärme)
Demand Characteristics (CH)Demand Characteristics (CH)Demand Characteristics (CH)Demand Characteristics (CH)
• Household AND Industry / Services
Source : OFEN 2010
• Heat use :
• Space heating + Domestic Hot Water (DHW) + process heat
• Different level temperature
• Different future development
Power in MW
Energy/Power and heat load profileEnergy/Power and heat load profileEnergy/Power and heat load profileEnergy/Power and heat load profile
Data source : CGC 2009 (1 year = 8760h)
Profil of an annual heat demand
Times in hours
Energy in MWh
Power (heat load duration curve) Energy
Source : Hollmuller, UNIGE
Power and EnergyPower and EnergyPower and EnergyPower and Energy
Note : dwellings with space heating and DHW
Géothermal Géothermal Géothermal Géothermal energyenergyenergyenergy : 2 dimensions: 2 dimensions: 2 dimensions: 2 dimensions
• Primary Energy (Eprim) → Final energy (Efinal)
• Hot water / steam: Energy = Flow * Temperature
• Low electrical efficiency (5 to 20%)
• Large quan7ty of heat → district hea7ng (DH)
V
E
R
T
I
C
A
L
HORIZONTAL : USE
Geo-RESOURCESource : CREGE,
Neuchâtel
Eprim
Efinal
Renewable Resources in SwitzerlandRenewable Resources in SwitzerlandRenewable Resources in SwitzerlandRenewable Resources in Switzerland
Source : Eicher&Pauli, 2014, Weissbuch Fernwärme Schweiz – VFS Strategie
“Brutto“ Potential
Swiss Heat Consumption today ≈ 84 TWh (300 PJ)
GeoGeoGeoGeo----Resource and GeoResource and GeoResource and GeoResource and Geo----usesusesusesuses
Source : M. Antics, GPC IP
Geothermal Heat UseGeothermal Heat UseGeothermal Heat UseGeothermal Heat Use
• If Temperature <100 °, direct use with DH more interesting than electrical production
• Using heat pumps to upper resource temperature and / or to lower return temperature is possible (better geothermal efficiency)
• Coupling with electrical production possible but more complex (in parallel or in cascade)
• Generally, 1 kWhel ≈ 5-10 kWhth
Source http://www.bine.info/
What role for District Heating (DH) ?What role for District Heating (DH) ?What role for District Heating (DH) ?What role for District Heating (DH) ?
• Benefits of DH:
1. Integration of renewable energy in the urban heating
2. Waste energy recovery (waste, combined heat and power, industry)
3. Mutualisation of resources and investments
Multi Resources DH (Lausanne)Multi Resources DH (Lausanne)Multi Resources DH (Lausanne)Multi Resources DH (Lausanne)
Source : data SIL, adapt from Ms thesis MUSE L. Michel, 2012
Day
Load duration curve by resource (DH Lausanne - 2010)
Da
ily P
ow
er
[MW
]
Sewage plant
Waste plant
Wood
Gas
Multi Resources DH (Lausanne)Multi Resources DH (Lausanne)Multi Resources DH (Lausanne)Multi Resources DH (Lausanne)
Re
ne
wa
ble
sha
re
Fossil share
Source : data SIL, adapt from Ms thesis MUSE L. Michel, 2012
Sewage plant
Waste plant
Wood
Gas
Power and Energy (DH Lausanne - 2010)
Re
lati
ve E
ne
rgy
%
Relative Power %
What role for District Heating (DH) ?What role for District Heating (DH) ?What role for District Heating (DH) ?What role for District Heating (DH) ?
• Benefits of DH:
1. Integration of renewable energy in the urban heating
2. Waste energy recovery (waste, combined heat and power, industry)
3. Mutualisation of resources and investments
4. Stabilization of power grid by coupling CHP and HP in winter
• Major constraints:
1. Minimum heat density
Linear Heat density and Heat lossesLinear Heat density and Heat lossesLinear Heat density and Heat lossesLinear Heat density and Heat losses
Source : Nussbaumer and Thalmann, 2014, Status Report on District Heating Systems in
IEA Countries, http://www.ieabcc.nl/publications/IEA_Task32_DHS_Status_Report.pdf
Source : District Heating and Cooling, Euroheat&Power, 2011 survey
Linear Heat density in Europe [MWh/m/y]
What role for District Heating (DH) ?What role for District Heating (DH) ?What role for District Heating (DH) ?What role for District Heating (DH) ?
• Benefits of DH:
1. Integration of renewable energy in the urban heating
2. Waste energy recovery (waste, combined heat and power, industry)
3. Mutualisation of resources and investments
4. Stabilization of power grid by coupling CHP and HP in winter
• Major constraints:
1. Minimum heat density
2. District heating temperatures
District heating Temperature EvolutionDistrict heating Temperature EvolutionDistrict heating Temperature EvolutionDistrict heating Temperature Evolution
• Temperature and heating consumption of buildings decrease
• But Temperature and consumption DHW not changed (55-65 °)
• If DH Temperature decrease, then resources Temperature could decrease
Source : Hongwei Li et al, 2014, TOWARD 4th GENERATION DISTRICT HEATING:
EXPERIENCE AND POTENTIAL OF LOWTEMPERATURE DISTRICT HEATING, The
14th International Symposium on District Heating and Cooling, Stockholm
District District District District heatingheatingheatingheating TemperatureTemperatureTemperatureTemperature optimizeoptimizeoptimizeoptimizefor for for for GeothermyGeothermyGeothermyGeothermy : an : an : an : an exampleexampleexampleexample
• Example in Paris region
• GEOTHERMY :
• 25% Power = 60% Energy
• Tresource = 75°C
• multi-tube district
• Sequential system
• Average return Temperature : 35-40°C
source Semhach (http://semhach.fr/)
What role for District Heating (DH) ?What role for District Heating (DH) ?What role for District Heating (DH) ?What role for District Heating (DH) ?
• Benefits of DH:
1. Integration of renewable energy in the urban heating
2. Waste energy recovery (waste, combined heat and power, industry)
3. Mutualisation of resources and investments
4. Stabilization of power grid by coupling CHP and HP in winter
• Major constraints:
1. Minimum heat density
2. District heating temperatures
3. Substantial investments ("capital cost")
Boundaries of the cost of DHBoundaries of the cost of DHBoundaries of the cost of DHBoundaries of the cost of DH
Source graphique : ViaSeva, guide des usagers du chauffage urbain, 2009
R1
R2
P1+P2
primary District (R)
Secondary District (P)
R1 : consumption proportional to the heat consumed (variable component)
R2 : fixed subscription corresponding to the size of the substation ("pipe size") (fixed component)
→ typical Contract : 10 to 25 year
PRODUCTION CONSUMPTION
Sale price of DH Sale price of DH Sale price of DH Sale price of DH –––– France exampleFrance exampleFrance exampleFrance example
Source : AMORCE, Prix de vente de la chaleur en 2013
Sale price based on the majority
of the energy use in the DH
Sharing between fixed (red)
and variable (blue) price
What role for District Heating (DH) ?What role for District Heating (DH) ?What role for District Heating (DH) ?What role for District Heating (DH) ?
• Benefits of DH:
1. Integration of renewable energy in the urban heating
2. Waste energy recovery (waste, combined heat and power, industry)
3. Mutualisation of resources and investments
4. Stabilization of power grid by coupling CHP and HP in winter
• Major constraints:
1. Minimum heat density
2. District heating temperatures
3. Substantial investments ("capital cost")
• Conflicts and / or synergies between development of DH and retrofits buildings ?
�REMUER project ongoing (multi-efficient and renewable resource district heating)
http://www.unige.ch/energie/fr/activites/axes/energie/remuer/
RetrofitLogic
Demand Evolution VS expansion of DHDemand Evolution VS expansion of DHDemand Evolution VS expansion of DHDemand Evolution VS expansion of DH
DH expansion Logic
RetrofitLogic
For a same heat demand (370 GWh), wecan : • Use more waste heat
• Improve relativ share of waste heat inethe DH energy mix
• Lower the heat production cost• Decrease consumption of total fossil
fuels
This requires combining two approaches::
• DH Expansion
AND
• Retrofit Buildings (on the DH)
Source : UNIGE project REMUER, adapt from L. Quiquerez
Example DH «CADIOM-CADSIG» in Geneva
DH
Dem
an
d [
GW
h]
Base Load Peak Load
Conclusions Conclusions Conclusions Conclusions –––– key pointskey pointskey pointskey points
• 2 dimensions of geothermal energy :
• Geo resource vertical AND use horizontal
• First energy use = thermal use (heating and cooling)
• Geothermal resource → low temperature (<150°C)
�Easier to use with DHC
• Key Elements of DHC:
� Importance of multi-resource
� Importance of inventory uses (SH, DHW, Industrial, Cold)
�Need for a minimum heat density
� Importance of temperature levels
�Substantial initial investments (capital cost)
�prices and costs of heat, competitiveness (economic approach)
�development scenarios (geographical approach)
�Possible synergies with retrofits buildings
� It takes time !
Thank you for your attentionThank you for your attentionThank you for your attentionThank you for your attention
• http://www.unige.ch/formcont/geodh