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This presentation discusses the relation between urban density and energy consumption in the transport and residential sectors. It explores the impact of density on mobility modes and heat demand, and presents improvements in modeling distributed energy sources. The presentation also introduces the spatialization of the POLES model to incorporate the urban dimension.
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PACT - 3rd technical meetingPOLES development Philippe MENANTEAU, Silvana MIMA LEPII – EDDEN Grenoble 11 / 04 / 2011
Outline of key points • Introduction • Spatialisation of the model • Impact of density in the transport sector • Impact of density on residential and service heat demand • Development of district heating modelisation • Improvements in modelisation of distributed energy sources (PV)
Preliminary comments • POLES is a global energy model adapted to simulate energy / climate policies, hypothesis of accelerated technical progress or limited resources, … but it is not spatialized (infra national level). • The urban dimension was not taken into account : which impact on consumption paths (buildings, transport), or infrastructures (energy networks, transport …). • Our objective was to introduce the urban dimension in the model and a density variable in order to be able to differentiate urban areas from sparse settlements and to distinguish between different urban forms
Preliminary comments (follow.) • This presentation will not go into details of the modifications which have been introduced in the model • The aim is to illustrate how the model behave following the introduction of the density variable • The model is not fully calibrated yet • So the results presented are clearly preliminary and will be reconsidered when the specific parameters corresponding to the 3 PACT scenarios will be introduced
Relation between urban density and energy consumption in transport
Urban density is a key factor for energy consumption in transport sector
Relation between density and urban form Low density Average d. High density High proportion of individualhousing High proportion of multi family / highrise buildings
Dense vs sprawled cities : no clear model of sustainable city Density Dense cities: Lower car mobility Less heating (surf / cap effect) ! Network energy supply Sprawled cities: Higher dispersed renewable resources per cap Energy demand Renewable Energy production
Outline of key points • Introduction • Spatialisation of the model • Impact of density in the transport sector • Impact of density on residential and service heat demand • Development of district heating modelisation • Improvements in modelisation of distributed energy sources (PV)
Introducing density and urban form in the POLES model : density gradients • 3 different steps • To estimate urban / non-urban population • To distinguish urban center / periphery (density frontier) • To introduce specific urban forms according to different regions (density gradients) • Classical function for describing urban form (Clark, 1951) • D(u) = D0*e(γu + ε) • It allows to allocate pop in two urban zones of different densities : • Urban center > 75 hab / km² • Urban periph < 75 hab / km² Asia Europe center / periphery U.S.A Bertaud, 2001
Spatialization of the model Urban cores Suburbs (1st ring) In POLES Do it fast Urban center - UCEN Urban periphery - UPER II I Do it alone Do it together IV III Medium to small towns (compact cities) Sparse development (periurban, diffuse cities) Extra - Urban sparse settlements - EXTU Do it slow
Evolution of population according to scenarios • Reference scenario : pop growth in periphery • Scenario S1 : almostsimilar to REF (lowergrowth in UP) • Scenario S2 : high pop growth in urbancenters • Scenario S3 : break in pop decrease in extra-urban areas
Evolution of the population (abs.) according to the scenarios Population • UCEN large increase in S2, lowerincrease in S1 • UPER limiteddifferentiation, smalldecrease in S2, S3 compared to REF • EXTU decrease of population in EXTU isstopped in S3
Evolution of the population (share) according to scenarios - • Scenario S1 : share of pop in different zones is similar to REF • Scenario S2 : share of pop is increasing in UCEN • Scenario S3 : the share of pop stops decreasing in EXTU Population
Density and population • DENSn = DENSn-1 * [ POPn / POPn-1]^El • Elasticity of density • Hypothesis of continuing sprawl in periphery for the reference scenario
Evolution of density according to scenarios - • REF: density is slightly decreasing in UPER • S1 : similar to S1 but density is stabilised in UPER • S2 : density increases in UCEN • S3 : limited impact on density (stabilised in UCEN) Density
Outline of key points • Introduction • Spatialisation of the model • Impact of density in the transport sector • Impact of density on residential and service heat demand • Development of district heating modelisation • Improvements in modelisation of distributed energy sources (PV)
Transport : relation between density and mobility modes • Different mobility behaviour : • Lower car mobility as density increases (ie urban centers) • Higher public transport use as density increases Total pkm per capita (all modes) Modal shares Total = 100% Slow modes Cars Public transport Non – urban Périphery Centre Density
Modeling mobility in POLES model • Total mobility = Private mobility + Public mobility • Private mobility = fc (income effect + price effect + density) • Public mobility = fc (income effect (infrastructure) + price effect (opposite to price effect for private mob) + density (idem) + subsitution effect) Price effect : Short termelasticity Long termelasticity
Car mobility according to urban areas Car mobility per capita (Pkm) • Urban Center : • Individual car mobilityislower in UCEN compared to UPER • Individual car mobilityisdecreasing in scenario S2, as a result of densityincrease (compared to REF) • UrbanPeriphery : • Limited evolution of density in S2 compared to REF ; does not lead to significant impact on individualmobility
Public transport mobility according to urban areas Public transport per capita (Pkm) • Urban Center : • As a result of increaseddensity in urban center, passenger – km by public transport isincreasing in S2 scenario • UrbanPeriphery : • The highersensitivity of public transport mobility to densityleads to a lowerdecrease of public transport use in periphery
Public transport according to urban areas (France) Share of public transport • Share of Public Transport : • The evolution of PT marketshareis positive in S2, but the differenceis not thatsignificantat the global level • Public Transport in Urban Center : • The impact of higherdensityis more significant in urban center with a clearincrease of PT share
Public transport according to urban areas (Spain) Share of public transport • Share of Public Transport : • The evolution of PT marketshareis positive in S2, but the differenceis not thatsignificantat the global lever • Public Transport in Urban Center : • The impact of higherdensityismuchhigher in urban center with a clearincrease of PT share
New technologies : the Light Urban Vehicle • Light UrbanVehicle : • Limited mobility : urban center and periphery • Lowercosts • Lowerconsumption, loweremissions • Twodifferent technologies • Thermal engine • Electric engine
Development of new technologies : the Light Urban Vehicle • Light Urban Vehicle : • Limited autonomy restricts usage to urban center and periphery • Lower consumption, lower costs • Two different technologies • Thermal engine • Electric engine
Development of new technologies : Electric / hybrid vehicles Marketshare of car technologies • Reference : • No LUV available – development of hybrid cars • Scenario S2 • No LUV – technicalbreakthrough on hybridengines and electricstorage • Scenario S1 • Idem S2 plus light urbanelectricvehicle
Development of new technologies : Electric / hybrid vehicles • Scenario S1 • Multi Fonction Vehicle : conventional / hybrid • Light UrbanVehicle : conventional / electric
Outline of key points • Introduction • Spatialisation of the model • Impact of density in the transport sector • Impact of density on residential and service heat demand • Development of district heating modelisation • Improvements in modelisation of distributed energy sources (PV)
Modeling energy consumption in residential sector • Energy consumption per m² is supposed to be similar in different urban zones (ie in collective buildings and individual houses) • But surface per capita is supposed to be different between indiv./coll. dwellings and as a consequence in different urban zones • The surface per capita has been adjusted according to the share of collective / individual housing in the different urban areas
Evolution of energy consumption in the residential sector • Main parameters are similar in the 3 scenarios (no specific climate / energy policy at this stage) • Total final energy consumption for heating in residential sector integrates numerous factors including, unit surface, unit consumption, population, etc • Energy consumption for heating differs in the 3 scenarios : lower consumption in S2 (densification) and higher consumption in S3 (more dispersed housing)
Outline of key points • Introduction • Spatialisation of the model • Impact of density in the transport sector • Impact of density on residential and service heat demand • Development of district heating modelisation • Improvements in modelisation of distributed energy sources (PV)
Simulation of district heating supply • No representation of district heating in the previous version of the model : • Introduction of a simplified representation DH in residential and service sectors • Modulation of DH development to take into account the density of heat demand
District heating in residential sector Heatdemand in RES sectorfrom district heating • The development potential of DH is a function of total heat demand and urban density • Higher density in urban center compared to periphery leads to higher contribution in absolute terms • The densification in urban center in S2 scenario is favourable to the development of DH (higher population – higher density)
District heating in service sector Heatdemand in SER sectorfrom district heating • Behaviour is similar for the service sector in urban center – positive reaction to increase of density • Behaviour is more complex in periphery • Very limited evolution of density (decrease in REF) • Increase of population (higher in REF) and increase in heat demand for SER
Outline of key points • Introduction • Spatialisation of the model • Impact of density in the transport sector • Impact of density on residential and service heat demand • Development of district heating modelisation • Improvements in modelisation of distributed energy sources (PV)
Simulation of distributed energy demand (PV) • Individual housing (ie low density) facilitates the access to dispersed renewable sources • Decentralised PV in POLES • Potential is estimated as a function of new and refurbished buildings (share of m²) • No distinction is made between the type of buildings • Introduction of urban zones • Estimation of potential according to effective roof surface • ie. according to type of buildings (IND / COLL) or density • PV potential per dwelling adjusted according to the share of collective / individual housing in the different urban areas • Highest potential per dwelling in EXTU • Lowest potential per dwelling in UCEN • Influence of potential • Absolute ceiling • Differentiated dynamics in UCEN, UPER and EXTU
Simulation of distributed energy demand (PV) : access to potential • Differentiated access to solar resource according to density (ie urban areas) • Still limited (but increasing) gaps in 2050 • Per capita access to solar resource is higher in EXTU and lower in UCEN
Simulation of distributed energy demand (PV) : scenarios • Differentiated dynamics according to scenarios (public policies) • No / limited incentives in REF – higher in S2 and S3
Simulation of distributed energy demand (PV) : PV production • Total distributed PV production increases much faster in S1, S2 scenario compared to REF • Growth is more important in S3 (highest decentralised potential) • Possible ceiling effect on decentralised potential (S3 – ITA)
Conclusion • Significant modifications introduced in the model in order to be able to simulate different evolutions of urban form • Modifications concern transport, heat consumption in R&T, district heating and dispersed energy prod (PV) • Preliminary results show satisfying behaviour of the model • Next step is the introduction of scenarios variable not directly linked to urban form (carbon value, consumpt behaviour technology, etc.)