A regional planning approach for the promotion of renewable energies

\ PERGAMON

Renewable Energy 07 "0888# 206Ð229 www[elsevier[com:locate:renene

A regional planning approach for the promotion of renewable energies Y[ Sara_dis\ D[ Diakoulaki\ L[ Papayannakis\ A[ Zervos National Technical University of Athens\ Zo`rafou Campus\ Athens 04679\ Greece Received 11 October 0887^ accepted 3 November 0887

Abstract Besides the necessary policy measures concerning _nancial or legal aspects of the current energy market\ the deployment of renewables can be facilitated by the establishment of di}erent practices in energy analysis and planning[ The present paper shows that in order to promote renewables it is necessary to shift from a centralised view of the energy sector to a regional perspective[ A bottom!up approach intended to match\ at the regional level\ the supply of available renewable resources to the particular energy demand pro_le is presented[ The pro! posed methodology is illustrated by a case study concerning two di}erent Greek regions[ Þ 0888 Elsevier Science Ltd[ All rights reserved[ Keywords] Energy^ Regional planning^ Climate change^ Renewable energies

0[ Introduction Despite the remarkable progress made in the _eld of renewable technologies and their increasing competitiveness to conventional systems\ the contribution of renew! able energy sources "RES# in the gross energy consumption is still extremely low\ especially in the developed countries[ In the European Union it hardly approximates 5) with large deviations in the percentages achieved in the di}erent Member States ð0Ł[ The need to signi_cantly increase this share is stated in the Green Paper on Renewable Energies adopted by the Commission in 0885 which set the objective of 01) for 1909 ð1Ł[ The Community Strategy and Action Plan for renewables included in the Commission|s more recent White Paper is basically directed towards this goal of 01) which is proved to be an ambitious but realistic objective ð2Ł[ Furthermore\ it is emphasized that such a goal is indispensable in order for the EU to comply with

 Corresponding author[ Tel[] ¦290!661 21 43^ fax] ¦290!661 20 46^ e!mail] diakÝchemeng[ntua[gr 9859!0370:88:, ! see front matter Þ 0888 Elsevier Science Ltd[ All rights reserved PII] S 9 8 5 9 ! 0 3 7 0 " 8 7 # 9 9 7 9 7 ! 7

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its commitments at the European and international level as regards environmental protection and in paricular the abatement of the global warming e}ect[ Although objectives and policies for the promotion of RES are agreed at the international and national level\ they should be speci_ed and implemented at a much lower scale[ This implies that the integration of RES necessitates a much more detailed view on energy ~ows[ Thus\ along with the necessary policy measures aimed to remove existing barriers\ attention should be paid to the practices followed actually in energy analyses and in the planning of the energy sector[ Current practices in energy planning are in compliance with the need to centrally control energy ~ows in the economy[ Energy production is normally accomplished in large sized facilities\ which are intended to provide energy in large distances and for a long time horizon[ Centralization goes together with a macroscopic view on the energy system[ Energy representations are still highly aggregated and do not examine possible variations in the spatial distribution of energy demand and of the energy supply sources[ Such types of energy planning models are designed according to the market rules implied by conventional fuels\ but are also appropriate to handle nuclear energy ð3Ł[ Renewable energies are completely di}erent from these energy sources in both their physical characteristics and the technologies used for their exploitation[ Because of their low energy ~ux\ RES are usually exploited at the place of occurrence[ This restriction calls for small sized facilities sited in locations where RES have a su.ciently high energy density[ So\ although theoretically RES are present throughout the world\ in practice\ their availability varies considerably from place to place[ Further! more\ the recovered energy\ especially heat\ is not able to be transported over long distances\ since losses would render their exploitation practically infeasible[ The small size of renewable technologies is accompanied by a large variety of relevant devices\ each one intended to exploit a particular energy source and to satisfy a speci_c energy need[ The above features indicate that for e}ectively integrating RES into an energy system\ the scale of energy analysis and planning should be shifted from the national to the regional and local level ð4Ł[ At this scale\ a much more detailed approach to energy demand and supply should be performed in order to e}ectively match the two sides by taking account of the spatial and time distribution of RES[ Furthermore\ the need for a regional perspective in energy planning is intended to identify the most advantageous sites and technologies in order to maximise economic bene_ts and minimise environmental damages[ The purpose of this paper is to present the analytical stages of an energy planning procedure intended to reveal the possibilities for maximum RES penetration at the regional level[ The proposed approach is applied in two di}erent Greek regions for illustrating the completely di}erent priorities that should be followed in each case[ 1[ Methodological approach 1[0[ Ener`y demand estimation The detailed breakdown of regional energy demand cannot be drawn from statis! tical data which refer mostly to the national level[ The amount of data recorded at

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the regional level is usually restricted to the total consumption of the various energy forms "e[g[ diesel oil\ gasoline\ electricity#[ In order to overcome this obstacle and to attain the required degree of detail\ a bottom!up approach should be developed[ The rationale under these approaches is that there is no need for electricity\ fuel oil\ gasoline etc[ as such[ What is needed is the energy service required for accomplishing the various activities undertaken in each sector[ This service is provided by means of an end!use device "boiler\ engine etc[# which transforms fuels\ electricity or other energy forms to useful energy ð5Ł[ Such an approach not only provides the basis for establishing regional energy balances but also allows for better approximating the likely penetration of renewable technologies in the end!use activities "e[g[ solar col! lectors for water heating#[ The analytical steps included in the developed modelling procedure are as follows] 1[0[0[ Estimation of useful ener`y demand Energy demand is _rst disaggregated into distinct end!use activities as shown in Fig[ 0[ For each end!use activity energy requirements are estimated by means of technical models relating present or future energy demand to a number of known or predictable key!parameters ð6Ł[ These parameters can be classi_ed into the following categories] "a# structural characteristics\ such as population\ type\ number\ and magni! tude of dwellings etc[^ "b# natural characteristics\ such as climatic conditions and their seasonal variation^ "c# technological characteristics\ such as the type and e.ciency of the end!use devices^ and "d# behaviour characteristics such as life!style and mode of technologies use[ The procedures followed for the estimation of the energy demand in the de_ned activities\ can be classi_ed into _ve basic modelling categories\ which are presented hereafter ð7Ł[ 1[0[0[0[ Space heatin` method[ This method is used for estimating energy needs for space heating in the building sector[ It relies on a simpli_ed model of the thermal heat balance of dwellings[ Heat losses are calculated by a set of equations which represent heat losses through the building shell and air in_ltration[ The key parameters used in the estimation procedure are the number and the characteristics of buildings[ 1[0[0[1[ Appliance saturation method[ This method is used for estimating energy needs for air!conditioning and other electric uses in the residential sector[ The key par! ameters for the implementation of this method are the number of households and the appliance stock "saturation level per type of appliance\ technical characteristics\ mode of usage#[ 1[0[0[2[ Floor!space method[ This method is used principally in the electric uses of the tertiary sector[ It is similar to the appliance saturation method\ except that end!use activities are de_ned on the basis of the building|s cross!sectional area[ So electricity needs "for lighting\ air conditioning etc[# are expressed on a per unit of area basis[ The estimation of energy demand in agriculture is based on the same approach[

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Fig[ 0[ Energy demand disaggregation and the estimation methods adopted[

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Cultivation areas are used instead of building area together with machinery charac! teristics[ 1[0[0[3[ Basic thermophysical law[ This method is used for the estimation of energy demand for water heating[ The key parameters used are data on population and other users of hot water "e[g[ number of tourists#\ water consumption per capita and comfort standards "temperature of hot water#[ 1[0[0[4[ Statistical records of ener`y data[ Statistical data for fuels and electricity consumption in the industrial sector and for transport fuels are usually available at the regional level[ Since no further disaggregation is necessary for these sectors\ energy demand is drawn directly from statistical records[ 1[0[1[ Estimation of _nal ener`y consumption The energy consumption for each end!use activity is estimated by establishing the corresponding energy balance[ The data needed are the following] "a# the useful energy demand evaluated on the basis of the technical models presented above^ "b# the fuels available for providing the energy required^ "c# the share of the various conversion technologies used in each activity^ and "d# the e.ciency of each technology[ Energy consumption of the various fuels at each end!use activity are estimated by the following equation] n

Ej = pi\j\k ei\j\k k0

ECi\j  s

where] EC Energy consumption E Useful energy demand p Share of technologies e E.ciency of technologies i Fuel j End!use activity k Technology 1[0[2[ Ener`y demand forecastin` Energy demand is _rst estimated for a base year for which all the data needed for calculating useful energy demand and _nal energy consumption are available[ At this stage it is possible to check for inconsistencies in the modelling procedure[ More speci_cally\ it is necessary to con_rm the validity of the assumptions concerning highly uncertain parameters "e[g[ behaviour characteristics\ shares of technologies etc[# by comparing the resulting aggregate _gures of fuel consumption with existing statistical records[ This calibration procedure provides a safe basis for the energy planning procedure and allows for more reliable future estimates[ The forecasting procedure starts by estimating for the examined time horizon the values of the considered key parameters included in the technical models\ as well as

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the expected changes in the shares of the conversion technologies and in their e.ciencies[ Next\ the same procedure comprising the calculation of useful energy demand and the corresponding _nal energy consumption will be applied[ 1[1[ Estimation of RES potential The available RES potential is estimated on the basis of purely physical parameters which characterise the corresponding natural resources[ The analysis focuses on the main renewable resources for which commercial technologies are already at hand\ namely wind energy\ biomass\ solar energy and hydro!power[ For these RES\ the considered parameters are respectively\ wind velocity\ area and productivity of forests and cultivations\ solar radiation\ ~ow rate and hydraulic head of water streams[ The availability of RES in a certain region normally corresponds to a huge energy potential which does not represent the amount of energy that can be recovered in practice[ In order to translate the theoretical availability in terms of exploitable RES potential\ technical and economic limitations should be taken into account ð8Ł[ These limitations refer to] "a# the basic constraints and guidelines followed in the site planning of central facilities\ such as altitude\ land inclination\ distance from neighbouring communities\ archeological sites\ airports or other sites necessitating speci_c protection from annoy! ing activities "exclusive restrictions# and "b# the characteristics of exploitation tech! nologies and the organisational conditions that have to be satis_ed in the implementation of RES[ For instance\ the electricity generated by wind energy in a certain location depends upon the capacity of wind turbines installed and their arrangement at the site[ On the other side\ solar energy generates a di}erent amount of energy depending upon if it is used for water heating\ space heating\ air!conditioning or power generation[ Each of the above energy consuming activities relies on the use of di}erent devices characterized by di}erent e.ciencies[ This means that the exploitation of RES in a certain region depends not only on their availability but also on the exact pro_le of energy demand[ It is clear that a huge amount of data should be collected and elaborated for e}ectively accomplishing the above tasks[ Furthermore\ estimates of both demand and supply components are de_ned with respect to their spatial dimension and can only result from a detailed geographical analysis of the determining parameters[ So the whole analytical procedure relies on suitably organized databases\ connected to a Geographical Information System "GIS#[ The procedure followed for estimating exploitable RES potential is presented in more detail hereafter[ 1[1[0[ Wind ener`y For estimating the potential of wind energy only the sites where mean annual velocities are higher than 5 m:s "at 09 m height# are taken into consideration[ The total available area is then reduced by taking into account the following topographical and geographical restrictions ð09Ł] "a# altitude not higher than 0999 m^ "b# slope not higher than 69)^ "c# distance from inhabited areas\ military installations and archeological sites etc[ not less than 0 km^ and "d# distance from the road network not greater than 0 km[

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The _rst three restrictions are exclusive\ while the last one is more elastic[ The resulting area is translated into power units by assuming a standard capacity of wind turbines "499 kW# and their density at the site "01 Ha:MW#[ The estimation of energy production is based on data provided by the manufacturer relating energy production with mean annual wind velocity at hub height ð00Ł[ The power law is used for the extrapolation of the available wind velocity data at hub height[ 1[1[1[ Biomass The examined biomass resources comprise agricultural and forest residues[ In the case of agricultural residues\ the available potential is estimated on the basis of the total cultivated area\ the annual yield of the main agricultural product and its by! products\ the recovery factor of by!products and their energy content ð01Ł[ In the case of forests\ the available potential results by taking into account the maximum allow! able rates of exploitation "reduced by the amount of the wood products already used in other non!energy uses# together with the energy content of the corresponding type of wood ð02Ł[ In both cases\ technical and organisational restrictions are taken into consideration in order to arrive at the practically exploitable potential[ One such restriction is that the biomass density "TJ:Ha# should exceed a certain lower limit[ In addition\ areas should be easily accessible in order to avoid excessively high transportation costs[ The last restriction is a}ected by the slope of the area\ the existence of roads\ the climatic conditions etc[ In addition\ the following areas are excluded from the analysis] "a# areas characterised as physical ecosystems and "b# areas with alternative land uses "e[g[ grazing#[ The uses of biomass under consideration include space heating in both traditional and advanced wood burners "residential sector#\ heat and electricity generation in cogeneration units "agricultural related industries# and electricity generation in grid connected power plants "combustion of agricultural residues#[ 1[1[2[ Solar ener`y Solar energy potential is estimated on the basis of records concerning mean monthly solar radiation at di}erent tilts[ In this paper\ the exploitation of solar energy refers only to heat generation applications and more speci_cally to water and space heating in the residential and tertiary sector[ The exploitable potential is de_ned with respect to the speci_c end!use demand by using the f!chart method[ A maximum of three! storey buildings are considered for potential installation of solar collectors in order to avoid excessive heat losses and problems in their arrangement "lack of space\ shading etc[#[ 1[1[3[ Hydro ener`y The available hydro potential is de_ned on the basis of the water discharge for a given surface i[e[\ it is the sum product of the mean super_cial discharge and the mean hydraulic head up to a speci_c height[ Estimations are based on the mean rainfall volume with the respective discharge representing 49) of this volume[ It is assumed that] "a# all discharges can be controlled^ "b# a 099) exploitation of the available hydraulic head is possible^ and "c# there are no losses during conversion[ The main

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restrictions imposed are related to the available hydraulic head and the accessibility of the site "altitude\ distance from road network etc#[

2[ Application study for greece 2[0[ Present status of the Greek ener`y system Greece is endowed with a rich potential on several types of RES which remains mostly unexploited[ Instead\ the Greek energy system has a highly centralized struc! ture characterized by a persistent attachment to conventional energy sources along with a shift towards more polluting fuels[ As shown in Fig[ 1\ the contribution of solid fuels to the total primary energy demand has considerably increased during the last two decades[ This was mainly the result of the intensive use of domestic lignite in electricity production after the oil crisis intended to decrease the country|s energy dependence[ The share of oil to the total energy supply continues to be very high "about 59) in 0889# while natural gas which is the {cleanest| among all fossil fuels has entered into the system only in 0886[ Finally\ RES\ represent about 6) of the total gross inland consumption with the largest share refering to large hydro!power[ As shown in Fig[ 2\ the total primary energy demand has increased in the last two decades faster than the Gross Domestic Product "GDP#\ contrary to the trend observed in most industrial countries where energy intensity was steadily decreasing[ It is worth mentioning that despite the high rates of increase\ the per capita energy consumption in Greece is still much lower compared to other developed countries[ This indicates the {pressures| that are likely to be exerted by consumers for improved energy services\ but also points to the structural changes that have to be made on the

Fig[ 1[ Composition of primary energy supply in Greece\ 0869Ð0882[

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Fig[ 2[ Energy intensity and CO1 emissions of the Greek energy system[

supply and demand side of the energy sector[ Figure 2 also shows that the level of CO1 emissions followed an even higher rate of increase[ This was because during this time period\ besides the continuous rise of energy demand and the lack of substantial energy conservation measures\ a shift towards fuels characterized by higher CO1 emission factors took place ð03Ł[ 2[1[ Potential for RES penetration in Greek re`ions Two Greek regions will be examined in order to illustrate the energy planning procedure described in the previous section] Crete and Ipiros[ These two regions di}er considerably in their economic pro_le\ the structure of their energy system and the existing natural resources] Crete\ with a total population of 424\999 inhabitants is the biggest island of Greece\ located at the southeastern Aegean Sea and has an isolated energy system with an autonomous electricity network[ It is a densely populated region "53[7 inh:km1# with a fast growing economy[ In 0881 the per capita Gross Regional Product "GRP#\ based principally on tourism related activities and agric! ulture amounts to 727[1 thousand GRD "0889 prices# ð04Ł[ On the contrary\ Ipiros is a mountainous region in northwestern Greece with 226\999 inhabitants[ Ipiros is considered as one of the poorest regions of the country with a GRP per capita of 531 thousand GRD "0889 prices# and a much lower population density "25[8 inh:km1# ð04Ł[ As a result\ the energy demand pro_le in the two regions is quite di}erent and this di}erence is not expected to change in the near future[ The main prospects for RES exploitation in these two regions concern primarily electricity generation "from wind energy\ small hydro!power and biomass# and heat generation in the building sector "mainly solar energy and biomass#[ Energy con! sumption in the industrial and agricultural sector is in both regions relatively low\ while RES penetration in the transport sector "which represents more than the half of the total energy demand# is not envisaged for the near future[

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Table 0 presents for the two regions\ the results of the developed bottom!up approach giving the breakdown of energy demand into end!use activities for the reference year 0881[ It can be seen that the two regions present considerable di}erences due mainly to the di}erent populations\ climatic conditions and living standards[ Another major di}erence between the two regions is the considerable share of the tertiary sector in Crete which is mainly due to energy consumption in tourist settle! ments[ The aggregation of the di}erent energy sources used in all end!use activities gives the energy mix shown in Fig[ 3[ It can be seen that in both regions biomass covers a considerable share of the total energy demand[ It mainly represents conventional systems used for space heating in the building sector[ In Crete\ there is\ in addition a small share of solar energy which is used for water heating in the residential and tertiary sector[ The rest of the energy demand in both regions is satis_ed by oil products and electricity produced exclusively from conventional fuels[

Table 0 Energy demand in the two regions\ 0881 "TJ# Crete

Ipiros

Residential Space heating Cooking Water heating Electric uses Air conditioning

3553 1605 503 332 705 64

4575 3200 261 372 408 9

Commercial Space heating Water heating Electric uses Air conditioning

0864 176 508 731 117

795 228 55 249 49

Public Space heating Electric uses Air conditioning

420 005 393 00

146 020 012 2

Agriculture Machinery Thermal uses

780 657 012

401 334 56

Industry Electric uses Thermal uses

1065 318 0636

609 253 235

09\275 19\511

4831 02\802

Transport Total

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Fig[ 3[ Composition of energy supply mix for the year 0881[

By estimating the trend characterizing the key parameters included in the technical models applied for each end!use activity\ the corresponding useful energy demand has been calculated for the year 1909[ The likely contribution of RES to the satisfaction of this demand depends on the amount of the exploitable potential of the various RES in each region shown in Table 1[ It can be seen that Crete is rich on wind potential\ solar potential and biomass\ especially from agricultural residues[ On the other side\ Ipiros is primarily endowed with hydro resources and forest residues\ while its wind and solar potential although quite signi_cant in comparison with other European regions is much lower than the corresponding _gures of Crete[ It is clear that the de_ned RES potential could lead to many alternative exploitation scenarios[ For selecting the scenario that will form the basis of a regional action plan

Table 1 Potential of RES in the two regions Crete Wind "092 Ha# 5Ð6 m:s 6Ð7 m:s ×7 m:s

007[7 05[7 9[3

Hydro "GWh# Technical Economical

805 34

Biomass "ktoe# Agricultural Forestry

039 02[5

Solar "kWh:m1# Mean monthly radiation

0669

Ipiros

59[5 5[4 9[1

7210 303

34[7 21[4

0466

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for the development of RES one has to take into account] "a# the associated investment cost and the available funds^ "b# the associated economic and environmental bene_ts in relation to the replaced conventional fuel^ and "c# the general attitude and the traditions of the local population[ In addition\ attention should be paid to the stability of the electricity system which may be threatened by a high penetration of intermittent renewable resources[ This is especially true in the case of the autonomous system of Crete where wind power plants should not exceed 29) of the total installed capacity[ The scenario for RES development up to 1909 that has been found to be the most advantageous from an economic\ environmental and technical point of view is shown in Table 2[ It can be seen that the extent to which each type of RES will be developed in each region presents signi_cant di}erences[ In Crete\ the emphasis is placed on the electricity generation sector and more speci_cally on the exploitation of wind energy resources[ In addition\ solar collectors for water heating are possible to achieve a very high degree of penetration in Crete|s domestic and tourist sector[ On the contrary\ in Ipiros smallhydro systems appear more attractive than wind energy\ while the penetration of solar systems\ although signi_cantly increased\ does not reach the penetration degrees of Crete[ Finally\ biomass continues to play a signi_cant role in both regions[ The largest part concerns still the combustion of biomass for space heating "although principally in more e.cient devices\ such as thermodynamic ovens# and a smaller one is used in power generation or cogeneration units[ The above results are summarized in Table 2[ Despite the observed di}erences between the two regions\ it can be seen that the total amount of energy provided by RES can notably increase in both regions and reach 3874 TJ in Crete "total increase of 89) compared to 0881# and 2219 TJ in Ipiros "total increase of 39) compared to 0881#[

Table 2 Energy production from RES in the selected regions Energy production from RES "TJ#

Crete

Ipiros

0881

1909

0881

1909

9 109

39 874

9 69

19 219

Biomass Traditional systems Advanced systems Cogeneration Power plant

1399 9 9 9

0669 864 084 069

1299 9 9 9

0079 0799 9 9

Wind Hydro Total

9 3 1509

709 39 3874

9 9 1269

9 579 2219

Solar Space heating Water heating

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3[ Conclusion It is increasingly recognised that in front of the severe risks menacing the stability of the planet\ it is necessary to change the perspectives of acting and of evaluating the consequences of our actions[ Actually\ the common practice is to broaden the scale of human activities and to retain a narrow angle regarding the outcomes[ Instead\ it is necessary to combine a global view of the natural environment with a regional perspective in designing actions for economic development and personal welfare[ The energy sector is a characteristic domain to illustrate the signi_cance of the above statement[ First\ because it is a major source of environmental deterioration and second because solutions facilitating such a shift are already at hand[ In fact\ RES o}er a unique opportunity for gradually changing the dominant attitudes of energy producers and consumers\ thus of the whole society[ A great diversity of technologies is commercially available today for power or heat generation from the di}erent RES[ Due to the di}use character and the low intensity of RES\ the corresponding installations have to be small sized and highly dispersed[ Furthermore\ in order to increase e.ciencies\ technologies are often designed to be directly used by energy consumers[ It comes out that interventions for RES exploi! tation have to be scheduled at the regional and local level\ in order to take into consideration site!speci_c characteristics concerning both the availability of RES and the energy system|s characteristics[ To this purpose\ a bottom!up approach for estimating RES penetration at the regional level has been developed[ The application study presented in the paper con_rms that with the proposed regional planning approach it is possible to identify the opportunities for the most e}ective exploitation of the renewable resources avail! able in each region in order to achieve a substantial increase in the share of RES on the primary energy consumption[ It is furthermore shown that due to particular regional features "natural and anthropogenic#\ RES exploitation in various regions could be quite di}erent in both\ quantitative and qualitative terms[

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