On the elasticity of residential energy consumption Theodora Slini, Efrosini Giama and Agis M. Papadopoulos Department of Mechanical Engineering Aristotle University Thessaloniki Thessaloniki, Greece
[email protected] Abstract— The current paper discusses the analysis of the results that emerged from a field study conducted in two consecutive years, aiming at the assessment of the economic recession’s impact on the consumers’ behaviour regarding energy consumption and space heating. The field survey was carried out, by means of interviews with questionnaires, in Northern Greece, an area where there is an increased energy demand for space heating compared to Athens and Southern Greece and hence an intensive need for efficient and effective solutions. The results of the field study, which has been carried out between 2011 and 2013, were analysed in order to identify major tendencies, if any, in the consumers’ behaviour, with respect to the prevailing energy prices and the disposable household income. In that sense determining the degree of elasticity of residential energy consumption can be determined in a bottom-up approach and compared to the national average values for the same period. A further goal was to capture details that are helpful in order to understand technological choices and behavioural patterns when it comes to coping with a lesser income and increased energy costs. Keywords— Disposable consumption, elasticity
income,
residential
[3]. Alternative heating systems are being considered in by consumers, in order to cut down heating expenses, which are not always the greener or the most sustainable ones. The primary energy consumption is presented in Figure 1, where oil is the major fuel consumed, followed by coal and lignite use. It is noteworthy that according to data on housing conditions of the Greek Statistical Authority [4] the 26.8 % of the total population in 2012 lived in a house that was poorly heated during the winter, while the corresponding percentages of poor population (having income less than or equal to the poverty limit) and non-poor population were 36.2% and 24.1%. The rates for 2007 were: 17.2%, 26.7% and 14.7%, respectively. The majority of the population, 74.1 %, in 2012 had central heating in the house compared to 71.8% in 2007. A proportion of 19.5% in 2012 changed residence during the previous five years due to housing problems, while the corresponding rates for 2007 was almost double reaching the 38.4 %. At the same time, the proportion of the population
energy
I. INTRODUCTION According to the OECD Employment Outlook, total poverty in Greece is higher than the OECD average and among the highest in the EU. Unemployment is a key driver of poverty and more than 25% of jobless households in Greece seem to live under poor conditions. In the same study, it is suggested Greece to “focus on integrating environmental considerations into sectoral and economic policies with a view to achieving a low carbon and energy-efficient economy and to better exploit the associated employment and innovation opportunity” [1]. As Greece is facing a severe economic crisis, the protection against fuel poverty is an issue of major importance [2]. A special reduced tariff for electricity for low-income, vulnerable households is an example of measures taken by the Greek government towards this direction. However, energy consumption for heating has been reduced by approximately 60% between 2008 and 2012, at least according to the sales figure of the markets for oil, gas, biomass, wood and electricity
Fig. 1. Primary energy consumption in Greece compared to European and global average [5].
80% % 70% % 60% % 50% % 40% % 30% % 20% % 10% % 0% %
74,1%71,8%
26,8% 17,2 2%
20112 20007 38,4%
34,9% 31,22%
19,5%
poorly heaatedpoorly coooled
centraal heatinng
changee of residennce
Fig. 2. The conditions of housinng in Greek hoouseholds accoording EL.S STAT data.
who lived in a residence that was w not sufficciently cool duuring the summer was 34.9 % in 2012, 2 a slighttly lower thann the respeective rate forr 2007 reachinng the 31.2% (Figure 2). I that sense, it is proven extremely challenging to study In s the elasticity e of thhe domestic ennergy consumpption A field study s was conducted foor two consequuent winter periods by studdents of the t Departmeent of Mechhanical Enginneering, Arisstotle Univversity of Theessaloniki (AU UTh) in collaaboration withh the National and Kaapodistrian University U of Athens andd the Univversity of Piraaeus [6]. The results r of the first winter period is alrready publisheed in Slini et al. a (3), while at a the current study s the latest findings will be analyzed. Fuurthermore, major m tenddencies, technnological chooices and behhavioural pattterns whenn it comes too coping with a lesser incoome and increeased enerrgy costs will be b sought.
nonp parametric Sppearman correelation. The an nalysis was caarried out by b means of thhe statistical ssoftware IBM//SPSS. III. REESULTS The T analysis of the field survey indicaates that a tyypical housse was constrructed betweeen 1958 and 2006 2 with a mean m surfa face of approxximately 90m m2 and it is occupied by three resid dents. The majority m (63% %) lives in ap partments rannging betw ween the 2nd and a 3rd floor.. There was an n evident variiation of th he surface diistribution bettween Thessaaloniki and Laarissa (Maann Whitney Test, T with signnificance 0.02 26) as presentted in Figu ure 3. Regarding R thee central heatiing system, bo oth oil and gaas are wideely employedd for heating purposes, wh hile all responnders own n at least one o A/C uniit with instaalled capacity ty of 9000 0BTUor above, operating att average for 5 hours per daay. The T minimum m indoor and outdoor tem mperatures set as a bencchmark for sttarting the heeating operatio on also decreeased. How wever, in Lariisa the tempeerature limit seems s to be lower l than n the Thessalooniki limit vallue for both in ndoor and ouutdoor temp peratures. Onn average, thee indoor temp perature decreeased sligh htly from 177.6o C in 2011-12 to 16.4o C in 2012-13. Sim milarly, the ouutdoor temperaature from 12 2.5o C declined in 11.9 9o C (Figure 4)).
II. METHO ODOLOGY
S Students com ming from thhe Departmennt of Mechaanical Engiineering, AUTh, completeed the questioonnaire in onn-site interrviews carriedd out in the Thessaloniki Greater Areaa and Larissa, regions wiith increased energy demannd for heatingg and hencce intensive neeed for efficieent solutions. For F the purpoose of this paper, the sett of 24 questioonnaires colleected and anallyzed will be discussed,, with 13 corrresponding too Thessalonikii and 11 too Larisa. Desccriptive statisttics, qualitativve and quantittative indicces, was appplied in ordeer to identiffy the popullation charracteristics, whhile potential linear correllation betweenn the aforeementioned paarameters wass explored andd calculated by the
Fig. 3. The distributioon of house surfface (in m2) in Thessaloniki T and Larisa areass.
indo oor2011_12 indo oor2012_13 outd door2011_12 outd door2012_13
2 25 Temperature (oC)
A questionnairre was approppriately develooped consistinng of 50 questions q incluuding demogrraphic data, suuch as the num mber of reesidents, the buuildings’ locaation and age, the t heated surrface, houssing type, flooor number, annnual income annd capital spennt on heatiing for the laast three yearss. Details on the central annd/or alterrnative heatinng system, fuel type, air condition c usee and instaalled capacity,, hours of opeeration, climatte conditions, such as iddeal indoor tem mperature andd minimum ouutdoor temperrature for heating h operattion, and recennt retrofitting solutions appplied, suchh as change of o fuel type, were also inccluded. The hours h spennt in house weere monitoredd along with data d related too real amounts fuel conssumed (tons of oil, m2 of gaas, kWh of energy, tons of wood) andd their cost oveer the last two winter periodds.
2 20 15 10 5 0
Larisa
Theessaloniki
Fig. 4. 4 The minimum indoor and outdooor temperatures set as a benchmaark for startin ng the heating opperation in Thessaaloniki and Larisssa for the winter periods p 2011-12 and 2012-13.
tons 6
Larisaa Thessaloniki
5 4 3 2 1 0 oil_2011-12
oil_2012-13
((a) Fig. 5. 5 The annual incoome in Larisa andd Thessaloniki arreas for the years 201112.
m2 2100 1800 1500 1200 900 600 300 0
Larisa Thessalloniki
gas_2011-112
gas_20122-13
((b) Fig. 6. The total budgget spent for heatiing in the Larisa and Thessalonikii areas for thhe winter periods of o 2011-12 and 20012-13.
C Concerning thhe annual inccome per houusehold a steeadily decrreasing trend was w identifiedd over the timee period studieed as show wn in Figuree 5, affectingg the budget spent on ennergy conssumption. A statistical s signnificant differrence betweenn the two regions is demonstrateed (Mann-W Whitney test with signiificance at 0,012 for 20100-2011 and att 0,016 for 20012), mainnly due to the fact that Theessaloniki respponders are mainly m studeents, while in Larisa mainly m familyy householdss are captuured. As a result off the income shrinkage, the total budget spent A s on heating h has decreased in thee regions undeer study as weell as on average a by approximately a y 22%. The exact recordss are preseented in more detail in Figuure 6. Another intereesting finding is the evolutiion of the diffferent A fuel types and eleectricity consuumed for dom mestic heatingg. As show wn in Figure 7, there wass a dramatic cut of all typpe of conssumption, exccept wood, in 2012-13 compared too the respeective figuress of 2011-12. On the otherr hand, the usse of wood was almosst doubled inn Larisa whiile no data were availlable for the Thessaloniki T a area. The fact may m be also due d to the type t of househhold studied inn the later reggion, that is mainly m studeent houses weere questionedd.
Larisa Thessalo oniki
kWh 1800 1500 1200 900 600 300 0
electr_2011--12 electr_20012-13 ((c) tons
Larisaa Thesssaloniki
4 3 2 1 0
w wood_2011-12 2 wood_20122-13 ((d) Fig. 7. The average annual fuel and electricity consu umption for the winter perio ods 2011-12 and 2012-13 2 by type: (a) oil in tons, (b b) natural gas in m2, m (c) electrricity in kWh andd (d) wood in tonss.
IV. COMPARISON OF TWO FIELD STTUDIES
tonns
The overall exxperience of the T t two conduuctive surveyss can provvide some strrong and reliable hints onn the elasticitty of residdential energyy consumptionn in Greece. The details of o the first conducted suurvey can be found f in Slini et al. (3) meaaning that the current paper will focus on thee results andd the com mparison with the t current daata. Firstly, it is evident thaat the annuual income keeps shrinking following a linear relation over the last l 5 years (Figure 8). I effort to reduce the energy cosst the minim In mum tempperature benchhmark in ordeer to start the heating operration has dramatically decreased for f both inddoor and outtdoor tempperatures as sttated in Figurre 9, approxim mately by 11% % and 4% respectively. r W When it com mes to the total t consumpption for heating purpposes, it is prooven that the oil o consumptioon decreased about a 5 %, % as well as the t electricityy consumptionn by 60% (Fiigure 10). On the conttrary the natuural gas consuumption increeased sharpply by 160%, as a cost-effeective way of heating , while no validd data exist about a the woood consumptiion for the peeriod 20122-13 as explaiined in sectionn III. I addition as the hourrs of heating operation was In significantly decrreased by alm most 40% the total budget spent s on thhe purpose was w inevitablyy declined by 21% (Figuree 11). The later conclusiion suggests thhat the cost off heating rose..
Oil
1,6 65 1,6 60 1,5 55 1,5 50 2010_11
2011__12
20122_13
((a) Gaas
m2 10000 80 00 60 00 40 00 20 00 0 2010__11 kW Wh
20111_12 (b)
2012_13 2
Electrricity
30000 25500 20000
Incoome
k€€ 400
15500
y = -1216,2x + 31406 R² = 0,927 0
300
10000 5 500
200
0
100
20100_11
0 2009
2010
2011
2012
2013
Fig. 8. 8 The annual incoome evolution ovver the last five yeears in Greece.
to ons
2011_12 ((c)
2 2012_13
Woood
8 80 7 70
oC 200 188
Temperaature indooor outdooor
13
oC C
6 60 5 50 4 40
12
3 30 2 20
166
1 10 144
12
11 1indoor 2011 1oor 2 temperatures 2012 13 1set as a benchmaark for Fig. 9. 9 The 2010 minimum and outdo startinng the heating operation o for the winter periods 2010-12, 2011-112 and 2012--13.
0 2010__11
20111_12 (d)
2012_13 2
umption by type: (a) oil Fig. 10. The average annual fuel and electricity consu ns, (b) natural gaas in m2, (c) electtricity in kWh an nd (d) wood in tons, for in ton the winter w periods 20110-11, 2011-12 annd 2012-13.
Fig. 12. European household electricity and gas prices [VaasaETT, 2013].
(a)
(b) Fig. 11. (a) The average hours of heating operation and (b) the respective cost of heating in Greek households for the winter periods 2010-11, 2011-12 and 2012-13.
V.
CONCLUDING REMARKS
Energy prices in Europe, and natural gas prices in particular, had a decrease in the aftermath of the 2008 global economic crisis. However, signs of an economic recovery are visible, accompanied by expectations of a rising demand for both electricity and gas led to a rebound of prices after 2010. They fell slightly during 2013 (Figure 12). However, Europe can hardly be considered as an entity when it comes to the capacity of households to cope with their energy bills, as huge differences exist between member states 7, 8]. Plagues by the economic recession for six consecutive years, more than 26% of Greek household cannot afford to heat their homes properly, according to European Union figures (Figure 13). Italy, Portugal, Lithuania and Latvia are in a similar sad state. Despite the Greek government subsidies to support a collapsed oil-driven energy system, serious problems and difficulties remain in the society [9,10]. Green innovation,
Fig. 13. Percentage of population unable to heat their home properly [11].
energy conservation technologies and a strong renewable industry could be the answer to Greek economy vulnerability and social well-being. REFERENCES [1]
[2] [3]
[4] [5]
[6]
Organisation for Economic Co-operation and Development (OECD). Greece at a Glance: Policies for a Sustainable Recovery, http://www.oecd.org/greece/44785912.pdf IEA (International Energy Agency).Energy Policy Highlights, 2013. T. Slini, E. Giama, A.M. Papadopoulos, “The impact of economic recession on domestic energy consumption”, International Journal of Sustainable Energy. DOI: 10.1080/14786451.2014.882335. EL.STAT (Hellenic Statistical Authority), Survey on income and housing conditions of Greek households: 2012. 27 March [in Greek]. EEA (European Environment Agency). 2011 Survey of resource efficiency policies in EEA member and cooperating countries. Country profile Greece. ETC/SCP, May 2011. M. Santamouris, J. Paravantis, D. Founda, D. Kolokotsa, P. Michalakakou, A.M. Papadopoulos, N. Kontoulis, A. Tzavali, E. Stigka, Z. Ioannidis, A. Mehilli, A. Matthiessen, E. Servou, “Fuel/Energy Poverty and the Financial Crisis: A Household Survey in Greece”, Energy and Buildings, vol. 65, pp. 477-487, 2013, October 2013.
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[9]
IEA (International Energy Agency), Energy Policies of IEA Countries, Greece, 2011 Review.2011. ISBN 978-92-64-09474-1. Energy Efficiency Policies and Measures in Greece, ODYSSEE-MURE 2010, Monitoring of EU and national energy efficiency targets, CRES, Athens, December 2012. A.M. Papadopoulos, “Energy Cost and its Impact on Regulating Building Energy Behaviour”, Advances in Building Energy Research, vol. 1:1, pp. 105-121, September 2011.
[10] World Economic Forum, Energy for Economic Growth, Energy Vision Update 2012, Industry Agenda, Prepared in Partnership with IHS CERA, 2012. [11] Eurostat, the statistical office of the European Union, F4: Quality of life, Inability to keep home adequately warm, 2013.
