manfred gollner fuel wood consumption in austria ... · household survey quality standard ......

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Fuel wood consumption in AustriaHousehold survey Quality standardConversion factors

Manfred GollnerDirectorate Spatial

Statistics

Paris11 June 2012

www.statistik.at slide 2 | 15 June 2012

Household survey characteristics

Voluntary survey attached to the obligatory Labour Force Survey of Statistics Austria

Observation units: households at their main residence All households receive a letter to prepare the latest annual bills for

electricity, gas, district heating and other fuels Sample size: 22500, response rate is in a range of 50% to 75%

(at least 8500 valid responses) performed since 1975 in irregular, perennial periods;

since 2004 in biennial periods before 2004: "face‐to‐face" interviews, since 2004 "computer assisted

telephone interviews" (CATI) Grossing‐up occurs with size and age of the dwelling, number of gas

meters, number of installed wood chip and pellet boilers attributed to households


Questionnaire


Calculation of the Final Energy Consumption (FEC) and shares of the end‐use category

Plausibility checks and validation on single data level by calculation of amount/cost pairs

Reported FEC on household level: total of all consumed fuel amounts Assumed FEC on household level: average consumption for space

heating, water heating and cooking plausibility checks (tolerance ±50%)

Grossing up and aggregation of fuel consumption and end‐use category for Austria and the federal states on NUTS 2 level

Determination of fuel specific use for space heating, water heating, cooking and other use of electricity


Data validation in detail

For all fuels and end‐use categories:

Unit conversion with conversion factors Correction of unrealistic high or low amounts and prices (with average

values and upper limits) Correction of impossible combinations of fuels and purpose (e.g. district

heat or solar thermal heat for cooking) In case of missing amount OR price:

calculation with average amounts or market prices In case of missing amount AND price: e.g. if wood fuel is free of charge,

or bills got lost calculation with average amounts depending on the purpose, the fuel and the number of persons in the household or per m2

living space main fuel for space heating has a share of 70% compared to additional

fuels for space heating


Conversion factors

Conversion factors for fuels reported in various physical units

Fuel [Unit] kg l stere/bcm m³ kWh €‐Cent/unit GJ/unitNatural gas [kWh] 0,093 1 6,1 0,0036Natural gas [m³] 1 10,8 66,3 0,0389Fuel wood [kg] 1 0,0023 4,0 13,9 0,0143Fuel wood [stere] 431 1 1713,3 6000,0 6,1680Wood chips [kg] 1 0,0039 3,2 5,5 0,0114Wood chips [bcm] 256 1 810,2 1416,7 2,9169Fuel oil [kg] 1 1,189 11,9 85,6 0,0428Fuel oil [l] 0,84 1 10,0 72,0 0,0360LPG [kg] 1 1,724 12,8 137,9 0,046LPG [l] 0,58 1 7,4 80,0 0,0267

1 stere = 1 m³ of stacked wood pieces with a length of about 1 m1 bulk cubic meter (bcm) = 1 m³ of loosely poured wood


Upper limits

Upper limits of annual energy consumption with corresponding costs

Fuel [phys. Unit] Amount Costs [€]Hard coal [kg] 6.000 2.275Lignite [kg] 6.000 1.800Browncoal briquettes [kg] 6.000 2.240Coke [kg] 6.000 2.670Fuel wood [kg] 17.240 2.400Pellets [kg] 12.000 2.412Wood briquettes [kg] 12.000 2.640Wood chips [kg] 15.360 850Fuel oil [kg] 7.700 6.592LPG [kg] 2.900 4.000Non‐interruptible electricity [kWh] 20.000 3.603Interruptible electricity [kWh] 30.000 3.429Natural gas [kWh] 77.770 4.776District heating [kWh] 50.000 7.500Central heating (fuel unknown) [kWh] 50.000 7.500


Water heating and cooking

Average values of annual energy consumption

1 assumed as linear function; 2 assumed as a non‐linear function

End‐use category Nr. of persons in the household

Energy demand [ kWh ] [ GJ ]

Water heating 1 per Person 1199 4,32

Cooking ² 1 375 1,35

Cooking ² 2 475 1,71

Cooking ² 3 544 1,96

Cooking ² 4 714 2,57

Cooking ² 5 and more 883 3,18


Space heating

Average annual energy demand for space heating per m² in dependence on the building size and age

FuelDetached / semidetached houses Apartment houses

Construction period Construction periodtill 1960 1961‐1990 after 1990 till 1960 1961‐1990 after 1990

Hard coal [kg] 29,8 21,3 12,5 23,4 17,0 12,3Lignite [kg] 86,2 61,7 36,1 67,7 49,1 35,7Browncoal briquettes [kg] 43,3 31,0 18,1 34,0 24,6 17,9Coke [kg] 29,6 21,2 12,4 23,2 16,9 12,3Fuel wood [kg] 58,3 41,7 24,4 45,7 33,2 24,1Pellets [kg] 48,3 34,6 20,2 37,9 27,5 20,0Wood briquettes [kg] 48,7 34,9 20,4 38,2 27,7 20,2Wood chips [kg] 73,2 52,4 30,6 57,4 41,6 30,3Fuel oil [kg] 19,5 14,0 8,2 15,3 11,1 8,1LPG [kg] 18,2 13,0 7,6 14,2 10,3 7,5Heat pumps [kWh] 154,7 110,7 64,7 121,3 88,0 64,0


Example: data validation in case of missing amount AND price

Household: 4 Persons, in a flat with 90 m², constructed in the year 2000, calorific value of firewood = 14,31 MJ/kgWater heating: 4,32 x 4 = 17,28 GJfire wood: 17280/14,31 = 1208 kgadditional fuels: hard coal and charcoal briquettesfire wood: 1207,6/3 = 403 kgCooking: 2,57 GJfire wood: 2570/14,31 = 180 kgadditional fuels: hard coal and charcoal briquettesfire wood: 179,6/3 = 60 kgSpace heating: 24,1 kg/m² x 90 m² = 2169 kgfirewood as main fuel, additional fuels: hard coal and charcoal briquettesfire wood = 2169 * 0,7 = 1518 kg Total = 1981 kgShares: water heating: 20%, cooking: 3%, space heating: 77%


The quality standard of wood fuels

should support the implementation of reliable statistics on wood fuel consumption in households

Statistics on wood fuel is tricky, because of inhomogeneousmatter (different wood species and volume to mass conversion

factors, …) special market situation (non‐purchased quantities, informal or 'grey' markets,

…) inexperienced respondents, missing bills, different units (kg, stere, m³, water

content vs. moisture), ... focuses on consumer based surveys e.g. “face to face” or “telephone”

interviews In case of low importance of wood fuel consumption in households expert

estimates and modelling could be acceptable alternatives


Important steps to ensure reliable information

Consumption surveys with representative samples in adequate frequencies Experienced interviewers, self‐explanatory questionnaires Defined regional wood fuel mix (most frequent wood species) Average mass by volume units based on wood fuel mixes Average calorific values based on the wood fuel mixes and water contents Default values for consumption by purpose (space heating, water heating,

cooking) for data validation Well documented data validation procedure Availability of time series (at least 3 surveys to get an impression on data

reliability)


Energy content

The gross calorific value (GCV) of absolute dry wood is nearly on the same level for all wood species – only a minor difference between coniferous (19 MJ/kg) and deciduous (18 MJ/kg) wood, due to a higher resin and lignin content

The energy content of wood is much more dependent on the water contentthan on the wood species – there is a difference between water content and moisture

Water content w (%): w = (Wf-Wd)/Wf Moisture m (%): m = (Wf-Wd)/WdWf…fresh weight, Wd…dry weight

If you buy 1000 kg of fresh cut fuel wood with 55% w Wd = Wf*(1-w) = 1000*0,45 = 450 kg dry weight55% m Wd = Wf/(m+1) = 1000/1,55 = 645 kg dry weightDifference of 195 kg (20%)!


Water content and calorific value

0.0

10.0

20.0

0 5 10 15 20 25 30 35 40 45 50 55 60

MJ/kg

water content (%)

Net calorific value (NCVw) of fuel wood

12,6

14,7

17,3

7,2

fresh cut wood *)( =100%)

fuel wood, stored one season (+74%)

fuel wood, stored two or more seasons (+104%)

wood pellets

*) depending on wood species, age and season


Conversion factors

Compiled by the Austrian Energy Agencyin co‐operation with experts from: Universities and other research institutions (e.g.Biomass‐Logistics‐Technology Wieselburg), Austrian Standards Institute, Austrian Chamberof Agriculture, wood and wood products industries, pulp and paper industries

This factors could be used, if no national standards are established!

More detailed information on different wood fuel assortments: linkhttp://www.klimaaktiv.at/filemanager/download/30203


Please address queries to:Manfred Gollner

Contact information:Guglgasse 13, 1110 Viennaphone: +43 (1) 71128‐7573

fax: +43 (1) 71128‐ [email protected]

Thank you for your attention

manfred gollner fuel wood consumption in austria ... · household survey quality standard ......

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