Methodology and Summary Quality Report
on Energy Statistics
Country: Bulgaria
Year: 2011
This report has been prepared in accordance with the provisions laid down in Article 6 "Quality
assessment and reports" of the Regulation (EC) No 1099/2008 of the European Parliament and of
the Council of 22 October 2008 on Energy Statistics. It comprises information on all data
collections used at national level to make available the statistics covered by the ESR. In
accordance with the discussions and conclusions reached in the 2010 ESWP meeting, this report
comprises two parts:
1. Part A - General Information
This part is completed for each data collection used at national level to generate data
reported under the ESR.
2. Part B - Detailed information
This part is completed for those data collections that are deemed essential in responding
to the ESR requirements.
1
Methodology and Summary Quality Report on Energy Statistics
Part A - General Information
Country: Bulgaria
Year: 2011
In case the fields provided in this form offer insufficient space, then please refer to numbered attachments.
1. Name of the data collection
Indicate the name of the data collection.
Fuels and energy consumption
2. National body responsible
Indicate the name and address of the national body responsible for the data collection.
National Statistical Institute, 2, P. Volov Str.; Sofia, Bulgaria
3. Objective and history
Outline the overall objective, indicating the broad field covered by this data collection.
Also describe the way this data collection interacts with or complements other national data collections in order to respond to the ESR
requirements.
Summarise the evolution of this data collection over time (starting with the year of implementation) and give details of availability of
time series data, including break in series.
NSI implements data collection only.
Data for total consumption by type of main energy products have collected for more than
thirty years.
Since 1997, for more accurate data on final energy consumption, data collection is
implemented together with other data collections – “Balance of energy-transformation
processes”:
- “Electricity and heat generation”
- “Lignite briquettes production”
- “Coke oven coke production”
- “Blast furnace gas production”
- “Petroleum products production”
After the year 2000, the data by aggregate economic activities on scheme of overall energy
balance are available in website of NSI, under theme “Energy”, subtheme “6.1.Overall
energy balance sheet” - http://www.nsi.bg/otrasalen.php?otr=37
4. Reference period, frequency and transmission deadline
Indicate the reference period, frequency and deadline for data transmission.
Data are collected annually, for calendar year, up to end of March, following reference year by printed form in Regional Statistical Offices (RSO) or by electronic form online in
“Information System Business Statistics” (ISBS) on NSI’s server.
By the end of June, data from printed form are entered into ISBS from experts in RSO.
2
Methodology and Summary Quality Report on Energy Statistics
Part B - Detailed information
In case the fields provided in this form offer insufficient space, then please refer to numbered attachments.
5. Legal framework
Indicate the legal force (voluntary or mandatory). In the case of mandatory data collection, indicate any relevant national law (beyond
the Energy Statistics Regulation).
Data are collected mandatory, based on Annual National Statistical Program, which is
elaborated in accordance with Chapter Three of the Bulgarian Statistics Law http://www.nsi.bg/pageen.php?P=174&SP=175&SSPP=345 .
6. Statistical concepts and method
6.1 Variables surveyed and derived
Give a comprehensive list of the variables (flows) and all energy commodities covered by this data collection. Use the nomenclature of
the Energy Statistics Regulation to allow identification of the field (questionnaire and table) covered by the data collection.
Indicate the measure units used for reporting each energy commodity and any associated conversion factors used at national level.
1. The surveyed variables are:
- opening stock levels
- closing stock levels;
- total consumption and of which:
for non-energy use;
for transport;
for agriculture/construction engines and other stationary engines
These variables are collected in specific measure unit for each energy product.
2. With this survey are collected data for energy products included in national energy
classification “PRODENERGY”
(http://www.issc.nsi.bg/WEB_CE9/faces/classificationList.jsp - №56
ПРОДЕНЕРДЖИ – 2011).
National energy classification “PRODENERGY” is constructed on base Energy
Statistics Regulation.
3. Specific measure units are used for each energy product. Some of conversion factors
used on national level are available on
http://www.nsi.bg/otrasal-publikaciaen.php?n=311&otr=37 ;
Electronic edition of the publication 'Energy Balance Sheets 2010' – page „Specific
conversion factors”).
6.2
Type of data collection
Indicate the type of data collection (business/household survey or administrative source) and the survey format (sample survey or
census).
The survey is exhaustively and provides data from business branches – agriculture/forestry;
industry; transport.
Suppliers provide data for service sector by another survey – “Resources and deliveries”.
3
6.3
Population frame and reporting unit
Indicate the data source used to define the population frame, the size of the target population and the reporting unit, including any
thresholds applied.
Register of Statistical Units is the general source to define the data collection frame. It is
updated each year and it includes all entities that submit to NSI an Annual Activity Report.
The target population is part of Register of Statistical Units: all non-financial enterprises,
which compile balance sheet, have economic activity from 01 to 53 on NACE.Rev.2 and
declare expenditure for energy products.
6.4
Sample size and unit non-response rate
Specify the sample size and the sampling method. Provide information on the unit non-response rate too.
Not applicable.
6.5
Classifications
Indicate the classifications used in this data collection. In the case of national classifications, indicate any differences between the ESR
and the national classifications and the possible impact on data quality.
National classification “PRODENERGY”, based on the ESR.
6.6 Compilation of the final data set, models and statistical estimation techniques used
Provide information about validation procedures, models or estimation techniques used (in case of missing data) to obtain the final
indicators at national level
Validation data procedures are in force for each energy product and for each reporting
entity.
With them are controlled coverage of responsible entities and data completeness.
The check is first implemented at data entry in online “ISBS” and secondary at national
level from experts in NSI.
Data are aggregated at national level by economic activities.
6.7
Overall accuracy
Provide a qualitative assessment of the overall accuracy of the main variables collected by this survey.
Indicate the sources of errors (sampling, coverage, measurement, nonresponse and processing errors).
The variables collected by this survey have good accuracy and they are reliable.
6.8. Data revision policy
Provide information revisions policy and size of observed past revisions for the main variables.
Revisions of data are possible in case of errors.
4
7.
Supplementary documentation
7.1
Methodology
Provide web addresses for reference material on the method and questionnaires used.
The questionnaire used and the methodology for 2010 are available on website of NSI:
1. http://www.nsi.bg/files/GOD2010/P2/21%20-%20Goriva%20Energia_NF2_2010.pdf for all users.
2. In online “Information System Business Statistics” -, 2. Non-financial enterprises,
which compile balance http://www.nsi.bg/GOD2011_02_pagebg.htm?P=68&SP=580&SSPP=582 on
Bulgarian language only. Access is possible for responsible bodies, using electronic
signature only.
Since 2008 the original respondent data are available on NSI’s server. Access is allowed to
concerned experts of NSI only.
7.2
Quality documentation
Provide the web address where the detailed quality report is available at national level.
First quality report on Fuels and energy consumption data.
5