The analyses of the electricity consumption of the Spanish households by means of measurements, has been developed in the following stages: “in situ” measurements: obtaining of preliminary results; results debugging; and obtaining of final results.
1. “In situ” measurement
2.
Preliminary
Results
3.
Filter of results
4.
Final results
Additional information from previous studies/projects
Figure 1: Methodological scheme of the procedure followed to obtain the results
The measurement phase was planified according to the following steps:
 Selection of dwellings “type”
 Selection of technicians: A selection of students with technical background has been made from either the last courses of universities or official Masters, through a regime of practices, to develop the measurements in the dwellings.
 Training of technicians: Through informative campaigns, explaining the objective of the study, the measurement equipment functioning, and the data to request.
Additionally, an explicative letter from IDAE has been delivered which invites to join the project.
 “In situ” measurements and delivery of the field research data to the consulting company in charge of the data processing.
The starting point was a sample of 600 dwellings “type”, representative of the three main climate zones of Spain (Atlantic, Continental, and Mediterranean), considering 2 types of dwellings (single family dwellings and multifamily dwellings). The measurements were addressed to the permanently occupied dwellings.
The selection of dwellings was made with enough representativeness with regard to their characteristics and location.
The selection criteria integrated energy, geographic and socioeconomic factors, among which the following ones stand out:
 Selection of dwellings in areas with a GDP per inhabitant equivalent to the national average, which is justified by the relation between the energy consumption and the purchasing power. With this aim, middle classes neighborhoods were chosen, leaving out areas low- or high- income populations.
 Selection of a number of dwellings balanced by climate zone , with approximately
200 dwellings in each of the three climate zones (minimum 150 and maximum 250). In this way, it was possible to obtain valid information form each clime zones, which was later extrapolated to the national universe, through weighting factors, according to the weight of the total population in each zone.

 The selection of both single family and multifamily dwellings kept a relation close to a ratio 3 to 1 , in correspondence with the information available from the Spanish
Statistics Institute (INE).
The selection of dwellings took into account the distribution and density of population.
The access to the dwelling was facilitated through the collaboration with students from universities, with technical background, being enrolled in either the last courses of universities or official Masters, corresponding to each climate zone. Their involvement in the project was stimulated with the help of an informative letter of IDAE. Likewise, the dwellings were encouraged to participate by offering them the possibility of contacting
IDAE’s Service on Energy Efficiency and Renewable Energy Sources (SICER), so that they could receive assessment on issues related to energy and/or an energy diagnosis of their dwellings developed by the consulting company in charge of the measurements.
The organizational structure of the team responsible for taking the measurements was based on the following scheme shown in the figure 2.
COORDINATION
Consulting company responsible for the measurements process
Responsible
Atlantic Zone
Responsible
Continental Zone
Responsible
Mediterranean Zone
5 a 20 technicians
150 – 250 dwellings
5 a 20 technicians
150 – 250 dwellings
5 a 20 technicians
150 – 250 dwellings
Figure 2: Organizational structure of the team in charge of taking the measurements
The initial dwellings-type where the measurement could not be taken, were replaced with other of similar characteristics, in order to assure the measurements in a sample of 600 dwellings-type.
The measurements were taken in the period from 21 st June to 23 rd march in accordance to the following planning:
 Summer season: between 21st June to 23 rd


Autumn season: between 24
Winter season: between 24 th th
September,
September to 23
December to 23 rd December, rd March,
The spring season was assimilated to autumn because of the similarity of temperatures and energy demands.
The measurements were accompanied by a questionnaire addressed to the equipment, their technical characteristics and pattern of use , differentiating between working days and festivities. The questionnaire included a request on information based on the electricity invoices corresponding to the last 12 months. In particular, the questionnaire included the following questions:
 Province where the dwelling is located
 Type of dwelling: single family or multifamily dwellings.

 Electricity consuming equipment in the household: number of equipment items by type, power (kW) and, if possible, the power of standby.
 Habitual timetable of use of each equipment
 Type of lighting in each zone of the household, number and power (W) of the bulbs and timetable of use.
 Electricity invoices data: contracted power, consumed energy (kWh) and the period covered by the invoice.
The electricity equipment items, over which the measurements were taken, whenever the household had such equipment, were the following ones:
 Electrical service of heating: reversible and non-reversible heat pumps, electrical heaters, electrical convectors, electrical radiators and electrical boilers.
 Electrical service of water heating : electrical heaters of water.
 Refrigeration: air conditioning and reversible heat pumps
 Cookers : electrical; glass ceramic hob and induction.
 Household electrical appliances: refrigerators, freezers, washing machines, washing machines-dryers, dishwashers, TVs, dryers, ovens, PCs and rest of electrical equipment.
In order to take the measurements 600 electricity consumption measurer equipment were used, with the following characteristics:
 Consumption measurement in real time in watts-hours.
 Memory for the overall costs and energy consumed over the period chosen for measurements.
 Information on connection and functioning times.
 AC Voltage: 230V.
 Frequency: 50 Hz.
 4 Digits (up to 9999 Watts-hours).
 Precision: deviation < ±5%.
 Consumption measurement capacity up to 3.000 Watts.
Moreover, for each type of dwelling and climate zone (six in total), an electricity consumption register equipment was installed. This equipment is more powerful than the aforementioned (measurer equipment) and is connected to the main switchboard of the household. It provides enough information by taking hourly measurement during a determinate period. Additionally, the register equipment can store information hour by hour; so that the real load curves can be obtained, being additionally very useful for aspects such as the measurement of standby and/or the peak demands. The characteristics are the following ones:
 Frequency: 433.52MHz.
 Time of transmission: 6s/12s/18s.
 Scope of transmission: 40-70m.
 Voltage of the sensor: 110V-300V.
 Capacity of the sensor: 50mA - 95ª.
 Precision: >92%.
 Memory: 64K.
 Voltage and current of supply: 6V - 300mA.
 Batteries: 3xAAA, 3xAA.

The measurement equipment was directly obtained for the development of the project and the supplier company assured, through certificate, both the fulfillment of EC normative and the calibration of all the equipment.
The electricity consumption measurer equipment were located in the plugs of the electrical installation of the households where the equipment to be measured were later connected. Each technician was provided with 10 measurer equipment units, with the objective of taking measures of a household each week. The measurement equipment provided information on the electricity consumption (kWh) along the period of measurements as well as the functioning time of the measurement equipment. In order to assure the measurements in working days and festivities , the measurement equipment were installed for 4 consecutive days in each household, mainly from Thursdays to
Sundays.
The electricity consumption register equipment units were connected to the main switchboard of the households, in order to obtain hourly consumptions, providing hourly electricity consumption curves during 10 months. These curves were later used to contrast peak demands and the standby.
During the development of the Project, all the technicians were supervised through their responsible for areas, being all of then coordinated by the project leader.
The incidences encountered during the measurements phase were of two types: measurement equipment failure, and problems of access to some electricity consuming equipment, such as the ovens. When some of these incidences appeared, the procedure followed was the following:
 If a measurement equipment stopped to take measures for whatever reason during the measurement phase: another measurement equipment unit was installed whenever it was possible in the same day. On the opposite side, another measurement equipment unit was installed in the next week, during the same week days.
 If consuming equipment couldn’t be measured because of accessibility problems, then the preliminary results were estimated on basis of other measurement realized in similar consuming equipment.
The incidences reported amounted to 1% of the measurements taken.
Along the measurement phase, some quality control procedures were implemented, on level of field research and on level of treatment of preliminary results.
In this way, during the filed research, a triple quality control was applied:
 A checking of all the information received by the team of technicians, to check that all the data had been properly taken (measured). On the opposite side, individual revisions were realised.
 Individual checking of 5% of the “in situ” measured data , both during the measurements in the households, and through personal meetings with the technicians.
 Every two months some meetings were organized among the teams in charge of the measurements, both on the level of a same climate zone, and on the level of the whole of climate zones.
This procedure contributed to the previous identification of mistakes and their solution, guaranteeing the reliability and quality of the results.

Once the field research was finished, all the information obtained together with the questionnaire was integrated and processed. The preliminary results were obtained through a “bottom-up” method complemented with a “top-down” method. That is, a system which generates updated consumption curves, taking as inputs:
 Data obtained from the measurement equipment installed in the households.
 Data from the questionnaire.
 Data from the consumption “type” curves of each electrical equipment, known from former studies/projects . The consumption “type” curves, derived from previous studies, were used to weight the curves generated with the information obtained from the measurement equipment and the questionnaire data. These curves allowed to put on a homogeneous basis all the information obtained from the field research, with the aim of extrapolating the measurements, with the least margin of error possible, to the rest of households of Spain.
 Data obtained from the energy registers.
 Data from the electricity invoices: which allowed adjusting the load curves of the household in the period include in the invoice.
DATA RESULTS
(1) 600 electricity consumption measurer equipment units installed in
600 households
Initial load curve of each equipment, curve of each household (y stand-by) measured
(600)
(2) Questionnaire: data from electrical household appliances and energy consuming equipment and habits of use.
(3) Load curves “type” from previous experiences and projects.
Use of a load factor
(4) 6 electricity consumption registers
Checking of standby and peaks of demand
(5) Invoices of the households: adjustment of the curves to the value given in the invoices.
“other equipment”
For each household, and each equipment item, it’s obtained the hourly consumption, for each equipment unit, both consuming in active mode, and in standby mode, in working days and festivities, etc.
Figure 3: Methodological scheme to obtain the preliminary results
The aforementioned procedure was accompanied by a filtering process through a quality control of the preliminary results. This was developed through the design of a specific software programme for automated information analyses . The following checking took place:
 Absence of “gaps”: availability of all the necessary data corresponding to the equipment available in the households.
 Correspondence between the sums of the power of all the equipment, obtained from the questionnaires, with total power installed in the households.
 Correspondence between the consumptions related to the invoices of each household and the sums of the consumptions of all the equipment available in the household, for the period correspondent to the invoices.

Once the filter of the preliminary results took place, it was applied an adjustment of those values which did not overcome the required quality parameters, in a way the final values were obtained.
The debugged information was extrapolated to the universe of households by means of elevation factors for each geographical scope and type of dwelling. For the elevation of the results corresponding to each type of equipment, climate zone and type of dwelling, the equipment ownership obtained from the presence and phone surveys, realized in parallel to the “in situ” electricity measurements, were used.
The calculation algorithm used to determine the electricity consumption of a household, by grouping types of dwellings , has been the following:
Consumptio n , dw ( j )
 
 cons equip ( i , j )
 ratio ( i , j )
 i = index of equipment j = index of dwelling (u, b)
The calculation algorithm used to determine the electricity consumption of a household, by grouping climate zones, has been the following:
Consumptio n , dw ( k )

  cons equip ( i , k )
 ratio ( i , k )
 i = index of equipment k = index of climate zone (A,C,M)
The calculation algorithm used to determine the electricity consumption of all the households, on national level , has been the following:
Consumptio n , national

 cons equip ( i , j , k )
 ratio ( i , j , k )

Ndwelling ( j , k )
  i = index of equipment j = index of dwelling (u,p) k = index of climate zone (A,C,M)
As starting hypotheses have been to assume that a year has 365 days, and 4 seasons of
91.25 days per season. One season has 13.04 weeks and y 1 week has 7 days (2 festivities y
5 working days).
The information extrapolated was contrasted with external and official information obtained from other sources of information in order to get a better validation of results.
Gained Experience:
 The Project itself has been pioneer in Spain and in some aspects, such as the measurement of the standby, in Europe.
 Specific software has been developed for support, quality control, information contrast and validation, and generation and analyses of results, disaggregated by scopes of analyses (types of dwellings and climate zones).
 A multidisciplinary team of experts integrated by specialists in management of energy information systems, engineers with energy specialty, and field research engineers.
 The work developed has followed a continuous quality control system which has allowed identifying whatever deviation and implementing corrective actions, such as the integration and homogenization of the different sources of data.

Future Milestones
 It’s advisable to take measures over a larger number of households during a larger number of days for some equipment items which consumption can vary remarkably
(washing machine, dishwasher, etc.)
 An exhaustive campaign of specific standby measurements would be desirable, mainly because of the importance this consumption is getting derived from the increase in the electronic equipment ownership.
 A comprehensive study which incorporated the “in situ” measurement of the consumption of all the existent energy sources in the households, would be necessary

Country
Organisation
Name of the project
Project purpose
Spain
IDAE
SECH – SPAHOUSEC PROJECT – Analyses of the energy consumption of the household sector in Spain- “ Measurements of Electricity
Consumption
In the Household Sector”
 Equipment ownership ration of the households in each climate zone.
 Unit electricity consumption of the electrical equipment of the household.
 Patterns of use of each electrical equipment units, in working days and festivities.


“Standby”
Hourly, daily, seasonally, and yearly load curves of the electrical equipment of the household, with a distinction between working days and festivities.
Sample design Selection of a sample of households, on a basis of energy, geographical and socioeconomic criteria: GDP per inhabitant equivalent to the national average; number of dwellings balanced by climate zone; ratio single family /multifamily dwellings : 3-to 1, similar al del INE
INE, Census Sample sources
Equipment used
Sample size
Frequency
Time to collect measurements
Who takes measurements
End-uses measured
Geo-climatic measurements
Electricity consumption measurers and registers of hourly consumption
600
4-5 years
4 consecutive days, from Thursdays to Sundays (2 working days and festivities)
Team of technicians distributed by climate zones
Electrical heating, Electrical water heating, Refrigeration, electrical cookers, Household electrical appliances: refrigerators, freezers, washing machines, washing machines-dryers, dishwashers, TVs, dryers, ovens, PCs and rest of electrical equipment.
3 climate zones (Atlantic, Continental and Mediterranean) and 2 types of dwellings (single-family and multifamily dwellings)
Main Challenges
Recommendations
Key best practice


Access to dwellings
Incidences with measurement equipment and accessibility to consuming equipment
 Quality control in the measurement phase
 Processing and debugging of preliminary results
Advisable to take measures over a larger number of households during a larger number of days for some equipment items which consumption can vary remarkably (washing machine, dishwasher, etc.)
An exhaustive campaign of specific standby measurements would be desirable
A comprehensive study which incorporated the “in situ” measurement of the consumption of all the existent energy sources in the households, would be necessary
 Pioneer project in Spain and in some aspects, such as the measurement of the standby, in Europe.
 Specific software has been developed for support, quality control, information contrast and validation, and generation and analyses of results, disaggregated by scopes of analyses (types of dwellings and climate zones).


Creation of a multidisciplinary team of experts
Implementation of a continuous quality control system