European local authorities are collecting data on water, electricity and gas consumption in buildings. Most of this data is gathered by the traditional method of manually reading utility meters, with relatively few authorities collecting data automatically through electronic billing systems or through automatic meter reading systems.
The main reason for collecting this data is to identify potential high levels of consumption, verify utility billing data and to evaluate the success of investment in energy and water reduction measures.
In a survey of 76 municipalities in 19 European countries, 71 municipalities collected electricity consumption data, 65 building water consumption data and 62 gas consumption data. In addition oil data was collected in over half of the municipalities and heat data collected in one third. The survey was administered with the help of European networks of cities and local authorities which are active in sustainability, climate change and energy issues, such as Energie-Cités, ICLEI-Europe and CEMR. Therefore the local authorities that responded to this survey were likely to be more engaged in energy management compared with other European local authorities. Consequently the results may reflect what is considered to be amongst the best practice in Europe.
The survey was conducted as part of a PhD research project carried out by Vasco Ferreira, Research Assistant at the Research Group on Energy and Sustainable Development at the Technical University of Lisbon, under the supervision of Professor Paul Fleming from the Institute of Energy and Sustainable Development at De Montfort University, Leicester in the UK..
The survey found that nearly all the European local authorities in the study were collecting data on water, electricity and gas consumption in buildings. Most of this data was collected by conventional manual data collection systems – paper bills and manual meter readings (68%). Only a small number of municipalities collected energy and water data automatically through electronic bills (17%) and with about the same (15%) through automatic meter reading systems.
FREQUENCY OF DATA
Typically, the ‘average’ European local authority collects water, electricity, gas, oil and coal information from utility paper bills, heat and biomass use from manual meter readings. Solar energy and (outside and inside) temperature data is usually collected by automatic systems.
Consequently the vast majority of water and energy data from municipal buildings is collected in monthly periods with some quarterly and annual collection. Only a small percentage of data is collected in sub-daily periods, ie in hourly (or less) intervals.
Less than 20% of water and energy data is collected in short time series (half-hourly or less). The exceptions are solar thermal energy production and temperature data (inside and outside). Half-hourly electricity data collection is a more frequent than half-hourly water and gas data. However, for water, electricity and gas consumption, monthly data collection is the most common metering/monitoring frequency. Quarterly and annually collected data are also common.
Responsibility for collecting water and energy data is usually distributed between different local authority departments. From the figure below it is possible to conclude that most of the data is collected internally, by a local authority department or energy agency – the property department in most cases. Energy agencies also have a role in the collection of water and energy data.
In some cases there is an energy section within the local authority or a dedicated person – energy manager – responsible for collecting the data. The main reasons for collecting the data are quite varied. The respondents were invited to select multiple answers from a list. The results are presented in the form of ranking derived from the number of answers on each of the items in brackets:
- To identify excessively high levels of consumption in normal use (61)
- To verify utility billing data (59)
- To monitor unusually high or low consumption to identify energy wastage (58)
- To measure and verify energy/water savings measures (55)
- To communicate with buildings’ occupants in order to change behaviour (51)
- To perform benchmarking analysis with similar buildings (47)
- To negotiate with utilities (eg in calls for tender for energy supply) (41)
- To measure municipal buildings’ greenhouse gas emissions (40)
- To communicate with general public, by displaying building performance (36)
- To check for faults affecting consumption permanently (35)
- To prepare dossiers for performance contracting in municipal property (23)
- To ensure that consumption is within the utility contract and avoid penalties (20)
- Not effectively used (11).
Additionally, respondents’ comments suggested that data is also used to perform water and energy costs calculation and there were several references to calculation of indicators (carbon emissions, environmental management, DISPLAY® Campaign and Normalised Performance Indicators) and to building certification under the European Directive on energy performance in buildings.
PROCEDURES, TECHNIQUES AND TOOLS
The second part of the survey focused on the specific procedures, techniques and tools used to analyse collected data. The Current and Past Consumption and annual Performance Indicators (PI) were the most common analysis techniques, followed by the Simple trend lines (energy against time).
References to the use of benchmarks (published and internal to the local authority), based on PI were quite abundant over the entire set of submitted replies. Simple visualisation techniques are also applied in practice, as well as degree-days and regression analysis. However, there was only one direct reference made to the use of half-hourly electricity data in the analysis, and it concerned the use of profiles (electricity against time).
About 54% of the respondents used a software tool to analyse collected data. These local authorities had invested in the development or acquisition of analysis software tools, to analyse buildings’ electricity, gas and water consumption. This figure was relatively high in the UK where 81% of the respondents said that they used data analysis software packages while in continental Europe only 46% of the local authorities had access to this type of software.
NEEDS AND EXPECTATIONS
This final question was about the needs and expectations of the people in charge of metering and monitoring water and energy consumption in municipal buildings in Europe. This showed that European municipal energy managers are requesting more automated, accurate (real data not estimated), robust and flexible metering of water and energy consumption in municipal buildings. They expressed the need for a harmonised methodology for the overall assessment of building performance, by using performance indicators, labelling and benchmarking (internal to the local authority and using approved standards). They also suggested that metering and monitoring can help the implementation of the EU Directive on energy performance in buildings. There is a demand for continuous monitoring (and targeting), which includes visualisation of data for rapid identification of trends. There is also a demand for better analytical capabilities, benchmarking, detection of unusual consumption profiles (exception reporting) and budget forecasting. Finally local authorities effectively used the metering data for reporting and communication activities both inside and outside the local authority.
Research work is now focusing on addressing the energy managers’ needs in terms of better analytical capabilities for energy data monitoring. An approach has been developed based on a set of indicators applied to the energy demand profiles with advanced visualisation techniques providing additional information. The validation of this is being tested on utility data from over 250 premises. Typically the data collected is total energy and water consumption directly from the primary meter and the data collection frequency is 30 minutes. There is also external ambient temperature available. This innovative approach to the analysis of primary utility meter data is identifying potential saving opportunities for European energy managers. The results are expected to be published in early 2009.