CIBSE REVIEW OF ENERGY BENCHMARKS FOR DISPLAY ENERGY CERTIFICATES

Transcription

1 CIBSE REVIEW OF ENERGY BENCHMARKS FOR DISPLAY ENERGY CERTIFICATES Harry Bruhns UCL Energy Institute Phil Jones - Building Energy Solutions Robert Cohen - Camco Phil Jones philjones100@virginmedia.com DISPLAY ENERGY CERTIFICATE (DEC) Introduced in 2008 under the EPBD A-G scale Based on real annual energy consumption Compared to a benchmark Giving an Operational Rating And energy/m 2 for electricity and fuel 1

2 CIBSE TM46 Provides the statutory benchmarks 29 benchmark categories These underpin the DEC process BACKGROUND By mid February 2010 some 45,000 DECs had been lodged Review undertaken Summer 2010 Funded by the CIBSE Research Fund Rapid review before DEC renewals began in September 2010 Study focused on identifying issues that might need attention in the short term CIBSE set up a broadly-based Benchmarks Steering Committee to oversee the review 2

3 ANALYSIS SAMPLE Database has 45,000 DECs from 33,419 unique buildings Analysis based on the most recent ratings for each property Electrically heated buildings eliminated Removed defaults: rating value of a G = 200 Excluded implausible values for floor area and rating This reduced the sample to a total of 29,320 DECs, each for a different building NUMBER OF BUILDINGS 3

4 MEAN FLOOR AREA SECTOR HISTOGRAMS ELECTRICITY kwh/m 2 FOSSIL kwh/m 2 OPERATIONAL RATING DEC GRADE 4

5 SECTOR SAMPLE SIZE 15,300 SCHOOLS 444 WORKSHOPS SUMMARY Operational Rating of 100 sits on the D-E boundary 50% of sample should fall either side if the benchmark is correct 5

6 Category Building Type No. of Bldgs Mean Floor Area DEC EuiElecR Median DEC EuiHtgR Median DEC Rating 1 General office 3,230 2, High street agency 289 2, General retail 37 4, Large non-food shop 3 5, Small food store Large food store 1 6, Restaurant 71 1, Bar, pub or licensed club 23 2, Hotel 34 4, Cultural activities 676 2, Entertainment halls 268 2, Swimming pool centre 588 2, Fitness and health centre 107 3, Dry sports and leisure facility 895 2, Covered car park 2 12, Public buildings with light usage 7 1, Schools and seasonal public buildings 15,335 1, University campus 2,637 3, Clinic 657 1, Hospital - clinical and research 1,117 9, Long term residential 1,467 1, General accommodation 361 2, Emergency services 802 1, Laboratory or operating theatre 165 3, Public waiting or circulation 9 2, Terminal Workshop 444 1, Storage facility 84 2, Cold storage 1 5, Focused on categories that are more than 25% (one grade) above or below the benchmarks RED = more than 25% out OR more than one grade out AMBER = sample too small GREEN = within 25% KEY FINDINGS 3,200 OFFICES 15,300 SCHOOLS The median for offices is almost exactly at the TM46 benchmark level The median for schools is within 2% of the TM46 benchmark 6

7 KEY FINDINGS 94% of buildings are in categories with medians within 25% (one grade) of the TM46 benchmark Only 4 benchmark categories and 10 building types have medians outside this threshold This is very good considering the age and provenance of the benchmarks NON-COMPLIANCE NO DEC EIA estimated that 42,000 buildings would be caught by the DEC Regulations But only 33,419 unique buildings on the database Implies at least 20% non compliance NO RENEWAL Only half the properties have a renewal DEC Need to find ways to improve compliance 7

8 DEFAULT DECs 4,700 DECs (~10%) are defaults Ranging from ~2% for Hotels to 17% for Offices Default DEC is no longer an option Will this force defaulters to get proper DEC or increase noncompliance? ELECTRICITY VERSUS HEATING Often electricity higher, heating lower than benchmarks: General growth in electrical equipment Heat demand lowered by internal gains, improved insulation, boilers and heating controls, and a warmer climate Combined effect on CO2 helps some categories to have medians close to the total CO2 benchmark Need to review the electricity and heating benchmarks 8

9 SEPARABLES Some special end-uses can be separated out of the rating calculation But only if sub-metered Only 153 buildings (0.3%) have used this option Significant opportunity to improve DEC ratings by submetering separables Currently, most technical equipment in hospitals and universities not eligible as a separable but probably should be allowed OCCUPANCY DENSITY There are calls to adjust DEC benchmarks for occupancy density But, difficult to define a robust measurement system Few buildings have technology to record actual occupancy Even where measurable, little evidence available to calibrate scale of such an adjustment Such an allowance could be open to abuse Need further work to build up the evidence base 9

10 CHANGES TO THE TM46 VALUES 2011 study of 85,000 DECs now in database aims to recommend: Any need for new Benchmark Categories or Building Types Changes to benchmark values (kwh/m 2 ) Changes to standard or maximum hours of use and the allowances given for extended hours Expanding the options for mixed use and separables Study paves the way for processing the data from a soft start for the extension of DECs to all buildings visited by the public Strategy may be to make all changes in one go FUTURE WORK What should we be rating? Buildings i.e. CO2/m2 or Annual league tables Develop technical (iconic) benchmarks for all categories (like ECON19 for offices) Analyse DEC database in depth to extract maximum value Collect occupancy density (intensity of use) data Building use i.e. CO2/person year of occupancy as used for the Low Carbon Workplace Standard 10

11 CIBSE REVIEW OF ENERGY BENCHMARKS FOR DISPLAY ENERGY CERTIFICATES Harry Bruhns UCL Energy Institute Phil Jones - Building Energy Solutions Robert Cohen - Camco Full report and annexe available at: Phil Jones philjones100@virginmedia.com