LINCOLN UNIVERSITY Electricity Use Trends in New Zealand Office Buildings John McDonagh Property Group, Commerce Faculty, Lincoln University New Zealand 17th ERES Conference Milan, Italy, June 2010

LINCOLN UNIVERSITY Background Globally, the built environment accounts for 40% of energy consumption (Kolokotsa et. al. 2009) The built environment is assessed as accounting for 70% of electricity consumption in the USA (Nicolay 2007) New Zealand generates most of its electricity from renewable hydro electric sources But there are limited opportunities to expand such generation. NZ government has been promoting energy efficiency as a means to reduce growth in electricity demand Focus to date on the residential sector.

LINCOLN UNIVERSITY Literature A lot of international energy research Continuing debate on efficacy of different efficiency strategies Very little in New Zealand on the office sector Engineering orientated Some case studies International benchmarks not applicable in NZ Some benchmarking work still underway

LINCOLN UNIVERSITY Methodology Property Council office building OPEX survey data 418 buildings included - city - location - lettable area - vacancy - office quality grade and energy expenditure (electricity oil and gas) for Common Area and Central Services Identified national and city electricity expenditure trends (mean $/m2) Identified electricity expenditure trends for different office grades Identified electricity price trends ($/kwh) Converted expenditure to consumption (kwh/m2) using price data Converted common area and central services consumption to total building consumption using ratios from the data available

LINCOLN UNIVERSITY Results Mean Common Area & Central Services Electricity Expenditure - $/m2 National trend

LINCOLN UNIVERSITY Mean Common Area & Central Services Electricity Expenditure - $/m2 City comparison

LINCOLN UNIVERSITY Mean Common Area & Central Services Electricity Expenditure - $/m2 Office grade comparison

LINCOLN UNIVERSITY National Electricity Prices - $ per kw/h Mean of all Suppliers

LINCOLN UNIVERSITY Electricity Prices – $ per kw/h Comparison of Major Suppliers in Large Cities

LINCOLN UNIVERSITY Electricity Prices – $ /kwh Comparison of Commercial Price Indices

LINCOLN UNIVERSITY Electricity Consumption Common Area and Central Services – kwh/m2 Mean Expenditure Divided by Electricity Price Indices

LINCOLN UNIVERSITY Electricity Consumption Trend Whole Office Building – kwh/m2

LINCOLN UNIVERSITY Conclusions Electricity expenditure for common area and central services in NZ office buildings has remained relatively constant since1990 This trend applies to all major cities and office quality categories in NZ Lower quality office buildings have lower electricity expense Office buildings in Christchurch have lower electricity expense Nominal electricity prices for large commercial users have been relatively stable and declined in real terms until recently Recent electricity price increases have been offset by efficiency gains with consumption in kwh/per m2 declining slightly Conversion of common area and central services to total building electricity consumption was problematic but indicates an average overall rate of 150kwh/m2 The research highlighted the need to collect more comprehensive electricity use data.