Mapping the when, how much and why of the energy use in our buildings can help the evolution of more energy efficient cities.
Buildings are a major contributor of greenhouse gas emissions
The buildings we live, work and play in account for a staggering 40 per cent of the world's energy consumption and one third of global greenhouse gas emissions. Lighting, appliances and indoor climate control consume a large amount of energy, but this can vary enormously across buildings of different types, ages, and purposes.
As global carbon emissions continue to rise, the energy consumed in buildings represent a relatively easy target for emissions reductions. Federal and state governments have attempted to address energy consumption in buildings through a variety of direct and indirect mechanisms that are designed to promote energy efficiency and therefore reduce greenhouse gas emissions.
Until now, we have not been able to get a detailed picture of how and where energy is consumed in buildings, meaning we have not had the ability to model the potential benefits of interventions to reduce energy consumption, or to accurately assess the impact of their implementation.
Previous attempts to do this have been hampered by analyses that have only looked across the sector and not allowed modellers to look at the cost-effectiveness of specific interventions. These early analyses also took a too-simplistic approach to voluntary schemes, and to assessing the impact of variables that are related to the building type and behaviour of its occupants.
Mapping energy use across a city
CSIRO has developed a range of tools that can model the many factors that influence the energy use of a city region, map the actual energy use of that region and assess the impact of interventions on energy use.
For example, one model explores the effects of rebates and incentives on the adoption of both existing renewable energy technologies, such as solar photovoltaic (PV) panels and solar hot water systems, and newer technologies such as hybrid and electric vehicles.
Other potential applications are related to scenario impact assessments of disruptive technologies such as home batteries working in combination with solar PV and smart charging and discharging control.
CSIRO's new approach allows users to look in detail at the impact of programs on the electricity demand pattern across service areas and/or local jurisdictions.
It also allows the mapping of current annual electricity use in residential and commercial buildings, as well as modelling of future energy use and greenhouse gas emission scenarios.
Putting inner Melbourne on the energy use map
The City of Melbourne and three other Melbourne councils have been working with CSIRO to use this technology to produce the first maps of residential and commercial energy use, at a block level, across inner Melbourne.
The map takes into account the different building types in these city areas, and can even break down to show use in different categories such as space heating and cooling, water heating, lighting and other appliance use.
The map shows energy consumption data from 2011 and simulates energy consumption projections for 2016, 2021 and 2026, using combined data from the 2011 Census, Council property data, and data from electricity provider CitiPower.
As well as showing current energy usage on a block-by-block basis, the model is a physics-based building energy simulation tool. This allows stakeholders such as policy makers, property owners, utility companies and building tenants to see the impact that changes to factors like lighting, air conditioning, appliances and occupant behaviour will have on energy use.
While this study is focused on the city level, it has been used at a state or even national level (for instance, it was used to estimate the energy consumption of NSW and Victoria). It could also be adapted for other purposes, such as analysing peak energy demand patterns, mapping and analysing greenhouse gas emissions, and looking at the feasibility of distributed energy resources such as solar PV, battery storage and wind power.
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