Strategies which can be adopted to electrify existing buildings throughout Australia have been revealed.

The Green Building Council of Australia (GBCA) has released the final edition of its guide to the electrification of existing buildings.

Sponsored by technical partner Cundall and financial partners in the NSW Government and the Clean Energy Finance Corportion, the guide argues that electrification of buildings is an effective means by which to reduce the carbon footprint of Australia’s homes and buildings in a short space of time.

As things stand, natural gas typically represents around 10 to 30 percent of all greenhouse gas emissions within existing buildings.

As the electricity grid moves toward decarbonisation and with clean, renewable energy now being readily procurable, the guide argues that replacement of gas with electricity run by renewables and backup storage is now the preferred pathway to decarbonise our built environment over the longer term.

Moreover, GBCA argues that delivering all-electric buildings today can deliver substantial benefits.

These include:

  • Better access to sustainable finance – potentially at lower interest rates – as investors are looking for assets which are on a clear decarbonisation pathway.
  • Better future-proofing of buildings by avoiding the need to retrofit assets and remove equipment which uses fossil fuels from service in the future as we move toward decarbonising the economy.
  • Public health benefits as avoiding the use of natural gas for cooking in buildings will avoid generation of pollutants to which occupants can be exposed during combustion as well as due to leakage. These pollutants can exacerbate conditions such as asthma and respiratory illnesses.
  • Compatibility of buildings with objectives of many commercial tenants who have made public commitments toward decarbonisation as well as with expectations of consumers.

The release of the guide comes as Australia’s electricity grid is undergoing transformation toward clean energy sources.

Already, renewables account for 29.1 percent of Australia’s electricity generation. By 2025 and 2030, this is expected to increase to 50 percent and 69 percent respectively.

As this happens, electrification is emerging as the preferred strategy over gas through which to decarbonise buildings and to eliminate use of fossil fuels within our buildings.

According to the guide, the most common uses of fossil fuels within buildings include use of natural gas for space heating, domestic hot water and cooking as well as diesel for emergency/backup generators and fire system pumps.

It suggests that electrification strategies could include:

  • Replacement of central gas boilers, gas radiant systems and ducted gas heater systems with heat pumps, variable refrigerant flow systems (heating and cooling) and/or electric radiant heaters.
  • Replacement of central gas boiler domestic hot water systems with heat pumps with thermal storage tanks and replacement of local gas boiler systems for domestic hot water with instantaneous electric systems or heat pumps.
  • Replacement of gas cooktops, flame & char systems, wok burners and gas ovens with induction cooktops, electric charcoal grills/portable renewable gas cooktop/electric grille with steam for moisture, induction wok burners and electric ovens or electric steam ovens.
  • Replacement of diesel generators which are used for emergency power during electricity blackouts with options such as biofuel, batteries and green hydrogen.
  • Design of new buildings to accommodate the additional loads and space which is needed to support electric vehicle uptake.

The guide acknowledges that aforementioned solutions require several issues to be considered.

Whilst use of heat pumps will deliver lower operating costs, no air pollutants and zero greenhouse gas emissions (if the electricity is powered by renewables), it will also require a greater capital investment up-front along with larger plant room and natural ventilation.

On replacement of diesel generators for backup power, meanwhile, biofuel needs fuel tanks which are designed for biofuel. Meanwhile, battery storage solutions as another form of alternative would need to be used in conjunction with other systems as power outages may not necessarily occur at a time when the battery is fully charged.

The guide outlines case studies where solutions have been applied.

In New Zealand, Te Whatu Ora Te Tai Tokelau (formerly the Northland District Health Board) replaced its centralised diesel boilers at each of its Kawakawa, Dargaville and Kaitaia hospitals with modern heat pumps which are used for both hot water and heating.

Each new system can operate independently, providing each building with domestic supply of hot water and heating.

The heat pumps can be adjusted in response to seasonal variations, building occupancy and the fact that not all wards are open day and night.

The electrification has also enabled removal of  the steam reticulation pipes to the boilers – a common source of energy and carbon savings as these pipes continually lose heat.

Across the three hospitals, the project is expected to deliver 40 to 60 percent reductions in energy consumption as well as annual savings on energy and maintenance costs worth $152,600 per annum at the Dargaville hospital and $142,900 per annum at the Kaitaia hospital.

During upgrades of end-of-trip (EoT)facilities at its 275 Kent Street and 8 Chifley Square buildings in Sydney, meanwhile, developer Mirvac replaced use of gas for hot water and instead installed electric heat pumps.

Whilst the pumps were able to be installed in a dedicated plant room at 275 Kent Street, in the case of Chiefly Square, space considerations meant that one parking space needed to be sacrificed as there was insufficient plant room space close to the EoT facilities.

Whilst, heat pumps generally have a higher purchase and installation cost, meanwhile, data at 275 Kent Street shows that they are already generating operational cost savings.

GBCA CEO Davina Rooney said the importance of electrifying buildings should not be underestimated.

Rooney has called for a drive toward electrification to be incorporated into the next three-year of the National Construction Code in 2025.

She points out that most buildings which are standing today will still be standing by 2050 when Australia is set to deliver upon its NetZero objective.

“While many of our industries will take time to decarbonise, the technology for buildings already exists,” Rooney said.

“We can electrify them now, power them with renewables and put Australia on the path to decarbonisation.”

Cundall Director David Collins said that asset owners are already looking for guidance to plan their transition and plan for the capital expense and logistics of switching to all-electric.

“The business case is boosted by the opportunity to simultaneously upgrade existing building performance during works, delivering long term wins for occupants, owners and the power to align operations and management with carbon neutral ambitions,” he said.