A technical study from Rewire Australia has summarised the impacts of whole-household electrification in Australia, including cost and emissions reductions, by replacing current machines with lower emission alternatives such as heat pumps.
Castles and Cars: Savings in the suburbs by electrifying everything, a report led by Dr Saul Griffth, includes research that builds on the leading work by Rewiring America which is used in designing climate policy with US Senators and the Biden administration.
The report found that Australia’s ten million households are responsible for the largest portion (~42 per cent) of domestic emissions, with 33.5 per cent attributed to home energy and personal vehicle usage.
The model used by researchers considers detailed household energy and vehicle use data by state, and projects the capital and operating costs of the electrified substitution technologies each year through to 2035.
Price and performance improvements of rooftop solar-PV, batteries, electric vehicles (EVs) and eight key household appliances are modeled through the same period with known cost reduction learning curves.
A financing model was used to compare existing household energy costs with future costs that include the financed replacement items and ongoing fees.
The report shows that with appropriate financing of the purchase cost, these technologies will provide lower annual expenses than conventional technologies for virtually all households by 2024.
By 2030, Australia’s households could be saving over $40 billion a year, which is close to – and in future could overtake – national export earnings from coal.
The report finds the most economical path to powering Australian’s everyday lives is to significantly increase rooftop solar take-up and fully engage the associated storage capacity in vehicles, home batteries, and thermal systems, including hot water.
Roughly three million Australian homes already have solar power infrastructure on their roofs and are receiving some of the lowest costs of delivered electricity in the world.
The average Australian household currently uses just over 100kWh of energy, including the energy lost in thermoelectric power generation and the energy required to power personal vehicles.
If all users switched to electric solutions, this drops to only 37kWh and can be nearly completely satisfied with a 10-12 kW capacity solar installation and a compatible battery. The technical potential of Australian rooftop solar is 179GW(DC) or 245TWh per year.
Residential alone is 96GW, or 130TWh, which is very close to the 135TWh of yearly electricity required for ten million 37kWh Aussie homes. Cars are the largest contributor to household emissions and energy cost, accounting for 38 per cent of household emissions and averaging ~$3,000 per household in annual fuel expenses.
By 2030 Australian families could be saving $5,000 per year by replacing their current cars with EVs and switching their natural gas heating systems (water heating, space heating, or kitchen) to electric heat pumps.
Space heating is one of the largest energy uses in the average Australian household, accounting for 37 per cent of the average appliance load, and 11 per cent of the total energy load when cars are included.
Households stand to gain significant energy use and cost benefits from the electrification of space heating. Current space heating is done primarily with a mix of natural gas, electric reverse cycle air conditioners (heat pumps), electric resistance heating, and wood fires.
Natural gas heating has an efficiency of approximately 0.9. Every 1 energy unit of natural gas is converted to 0.9 units of heat in a room. Electric resistance heating has an efficiency of approximately 0.95.
Wood fires have an approximate efficiency of 0.75, converting 1 unit of energy in a log to 0.75 units of heat in a room.
By comparison, reverse-cycle air conditioners (heat pumps), have an approximate efficiency of a whopping 3.8 in the average Australian household. This means for every 1 unit of electricity, 3.8 units of heat in a room are created.
Upgrading to an electrified home with heat pumps saves energy and money with no sacrifice in comfort.
Economics can be improved further with weatherization, LED lighting, and other efficiencies.
The report finds if this shift is embraced right now and Australia replaces current machines with zero-emission alternatives (from heaters, to cars, to power plants), it will be possible to keep track with emissions trajectories commensurate with a 1.5 degree world.