According to the official YourHome website 48% of energy used for hot water comes from natural gas and 45% from grid powered electricity (predominantly coal).
Based on the Energy Rating Baseline 93% of Australian homes have either a gas or electric hot water system and will consume in 2020 a total of;
- Natural Gas 47.5PJ / year or 13.2*10^9 kWh / year
- Electricity 35.8PJ / year or 9.9*10^9 kWh / year
According to the National Greenhouse Account Factors the greenhouse emission factors for natural gas and coal are;
- Natural Gas Greenhouse Emissions are 51.4 kg CO2-e/ GJ or 0.185 kg CO2-e / kWh
- Coal (not brown or coke) Greenhouse Emissions are 90 kg CO@-e / GJ or 0.324 kg CO2-e/kWh
CO2 emissions for 93% of Australian homes (2020) can be calculated using;
- GAS HOT WATER= 0.185 kg CO2 / kwh * 13.2*10^9 kWh/year * 1*10^-9 Mt/kg = 2.44 million metric tonnes CO2/year
- ELECTRIC ELEMENT HOT WATER = 0.324 kg CO2 / kwh * 9.9*10^9 kWh/year * 1*10^-9 Mt/kg = 3.21 million metric tonnes CO2/year
From a Home User Perspective;
- According to the Energy Rating Baseline in 2020 conventional hot water units will account for 89.6PJ of the 361.9PJ total energy consumed in an average home, which is 24.8% of your total energy bill.
- Conventional hot water systems produce a total of 5.65 million metric tonnes of greenhouse emissions that could be eliminated / significantly reduced by using a combination of home solar generation & heat pump hot water storage as recommended by YourHome website.