Greenhouse emissions in Australia

I thought I would take the opportunity today to talk about energy production and greenhouse gas emissions in Australia. The chart below shows the populations (blue bars) and population densities of the six Australian states plus the Northern Territory. Note that New South Wales, Victoria, and Queensland have the highest populations (8.2, 6.7, and 5.2 million respectively), while the Northern Territory has the lowest. However, given its smaller area, Victoria has the highest population density (29.4 people per sq km), while Western Australia and the Northern Territory have the lowest population densities (1.1 and 0.2 people per sq km respectively).

The next chart shows the per capita electricity production of the six Australian states and the Northern Territory, by type. These figures are adjusted for net electricity transfer between states. For example, Tasmania imports some mainland coal-fired power.

Notice that the totals are high in the less densely populated regions (Western Australia and the Northern Territory). The total is also high in Tasmania, because of the widespread use of hydro-electrically produced electricity for heating there.

Total per capita electricity production is lowest in Victoria, in part because of the widespread use of natural gas for heating and cooking (total gas use in Australia generally is about 4 times its use in electricity production). Victorian electricity is the dirtiest, however, with heavy use of brown-coal-fired production. Brown coal is by far the dirtiest fuel; it produces about 47% more greenhouse gases per MWh than black coal, and triple the greenhouse gases per MWh of natural gas.

South Australia has achieved 50% renewable energy, but this is not without its problems:

  • Wind and solar power are more expensive, so that South Australians pay about $360 per MWh for their electricity: 44% more than the two large states
  • The sun does not always shine and the wind does not always blow: this means that, in the absence of massive-scale energy storage, South Australia has to “borrow” coal-fired power from the East, although this is eventually repaid with interest
  • Solar and wind power cause substantial grid stability and grid synchronisation issues, which become very apparent at the 50% renewable level – good solutions are needed for this; South Australia currently copes by turning solar power off

To avoid “borrowing” electricity, massive-scale energy storage is required. South Australia would need several days worth of demand, at 40 GWh per day. Their famous Tesla battery has been expanded to a capacity of just 0.2 GWh, which is about a thousandth of what is needed. Batteries appear inadequate for energy storage at the required scale, and hydrogen storage is probably what we want.

Tasmania operates at a 92% renewable electricity level, thanks to multiple hydroelectric dams, which do not suffer from the problems of wind and solar (and availability is only an issue during lengthy droughts). In addition, hydroelectric dams can also provide energy storage for solar and wind power, simply by pumping water uphill. It is unfortunate that environmental groups in Tasmania have campaigned heavily against hydroelectric power.

The last chart shows the per capita CO2-equivalent emissions for state electricity generation, plus other emissions (including agriculture, other energy use, industrial processes, waste, forestry, and land use change). Agricultural emissions are highlighted in green. A note of caution, however: the electricity generation data is for 2019, but the total greenhouse emissions are for 2018 (the latest I could find). These numbers cannot be compared to those of other countries, unless the numbers for other countries are equally recent and also include the full range of emissions, per UNFCCC standards (some comparable national averages are shown on the left).

Note that net greenhouse emissions for Tasmania are negative, largely due to tree-planting. Per capita emissions for the large, less densely populated areas are higher than those for New South Wales and Victoria; in part due to transportation requirements (shifting commuters and freight from road to rail would help here). Agricultural emissions per capita are particularly high in the Northern Territory, because the impact of cattle farming is being divided among a tiny population of just 0.2 million people. The overall Australian average of 21.2 tonnes per capita is quite significantly affected by the inevitably high emissions for the large, less densely populated areas. There is also the question of whether emissions due to mining and agriculture should be attributed to the producing country, or to the country of final consumption.

Economically and geographically, Australia is in many ways more like a Central Asian country than a European one, given its large size and its heavy reliance on mining and agriculture (Australia’s greenhouse emissions are comparable to those of Kazakhstan, which produces 21.7 tonnes per capita). However, progress could be made in Australia with more energy-efficient housing and transportation.

It should also be emphasised that, given its small population, Australia’s greenhouse emissions make a neglible contribution to the global and regional climate. If increasing atmospheric CO2 has an effect in Australia’s region, that is due primarily to emissions by the large countries of the world, particularly China (which produces about a third of the world’s CO2). Australia should, no doubt, reduce its greenhouse emissions, but whether Australia does so or not will make no measurable difference to the global or regional climate.